Installation Tips by Copper in Built Environment

Installation Tips

Index Bending Copper Tube by Machine ....................................................................... 3 Bending Copper Tubes - Setting Out for Spring Loading ...................................... 5 Cabling Soft Copper ............................................................................................. 7 Component Connections...................................................................................... 9 Copper Oil Pipelines ..........................................................................................11 Domestic Gas Installation Part 1: Pipe Sizing .................................................... 13 Domestic Gas Installation Part 2: Testing........................................................... 15 Domestic Fire Sprinklers .................................................................................... 17 EN Standards for Copper Tube and Fittings....................................................... 19 Fixing Copper Tube ........................................................................................... 21 Flame-free Jointing ............................................................................................ 23 Flushing and Disinfection of Hot & Cold Water Systems .................................... 26 Fluxes and Solders ............................................................................................ 29 Guide to Suitability of Copper with Various Chemicals ....................................... 31 Insulation against Frost & Heat Gain .................................................................. 33 Jointing of Copper Tubes – Capillary Joints ....................................................... 35 Jointing Copper Tubes – Compression Joints .................................................... 37 Jointing Copper to Dissimilar Materials .............................................................. 39 Copper in Medical Gases and Vacuum Systems................................................ 41 Pipe Freezing ..................................................................................................... 43 Pipe Sizing for Hot & Cold Water Part 1: Basic Principles .................................. 45 Pipe Sizing for Hot & Cold Water Part 2: Tabulation Method .............................. 47 Installing Copper Pipework in Suspended Flooring Systems .............................. 49 Planning and Positioning of Pipework ................................................................ 51 Plastics Covered and Chrome Plated Copper .................................................... 53 Copper Pressure Piping Systems....................................................................... 55 Pressure Testing Piping Systems....................................................................... 57 Copper for Refrigeration Pipelines ..................................................................... 60 Systematic Installation of Copper to Save Money, the Basics ............................ 62 Systematic Installation of Copper to Save Money, Installation............................ 64 Copper in Small-Bore Heating Systems ............................................................. 66 Solar Hot Water Systems ...................................................................................68 Copper for Steam-Condense Pipelines .............................................................. 71 Underground Copper Water Services ................................................................ 73

https://issuu.com/copperinarchitecture/docs/installation_tips © European Copper Institute

Bending Copper Tubes By Machine

ending copper tubes using a bending machine should prove economical where numerous bends are required especially when bending the smaller sizes of tube. Rotary bending machines of various types and sizes, worked by direct hand power, can be obtained to bend copper tubes up to 42mm diameter. For larger diameters, ratchet action or geared machines are required. The most useful type of machine for 15 and 22mm tube is the portable type or Handy-bender which is light in weight and requires no adjustment in use. The advantages of machine bending over spring bending can be summarised as follows: bends can be formed quickly; multiple bends can easily be formed on tubes if required; bends can be formed very close to the end of the tube; bend radius, quality and accuracy can be maintained over time. The production of accurately positioned bends depends on the ability to determine the bending point and position of the tube in the machine. To establish the bending mark position when making a 90° bend, measure the end to centre length

Pressure roller Measured end Tube Tube stop

Handy-bender Figure 2 © European Copper Institute

End to centre

Measuring for a single 90 bend

Add 1/2 tube dia to obtain bending mark position

Bending mark

When measuring for two 90 bends the centre to centre measurement can be marked as shown

Bending mark

Measure centre to centre Marked inside to back gives bending mark position directly Figure 1

required and add 1/2 a tube diameter before placing the bending mark. Where a second 90° bend is required measure the centre to centre length required. Then mark the tube by measuring from inside to the back of the required bend. As shown in Figure 1. Figure 2 illustrates how to accurately position the bending mark in the machine for 90° bends. When more than one bend is required on a length of tube remember to check Mark whether the bends will Guide Square align correctly in the same plane BEFORE pulling the second bend! When bending single Set position of tube so or double offsets you that the square touches mark and edge of former can use a 600mm folding then bend to 90 rule to determine a suitable angle for the bends. Figure 3 shows how to stagger the ends of the rule to obtain the angle. Simply subtract

the offset size required from 600mm, in this case 600 - 75 = 525mm. Next close the rule to this length.Then bend to the angle formed using the rule as a guide. To determine the bending mark for the second bend of a double offset: first, align the first bend parallel to a straight edge with the inside edge of the tube the required distance from the straight edge; the position of the bending mark is in line with the straight edge. Next reposition the tube in the bender so that the bending mark forms a tangent (It just touches the edge) of the former and pull the second bend parallel to the first. Where an offset has to be formed to pass an obstruction the distance from the fixed point to the centre of the first bend has to be found.This is achieved by placing a temporary mark on the tube equal to the actual distance from the fixed point to the obstruction. Next find the position of the bending mark by measuring BACK from the first mark a distance equal to the offset required PLUS two tube diameters. Now position the tube in the machine so that the 3

Required offset 75

Straight edge

Stagger folding rule to determine bend angle

Bending mark Required offset

Reposition tube in bender so that bending mark forms tangent to former edge and bend till parallel

600 75

Bending mark

Bend first set to angle formed by rule

Figure 3

Figure 4

bending mark bisects the angle of the staggered rule when one leg is parallel to the tube and both legs of the rule are touching the edge of the former then bend until parallel. See Figure 4 and 5. When using a press bending tool to form 90Â° bends on 6, 8 and 10mm soft coils (formerly Table W) tube mark the required length end to centre and then measure BACK 1 tube diameter to get the bending mark. Figure 6 shows how to align the mark with the small notch in the centre of the former. Rippling or throating of tube in machine made bends The design of the bending machine former and back guide supports the

Bending mark

throat and sides of the tube against collapse. Corrugations will occur in the throat of a bend if the pressure of the roller on the guide is exerted in the wrong place. The correct pressure point is slightly in front of the bending point, this is where the tube touches the former before bending takes place. As the bend is made these two points move forward maintaining the same distance apart. If the pressure point is too far in front of the bending point corrugations will occur. If the pressure roller is tightened too much the pressure point will be too far back and the tube will be excessively 'throated' or made oval in section. If corrugations occur when using

non-adjustable 'handy-benders' the pressure point can be moved back by inserting a thin piece of strip steel about the thickness of a hack-saw blade between the guide and the pressure roller to remedy the problem. Finally, if you use plastic coated copper tube why not get a set of formers to fit the increased outside diameter? You can make machine bends directly on plastic coated copper tube if the correct formers are used.

Required length Measure back 1 dia

Temporary mark Measure back offset required plus 2 tube dia's

Align bending mark with notch on former Measure fixed point to obstruction

offset required

Bending mark

Position mark so that it touches the former at the bisection point of the angle of the steel rule

Figure 5 ÂŠ European Copper Institute

Press bender

Figure 6 4

Bending Copper Tubes Setting Out for Spring Loading

here is little difficulty bending light gauge tubes once the necessary skills have been developed and practised. This article illustrates and describes methods of setting out bends without the use of elaborate drawings. These methods can quickly enable high quality, accurate bends to be formed on copper tubes without "wrinkling" or flattening. Bending springs are used to support the tube walls while the bend is made. Springs are available for all EN 1057 "Kite marked" standard tube diameters in both half-hard thin and thick wall tube formerly table X and Y from 10 to 22mm, which is the maximum recommended for spring loading. It is possible to bend half - hard thin wall (table X) tubes up to 22mm diameter by hand without softening provided care is taken. Whilst most people who work with copper tube know that good quality copper tubing is made in accordance with a British Standard, not so many seem to be aware that there is also a matching British Standard for bending springs (B.S. 5431) which means that correctly sized springs are available for all of the different tube diameters and wall thicknesses. It is important to use the correct sized spring to support the tube walls during bending. If the spring used is undersized then this can cause wrinkling or even result in good quality tube snapping during bending. Another

Measured length (End to Centre) Measure back 4 tube dia's

2nd mark

2 tube dia's

1st mark

3rd mark

Bending length

Completed bend

Figure 1 Marking for bending length for 90o bend

common cause of tube snapping during bending is the use of rusty springs. Applying a little grease or lubricating oil to the spring before use will both assist the bending operation and prolong the life of the spring.

the bend will be made to the correct radius. There are two factors to consider when setting out. These are: the 'gain' of material when the bend is pulled and the bending point.

Marking out of bending lengths When bending there are advantages to be gained by marking out the bending length. For example: the position of the bend can be made more accurately, saving tube and time; also, the bend throat is not likely to wrinkle, because

The 'gain' of material When a tube is bent to pass around a corner or an obstruction the tube takes a 'short cut' and so tube is gained. The actual amount of tube gained depends on the angle through which the bend is pulled and the bend radius to be used. This radius in turn depends on the diameter of the tube. As a general rule: The radius of a spring loaded bend should be equal to 4 times the outside diameter of the tube. This radius is slightly greater than the radius of a typical machine - made bend but, choosing a radius of 4 tube diameters simplifies setting out. Note, the minimum bend radius measured to the throat is 3 tube diameters for all tube sizes.

Measured length (End to centre) Back 1 tube dia

1st mark Bending point Figure 2 Bending point for spring loaded 90o bend ÂŠ European Copper Institute

Measure forward

Measured length Back 1/2 a tube dia

Bending point for first bend Back 1/2 a tube dia First mark on centre line of tube Second bending point

Offset required

Figure 3 Bending point for offsets

Measured length

Measure back 2 dia's Figure 4 Setting our for offset bending length

For example to mark out the bending length for a spring loaded 90° bend on 22mm diameter tube 200mm from the end of the tube to the centre of the bend. See Figure 1. First, mark the measured length position. In this example the mark will be 200mm from the end of the tube. Next, decide on the bending radius. Usually this will be 4 times the tube diameter. So, 4 x 22 = 88mm. Now, mark the START of the bending length.The position of this mark is 4 tube diameters (88mm or one bend radius) BACK from the first mark. The last mark required is the END of the bending length. The position of this mark is 2 tube diameters (44mm or 1/2 a bend radius) FORWARD from the first mark. Then insert the correct sized, lubricated spring and bend to the required angle. The bending point With a bend radius equal to 4 diameters the 'gain' is 1 tube diameter. Figure 2 shows the bending point for a 90° bend, this is measured BACK 1 tube diameter from the measured length position. This gives the centre of the bend and the position where the knee should be placed if it is used to form the bend. © European Copper Institute

Forward 1 dia

If the set is to be pulled through 45° the bending point will be 1/2 a tube diameter back from the measured length. As shown in Figure 3. Also, the bending length will be half of that required for a 90° bend. So, the start point for bending will be two tube diameters back from the measured length point and the finish point one tube diameter forward from the measured length point. As in Figure 4. The methods of setting out described for 90° bends and 45° sets can also be used when forming partial or full tube pass-over bends. Remember to allow sufficient clearance where the tubes are to be insulated especially where correct water bylaw insulation thickness is to be used. One advantage that a spring loaded bend can have over a machine bend is that the bend radius can be varied. This enables tube centres to be carried around bends. The appearance of the bends is improved because the radii are concentric and so they 'match' because the gap between the tubes is even. Figure 5 shows how to establish the outer bend radius. Once this is determined the increased radius is used to mark out the start and end of the softening length, as for the simple 90° bend described previously.

Pulling power As the bend is pulled the throat and back of the bend tighten on to the spring gripping it tightly. So, to make spring removal easier the bend should be pulled to an angle which is slightly more than necessary and then pulled back to Tube centre spacing R2. the correct angle required. This releases pressure on the spring and should enable it to be pulled out R1. without difficulty, especially if the spring is given a slight twist in the direction it is coiled R1 = 4 times dia of pipe as it is pulled. The R2 = R1 + tube centre spacing effect of the twist Eg. Two 22mm dia tubes @ 80mm centres is to reduce the R1 = 4 x 22 = 88mm R2 = 88 + 80 = 168mm spring diameter. When bends of So, set out inner bend as before then for outer bend measure back distance for outer bend = 168mm. less than 90° are to Measure forward distance = 84mm. (Both from first mark) be made, for single and double sets or Figure 5 Maintaining tube centres around bends pass-over bends, the 'gain' will be proportionately less 6

Cabling Soft Copper

mall diameter soft condition copper tube to EN 1057 is available in coils from 10m to 50m in length. It is easy to cut, install, bend and joint, and has been used for many years in minibore and microbore heating systems, (see Figure 1) with the following advantages:

Figure 1

Manifolds

Less structural disturbance, fewer floor-boards to lift, holes through walls can be drilled easily, runs of tube can be hidden easily. • Lower installation costs, due to speedy installation. Fewer fittings required. • Easy installation, the small diameter, soft condition tube can be cabled through floors and concealed in small ducts. • Lines can be clipped easily, using plastics single nail fixings.The tubing, after uncoiling, remains fairly rigid and self supporting, which in turn reduces the

•

Microbore tubes to each emitter

Flow & return mains

Boiler

number of clips required. • Neat inconspicuous finish. Where tube is surface fixed it can be uncoiled on to the skirting board and clipped as it is

Table 1 Flow rate (litres/second) for various tube diameters

Tube diameter

Water volume of tube (litres/metre)

Water velocity (metres/second) 1

1.5

2.5

0.018

0.027

0.036

0.045

0.036

0.054

0.072

0.090

0.058

0.087

0.1 16

0.145

0.085

0.127

0.170

0.212

0.145

0.217

0.290

0.362

0.321

0.481

0.642

0.802

0.539

0.808

1.078

1.347

Flow rate too low for effective use except on spray taps © European Copper Institute

installed to give a neat finish. Alternatively, plastics channels can be used to conceal and fix the tube. • Reduced number of fittings, number of possible leak sites are reduced as flow and returns to emitters are fitted in continuous lengths. • Reduced water-flow noise, due to the damping effect of soft temper copper tube. • Greater system efficiency, due to lower water content enabling faster response to controls and reduced heat loss from tubes. • Reduced chance of air-locks, where the tube dips, say between joists, the water velocity (up to 1.5m/s) is usually sufficient to move any air bubbles present in the minibore or microbore tube. • A potentially self-balancing system, by selecting the most appropriate tube diameter for each heat emitter at the design stage, the system will tend to be self-balancing, (see Table 1). Copper based microbore systems are suitable for all types of property, 7

Span S

Table 2 Flow rates at sanitary fittings (l/s) Fitting

0.4S

Flow rate

Washbasin (spray tap)

0.05

Washbasin tap

0.1

Bath tap

0.3

Shower

0.1

WC flushing cistern

0.1

Sink tap

0.2

whether new or existing, flats, houses or large buildings, (multi-story flats, office blocks). There is no limit on the size of installation. New buildings A cabled copper installation is easy to install in a new building. When first fixing, tube and manifolds can be installed quickly and, because of its size, the tube can be buried in the thickness of the plaster, covered by plastics cable sheathing, or in the depth of the floor screed. In this case, either in channels to allow for access, or plastics coated if buried. Existing buildings In existing proper ties a cabled copper installation can be installed with less disturbance than other systems. This is mainly due to the malleability of the copper tube used. Installation points to note Only cut small diameter soft condition tube with a junior hacksaw, not a wheel cutter.This is to avoid restricting or reducing the diameter of the bore significantly. Then remove burrs with a file. When feeding tube in line with the joists beneath floors, seal the end to prevent dirt entering. Where the tube has to be run across the joists, these can be drilled or notched, (see Figure 2). On drop loop circuits, where the tube has to be run down the wall a choice of methods is available. A chase can be cut into the plaster, the tube installed and covered by plastics sheathing. The tube can be clipped direct to the wall and covered with plastics channel. Where ÂŠ European Copper Institute

0.25S

0.25S Holes drilled on neutral axis

0.07S

Holes in this zone

Depth d

Not less than 3 dia's apart centre to centre. Max dia of holes d/4.

Development of modern plumbing systems Modern plumbing systems are developing in ways that can enable installers to benefit from many of the above advantages. Many taps now come with soft copper tails for connection to the water services. A large number of new and refurbishment installations make use of mains pressure for both cold and hot water, (combi-boiler and instantaneous multi-point systems, as well as unvented domestic hot water storage systems). Hard water need not be a problem with the many types of water conditioners and small baseexchange water softeners that are available. Also, many installations are

Notches should be in this zone.

Up to four 10mm tubes can be cabled through a 25mm hole

Figure 2 Detail of holes and notches

runs are surface fixed pass the tube through a straightener to help achieve a neat finish. Minibore and microbore tube can be easily bent by hand, but for tight radius bends an external spring, a hand former or mini bender, (see Figure 3) should be used.

Max depth of notch d/8

designed with totally concealed pipe runs in mind. So, why not use smaller tube diameters and the cabling type of installation techniques that are employed on microbore heating in appropriate areas of domestic hot and cold water systems? This might be particularly useful where sanitary fittings are closely grouped. Providing there is sufficient head pressure available, and that appropriate tube diameters are selected, (to give water flow velocities that do not create unacceptable noise levels or pitting and scouring) the system will perform to a satisfactory standard.Table 1 gives details of the flow-rates that can be expected from different tube diameters for various water velocities.These can be compared with the flow-rates required for various terminal fittings shown in Table 2. This shows that 10mm tube could be used to feed washbasins and WC's and 15mm is adequate to feed a bath tap or up to 3 low demand appliances simultaneously.

Measured length Mark back 1 dia. Align bending mark with notch on former

Mini bender

Hand former

Tube straightener

Figure 3 8

Component Connections

hen faced with the need to connect copper tube to plumbing and heating equipment or components the installer has a wide range of alternative fitting types to choose from. The best choice for a particular situation will depend on a number of factors not least of which is the need to use appropriate types of de-mountable joints to facilitate repairs and maintenance.

Location of servicing and drain valves To prevent waste of water when work is to be carried out on the system the Water Regulations demand that stopvalves and servicing valves are installed in certain situations. This is to enable the flow of water to individual or groups of appliances to be controlled and to limit the inconvenience caused during maintenance and repair work.

Figure 1 shows the locations and various types of valve that can be used. Once the location and type of servicing valve has been chosen it must be installed so that it is accessible.

Note: Servicing valves should NOT be fitted on the cold feed pipe from a feed and expansion cistern to a PRIMARY hot water circuit.

> 18 litres capacity < 18 litres

less than 1 bar (10m head)

valve not required

> 18 litres more than 1 bar (10m head)

Up to 50mm diameter BS 5433 or BS1010 stopvalve Over 50mm diameter BS5163 flanged gatevalve BS 2879 drainvalve WC cistern

WC cistern

BS 6675 screwdriver-operated ball-type servicing valve

Hard water scale In soft water areas spherical plug

valves ('ball' type valves) can give satisfactory results when used as service valves. Where hard water scale is expected to form in the system the valve ball can, in time, become trapped by hard scale thus preventing closure. It might be better to use a proper EN 1074 stopvalve in these situations.

BS 6675 lever-operated ball-type servicing valve BS 5154 wheel-operated gate-valve Figure 1 Service valves, type and position ÂŠ European Copper Institute

Any stopvalve that meets the requirements of bylaw 64 9

Joint washer compressed to form seal Conical wedge forced into tapered hole forms seal

Figure 2 Flat faced and taper unions Gas appliance shut-off valves When installing appliance shut-off valves on gas lines make sure that you install the valve with its union end downstream. Once the valve is shut the union can be disconnected to remove the appliance burner.

washers or jointing compounds. Flat faced unions are used to connect components such as circulator pumps. They enable the pump to be removed easily without the necessity to 'spring' apart the connections as would be required if taper unions were used.

Unions or compression joints? When connecting to equipment which might require disconnection on relatively rare occasions, such as on a low-water-content boiler with plain copper tube flow and return connections, then an appropriate pattern of non-manipulative compression joint would allow occasional easy disconnection. On the other hand, where equipment that will require more frequent regular maintenance is to be connected, such as water filters or gas burner controls, the fitting chosen should make use of a purpose designed union which will give better service over the long term even after many disconnections.

Taper / parallel joint threads Take care to examine any threads provided by the manufacturer of the equipment. If the thread provided is female it will probably be parallel, if male it could be either tapered or parallel. If a fitting is chosen so that both threads of the joint are parallel then the thread will not tighten as the fitting is assembled so a flanged connector or flat faced union and fibre washer will make a better joint. Where one thread is tapered and the

Taper union or flat faced union? Figure 2 shows the internal features of flat faced and taper unions. Flat faced union joints are similar to flanges or tap connectors and require the compression of an approved fibre or rubber washer to seal the joint. This could be damaged or displaced if care is not taken when aligning and tightening.Taper unions use a different principle, as the taper union is tightened the effect is like a wedge being forced into a tight gap creating a water or gas tight seal without the use of ÂŠ European Copper Institute

other parallel then approved jointing material such as PTFE tape on the male thread will be compressed as the tapered male thread is tightened to produce a reliable joint. See Figure 3. Long-lasting Properly installed using approved materials and correct working methods, copper tube and fittings will give many years of trouble-free service. A few moments thought, when choosing a fitting for a particular situation, will pay dividends in the future if essential maintenance jobs are made easier. By using the most suitable type of fitting for the job the professional installer can solve any problem with copper - and rely on the result.

Female thread on appliance or fitting Joint washer compressed to form seal Approved jointing material compressed into diminished gap to form seal

Note: Taper exaggerated to illustrate effect

Parallel / parallel

Parallel / taper

Figure 3 Parallel / Taper threaded joints 10

Copper Oil Pipelines

opper's neat unobtrusive appearance, flexibility, ease of jointing and high degree of fire resistance make it an ideal material for oil pipelines.

Tube diameter selection The diameter of tube required to feed a particular installation depends on the relative height of the storage tank to the burner, the length of run of tube and the quantity of oil required. Figure 1 illustrates the relationships, and can be used to select a suitable tube diameter by reference to burner power in kW's and length of tube. It is based on a

105 90 75

Length (m)

Tube and fittings Supply pipes for small oil boilers are usually installed using 10, 12 or 15mm diameter EN 1057 half-hard thick wall, formerly Table Y copper tube. Also, EN 1057 thin wall formerly Table X tube can be used for surface fixed applications. Joints are made using flared type EN 1254 manipulative (type 'B') compression fittings. These are used because of their superior strength. Threaded ends of fittings for connection to pipeline components such as valves and filters should be sealed using petroleum resistant jointing compound or PTFE tape.

120

15mm

60 45 12mm 30 15 10mm 0 0

12 18 24 30 36 42 48

Burner rating (kW) Figure 1 Recommended maximum length of copper oil lines

minimum head of 300mm of oil above the burner for gas-oil, which has a viscosity of 35 seconds Redwood scale (commercial kerosene, viscosity 28 seconds, will give a slightly increased flow rate). TYPES OF SYSTEM Single pipe system Where the storage tank can be located above the level of the burner, a single pipe gravity fed system can be used. In this case the bottom of the tank should be at least 300mm above the

External wall of building Oil storage tank Fire valve sensor Isolating valve

Minimum head of oil 300mm above burner unit

Boiler Table Y Copper tube Remote-operated fire valve Servicing valve Filter Flexible connection Burner oil pump

ÂŠ European Copper Institute

Figure 2

Single pipe system

level of the burner to give sufficient static head. Vaporising burners that use an oil level control also often require that the tank is not too high above the burner, the maximum is usually 3m. A typical single pipe system with its ancillary components is shown in Figure 2. Two pipe system Pressure jet oil burners incorporate an oil pump that can be used to lift the oil up to the burner in installations where the tank is situated below the burner.This is achieved by using a two pipe system. Alternatively, a single pipe system and deaerator device can be used.The two pipe system is shown in Figure 3. The nonreturn valve fitted into the supply pipe is necessary to prevent oil from running back into the tank when the burner stops. Without the NRV the burner would become unprimed and then fail to re-ignite causing lock-out. Bleeding and priming of the oil line would then be required before the burner would run properly. Note: if the top of the tank is above the level of the burner a second non-return valve is also needed to prevent oil from siphoning out of the tank along the return line during burner maintenance. Single pipe system with de-aerator device If a single pipe system and de-aerator is used then the de-aerator must be fitted close to the burner. Any air that is drawn along the single pipe between the tank and the de-aerator is bled off by the device. It is connected to the burner oil pump using flow and return pipes as shown in Figure 4. Pipe installation When installing the oil pipe(s) arrange for a slight rise in the direction of flow, approximately 1:600 will be sufficient. This is to facilitate air venting. If 11

External wall of building

Fire valve sensor

Oil return line

Boiler

Remote- operated fire valve Table Y Copper tube Oil storage tank Servicing valve Filter Non-return valve (see text) Flexible connection Burner oil pump

150mm Isolation valve Non-return valve

Figure 3 Two pipe system

Oil supply line

the oil pipe is to carry gas-oil then consider insulating the pipe, or even electrical trace heating in very exposed situations, to prevent waxing. Waxing can quickly clog filters in very cold weather, and is a danger if summer grade fuel remains in the tank. If the oil pipe is to be buried then ensure that it is deep enough to provide sufficient cover to minimise the risk of damage by, for example, garden digging. In general, it is prudent to ensure that underground sections are suitably protected with a factory applied plastic covering. Pipeline components Use a full way gate valve as the tank isolation valve and fit it as close as possible to the tank. An oil filter (disposable paper element type) should always be fitted in the pipeline. This can be fitted close to the tank or close to the burner. Composite tank fittings are available that comprise an isolation valve, filter and tank contents gauge (sight glass) in one unit. A remote operated fire valve is an important part of the installation. It should be installed outside the building.The fire valve is activated by a remote sensor that is located over the burner. Take care not to kink or damage the capillary connecting tube during installation. Although it requires slightly more work to install, a remote fire valve is better than using a fusible head valve, which has to be installed close to the burner, because it cuts off the supply outside the building in the event of a fire. ÂŠ European Copper Institute

Burner oil pump Fire valve sensor

De-aerator device Wall mounted boiler

Oil supply pipe

Flow & return pipes from de-aerator to burner oil pump

Figure 4

De-aerator connection details

Domestic Gas Pipework Part 1 - Pipe Sizing opper's strength, neat unobtrusive appearance, fire and corrosion resistance make it an ideal material for gas installation pipes.

Determining tube sizes BS 6891 is the industry standard for mains gas piping installations. It states that in a domestic natural gas installation the pressure drop along the pipeline at periods of maximum demand should be no more than 1mbar.The reason for this is that, if under-sized pipes are installed, the pressure at the burner could become so low that incomplete combustion occurs, which is dangerous as carbon monoxide will be produced! So, when planning a gas installation it is important to ensure that the tube diameters chosen are able to supply the volume of gas required by the appliances without excessive pressure loss. Manufacturer’s installation instructions will only give guidance on the appropriate diameter of tube to be used to supply their own gas appliance.Where more than one appliance is to be installed, it is necessary to determine suitable tube diameters for the installation that can satisfy the maximum demand without excessive pressure loss. Figure 1 shows a typical domestic natural gas piping installation; it supplies a gas fire with a heat input of 7kW and a cooker with a heat input of 16kW. The main existing piping run (1-2) is installed with 22mm tube. A boiler (with piping shown dashed) with a heat input of 35kW is to be added to the installation. Assessing the existing meter capacity Before extending an existing installation to add another appliance it is necessary to consider the existing meter capacity. In the UK the standard domestic © European Copper Institute

Note: Flow rates are for lowpressure supplies with 1mbar differential pressure between ends of pipe for gas of relative density 0.6

gas meter has a maximum volume flowrate of 6m3 of gas per hour (Q max on the meter data plate), which equates to a maximum of 64.1kW of appliance heat input. This figure should not be exceeded, otherwise the meter will be overloaded and the pressure drop will be too great.

Determining the gas flow rate for an appliance To determine the gas-rate for an appliance divide the appliance heat input in kW by the ‘calorific value’ (CV) of the gas being burnt. In the case of natural gas this is 38.5MJ/m3. For example, for a 10kW appliance the flow rate will be: 10 ÷ 38.5 = 0.26litres/second. This figure can then be multiplied by 3.6 to convert the flow rate from l/s to m3/hour = 0.26 x 3.6 = 0.936m3/hour.

So, to check for spare capacity on an installation, first examine the data plates of the existing appliances to find their heat input in kW. Then total these and subtract the total from 64 to determine any spare capacity for the extra appliance. In Figure 1 the existing heat inputs are 7 + 16 = 23kW, and 64 – 23 = 41kW of spare capacity, which is more than is required for the new boiler with a heat input of 35kW.

Table 2 - illustrates how the tube sizes needed to supply the appliances shown in Figure 1 can be found. First, each numbered pipe run is identified on the drawing and then listed in column 1 of the table. Next, the total gas flow in kW through each pipe run is found. This is determined by totalling the number of kW each pipe run supplies; this is then noted in column 2. For example, pipe run 1-2 has to serve all appliances and so will need to pass 7 + 16 + 35 = 58kW. Pipe run 2-4 serves the cooker and boiler, so it will need to pass 16 + 35 = 51kW. These figures can then be converted

Note: if there is insufficient capacity for the extra appliance, the gas supplier should be contacted before commencing work to extend the installation. Table 1 gives details of maximum lengths of copper tube for various flowrates for natural gas. We can use it to select suitable tube diameters for the installation.

Table 1 Approximate flow of gas (m3/hour) in straight horizontal copper tube Tube size Length of pipe run (m) (mm) 3 6 9

10 x 0.6

0.84

0.56

0.51

0.36

0.31

0.22

0.17

0.14

12 x 0.6

1.52

1.01

0.84

0.82

0.67

0.51

0.39

0.33

15 x 0.7

2.9

1.9

1.5

1.3

1.1

0.95

0.92

0.88

22 x 0.9

8.7

5.8

4.6

3.9

3.6

2.8

2.6

2.3

28 x 0.9

9.4

7.2

5.4

4.8

Flow rates are for low-pressure supplies with 1mbar differential pressure between ends of pipe for gas of relative density 0.6. Add 0.3m for each 90° bend and 0.5m for each elbow or tee fitted to the actual length of the tube to obtain the total effective length. 13

into m3/hour by dividing each in turn by 38.5 and then multiplying by 3.6 and these results are noted in column 3. The measured length of each pipe run is then listed in column 5. Next an allowance has to be made for the pipe fittings. Allow 0.3m for each 90Â° bend and 0.5m for each elbow or tee that creates a change of direction and note the total fitting length for each pipe run in column 6.The figures in each row of column 5 and 6 can then be added to give an effective length for each pipe run, which is then noted in column 7. By referring to the sizing table (Table 1) we can now select a provisional tube size (or check an existing tube size) and note this in column 4. To use the table, first look down the column of the table that shows a length of pipe equal to or above the effective

length of the pipe run in question until the flow rate required is reached; look to the right to see if longer lengths of pipe will give the required flow rate. If they do then use the longest possible length in column 8, then read off the tube diameter from the left-most column.

In this example we are concerned to check whether the existing pipe runs 1-2 and 2-4 are adequate to serve the new boiler: from the table we can see that the progressive pressure drop along pipe runs 1-2 and 2-4 when supplying the new boiler will be 0.92 + 0.67 = 1.58mbar. This is well over the maximum allowed so a larger tube size (say 28mm) will have to be selected and noted in column 4 and the figures reworked to determine whether this is satisfactory. If the boiler is supplied by 28mm tube for pipe runs 1-2, 2-4 and 22mm tube for pipe run 4-6, the reworked progressive pressure drops are 0.18 + 0.13 + 0.17 = 0.48mbar, which shows that these tube sizes will be adequate to supply the new boiler.

In the case of the 22mm existing pipe run 1-2 with an effective length of 5.5m we look down the 6m column until we reach the figure 5.8m3/hour. Column 8 is then used to note the maximum length of tube that can supply the flow rate required; in this case 6m. Column 9 is used to record the actual pressure drop along the pipe run; the actual pressure drop is found by dividing the figure in column 7 by the figure in column 8.Then the progressive pressure drop can be found; this is done by totalling the pressure drops for each pipe run supplying an appliance.

Brian Curry: March 2008

Table 2 Tabulation form - gas pipe sizing Pipe length

Flow rate Assumed Effective {col 2 x 3.6} Measured Extra for diameter {from length cv length (m) fittings (m) Table 1} (mm) {5 + 6} (m) 3 (m /hour) Col 3 Col 4 Col 5 Col 6 Col 7

Power (kW)

Maximum length {from Table 1} (m) Col 8

Actual pressure drop {7Ăˇ8} (mbar) Col 9

Progressive pressure drop (mbar)

Col 1

Col 2

Col 10

1-2

58.00

5.42

22.00

4.00

1.50

5.50

6.00

0.92

2-4 4-6

51.00 35.00

4.77 3.27

22.00 22.00

4.00 2.00

0.00 0.50

4.00 2.50

6.00 15.00

0.67 0.17

1.58 1.75

Re-work pipe runs 1 - 2 and 2 - 4 with 28mm tube size due to pressure drop being greater than permitted 1-2

58.00

5.42

28.00

4.00

1.50

5.50

25.00

0.22

2-3

7.00

0.65

12.00

3.00

1.00

4.00

15.00

0.27

0.49

2-4

51.00

4.77

28.00

4.00

0.00

4.00

25.00

0.16

0.38

4-5

16.00

1.50

15.00

2.50

1.00

3.50

9.00

0.39

0.77

4-6

35.00

3.27

22.00

2.00

0.50

2.50

15.00

0.17

0.55

New boiler 35kW

Gas meter 2m

Existing

16kW cooker 4

22mm piping

2.5m

4m 4m

2 Figure 1 ÂŠ European Copper Institute

7kW gas fire

3 14

Domestic Gas Pipework Part 2 - Installation and Testing Copper tube and fittings Copper tube to EN 1057 can be used for gas installations. It can be jointed using EN 1254 capillary or compression fittings. According to BS 6891 compression fittings should only be used where they are readily accessible for tightening and inspection. This means that they cannot be buried underground, buried in the structure or used in ducts or under floors. Jointing When using capillary fittings it is important to visually examine every joint to ensure that the solder has run. The flux used must only be corrosive during heating and any residue should be removed after making the joint. Apply a thin coating of flux to the outside of the cleaned tube only, not into the mouth of the fitting. Twist the tube as it is assembled into the cleaned fitting to spread the flux and then wipe off any excess before completing the joint. Use only EN 751 approved non-setting jointing compound on threads or the thicker type of approved PTFE tape wrapped with a 50% overlap, as in Figure 2.

PTFE tape

be fitted before the meter is disconnected, dust caps fitted, and the end of the pipework sealed. The existing pipes should be purged out of service to remove fuel gas before using a blow lamp. Any open ends of pipework must be sealed before the work is left unattended.

Pipe in screed

Screed

Installing tube in walls and floors Typical methods of installing gas piping in walls and floors are shown in Figure 3. Where copper tube is to be buried in solid floors or walls, the number of joints should be kept to a minimum. Ideally the tube should be run in a preformed duct with a suitable

Pipe in brick or block wall

Corrosion protected pipe

T Gas pipe in chase in plastered wall Base concrete

Maximum chase depth: T÷3 vertical pipes T÷6 horizontal pipes

Pipe behind plasterboard on dabs Pipe in ground bearing slab

Adhesive dabs Soft copper tube in plastic sleeve

Gas pipe behind plasterboard

Individual adhesive dabs

Insulation Concrete slab

Pipe in precast beam & block

Chipboard over insulation

Continuous dabs to surround pipe

Pipe laid in insulation layer

Pipe behind plasterboard on battens Figure 2

50% overlap

Installation During installation prevent dirt and water entering the tube by use of adhesive tape over the ends. Remove burrs left by tube cutters to minimise pressure drop due to turbulent flow. If work has to be done on existing pipes already connected to a meter, a temporary earth continuity bond should © European Copper Institute

Full length timber batten

Precast beam & block

Pipe in raft

Chipboard over insulation Pipe laid in insulation layer

Gas pipe behind plasterboard

Pipe in timber wall Ply sheathing Vapour barrier

Timber studs

Figure 3

Full length timber blocking piece Gas pipe behind plasterboard 15

Flexible mastic Consider extending sleeve above floor in areas like kitchens

point. Slowly turn on the gas and note the reading; this should be 20mbar or a little above. If the pressure reading is above 25mbar the meter governor may be faulty and the gas supplier should be informed. The reading should then be checked with the appliances operating, this gives the meter outlet working pressure. If the pressure drop across the meter and governor is greater than 1.25mbar there could be a problem, due perhaps to overloading the meter or an inadequate or partially blocked service pipe. In any event the gas supplier should be informed.

Sleeve

Checking the installation piping for pressure drop Once the meter outlet working pressure is known,

protective cover. Use plastic sheathed copper laid on top of the base concrete and soundness test the installation piping before wrapping any joints and covering with a suitable screed. Alternatively, pass plastic sheathed soft coiled copper through a larger tube that has been previously set into the concrete.Try to run vertical pipes in walls in ducts, with access if possible, never inside the cavity. If the wall is thick enough to provide proper cover the pipe can be run in a chase. If the pipe is to be installed behind plasterboards, timber battens or continuous adhesive dabs should be used to surround the pipe. Where tube is to be laid in timber floors running across the joists, these should be notched or drilled to accommodate the tube. Care should be taken to mark floor boards so that fixing nails and screws do not damage the tube.Tubes installed parallel to the joists should be properly supported. If tube has to be installed in purpose-designed ducts, these must be sealed to prevent the passage of gas into the wall cavity. If the duct has a cross-sectional area of more than 10,000mm2 it should be vented at high level to allow any escape of natural gas to dissipate into the rooms, and if possible cover the duct with a metal plate to minimise the risk from nail punctures. Sleeves Always sleeve the pipe where it passes through solid walls or floors. Build the sleeve into the wall or floor and seal the gap between the gas pipe and sleeve with flexible fire-resistant compound at at least one end, as in Figure 4.

Solid or cavity wall

Cement mortar

Solid Floor

Flexible mastic

Sleeve Tube

person before the meter is connected. If work is to be carried out on an existing installation it must be tested before starting and any faults traced and rectified or the installation made safe. On completion of the work a further test must be carried out and if satisfactory the installation purged into service. The testing and purging of domestic installations must be carried out in accordance with BS 6891.

Other services Keep a gap of at least 25mm between gas pipes and other services and keep at least 150mm away from electricity meters and fuse boxes. Where electrical cross bonding is necessary, a clamp is used to connect the protective conductor near (ideally within 600mm) the outlet side of the meter in accordance with BS 7671 Requirements for Electrical Installations.

Dynamic performance testing gas installations Note that once the gas piping installation is completed and the installation has been tightness tested, purged and brought into service the gas appliances must also be tested to make sure that they operate in accordance with the manufacturerâ&#x20AC;&#x2122;s instructions and the Gas Safety Regulations. In cases where the correct burner pressure or gas rate cannot be achieved, taking pressure readings at the meter and the inlet pressure test points on the appliances can identify the likely source of the problem.

Testing for soundness The Gas Safety Regulations require that new installations be installed and tested for gas tightness by a competent

Checking the service entry piping and meter installation for pressure drop Turn off all appliances and connect a mano-meter to the meter outlet test

ÂŠ European Copper Institute

Figure 4 the installation pipework can be checked for pressure drop. Attach a manometer to the inlet pressure test point before the appliance governor and, with the appliances lit, take a reading. If this is more than 1mbar below the meter outlet working pressure, the pipework is either too small in diameter for its length, or a section of piping may have been crushed or be partially blocked by debris. Whatever the cause, the problem is within the installation. If the installation pressure drop is satisfactory, and the burner pressure cannot be achieved, then the problem lies within the appliance, possibly in the appliance governor. Brian Curry: March 2008.

Domestic Sprinkler Systems

ach year in Britain there are over 60,000 fires in the home, these cause at least 600 deaths and 10,000 serious injuries. Many could be prevented by the installation of a domestic fast response sprinkler system. Designed to detect and control the fire automatically in the early stages, without reliance on personnel, sprinklers limit the growth of fire and minimise potential smoke, fire and water damage. When a fire starts only the sprinkler heads affected by the heat of the fire operate. The sprinkler heads are extremely reliable and are only activated by temperature, not smoke. Copper tube to EN 1057 is the ideal material to use for the system. Compared to the other approved materials, copper has a smaller outside

Flow switch Domestic water supply Drain and test valve

Check valve

Optional check valve

Optional stopvalve Sprinkler and domestic supply main stopvalve Min 25 internal diameter from main to stopvalve Water authority stopvalve Town main

Figure 2 Typical connection and stopvalve arrangement

Sprinklers in loft

Upper floor sprinklers

Ground floor sprinklers

Supply to water fittings

Water main

Figure 1 Typical domestic sprinkler system layout ÂŠ European Copper Institute

Pressure gauge

Sprinkler installation

diameter and low friction losses. It requires relatively few supports, is lighter to handle and easier to join, especially in confined spaces. Its excellent corrosion resistance gives a long trouble free service life. It can be jointed using the same EN 1254 Part 1 capillary fittings with tin/copper solder to EN ISO 9453 alloy number 23 that are used on ordinary water services. Installation pipework A wet pipe installation must be used, so the system is constantly charged with water, preferably direct from the mains. Sprinkler installation pipe diameters must be chosen to supply not less than 60 l/min

through any single sprinkler and 42 l/min through any two sprinklers operating simultaneously in a single compartment. For a single dwelling the incoming service pipe must be at least 25mm nominal internal diameter, so 28mm plastic sheathed half-hard thick wall formerly Table Y copper tube will best meet this requirement. If the service pipe only serves the sprinkler installation it must be capable of supplying the above water flow rates. If the service pipe also supplies domestic water the above flow rate plus 50 l/min is required.The internal pipework should be run in the standard half-hard condition thin wall formerly Table X copper tube. Because no bending of the tube is allowed on the sprinkler installation pipework, fittings must be used for all changes of direction. Sprinkler heads are positioned in all parts of the dwelling, including the loft, wherever there is a potential ignition source. Figure 1 shows a typical layout. All pipework must be protected against freezing by either: the manner of its installation; insulation; or, for example in 17

the loft, by insulation and electrical traceheating. The sprinkler heads must, of course, remain exposed. Control valves and monitoring equipment Figure 2 illustrates a typical sprinkler connection arrangement. Where the sprinkler installation and the domestic water system share a common water supply the main stop valve must isolate both. A check valve must be fitted to the sprinkler installation. It makes good sense to fit another stop valve and check valve to the domestic supply so that the sprinkler installation can be kept operational whilst any work is carried out on the domestic side. A flow switch is fitted so that an alarm is activated if a sprinkler discharges. A drain and test valve, minimum 15mm nominal bore, is required; this enables both draining and a check of the water flow rate to be carried out. A pressure gauge is also required to enable monitoring of the water pressure. Sprinkler heads There are two types of sprinkler head: one uses a glass bulb filled with heat sensitive liquid; the other has a fusible pellet and heat collecting fins, see Figure 3. Glass bulb sprinklers are available for concealed, recessed, pendant and ceiling mounting. Pellet types are pendant and ceiling mounted with escutcheon plates. Table 1 gives details of the temperatures and colour codes. Sprinkler spacing Sprinklers should be spaced so that the area covered by a single sprinkler is not more than 12m2 and the maximum distance between sprinklers does not exceed 4m. Also, the maximum distance from the sprinkler to any wall should not be more than 2m. The minimum distance between sprinklers in a compartment is 2m. Bearing the above in mind, most rooms will require only one sprinkler head. Commissioning Commissioning of the system is straightforward and consists of a pressure test for leakage and a flow rate check. The installation must be tested by filling with water and visually checking each joint for leakage. The installation ÂŠ European Copper Institute

Table 1 Sprinkler temperature ratings and colour codes Sprinkler type

Temperature rating Â°C

Colour code

68 to 74

Uncoloured

93 to 100

White

Red

Yellow

Green

Fusible link

Glass bulb

1/2"BSPT Valve plug Escutcheon Glass bulb sensor Deflector

Sensor fins

Fusible pellet pendent type

Glass bulb recessed type

F igure 3 Detail of sprinkler heads pressure should then be increased to 110% of the maximum service pressure. The system should then be isolated and the pressure checked after an eight hour period. There should be no significant pressure drop. The drain and test valve should then be used to establish that the design flow rates can be achieved, this check should be carried out when the standing pressure is at its lowest level. Documentation Full documentation should be provided for the building user.This should include a statement of compliance with all specifications, plans of the installation, details of approvals granted, an inspection and maintenance programme and an emergency telephone contact number.

sprinkler systems have more than fifteen years of proven service and many systems have been installed there. Further technical information on domestic sprinkler systems can be found in BS 9251 Sprinkler systems for residential and domestic occupancies â&#x20AC;&#x201C; Code of practice, published by British Standards Institution. Note: the installation of new, or alteration of existing sprinkler systems, should only be carried out by contractors who have received the appropriate training.

Customer peace of mind Anything that can add value to a plumbing installation, give lasting peace of mind to the customer, and might one day save the property and lives of everyone in it, just has to be a good thing, both for the installer and the customer. We should follow the examples set by other countries and promote the installation of domestic fast response sprinkler systems. For example, in Canada domestic 18

EN Standards for Copper Tube and Fittings

standards have been written to harmonise copper tube and fitting standards throughout the 18 member nations of the European Committee for Standardisation.

Tube standard EN 1057 Copper and copper alloys Seamless round copper tubes for water and gas in sanitary and heating applications, is one of a series of European Standards for copper and copper alloy tubes that are in the course of adoption. It specifies the requirements for copper tubes from 6mm up to 267mm diameter for: • distribution pipework for hot and cold water; • hot water heating systems, including under-floor heating systems; • domestic gas and liquid fuel distribution; • waste water sanitation. The tube standard gives details of nominal cross-sectional dimensions in millimetres (nominal outside diameter x nominal wall thickness) and material temper. It also gives product designation details and sets out tests that are carried out by the manufacturer to ensure that the tube supplied is free from defects and meets the requirements of the standard. With 46 recommended combinations of diameter and wall thickness, available from the 26 different diameters and 12 different wall thicknesses, together with a further (non-recommended) 57 other combinations, and 12 other combinations included for a limited period, ordering copper tube might not be quite the simple task it is today! The main combinations of diameter and wall thickness are set out in Table 1. In the table, 'R' indicates a European recommended dimension, 'X' indicates © European Copper Institute

Table 1 Tube size 6 8 10 12 14 15 16 18 22 25 28 35 40 42 54 64 66.7 70 76.1 80 88.9 108 133 159 219 267

EN 1057 Outside diameters and wall thicknesses (mm) 0.5 X X X X

0.6 R R R R

0.7

R X X R

X X X X

0.8 R R R R X R X R X X X X X

0.9

X R

R = European recommended dimensions

Material temper

Nominal Wall thickness 1.0 1.1 1.2 1.5 2.0 R R R R X R X X X X R X X R X R R X X X R R R X X R R X X X X R R X X R R R X R X R X X X X R R X X R X R X R X X R

2.5

3.0

X X X X X R

X X R R R R

X = indicates other European dimensions

Nominal outside diameter d, mm

Tensile strength Rm, MPa

Hardness indicative

Designation in accordance with EN 1173

Common term

min.

max.

min.

HV5

R220 R250

annealed half hard

6 6

54 66.7

220 250

(40 to 70) (75 to 100)

R250

half hard

159

250

(75 to 100)

NOTE 1: Hardness figures are given for guidance only. NOTE 2: Minimum elongation values range from 40% to 20% for annealed and half hard tempers. 19

Table 3 Form of delivery Form of Tube dia. (mm) Length Material delivery from up to & inc. (m) temper Coils Straight lengths

6 6 6

28 267 267

10-50 3-6 3-6

R220 R250 R290

other European dimensions, whilst the shaded boxes indicate our current BS 2871: Part 1 tube sizes. The 'R' marked dimensions have been chosen as a first step towards a rationalised standard with not more than three wall thicknesses for each diameter together with a restricted number of diameters.Table 2 sets out the mechanical properties of the tube in its three states of temper whilst Table 3 gives details of the recommended form of delivery, in terms of straight lengths and coils. Ordering the product When requesting prices or ordering tube it will be important to correctly state a number of items of information to be certain of receiving correct information and then delivery of the particular tube required. The standard sets out the following items of information that should be supplied: • quantity of material required, (in metres); • denomination of the product, (copper tube); • number of the European standard, (EN 1057); • temper designation, (see Table 2); • nominal cross-sectional dimensions: outside diameter x wall thickness, (see Table 1); • form of delivery, (see Table 3). An example: Ordering details for 150m of copper tube conforming to the standard, in temper R250 (half-hard), outside diameter 15mm, wall thickness 0.7mm, in 3m straight lengths. (In other words our tried and trusted 15mm Table X tube.) This should be identified as follows: 150m copper tube EN 1057 - R250 - 15 x 0.7 - 3m straight lengths. Quite a mouthful, I think you'll agree! But, necessary if you are to be certain of receiving the particular type of copper tube you require.

Fittings standards The EN 1254 standard seven separate parts for specifications of the fitting ends:

has the

• EN 1254-1 covers capillary ends for copper tube; • EN 1254-2 covers compression ends for copper tube; • EN 1254-3 covers compression for plastic tube; • EN 1254-4 covers male and female threaded ends; • EN 1254-5 covers short cup ends (for brazing only); • EN 1254-6 covers push-fit ends; • EN 1254-8 covers press ends for plastic tube; • also, • BS 8537 for press ends for metallic tubes.

Ordering fittings The main change that we, as installers, are likely to notice is in the method of designating the particular fitting we require. To be certain the following information should be quoted: • either the manufacturers catalogue number or common name (elbow, tee, coupling); • the number and part of the standard, (for example EN 1254-1 would specify a capillary fitting); • the size of the connecting ends (see below for sequence) or, in the case of fittings with threaded connections in accordance with EN1254-4, or other threads, by the thread designation; • if a 'slip' fitting is required this will have to be stated; • if dezincification resistance is required this will have to be stated; • if required, the type of plating will have to be stated.

Sequence for specifying ends In the UK we have ordered tees (and crosses) using the following sequence: run-run-branch(-branch).This will be the non-preferred method. The preferred method will be to order using the sequence: run-branch-run(-branch). This could cause confusion. If the order does not make it clear that the non-preferred sequence was used the supplier will assume that the run-branch-run sequence is required, (see Figure 1). Confused! There is no need to be confused or in any way intimidated by the new terminology. Some of us still remember metrication in 1971 with the change from inches to, the then alien, millimetres. However, usage becomes second nature and expressions such as "15mm Table X" are now familiar to all of us. As one would expect, copper tube and fittings manufacturers are fully conversant with the European standards and, if you have any doubts regarding the new terminology, cross reference can be made to the former standard and the manufacturer will do the rest. For example that old favourite 15mm Table X could be ordered by requesting 15mm tubing to EN1057 aligning with the former Table X. It will be just as easy to order fittings by quoting EN1254 in conjunction with the manufacturers catalogue number or common name (e.g. elbow, tee, etc.).

28mm 22mm 15mm

Old ordering system: tee specified as 28 x 15 x 22mm. New standard: tee specified as 28 x 22 x 15mm.

Figure 1 Specifying Tees © European Copper Institute

Fixing Copper Tube

Table 1 Recommended Maximum Fixing Intervals for Copper Tube Supports. Diameter of Copper Tube mm

Multiple bracket Pipe ring and backplate

Saddle band

Intervals for Vertical Runs in m

Intervals for Horizontal Runs in m

Hanger bracket

Two piece spacing clip

Screw on bracket

Plastic clip

Figure 1 Typical clips and brackets

opper tube installations have been tried and tested over many years of use in all parts of plumbing and heating systems. Copper's versatility in such a wide variety of situations has resulted in the design and development of many different types of fixing clips and bracketing systems. All pipework systems must be adequately supported if they are to give trouble-free service especially over the long life of a copper system. Manufacturers' catalogues illustrate a vast range of clips and brackets to meet specific requirements, a few of which are illustrated in Figure 1. Selection of the most appropriate pattern of clip or bracket depends on a number of factors which will vary with the type of job and position or situation in which the tube is installed. For example, where a tube has to be insulated against heat or frost in accordance with Water Regulations. In this situation, a simple plastic stand-off clip will not give sufficient clearance for the thickness of insulation required between the tube and the fixing surface. Therefore, an alternative type of support must be chosen, such as a ring bracket with a threaded rod and backplate.

ÂŠ European Copper Institute

Another factor which can have a very significant effect on the overall cost of an installation is the actual number of tube supports required. Because copper tube is a relatively rigid and self supporting material, it requires comparatively few supports when compared to nonmetallic tube. How far apart should the supports for copper tube be placed? The recommended intervals are set out in Table 1. Studying the table will show that fewer supports are required on vertical runs. This is because the vertical tube will not be subjected to Anchor for bracing

6 8 10 12 15 22 28 35 42 54 67 76 108 133 159

0.6 0.9 1.2 1.5 1.8 2.4 2.4 3.0 3.0 3.0 3.6 3.6 3.6 3.6 4.2

0.4 0.6 0.8 1.0 1.2 1.8 1.8 2.4 2.4 2.7 3.0 3.0 3.0 3.0 3.6

possible sagging between supports. Excessive sagging will occur on horizontal runs of tube made from any material if the supports are too far apart. Another factor which must be borne in mind, especially when considering supports for larger diameter tube and/or

Bracket to support loop

12.5m

Bellows or gland expansion joint

25m

Figure 2 Anchor fixings for bracing to accommodate expansion on long runs of tube 21

Horseshoe expansion loop

clip

Bellows or Gland type expansion joints

Expansion loop, for minibore tube only

Crossover tee arrangement

Direction of movement Figure 3 Methods of allowing for expansion

lightweight building structures, is the method to be used to fix the tube support to the building fabric. The fixing method used must be able to transmit the weight of the tube and its contents as well as any other forces acting on the tube to the building fabric without damage. Bracing long runs of tube On long runs of tube with fixing supports such as hanging brackets anchor bracing should be used at 12m centres to avoid swaying. The distance between anchor fixings used for bracing and expansion joints in hot water lines is determined by the type of expansion joint used and the amount of movement which the joint can accommodate. Figure 2 shows how a long run of tube can be anchored by means of supports at each change of direction. The expansion can then be accommodated by an expansion joint or by fabricating an expansion loop, either from fittings or by bending the tube. If an expansion loop is used it should be installed and supported in the horizontal plane to prevent air locks. Where a gland type expansion joint is used and the tube is subjected to a temperature difference of 60°C, then if the expansion joint can accommodate 25mm of expansion the length of straight tube each side of the joint to an anchor fixing can be up to 12.5m. This is because each 1 metre length of copper tube will change in length by approximately 1mm when its temperature is changed by 60°C. So, 1mm of movement within the expansion joint permits 1m of pipe length between expansion joint and anchor points. Similarly, if a bellows type expansion joint is used, the tube should be installed so that it stretches the bellows. By applying "cold draw" in this way the bellows will be able to accommodate the expansion. © European Copper Institute

Note: Notches or holes for pipes must NOT be cut in roof rafters. Figure 4 shows the permitted limits of notches and holes in floor and roof joists.

In order to avoid possible breakdown of branch joints connected to a heating or hot water main, it may be advisable to use the branch joints as anchor fixings. Where, however, the branch is connected to a tube which will itself be moving due to thermal expansion, then the leg of the branch should also be able to move. In this situation "cross-over tees" should be used to permit the movement as in Figure 3. All pipe runs should be aligned correctly to prevent undue strain. This is particularly important when connecting tube to a plastic cistern. Suitable backing plates or washers without sharp edges should be fitted between the tube connection and the cistern to spread any load.

Cabling soft copper tube through joists The ability to drill holes through joists means that where soft coiled copper tube (up to 10mm O.D. Table W or up to 12mm O.D. Table Y) is to be installed it is quite easy to drill and cable the tube through the joists. This means that in new build work the tube can sometimes, if desired, be installed from below after the floorboards have been laid but before ceilings are boarded. Use of Joist Clips Where straight lengths of half - hard copper tube are required to be run in floors they can be laid in notches. By using pipe joist clips with integral protective metal plates, the risk of damage due to punctures from nailing accidents should be eliminated. Furthermore, the rectangular shape of the joist clip can be used as a template when notching joists. This should avoid the joists being weakened accidentally by excessively deep notches. Although unseen when the installation is complete, joist clips improve the overall quality of the installation. They do this by helping to align the tube and permit expansion movement due to temperature changes in hot water lines. This will help to prevent clicking noises and the water hammer which can arise due to badlyaligned pipework.

Notching and drilling floor and roof joists Notches and holes in simply supported floor and roof joists should be within the following limits:Notches should be cut no deeper than 1/8 of the depth of the joist. They should not be cut closer to the support than 0.07 times the span, nor further away than 1/4 of the span. Drilled holes should be no greater in diameter than 1/4 of the depth of the Span S joist. They should be drilled on the neutral axis and 0.4 S 0.25 S should be not less 0.25 S 0.07 S than 3 diameters Max depth Holes in apart, measured of notch this zone Depth d Neutral d/8 from centre to axis centre. Holes should be located in the area Notches should Not less than 3 dia's be in this zone. apart centre to centre. between 0.25 and Max dia of holes d/4 0.4 times the span of the joist from Figure 4 Recommended locations of holes and notches the support.

Flame-Free Jointing Copper push-fit and press fitting jointing systems offer a high-quality modern solution that meets the challenge of changing working practices, evolving construction techniques and the more stringent health and safety regulations present in today’s workplace. They offer flame-free jointing, quick installation, shortened project times, and are ideal for the installation of copper building services with fast-track building systems. Push-fit jointing Copper and copper alloy push-fit joints are ideal for making final connections to terminal fittings and heat emitters; they are available to suit tube sizes from 10 to 54 mm and can be used on hot and cold water services including direct, indirect and pressurised systems. They can also be used on heating systems and chilled water applications within permitted temperature and pressure parameters. Neither spanners nor naked flames are needed to install copper and copper-alloy push-fit joints. Furthermore, the ability to rotate the fitting once it has been pushed on to the tube means that installation in confined spaces is facilitated; this versatility is also useful when carrying out alterations to pipework, repairs and maintenance. Push-fit joints rely on a mechanical mechanism to join tube and fittings. There are a number of designs that use similar principles. Some create a permanent joint and once pushed on to the tube they cannot be removed; others are demountable by using a release tool. Generally, when a length of tube is pushed into the demountable joint it passes through a release collar and then through a stainless steel grip ring.This has a series of teeth that open out and grip on to the tube, securing it so that it can only be released using some form of © European Copper Institute

disconnecting tool. Pushing the tube further into the joint ensures that it passes through a support sleeve, which helps to align the tube and compresses a pre-lubricated EPDM ‘O’ ring between the wall of the fitting and the tube. Only when the tube has passed through the ‘O’ ring and reached the tube stop is a secure joint created. Push-fit jointing method 1. Ensure the fitting is the right size for the tube. 2. Cut tube using a tube cutter, ensuring the tube end is round and free from damage. 3. Use a deburring tool to ensure that the end of the tube is free from any burrs or sharp edges. It is essential that all burrs are removed and the outside of the tube is chamfered around the full circumference to remove any sharp edges. 4. Mark the socket insertion depth to provide visual evidence that the tube has been fully inserted. 5. Keeping the fitting and tube in line, insert the tube through the release collar to rest against the grip ring. 6. Push the tube firmly with a slight twisting action until it reaches the tube stop with a positive ‘click’. Note that excessive force should not be necessary to assemble tube and fitting and, if required may indicate damage to the tube end.

with capillary fittings as the heating may damage the non-metallic components. • Correct tube support should be used to secure finished pipework and prevent movement and vibration. • Avoid contact with mineral oils as these may affect the ‘O’ rings. • Copper and copper-alloy push-fit joints are pre-lubricated with silicone; it is not necessary to add further lubricant. • Where parallel threaded connectors are used, a good quality fibre jointingwasher should be used to form the seal. Disconnecting demountable pushfit joints Place the disconnecting tool on the fitting assembly. Squeeze the tool with one hand to compress the release collar and twist out the tube with the other. Press fittings Press fittings are available to suit tube sizes from 12 to 108 mm diameter, and can be used for systems operating from -20°C up to 200°C and up to 16 bar pressure. Pressfit jointing is a fast, efficient, flame-free, and very cost effective method of connecting copper tubes. Mechanical and electronic tools are used to compress the fitting on to the tube to provide a secure, positive interlocking and frictional restraint without the need for any solder, adhesives, or additional jointing materials.

7. Pull on the tube to check that the fitting is secure and the grip ring is engaged.

For potable water an EPDM ‘O’ ring seal is used, and there are various other seals available for various applications, including gas, solar, compressed air and chemicals, to name a few.

Other points to note • Copper and copper-alloy push-fit joints do not need flux or heat to achieve a joint • Do not use push-fit joints directly

Press fitting method Select the correct size of tube and fitting for the job, and ensure that both are clean and in good condition and free from damage and imperfections. 23

1. Cut the tube square using a tube cutter whenever possible. 2. Use a deburring tool to ensure that the end of the tube is free from any burrs or sharp edges. If a hacksaw has to be used, take care to cut the tube square and properly deburr. 3. Mark the tube insertion depth with a marker pen so that full insertion depth is ensured on assembly. 4. Check that the ‘O’ ring is seated correctly in the fitting socket and assemble the joint ensuring that the tube end meets the tube stop; this can be confirmed by checking the mark made on the tube earlier. 5. With the correct size jaws inserted into the press-tool, place them over the bead of the fitting maintaining a 90° angle between the tube and the tool. Depress the trigger to commence the compression cycle, the jaws will fully enclose the mouth of the fitting, compress the assembly and the tool will stop automatically when complete.

Press fitting tools The making of a press fitting joint relies on the use of a press-tool together with the appropriate size and profile of clamping jaws, (and slings for larger fittings of 42 mm and above). Mains powered or cordless electric press tools are available, with jaws from 12 to 108 mm. press fitting tools can complete a joint in as little as 6 seconds, although 108 mm fittings require a double press to complete the joint. An automatic mechanism ensures that the correct amount of force is always used to create a sound joint and a safety clutch switches the machine off as soon as maximum pressing force is attained.The tool is easy to use. Some tools also have additional features, such as an automatic monitoring function to ensure consistent jointing quality. Design considerations When designing the pipework layout, allowances should be made for the clamping jaw and press fitting tool access so that there is sufficient room around the tube for the jaws of the tool to

operate without hindrance. This requirement will usually be achieved if allowance for the correct insulation thickness for the tube size as specified by BS 6700 is made. Also, when pressing fittings on complex pipework or when working in difficult locations it may be important to plan the sequence to ensure tool access. Fitting spacing and projection – A minimum gap between fittings is necessary.This is generally 10 mm for 15 to 35 mm fittings and 20 mm for 42 mm fittings and above. Where a pipe stub projects through a wall, allowance must be made for the size of the press-tool, see Figure 6. Thermal movement - Another consideration when designing piping systems is thermal movement. Regardless of the materials they are made from, all piping systems will expand and contract with changes in temperature and so will be subjected to stress if their movement is restricted. Therefore, particularly with central heating and hot water

Press fitting jointing procedure

Figure 1 – use tube cutter

Figure 3 – mark insertion depth © European Copper Institute

Figure 2 – deburr

Figure 4 – assemble ensuring full insertion 24

Figure 5 – press to complete joint distribution systems in large buildings, it is always good practice to allow for the effects of thermal movement. But note that press fittings and push-fit fittings should not be subjected to “cold-pull” on flanges when connecting to expansion couplings and anchor points. The stresses imposed by thermal movement can be considerable if no allowance is made. So in large buildings expansion loops, cross-over tees or bellows devices should be incorporated at appropriate points within the system to accommodate thermal movement. Also, wherever pipework is to be installed under screed or plaster, it is very important to make adequate allowance for thermal movement. The preferred practice is to lay tubing in ducts surrounded by loose, non-rigid material such as vermiculite or glass wool. Large contracts By specifying press fittings for the first-fix piping in risers and run-outs in ducts and ceiling voids and making final connections to terminal fittings, heat emitters and cooling coils using copper push-fit, a completely heat-free piping installation can be achieved.This is done without the use of any potential contaminants such as flux and steel wool. Furthermore, the use of heat-free jointing removes the necessity of applying for hot-work permits and the danger of flame damage during refurbishment projects. The ease of the jointing process significantly reduces the amount of © European Copper Institute

Figure 6 – minimum spacing & projection

time spent on site because installation is significantly speeded up! The only jointing tool required is the press fitting clamp, so there is no need to purchase and store fuel gases, adhesives, fluxes, solders or any other jointing materials. Often, prefabrication of pipework can be an advantage, especially if the installation is in a confined or restricted space. Bending, jointing and assembly of complicated piping can be done more efficiently in the workshop – press-jointed systems are ideally suited to this method of working. In conclusion The correct specification and installation of press and push-fit jointing methods will enable professional installers to offer their customers all the peace-of-mind and proven benefits of copper in a fit-andforget, resilient, maintenance free piping system that gives excellent protection against contaminants that threaten the water supply. Brian Curry, January 2007.

Flushing and Disinfection of Hot and Cold Water Systems BS 6700* requires that every new water service, cistern, distributing pipe, hot water cylinder, or similar appliances and modifications to these services, be thoroughly flushed with drinking water before being used. Where the piping system is not used immediately after commissioning, and has not been flushed at regular intervals (of up to 30 days depending on the characteristics of the water), it must be disinfected before use. Furthermore, BS 6700 requires that water-piping systems be disinfected in the following situations: ● In new installations (except for private dwellings occupied by a single family) ● Where major extensions alterations have been carried out

● Where underground pipework has been installed (except where localised repairs have been carried out or a junction inserted after the fittings have been disinfected by immersion in a solution of sodium hypochlorite that has 200 parts per million of available chlorine) Note: 1ppm is equivalent to 1mg/l ● Where it is suspected that contamination may have occurred, for example: fouling by sewage, drainage, animals or physical entry by site personnel for interior inspection, painting or repairs ● Where a system has not been in regular use and not regularly flushed Furthermore, cleaning and disinfection of water systems on a scheduled routine basis is good engineering practice. It is a statutory requirement to disinfect water systems in premises where water is stored and used in a way that could *Specification for "Design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages".

create the foreseeable risk of legionellosis (Legionnaires’ Disease). Disinfection process The disinfection is normally carried out by thorough flushing and then filling the system with chlorinated water at an initial concentration of 50ppm for a contact period of 1 hour. The process has been successful if the free residual chlorine level is not less than 30ppm at the end of this period. Safety The piping system must not be used during the disinfection process and all outlets should have a temporary sign stating “DISINFECTION IN PROGRESS, DO NOT USE”. To avoid generating toxic fumes, caused by adverse chemical fumes, no other chemicals - such as toilet cleansers for example - should be added to the water until the disinfection process is complete. All building users (including people not usually present during working hours such as cleaners and security guards) should be informed of the disinfection before it is carried out. Operatives should refer to the COSHH data provided by the chemical suppliers and wear appropriate PPE (goggles or face shield, plastic apron and sleeves/ gloves) when handling and mixing the disinfectant. Disinfectants The chemicals used to disinfect the system must be approved by the Drinking Water Inspectorate for use with the supply of water for drinking, washing, cooking or food production purposes. They must therefore conform to the specifications of either EN 900 for Calcium Hypochlorite or EN 901 for Sodium Hypochlorite. Sodium hypochlorite concentration Sodium hypochlorite solution (household strength bleach) contains 5% available

chlorine (equivalent to 50,000ppm). If we wish to create an initial concentration of 50ppm chlorinated water then we need to add 50 ÷1,000,000 x 100 ÷ 5 = 0.001 parts of sodium hypochlorite solution to 1 part water. This equates to a ratio of 1 litre (of 5% sodium hypochlorite solution) to every 1000 litres of water system volume. Commercial strength products often contain 10% available chlorine, so where these more concentrated products are used we would need to add 50 ÷ 1,000,000 x 100 ÷ 10 = 0.0005 parts of sodium hypochlorite solution to 1 part water. This equates to a ratio of 1 litre (of 10% sodium hypochlorite solution) to every 2000 litres of water system volume. Assessment of system volume In order to achieve the correct concentration of disinfectant solution for a gravity-fed system it is necessary to estimate the cistern water volume. The volume, in litres, can be obtained by multiplying the length, width, and height up to the water level in metres and then multiply the result by 1000. Copper tube to EN 1057 Tube size

Water volume (litres per metre run)

15 x 0.7

0.145

22 x 0.9

0.320

28 x 0.9

0.539

35 x 1.2

0.835

42 x 1.2

1.232

54 x 1.2

2.091

66.7 x 1.2

3.247

76 x 1.5

4.197

108 x 1.5

8.659 26

System discharge points Temporary supply

Procedure for gravity fed systems 1. Thoroughly flush the system to remove any flux residue, swarf or other contaminants

Air gap (type AA)

The volume of a mains-fed system can be found by totalling the lengths of the different tube sizes and multiplying these by the appropriate figure in the table, then adding the volume of any hot water storage vessel.

2. Close all outlets, once the cistern is full close the servicing valve on the supply

Temporary connection

3. Assess the capacity of the cistern and determine the quantity of disinfectant to use 4. Add this to the water in the cistern and mix to give the initial strength of 50 ppm required 5. Working away from the cistern, open each draw-off fitting until disinfectant solution is detected, then close the fitting to progressively draw the solution around the system 6. As chlorinated water is drawn off, it will be necessary to add further measured amounts of disinfectant to maintain the initial concentration up to the overflow level of the cistern during the filling process 7. Once the entire system is full the 1-hour contact time can commence

Procedure for supply pipes, service pipes and unvented hot water systems A small diameter plugged and valved branch needs to be fitted at the upstream end of the supply/service pipe during installation to facilitate disinfection. 1. Thoroughly flush the system to remove any flux residue, swarf or other contaminants, then close all outlets and the servicing valve on the supply 2. Using the valved branch, connect a suitable pump, check valve and the storage cistern outlet to the installation, (see diagram) 3. Determine the capacity of the system and the quantity of disinfectant to use 4. Add this quantity of water to the cistern and add disinfectant to give the initial strength of 50 ppm required, mix ÂŠ European Copper Institute

Pump Check valve Valved branch Supply pipe

then start the pump to inject the disinfectant solution into the system 5. Working away from the temporary connection, open each draw-off fitting until disinfectant solution is detected then close the fitting to progressively draw the solution around the system 6. As chlorinated water is drawn off, it will be necessary to add further measured amounts of disinfectant to maintain the initial concentration during the filling process The 1-hour contact time will start when the entire system has been filled with water containing 50ppm chlorine. Testing for residual chlorine If the free residual chlorine measures less than 30ppm at the end of the 1-hour contact period, it will be necessary to repeat the process as required by BS 6700. How can we know what the residual chlorine level is? People with a normal sense of smell might just be able to detect the smell of the normal level of chlorine present in ordinary tap water (<1ppm), and they should easily detect the smell formed by a residual chlorine level of 30ppm. This isnâ&#x20AC;&#x2122;t very scientific however, and so a

simple colorimetric chemical test has been developed. The test procedure consists of filling a clear plastic tube with a sample of the water to be checked and adding a tablet of indicator chemical.This is shaken to dissolve the tablet and the water must be examined to judge the colour change to estimate the chlorine level.

Water colour

Chlorine level ( ppm or mg/l)

Clear

None

Faint pink/pink

0.2 - 1

Pink/red

1- 5

Red/purple

5 - 10

Purple/blue

10 - 20

Blue/grey-green

20 - 30

Grey-green/ yellow

30 - 50

Muddy brown

Over 50

Colour develops and then goes clear

Excessive 27

Completion of the disinfection process It is vital to thoroughly drain and then flush out all the disinfectant once the 1 hour contact period is complete. Flushing should continue until the level of free residual chlorine is equal to the level present in the drinking water supplied. If the chlorinated water remains in contact with the tube, the system will be damaged because the chlorine will react with the copper to eventually form insoluble cuprous chloride, which can continue to attack the tube. Chlorine neutralising chemical Where it is necessary to remove chlorine before the system water is discharged into a drain or water course, a neutraliser chemical (for example Sodium Thiosulphate) can be added at the rate of: System volume (m3) x ppm (mg/l) chlorine x 2 = No. of grams required. Cisterns and components with internal coatings Take care to check whether any coatings have been applied to the inside of the storage cistern. High chlorine concentrations can adversely affect new coatings and release chemicals into the water, so it is necessary to ensure that enough time has passed to allow complete curing of any internal coating before disinfection is carried out.

Disinfection Do’s and Don’ts ● Do take care to warn people before starting, and handle chemicals with care they are dangerous ● Do calculate the amount of chemicals to use accurately - using too much will not produce better results ● Do use chlorinated water to replenish the storage cistern up to the overflow level - to keep the disinfection concentration correct

Commissioning heating system pipework It is important to thoroughly flush every heating system as soon as possible after installation. Fill and vent the system with cold water and check all connections for leaks before draining. Refill and commission the boiler and heat up the system. Leaks can be found at this stage, (sometimes due to heat melting grease based fluxes) so check again before draining the system whilst still hot. By following these key steps, you will be able to develop a system with a long and trouble free service life.

● Don’t leave the chlorinated water in the system longer than 1 hour and NEVER overnight ● Do check for residual chlorine at the end of the contact period - to ensure an effective disinfection ● Don’t discharge highly chlorinated water into a drain or into a watercourse without first notifying the Water Authority or the Environment Agency. It is highly toxic to fish and other aquatic organisms ● Do leave systems full and flush through regularly with fresh water as it is virtually impossible to effect a 100% drain-down of systems. It is recommended that systems which are not coming into immediate use be left full and flushed through at regular intervals (by opening-up all terminal connections) in order to periodically introduce fresh water into the system and thereby enhance protective scale formation within the pipework

Fluxes and Solders

ho would have thought, as we plumb into the 21st century, that there are still 'professionals' in our industry who donâ&#x20AC;&#x2122;t know that leaded solders have been banned from use in our potable water systems since the 1980's. Unbelievable? No, it's true, at least in the case of the Yorkshire installer who risked a fine and criminal record when he recently admitted the fact to an official of Yorkshire Water! There are non-leaded jointing solutions such as integral solder ring (guaranteed to use lead-free solder) and push-fit and press-fit fittings which do not need heat.The following is the up to date information on soldering. Capillary jointing systems Copper tube and capillary fittings are manufactured to very close tolerances, so that a small but even gap results on assembly. When a clean, fluxed copper tube is inserted into a clean, capillary fitting and heated to the melting temperature of the solder used, the forces of adhesion and cohesion cause liquid solder to flow into the capillary gap. Flux enables the solder to wet, adhere to and alloy with the surface of the copper and cohesion causes sufficient solder to be drawn in to completely fill the gap so a strong, watertight joint results. Because there are a number of designs of capillary fittings and a wide variety of different fluxes, solders and brazing alloys available, reference should be made to manufacturers technical literature for advice on any particular jointing system. However, the methods of making capillary joints are similar, involving the following steps: 1. Cleaning 2. Fluxing and assembly 3. Heating 4. Finishing off ÂŠ European Copper Institute

Measuring and cutting tube Although measuring is not strictly a part of the jointing process it can have an effect on joint quality. If tube is cut too short and does not reach the full depth of the socket a proper joint cannot be achieved. Also, if tube is cut too long the correct alignment might not result and this can also affect the capillary gap. Always cut tube square and de-burr inside, to enable full water flow, and outside to ease entry to the fitting. Use a junior hacksaw on 6 to 10mm tube and either a rotary tube cutter or a hacksaw with a minimum of 32 teeth per inch on larger sizes. When using a tube cutter be careful not to exert too much force when tightening the cutter on to the copper tube.This can result in 'nozzling' where the end of the tube is reduced in diameter. Nozzling makes the internal burrs more difficult to remove and can affect the capillary gap making it too wide at the base of the socket. Note: when making joints on soft-condition coiled copper tube it is good practice to re-round the tube end using a suitable tool so that the correct gap is maintained all round the joint. Cleaning Clean the outside of the tube and the inside surface of the fitting. Fine sand paper or brushes can be used, not steel wool. Abrasive impregnated nylon scouring pads (similar to washing-up 'greens') are best and recommended for potable services in order to prevent particles of steel, etc, entering the system. Fluxing and assembly Once cleaned the outside surface of the tube should be fluxed immediately. DO NOT apply flux to the fitting. Only apply sufficient flux to the tube to thinly coat the mating surfaces and assemble at once so that dust and dirt do not contaminate the capillary gap. Twist the fitting on to the tube to ensure an even coat of flux in the joint and make sure that the tube enters to the full depth of the socket. Wipe off any excess flux and the joint is ready for heating. Be sure to use a suitable type of flux for the solder used in the joint. For ordinary 'soft' soldered joints the commonly used fluxes are usually made from zinc chloride and/or zinc ammonium chlorides and some fluxes contain other

active ingredients such as amines. Fluxes have to be corrosive to some extent to clean the copper and so any residues should be removed after soldering. Socalled 'self-cleaning' fluxes contain free hydrochloric acid and are generally considered to be more aggressive than conventional fluxes. Whilst they are excellent fluxes, if they are employed, they should be used with extreme care and strictly in accordance with the manufacturers instructions. Type of solder The function of solder is to join two metal surfaces at temperatures that are below the metalsâ&#x20AC;&#x2122; melting point. Solder provides a metal solvent action between it and the metals being joined. This causes an intermediate alloy to be formed in the joint. Tin/Lead solder Tin/lead solder alloys used to be widely used in plumbing but as legislative concern over the hazards of lead increased they have been banned from use in domestic hot and cold (i.e. potable) water systems. The change of 29

solder to lead-free required a flux change. The changeover caused a problem for plumbers because some traditional fluxes used for tin/lead solder would burn and char before the new lead-free alloys would melt. Lead-free solder Lead-free number 401 tin / copper alloy soft solder to EN 29453 has a melting point of 230oC to 240oC and is suitable for making end feed capillary joints on all normal domestic plumbing, heating and gas systems. Your choice If you do decide to or have to use leaded solder for your gas and central heating runs, then buy coils that are on different coloured plastic bobbins so that the risk of mistaken use is minimised. After all, why risk a summons and possible fine when it is so easy for anyone to check whether you have used leaded solder by simply wiping a damped piece of test paper on the suspect solder joint, which will show red if you have. However, as number 401 tin-based solder is approximately 25% less dense (so you can make more joints per 500g coil than tin/lead) and it is inherently stronger than lead-based alloys (as it has better joint strength, fatigue, and thermal cycling properties), why not use it for all your end-feed fittings? Method of heating Heat is usually applied with an LPG blowtorch. Keep the flame moving until a complete ring of solder shows at the mouth of the joint on integral ring fittings. When making end feed fittings the solder should melt when it is brought into contact with the tube. The flame should then be moved away. If the solder does not melt, continue to heat and then try again. Keep the flame moving, this is to prevent localized overheating which can char the flux before the solder is applied. Only add sufficient solder to fill the capillary gap all round the tube. Any extra will simply form a bead at the bottom of the joint or possibly run inside the tube. As a guide on small tube diameters when using solder wire, a length of solder approximately equal to the tube diameter should be enough to fill the ÂŠ European Copper Institute joint. Integral solder ring fittings contain just the right amount of lead-free

solder. Don't add extra solder to integral ring fittings.The manufacturers have gone to great lengths to ensure that the correct amount of solder is already in the joint so adding extra to a properly prepared joint is simply unnecessary and wasteful. Alternatives to the blowtorch In situations where the use of a blowtorch might result in damage to the building fabric you could consider alternative methods of heating for small diameter joints. One alternative is an electric hot air gun, especially if an attachment is used which directs the flow of hot air around the tube. This has the result of both protecting the building fabric and also speeding up the heating process. Another method is to use an electric resistance-soldering tool. This consists of a pair of heating elements fitted with interchangeable heads, which are shaped to fit the tube. These are clipped around the joint to be made and heat is generated in the joint by the electrical current and heat travels into the tube and fitting by conduction. Finishing off Once the joint has been made it is important to allow it to cool so that the solder has solidified before any disturbance. It is also important to remove any residue of flux from the outside of the tube by wiping with a wet cloth and warm water. The pipeline should also be flushed with water as soon as practicable to wash out any flux residues, filings, etc. from the bore. A good cold water flush will usually remove water-based fluxes. Grease based fluxes, on the other hand, will tend to remain and a hot water flush would be better, since if fluxes are not flushed away corrosion damage can occur. If you use self-cleaning flux this flushing is even more important, and remember that gas runs aren't flushed at all, so it is vital that care is taken to prevent flux entering the tube bore!

overheat or burn the plastics. Wrapping the end of the plastics and a little of the copper with a wet rag is helpful in preventing this. Once the joint has been made and any remaining flux has been removed the plastics cover can be unfolded over the tube before carefully spirally wrapping with self adhesive polythene or PVC tape to maintain the protection provided by the plastics coating. Tape should also be applied, especially to castellated plastics coated tube, at the point where the coating terminates to prevent moisture entering any gap caused by the coating disturbance or the channels in the castellated product. The tape should be wrapped over the last 25mm of intact plastics covering and at least a similar length of immediately adjacent bare copper tube too. Proven reliability The capillary jointing system has been continuously evolved and improved for over fifty years to the point that capillary fittings are, in the hands of the competent, professional installer, utterly reliable. Also, the unique properties of copper tube and fittings combine to give a long, trouble-free, safe and costeffective service life on gas, water, sanitation and heating services. So why put at risk your customersâ&#x20AC;&#x2122; health by using banned substances such as lead, and why risk callbacks by skimping when commissioning systems?

Plastics coated tube When jointing plastics coated tube using capillary fittings, the plastics cover should be slit and folded back for at least 100mm and care should be taken not to allow any excess flux to run in between the tube and its plastics coating. Also, do not allow the flame of the torch to 30

Guide to the Suitability of Copper With Various Chemicals

opper is well known for its unrivalled, long-term proven performance. Correctly installed, it gives consistently good results in all types of plumbing and heating installations. But the use of copper isn't just confined to carrying water and natural gas, copper tubes are also widely used in industry to carry a variety of chemical products. This article gives general information on the suitability of copper with various types of water and chemicals.

Drinking water Copper is generally highly corrosion resistant to potable water that conforms to EEC directives and WHO guidelines. Copper is not a toxic metal as are lead and mercury for instance, in fact it is a desirable 'trace element' with the human body requiring about 2.5 to 5mg/day to maintain normal health. Softened water Hard waters can be softened to avoid build up of scale in boilers and hot water services by replacing insoluble calcium and magnesium salts with soluble sodium salts. However, softening should

Solid or Cavity wall

Cement mortar

Flexible mastic

Sleeve Tube

Figure 1 ÂŠ European Copper Institute

be carried out with care bearing in mind that water regulations do not allow the softening of water to kitchen and drinking water taps. So only cold supplies to hot services should be softened and then only to a minimum total hardness of between 60 and 120 ppm (as CaCO3).

Vertical tube

Flexible mastic Consider extending sleeve above floor in areas like kitchens

Solid floor

Sleeve

Figure 2

Deionised water Deionised water is equivalent to distilled water, both anions and cations having been removed by ion exchange resins. Deionised water is, to some extent, aggressive to all but the noble metals, (such as gold and platinum). If deionised water is used as a heat transfer fluid, for example in air-conditioning equipment, an appropriate inhibitor, such as benzotriazole, should be added.

hypochlorites or ammonia can attack copper and should be used with great care. If tube shows evidence of vivid discolouration this could be a sign of the use of strong solutions of ammoniacal bleach. Where vertical runs of tube pass through floors that are likely to be frequently wet-cleaned, such as commercial kitchens and laundries, consider extending the sleeve above the floor finish as shown in Figure 2, or use plastics coated copper tube.

Traditional building materials It is well known that copper is highly resistant to corrosion by most building materials: brick, plaster and concrete or mortar based on Portland cement do not cause problems. Coke breeze and acid plasters and cements, however, should not be allowed to come into contact with metals as they can, if damp, cause corrosion. Where copper tube has to pass through walls it should be sleeved, see Figure 1. Plastics coated copper tube is available and should be considered for use in potentially aggressive environments.

Disinfection of pipeline systems Where sodium hypochlorite solutions are used to disinfect copper pipeline systems the strength of solution should be limited to 50ppm free residual chlorine for no more than 1 hour, (the solution must never be left in the pipes overnight) and when the process is complete, the system must be flushed through with fresh water until the free residual chlorine is at the level present in the drinking water supplied. Reference should be made to BS EN 806.

Household products Nitre cake toilet cleaners made from sodium hydrogen sulphate do not cause problems because they do not attack copper. However, cleaners containing

Heating installation corrosion inhibitors Hydrazine (or nitrite) base corrosion inhibitors are sometimes added to heating installations to avoid galvanic 31

action where mixed metals are used. The inhibitor can be converted to ammoniacal species, by breakdown or reduction, which can cause corrosion of copper or its alloys, (brass). When corrosion occurs, the concentration of the inhibitor is often reduced, but this is precisely the wrong action. Because ammonia is not aggressive to copper in the absence of oxygen and hydrazine is an oxygen scavenger, their concentration should be increased to between 4 and 7 times the value, (in ppm) of the dissolved oxygen content of the water in the system. However, where water treatment is employed it should be carefully controlled and monitored by a suitably qualified expert. Various chemical substances Copper tubes are widely used in industry. Table 1 gives guidance on the suitability of copper when in contact with a variety of chemicals. These are divided into four groups, (A, B, C, D). Studying the table will show that copper is resistant to corrosion or resists corrosion well when in contact with most chemicals, (groups marked A and B in the Table). Copper will undergo slow corrosion when in contact with the relatively small group of chemicals marked C. Copper is not recommended in the presence of a few substances, (marked D in the Table) these being mainly acids.

Table 1 Suitability of copper with various chemical substances Acetic (Acid) Acetic (Anhydride) Acetone Acetylene (See note) Alcohols Alum Alumina Aluminium Chloride Aluminium Hydroxide Aluminium Sulphate Ammonia gas (Dry) Ammonia gas (Wet) Ammonium Hydroxide Ammonium Chloride Ammonium Nitrate Ammonium Sulphate Amyl Acetate Amyl Alchohol Aniline Aniline (Dyes) Asphalt (Dry) Atmosphere (Industrial) Atmosphere (Marine) Atmosphere (Rural) Barium Carbonate Barium Chloride Barium Hydroxide Barium Sulphate Barium Sulphide Benzene Benzine Benzoic Acid Beer Bordeaux Mixture Borax Boric Acid Brine Bromine (Dry) Bromine (Wet) Butane Butyl Alcohol Butyric Acid Calcium Chloride Calcium Disulphide Calcium Hydroxide Calcium Hypochlorite Cane Sugar Syrup Carbolic Acid Carbon Tetrachloride (Dry) Carbon Tetrachloride (Wet) Carbon Dioxide (Dry Gas) Carbon Dioxide (Wet Gas) Castor Oil Caustic Soda Chlorine (Dry) Chlorine (Wet) Chloroacetic Acid Chloroform

B B A D A B A B A B A D D D D D A A D C A A/B C A A B A A C A A D A A A A C A C A A B C B A C A C A B A D A B A D C A

A = Resistant to corrosion B = Resists corrosion well

ÂŠ European Copper Institute

Chromic Acid Cider Citric Acid Coffee Copper Chloride Copper Nitrate Copper Sulphate Corn Oil * Cottonseed Oil * Creosote Crude Oil (Low Sulpher) Drinking Water Ethers Ethyl Acetate Ethyl Chloride Ethylene Glycol (Inhibited) Ethyl Alcohol Ferric Chloride Ferric Sulphate Ferrous Chloride Ferrous Sulphate Fluorosilicic Acid Formaldehyde Formic Acid Freon Fruit Juice Fuel Oil Furfural Gasolene Gelatine Glucose Glue Glycerine Hydrobromic Acid Hydrocarbons (Pure) Hydrochloric Acid Hydrocyanic Acid Hydrofluoric Acid Hydrogen Hydrogen Sulphide (Dry) Hydrogen Sulphide (W et) Kerosene Lacquers Lactic Acid Lime Linseed Oil * Magnesia Magnesium Chloride Magnesium Sulphate Mercury (and its salts) Methyl Chloride (Dry) Methyl Alcohol Milk * Mine Water (Acid) Natural Gas Nitric Acid Nitrogen Oleic Acid

D A C A C C B A A A A A A A B A A D D C C C B B A B A B A A A B A D A D D D A A D A A B A B A B A D A A A C A D A C

C A B B A C B B B B D A A A C D B B B B B B B D C B C B A A C D A A B A B D A A B A D D C C B A C A C A B A A C C C

Oxalic Acid Oxygen ** Oxygenated Water Palmitic Acid * Paraffin Wax Phosphoric Acid Potash Potassium Carbonate Potassium Chloride Potassium Chromate Potassium Cyanide Potassium Sulphate Propane Rosin Sea water Silver Salts Soap (Solutions of) Sodium Bicarbonate Sodium Bisulphate Sodium Bisulphite Sodium Carbonate Sodium Chloride Sodium Chromate Sodium Cyanide Sodium Hypochlorite Sodium Nitrate Sodium Peroxide Sodium Phosphate Sodium Silicate Sodium Sulphate Sodium Sulphide Sodium Hyposulphite Solvents for varnish Steam Stearic Acid * Sugarbeet (Syrup) Sulphur (Dry) Sulpher (Molten) Sulphur Chloride (Dry) Sulphurous Anhydride (Dry) Sulphurous Anhidride (Wet) Sulphuric Anhidride (Dry) Sulphuric Acid (80/95%) Sulphuric Acid (40/80%) Sulphuric Acid (<40%) Sulphurous Acid Tannic Acid Tar (Dry) Tartaric Acid Toluene Trychloroacetic Acid Trychloroethylene (Dry) Trychloroethylene (Wet) Turpentine Varnish Vinegar Zinc Chloride Zinc Sulphate

Note: Home Office Regulations ban the use of copper or copper alloys containing more than 70% copper for carrying acetylene.

C = Undergoes slow corrosion

* = Product may deteriorate (due to auto-oxidation)

D = Copper is not recommendeed in the presence of this substance

** = Tubes for carrying oxygen must be grease free. Source: Copper Development Association

Insulation Against Frost and Heat Gain Water Regulations Requirements

here water systems are installed in situations where they might be subjected to freezing temperatures the professional installer will take care to ensure that the systems are installed in accordance with the Water Regulations. This should give a reliable trouble-free service, as far as possible, regardless of the weather. No amount of insulation will prevent freezing, insulation simply delays its onset. The better and thicker the insulation, the longer the delay. So, the best precaution against the freezing of water systems in buildings is the obvious one of keeping the building temperature above the freezing point of water.

End of warning pipe submerged to stop access of cold air

Heated building Clearance required otherwise insulated

All pipes in roof space should be insulated

Pipes uninsulated Internal floor

Loft insulation omitted under cistern if in a heated building External wall

Cistern in roof space

Unheated building

Flushing cistern insulated

Pipes insulated

Why might one frozen tube burst whilst another, also frozen, doesn't? Since copper tubing to EN 1057 thin wall formerly Table X is capable of withstanding a minimum of 30% expansion and the volume of water when frozen only increases by about 10%, it is an established fact that if a copper system is frozen uniformly, it will distend but not burst. In practice, local freezing results in the formation of a plug of ice. This grows until the pressure increase melts the surface of the ice at

Stop valve as near to entry point as possible

Internal floor Not less than 750

External wall

Service pipe insulated

Figure 1 Pipes in buildings the ice/tube interface. This phenomenon is called regelation, it allows the ice plug to move and equalise the pressure at each side. If the ice plug is prevented from sliding, by an elbow or terminal fitting, the pressure builds up as the ice plug grows until the hydraulic pressure in

Tube size (mm)

0.02 (W/mK)

0.025 (W/mK)

0.03 (W/mK)

0.035 (W/mK)

0.04 (W/mK)

0.045 (W/mK)

30 (30)

25 (62)

(124)

15 (12)

19 (20)

(30)

15 (8)

19 (12)

(17)

15 (6)

9 (9)

(12)

15 (5)

9 (7)

(9)

Note: Figures in brackets are calculated values shown in BS 6700.

Table 1: Recommended minimum thickness (mm) of insulation for indoor cold water systems ÂŠ European Copper Institute

Cistern and supply pipe insulated

Outside unheated WC

the unfrozen water exceeds the bursting pressure of the tube, the result is a "frost" burst. Regardless of the material from which the tube is manufactured, once an ice plug forms, the supply of water will be stopped and so frost precautions are still necessary. Water Regulations Water Regulations require that all water services (except warning or overflow pipes) and water fittings shall be protected, so far as is reasonably practicable, against damage from freezing. Where this protection is to be in the form of insulation, then Table 1 gives suitable thicknesses based on the Thermal Conductivity of the insulation and the nominal outside diameter of the tube. Studying the table will show that a small diameter tube requires relatively thicker insulation than a large diameter 33

tube.This is because the smaller diameter tube (especially when used to carry cold water) has relatively less heat energy in it. It will therefore cool to freezing temperatures more quickly and so need relatively thicker insulation than larger diameter tube.

Draw off tap on stand-pipe with back-syphonage protection

Outside draw off tap with back-syphonage protection Stop valve

Thermal insulation

Thermal insulation Surface box

Positioning services, appliances and water fittings Regulations require tube and water fittings to be installed in positions where the risk of freezing is reduced. Particular care should be taken where double check valves and other devices used to prevent backflow and back-syphonage are installed. Tube and fittings which are at risk must be insulated and be capable of being drained. Figure 1 illustrates situations where insulation is and is not required. Where tube feeds an outside tap a servicing valve should be fitted, see Figure 2. In ventilated roof spaces the insulation should be equivalent to outdoor standards.

Not less than 750 Stop valve

Figure 2 Outside taps and standpipes

Particular situations requiring special care include: Tube installed near windows, air bricks, external doors, where draughts are likely; Unheated roof spaces; Unheated cellars; Unheated outbuildings and garages; Tube in contact with cold surfaces, such as the inside of an external wall; Tube in chases and ducts formed in external walls; Positions where the service entry point is closer than Any distance 750mm to external walls, see Figure 3. Suspended internal floor

Not less than 750 Insulation required

More than 750 Solid internal floor

Not less than 750 Pipe in duct no insulation required

Less than 750 Solid internal floor

Not less than 750

Insulation required

Figure 3 Service entry detail ÂŠ European Copper Institute

Trace heating tape Where water systems have to be installed in unheated buildings or external situations above ground level, insulation must be used. It might also be necessary to use trace-heating tape if the water supply is not to be interrupted during severe weather conditions. Selfregulating trace-heating tape is available, this consists of two electrical conductors separated by a special compound Both are enclosed in a plastic covering. If the temperature falls the electrical resistance of the separating compound reduces and so electricity flows causing the tape to be heated. This heating results in the resistance increasing thus reducing the electricity

flow. Effectively the tape regulates its own temperature to keep itself as well as the tube it protects at the design temperature with the minimum use of electricity. The trace-heating tape should be fitted between the tube and its insulation. Waterproof insulation Where insulation is to be used where it can become wet, such as outdoors or underground, it must be waterproof. Closed-cell foam type is satisfactory. Insulation which can absorb water is actually worse than no insulation at all! This is because when wet the insulation loses it's insulating properties because water fills the small pores which trap the air. Also, because the insulation has a larger surface area than the tube it covers, heat is lost more rapidly resulting in quicker cooling. Prevention of warming of cold water services This is best achieved by designing the system so that the runs are kept a reasonable distance away from sources of heat. Where cold water services that are used for domestic purposes have to be installed near to sources of heat, or run through hot environments, such as in ducts with hot water or central heating mains,Water Regulations require them to be insulated against heat gain to prevent waste of water. This so that the water will not be warm when drawn from the taps. Furthermore, if the hot environment is also humid, such as in a changing room and showers, insulation can also be used to prevent excessive condensation forming on cold water services. 34

Jointing of Copper Tubes Capillary Joints

he choice of jointing systems that are available to installers and specifiers of copper tube is truly wide. As well as the ubiquitous Capillary Soldered Joint, as illustrated in Figure 1, we have High Duty Fittings that can be silver-soldered or brazed. We can also form joints on the tube directly and use brazing or bronze welding techniques, as in Figures 2 and 3, or we can use copper or copper alloy brazing fittings. We also have a variety of Compression Fittings available and all of these jointing systems have been continuously evolved and improved for over fifty years to the point that they are, in the hands of the competent, professional installer, utterly reliable. Furthermore, the unique properties of copper tube and fittings combine to give a long, trouble-free, safe and costeffective service life on gas, water, sanitation and heating services.

Integral solder ring fitting Before heating

After heating Solder fed in by operator

End feed fitting

Figure 1 Capillary joints © European Copper Institute

Capillary attraction Copper tube and capillary fittings are manufactured to close tolerances, so that a small even gap results on assembly. When a clean, fluxed copper tube is inserted into a clean, fluxed capillary fitting and heated to the melting temperature of the solder used, the forces of adhesion and cohesion cause liquid solder to flow into the capillary gap. Flux enables the solder to wet, adhere to and alloy with the surface of the copper and cohesion causes sufficient solder to be drawn in to completely fill the gap so a strong, watertight joint results. Capillary jointing systems Because there are a number of designs of capillary fittings and a wide variety of different fluxes, solders and brazing alloys available, reference should be made to manufacturers technical literature for advice on a particular jointing system. However, the methods of making capillary joints are similar, involving the following steps: Measuring Although measuring is not strictly a part of the jointing process it can have an effect on joint quality. If the tube is cut too short and does not reach the full depth of the socket a proper joint cannot be achieved. Also, if the tube is cut too long correct, alignment might not result and this can affect the capillary gap. Cutting Cut the tube square and de-burr inside, to enable full water flow, and outside to ease entry to the fitting. Use a junior

hacksaw on 6 to 10mm soft tube and either a rotary tube cutter or a hacksaw with a minimum of 32 teeth per inch on larger sizes. When using a tube cutter be careful not to exert too much force when tightening the cutter on to the copper tube. This can result in 'nozzling' where the end of the tube is reduced in diameter. Nozzling makes the internal burrs more difficult to remove and can affect the capillary gap making it too wide at the base of the socket. Note, when using capillary joints on soft coiled copper it is good practice to re-round the tube end using a suitable tool so that the correct gap is maintained all round the joint. Cleaning Clean the tube and fitting. Do not use steel wool! Fine sand paper can be used and abrasive impregnated nylon scouring pads (washing-up 'greens') are very effective and no particles of steel can enter the system if they are used. Fluxing and assembly Once cleaned the tube should be fluxed immediately. Only apply sufficient flux to thinly coat the mating surfaces and assemble at once so that dust and dirt do not contaminate the capillary gap. Twist the fitting on to the tube to ensure an even coat of flux in the joint and make sure that the tube enters to the full depth of the socket.Wipe off any excess flux and the joint is ready for heating. Be sure to use a suitable type of flux for the solder used in the joint. For ordinary ‘soft’ soldered joints the commonly used fluxes are made from zinc and/or aluminium chlorides. Fluxes have to be corrosive to some extent to clean the copper and so any residues should be removed after soldering. So called ‘self-cleaning’ fluxes contain free hydrochloric 35 acid. Whilst they can be excellent fluxes when used with extreme

Socket expander

soldering tool. This consists of a pair of heating elements fitted with interchangeable heads which are shaped to fit the tube.These are clipped around the joint to be made and heat travels into the tube and fitting by conduction.

Formed socket

Branch forming tool Tube Locating dimples control insertion depth

Flange body Composite flange

Steel flange

Figure 2 Socket and branch forming tools and brazing joints care, they are not recommended for general use because of their corrosive nature. If the capillary joint is to be made with ‘high duty’ silver solder or brazing alloy the flux used is made from borax. The flux powder should be mixed with water to a thin creamy consistency before application. Heating Heat is usually applied with an LPG blow-torch. Keep the flame moving until a complete ring of solder shows at the mouth of the joint on Integral Ring fittings. When making End Feed fittings the solder should melt when it is brought into contact with the tube. The flame should then be moved away. If the solder

Bell joint

does not melt continue to heat and then try again. Keep the flame moving, this is to prevent localised overheating which can char the flux before the solder is applied. Only add sufficient solder to fill the capillary gap all round the tube. Any extra will simply form a bead at the bottom of the joint or possibly run inside the tube. As a guide on small tube diameters when using solder wire, a length of solder approximately equal to the tube diameter should be enough to fill the joint. Don’t add extra solder to Integral Ring fittings. The manufacturers have gone to great lengths to ensure that the correct amount of solder is already in the joint so adding extra to a properly prepared joint is simply unnecessary and wasteful. When using oxy/acetylene equipment to make large diameter joints or for brazing use a large, soft flame set to neutral.

Reducing joint

Bell branch

Figure 3 Bronze welded joints © European Copper Institute

Alternatives to the blowtorch In situations where the use of a blow-torch might result in damage to the building fabric you could consider alternative methods of heating for small diameter joints. One alternative to consider is an electric hot air gun, especially if an attachment is used which directs the flow of hot air around the tube. This has the result of both protecting the building fabric and also speeding up the heating process. Another method is to use an electric resistance

Finishing off Once the joint has been made it is important to allow it to cool so that the solder has solidified before any disturbance. It is also important to remove any residue of flux from the outside of the tube by wiping with a wet cloth and warm water. The pipeline should also be flushed with warm water as soon as practicable to wash out flux residues from the bore. This is especially important on heating systems, if flux is allowed to remain in the system it can set up localised corrosion cells in the bottom of heat emitters. Slip fittings Where it is necessary to break into an existing installation for repair or to insert a new branch ‘slip’, couplings and tees are available.They have no tube stop and make the job much easier without disturbing the rest of the installation. It is a good idea to mark the tube so that the fitting can be correctly positioned to ensure a full capillary contact at both ends. Site formed joints for brazing The force of capillary attraction depends on having an even controlled gap. Because of this it is necessary to use special forming tools, see Figure 2, to prepare site formed sockets and branches directly on copper tube for brazing. Because brazing requires the copper to be heated to a dull red heat it is important to consider the effect on the tensile strength of the tube. Localised softening can result and so the maximum working pressure will be reduced.

Jointing Copper Tubes Compression Joints

Compression ring

After tightening

coiled condition EN 1057 half hard thick wall tube formerly Table Y.

Jointing method for type 'A' non-manipulative compression joints The jointing method for a type 'A' joint, illustrated in Figure 1, simply consists of Before tightening selecting the correct sized fitting for the tube, cutting the Figure 1 Type 'A' non-manipulative compression joint tube to the correct length, removing any burrs and checking that the tube end is ompression joints are made clean and free from deep scores or other mechanically by compressing a imperfections. If the tube end is oval it sealing, or compression ring, should be re-rounded with a suitable on to the tube. Unlike capillary tool. Now the tube can be fully inserted joints they do not require the application into the fitting until it makes contact with of heat. the tube stop. Next tighten in accordance with the manufacturers Types of joint instructions. For example:- tighten the There are two basic types of compression nut by hand and a spanner compression joints for use on copper until the compression ring grips the tube, tube to EN 1057. Type 'A' or non- so that it cannot be rotated by hand in manipulative soft joints, for general use the fitting. Now further tighten the nut above ground on half-hard condition. one third to two thirds of a turn using Type 'A' joints can also be used on two spanners, this is to cause the stainless steel tube to EN 10312 compression ring to bite into and slightly The type 'B' or manipulative joint, is for deform the tube. use underground or above ground on soft

Assembled joint Adaptor Flared tube end Compensating ring Compression nut

Figure 2 Type 'B' manipulative compression joint ÂŠ European Copper Institute

Points to bear in mind when using compression joints 1. Don't allow the jointing surfaces and threads to become dirty or full of grit. 2. A little light oil on the threads of larger sized fittings will reduce the turning force (torque) required to make the joint. 3. Over-tightening the joint will not result in a stronger joint. 4. Beware of using a short wrench with wide opening jaws on large diameter fittings, it will not have sufficient leverage. A spanner at least 750mm long is needed to tighten a 54mm diameter joint. 5. Jointing compound is not normally necessary or recommended on compression ends, however a thin smear can be used on the jointing surfaces (not the threads) if a slight weep occurs. Also, remember that an internal support or liner is recommended if using type 'A' non-manipulative compression joints on soft coiled copper tube of over 12mm OD. Similarly on polyethylene tube always use a liner of the correct type and diameter to support the tube wall when using a type 'A' compression joint. Jointing method for type 'B' manipulative compression joints The type 'B' joint, as shown in Figure 2, is designed to grip both the inner and outer surfaces of the tube, this results in a joint which can both support and tightly grip the soft condition tube for which it is designed.The jointing method consists of ensuring that the tube is of the correct specification and that the correct size of fitting is being used, next 37

Faces parallel after tightening Tube

Compression ring

5 2

Tightening sequence

Figure 3 Large diameter compression joint the tube is cut to length using a fine toothed hacksaw and the burrs moved inside and out. Slip the compression nut and compensating ring over the tube end and hammer the correct sized flaring tool or drift into the end of the tube to open out the end. Next check that the adaptor fits correctly into the end of the tube and the fitting body and tighten the compression nut first by hand and then with a spanner for about one full turn to produce a strong and leak-proof joint. Use of compression joints on pipelines carrying Natural Gas Copper tube up to 42mm OD can be used to carry Natural Gas. Compression fittings to EN 1254 can be used to joint the tube provided they are readily accessible and not buried in the structure of the building. Large diameter compression joints To obtain a secure joint on large diameter compression fittings without requiring excessively large spanners a slightly different method of tightening is used. A series of bolts and/or nuts are spaced around the joint to tighten it, as in Figure 3. To obtain a secure joint once the fitting is correctly positioned on to the tube, first tighten the bolts evenly by hand ensuring the flanges are parallel. Then further tighten them a minimum of two full turns in half turn stages working on diagonally opposite bolts in turn so that the backing flange and the face of the fitting body is kept parallel. ÂŠ European Copper Institute

Occasional disconnection Where tube is to be connected to appliances or components that require only occasional disconnection for maintenance or repair it makes sense to use a type 'A' compression joint. These can be easily de-mounted and reconnected occasionally without damage. Where regular disconnection for servicing is required it is better to use a proper ground-force union type joint as these enable frequent disconnection without damage or leakage.

Choice of jointing system When choosing from the various jointing systems available for use with copper tube the installer / specifier must consider many factors. Copper tube is durable, strong and resists damage and corrosion. The jointing method to be employed must also have these same properties if the customer is to have the benefit of a trouble-free, worry-free, healthy and safe installation. The installed cost of a copper installation is very competitive. If one adds in the intrinsic advantages of the metal - itâ&#x20AC;&#x2122;s resistance to corrosion and high water pressures even in high temperature environments and it's freedom from long term degradation it's easy to see why a copper system adds up to peace of mind.

Plastic push-fit joints These joints also use the compression principle. The traditional compression joint uses a compression ring to both seal and mechanically fix the tube. In the push-fit joint these two tasks are performed by separate components. The water seal is made by a rubber sealing ring which is squeezed between the fitting body and the tube. A specially shaped toothed grabring allows the tube to be easily pushed into the fitting. Once inserted the water pressure, or other forces, are resisted by the teeth of the grab-ring.Take care if you decide to use this type of joint on copper tube.You could affect the integrity of the supplementary earth continuity bonding if you fit this type of joint because the plastic body will act as an electrical insulator between the two ends of the Figure copper tube.

Plastic body Grab ring Washer O-ring

4 Pushâ&#x20AC;&#x201C;fit joint 38

Jointing Copper to Dissimilar Materials

he vast majority of plumbing and heating installations make use of copper tube and fittings for water and gas services. However, many other materials have been, and continue to be used to manufacture tube and fittings.This article describes and illustrates some methods of jointing copper tube to other materials. Connecting tubes made from dissimilar metals Water Regulations require that tubes and fittings made from different types of metals shall not be connected directly together except where galvanic action is unlikely or where effective measures are taken to prevent it. Galvanic Action What can occur when different metals are connected together is that an electric cell or wet battery can be created with water as the electrolyte. Although minute, a current flow causes one metal to corrode and eventually perforate. A common misconception is to say that 'the copper causes the other metal to corrode'. This is not the case, the culprit being the presence of dissolved oxygen in the water.

Sequence of metals As water flows along the tube, galvanic corrosion will not be a problem, provided that the metals follow this sequence of connection: from galvanised steel; to uncoated iron or steel; to lead; then finally to copper. Whatever type of joint is to be made the following can all be regarded as good practice: - use the minimum quantity of jointing material necessary to produce good quality joints; - keep jointing materials clean and free from contamination; - remove any cutting oil if used, as well as protective coatings and clean the surfaces to be jointed; - prevent the entry of surplus materials into the tube bore; - on completion of the joint, remove all excess materials and flush thoroughly. Note: Don't forget that hemp must not be used for drinking water applications, as it supports the growth of microbes and can contaminate the water supply. Use only Water Research Council listed and approved jointing materials.

A lead pipe system requiring repair would be best removed and replaced completely with copper. If a joint has to be made to lead pipe then a "lead-lock" type compression joint can be used.This type of compression joint, shown in Figure 1, makes use of a relatively large rubber compression ring to overcome the problem of the variability of diameter and soft nature of the lead pipe.To make the joint choose a straight section of lead and cut square. If the lead pipe has a raised identification strip this needs to be shaved off before fitting and tightening the joint in accordance with the manufacturer's instructions. If the copper replacement is to be installed underground it should be copper tube to EN 1057 thick wall half hard formerly Table Y - soft coiled copper, preferably plastic coated. EN 1254 Capillary joints or 'CR' marked Type 'B' manipulative compression joints can be used to joint it. If above ground then EN 1057 thin wall half hard formerly Table X tube and EN 1254 capillary or Type 'A' non-manipulative compression joints are usually used.

Connection to lead The Water Regulations prohibit the use of lead for potable water fittings.

Connections to Threaded Galvanised and Plain Steel Tubes Many patterns of capillary and compression fittings are available with both male and female BS pipe threaded ends, a few are shown in Figure 2. These can be used to connect to galvanised and uncoated steel tube. Only use approved sealing paste or the correct type of PTFE tape to make the threaded end of the joint. Only the thicker (0.2mm compared to 0.075mm standard PTFE), denser PTFE tape to EN 751-3 should be used on gas services. It must be wrapped around the thread with a 50% overlap. If the joint is likely to require regular disconnection then a proper ground faced union joint is best, see Figure 2a. A compression joint, Figure 39 2b, will allow

Securing ridges bite into lead R ubber sealing ring Capillary or compression joint

Tighten clamping screw after making seal Shave raised band off lead pipe

Figure 1 Lead to copper mechanical joint ÂŠ European Copper Institute

occasional disconnection. But, if a capillary joint with a threaded end is used to connect directly to the steel tube, as in Figure 2c, it will be difficult to dismantle or remake the threaded joint in the future. Stainless Steel Light gauge stainless steel tube to EN 10312 can be jointed using EN 1254 capillary or compression fittings. Stainless steel can be a difficult material to solder and a phosphoric acid based flux is used. This MUST be used strictly in accordance with the manufacturers instructions and thoroughly flushed out of the tube bore and washed off the outside of the tube after jointing. Because of the care required when soldering stainless steel, compression fittings seem to be the preferred method of jointing. Connecting copper to plastic tubes Provided the correct type of joint is chosen, plastic tube can easily be connected to copper. Polythene, Polyethylene and Polybutylene can all be joined using non-manipulative type 'A' compression joints with metal liners to support the tube wall as in Figure 3. It is very important to select the correct type and size of fitting and liner for the plastic pipe to be joined. Liners are often colour coded by paint marking on the flange. Blue Polyethylene tube (MDPE) to EN 12201 can be laid below ground, it can be jointed with EN 1254 compression fittings. Polyvinyl Chloride When connecting to Unplasticised PVC or Chlorinated PVC it is necessary to solvent weld a fitting with a threaded end to the PVC tube so that an appropriate compression joint can then be used. Oil based jointing compounds Do not use oil based jointing compounds to make joints on plastics. Both the plastic and the jointing compound are made from oil.The oil can

Union enables repeated disconnection

Compression joint allows occasional disconnection

Plain connector, disconnection difficult

Figure 2

Male & Female Connectors

Compression ring Liner

After tightening ring bites into soft plastic

Before tightening Figure 3 Typical type 'A ' non-manipulative compression joint with liner for plastic tube break down the plastic, in effect softening it so that the joint can fail after a short time. Use only PTFE tape, fibre washers or rubber rings to form a seal on plastic materials.

ÂŠ European Copper Institute

Copper in Medical Gases and Vacuum Systems

opper tube joined using capillary fittings is the preferred material for use with medical gas and vacuum suction pipelines. Medical gases are used extensively throughout hospitals, they usually comprise the following services: oxygen, medical compressed air, (oil and moisture free), vacuum suction, nitrous oxide, oxygen/nitrous oxide mixture, (O2 / N2 O). Oxygen and vacuum suction are used extensively in accident and emergency units and out-patient units; in-patient wards, operating theatre suites and maternity units. Vacuum and compressed air are used in dental surgeries and operating theatres for patient ventilators and powering surgical tools. Nitrous oxide is piped to operating theatre suites, maternity units and accident and emergency units. Also, oxygen/nitrous oxide mixture is piped to maternity delivery rooms. Health Technical Memorandum 2022 and Model Engineering Specification C11 are the standards covering this work and manufacturers can supply the specially

Table 1 Medical gas service names and identification symbols Service name

Identification symbol

Colour as shown on BS 1710 (except vacuum)

Oxygen

White

Nitrous oxide

N2O

French blue

Oxygen / nitrous oxide mixture, 50%V/V

O2/N2O

White and french blue

Medical air (or air) 400kPa

MA-4 Black and white

Medical air (or air) 700kPa and above

MA-7

Vacuum

VAC

Primrose

Surgical Nitrogen

Black

cleaned and degreased EN 1057 copper tube, and fittings, necessary on request. The tube is cleaned by a variety of methods including combinations of steam cleaning and drying, shot blasting, solvent degreasing followed by blowing through with medical quality air and visual inspection. Once cleaned and degreased the manufacturer fits plastic Copper tail to enable fluxless site brazed connection end caps to the tube to prevent contamination of the bore before bundling First fix terminal block and labelling "medical gas Pin index holes ensure correct socket assembly and position of holes is determined by service pipes". Fittings and valves, Spacer (preferably lever-operated ball type) are supplied cleaned and degreased in sealed, similarly labelled Exploded view of typical terminal assembly plastics bags. Housing assembly Socket assembly with mating pins on back Diameter of outlet varies according to service

Figure 1 ÂŠ European Copper Institute

Site installation and jointing Incorrect gas connections can create a hazard to the life of a patient so all medical gas cylinder and

terminal connections are gas specific. Cylinder connections use a pin index system to EN ISO 407. At the end of the pipelines a pin indexed terminal block is used for first fixing. A socket assembly with a plug-in bayonet facility designed to BS 5682 is bolted on as a second fix, see Figure 1. Great care needs to be taken to ensure that no crossconnections are made between the various gases when installing pipelines and these should be identified in accordance with BS 1710, see Table 1. Before 1982, medical gas pipelines were installed using a fluxed brazing technique. This caused internal contamination of the pipelines by flux residues, oxide deposits and verdigris. Some of these were not always removed during commissioning operations but became loose later to cause problems with terminal units and equipment. Because of this, all on site medical gas installation work must therefore be planned to make use of copper-tocopper joints using carbon dioxide as an internal shield gas in a fluxless brazing 41

Table 2 Carbon dioxide purge times, in seconds per 100m of tube Tube dia (mm)

Time

110

180

Supply pressure regulator set at 4 bar, flow rate 100 l/min process, (using EN 1044 type CP1 alloy, 80% copper, 15% silver, 5% phosphorous). Carbon dioxide is used because the cylinders have a different connector from other medical gases and this prevents the possibility of cross-connection. Purging before brazing Connect a supply of carbon dioxide (CO2 ) to the pre-assembled, unbrazed pipework through a pressure regulator, (set to 4 bar) and flow indicator, (able to read to 100 l/min). Then purge to remove air, see Table 2 for estimated purge times.The purge gas flow can then be reduced to 1 to 2 l/min to save gas whilst brazing is carried out. Safety Precautions need to be taken if working for prolonged periods in confined spaces to avoid the build up of CO2 , see Table 3 for effects. This can be achieved by ventilation or piping the waste gas out of the space. Note that CO2 is heavier than air so do not vent to an enclosed space at a lower level. The theoretical safe limit of CO2 for an 8 hour day is 0.5%, but up to 4% can be tolerated for a short period, however changes in breathing rate may be experienced.

Copper to brass joints Where copper is to be braze jointed to brass, gunmetal or bronze terminal fittings the joints are usually made using a copper-silver-zinc alloy and a suitable flux. This means that sub-assemblies, such as terminal fittings should be brazed up with a copper tail before cleaning, degreasing and bagging to the required standard. This involves immersion in hot water and brushing with stainless steel wire brushes to remove flux residues, followed by oxide removal by immersion in a 5-10% sulphuric acid solution at 65°C to which 25 to 50g/litre of potassium dichromate has been added, and final rinsing in hot water at 80°C. This should result in a bright clean component. Mechanical joints Where pipelines connect to valves and control equipment compression joints or screwed fittings are allowed, the threads being sealed using unsintered (degreased) PTFE tape. Inspection and testing Once the installation of tube is complete a proportion of site brazed joints, (1:200, minimum 2 maximum 5) will have to be cut out and quartered to establish the quality of workmanship.

Table 3 Effect of increased carbon dioxide levels

0.03%

Normal atmospheric level - no ef fect.

Slight increase in breathing rate.

Breathing rate increases plus headache.

Breathing laboured, headache, reduction in hearing ability .

4-5%

Signs of intoxication, slight choking feeling.

5-10%

Visual disturbance and confusion, followed by loss of conciousness within minutes. © European Copper Institute

Penetration of brazing alloy Due to tolerances of the capillary gap between tube and fitting, full penetration of the brazing alloy may not always occur, and is not necessary. A sound and mechanically strong brazed joint will result provided that the minimum penetration at any point is at least 3 x the tube wall thickness. The tube and fitting should be internally clean, free from oxides and particulate matter, some heat burnishing of the tube may be apparent, but this is acceptable. Purging carbon dioxide and particulates Once the cut-out joints have been reinstated the pipeline system can be purged with medical air to remove any particulate matter and CO2 .The pipeline system can then be tested by a suitably qualified person for particulates using a paper filter with the flow limited to 1.5 times design maximum flow rate. There should be no visible particles on the filter after a 1 minute test. Carbon dioxide is unlikely to be present in the system after the particulate test, even so every terminal unit has to be tested for residual CO2 . Once purging is complete the system has to be maintained pressurised with medical compressed air until hand-over to the client. Final commissioning, which includes filling and testing each pipeline system with its working gas and terminal fitting connection, to ensure correct identity, gas quality and purity will be supervised by the responsible officer and suitably qualified person.

Jointing procedure:

• • • • • • • • •

cut tube with a wheel cutter, not a hacksaw de-burr the tube, holding the end downwards clean tube and fitting with a plastic scourer, not wire wool assemble the joints connect the shield gas, purge, then reduce the shield gas flow heat the joint quickly add filler metal allow to cool before stopping the shield gas flow cap ends of tube to prevent the ingress of dirt 42

Pipe Freezing

ipe freezing can be a fast, clean and efficient method of carrying out plumbing repairs and piping alterations without having to isolate or drain an entire water piping system. Pipe freezing can be carried out on copper tube and other metallic and plastics piping systems to facilitate extensions to pipework; installing tees to feed additions to systems, such as plumbing in washing machines and dishwashers; central heating repairs and maintenance; exchanging faulty stopvalves and re-washering taps and float valves. Pipe freezing can be carried out on both small and large tube sizes by means of either a refrigeration machine, see Figure 1, or an aerosol spray kit, see Figure 2. Once formed, the internal ice plug can withstand the water pressure enabling a union or compression fitting to be dismantled or the tube to be cut through to fit a tee or service valve without having to search for or turn off a valve or cause a flood. How does it work? Pipe freezing uses the evaporation of a volatile fluid to remove heat from the pipe and its contents to form an ice plug

inside the pipe. Evaporation is the escape of molecules of gas from a liquid and it is this process that requires heat energy creating the cooling effect needed to freeze the water inside the tube. When using an aerosol spray to form the ice plug, the evaporation occurs from the volatile fluid direct into the atmosphere inside an insulated jacket, which is placed around the pipe. This means that, as the process is carried out, the volatile fluid is lost and so the aerosol can has to be replaced or refilled when it is empty. A refrigeration machine, on the other hand, retains the volatile fluid within a closed circuit so that it is not lost during the freezing process. An electric motor drives a pump that compresses the gaseous fluid and a heat exchanger cools this into its liquid state, a valve in the machine controls the liquid flow to the freezer head, which is clamped on to the pipe. When the pipefreezing machine is operated the valve is opened and the liquid flows through a small diameter capillary tube to the freezer head where the volume is increased.This increase in volume allows the liquid pressure to drop and consequently the liquid rapidly evaporates cooling the freezer head,

which in turn cools the pipe to freeze the water and form the ice plug. The vapour then flows back to the pump at a lower pressure via a larger diameter return pipe. Preparations for freezing â&#x20AC;&#x201C; points to note 1. Switch off circulation pump if freezing heating system pipes. 2. Ensure water in pipes is not flowing, and preferably cold. 3. Freeze horizontal pipes where possible - freezing a vertical pipe can cause water movement due to natural convection. 4. Anti-freeze or corrosion inhibitors used in some heating systems can affect freezing times and more aerosol spray will be required. 5. In warm ambient conditions (+25Â°C) more aerosol spray will be required. 6. A flame-free joint is an advantage, particularly if space is limited, so use compression, push-fit or press-fit fittings where possible. Capillary solder joints can also be used, but take care to leave a space of at least 200mm from the fitting to the freeze jacket or freeze head to prevent heat affecting the ice plug.

Figure 1 Typical pipe-freezing machine.

Figure 2 Typical professional aerosol freezer kit.

ÂŠ European Copper Institute

7. When using an aerosol spray in a confined space, it is important to remember that gas is given off during the process and so good ventilation is needed, especially in trenches, cupboards and under floorboards. 8.The use of flames, heat or smoking close to the aerosol spray or freezing jacket can result in noxious fumes being formed. 9. Avoid contact with skin or eyes; use gloves/goggles, as the spray will freeze skin. 10. Remember to fit a temporary electrical earth bond across the work area if cutting through a metal pipe to fit a tee. Freezing method using aerosol spray 1. Place the freeze jacket(s) around the pipe at least 200mm from the work area and tie each end of the jacket tightly with cable ties or string, see Figure 3. Connect the extension tube to the aerosol spray can and freeze jacket following the manufacturer’s instructions carefully. 2. Ventilate the work area and inject the freezing dose into the jacket, again following the manufacturer’s instructions as to the amount to be used and time taken but note that, if liquid escapes from the ends of the jacket whilst freezing, stop for a short time to allow the liquid to evaporate inside the jacket, then resume injecting. 3. Wait for the correct pause period before starting work on the pipe. 4. LEAVE the freezer jacket(s) in place until all work has been completed and checked! 5. Once work is complete, remove freezer jacket(s).The pipe will then thaw in a few minutes. Typical aerosol spray freezing times Tube size (mm)

Piping material Copper & stainless steel Lead & low carbon steel Polythene

15 22 28 15 22 28 15 22

Pause Ice plug time life (mins) (mins) 5 5 10 5 10 15 15 20

30 30 30 30 30 30 45 45

Freezing method using pipe freezing machine 1. If necessary, select and fit the appropriate adapters for the pipe material and diameter to the freeze head(s). 2. Clamp the freeze head(s) to the pipe, see Figure 4. 3. Connect the machine to the electrical supply and switch on. 4. Wait for the correct pause period before starting work on the pipe. 5. LEAVE the machine running and the freeze head(s) in place until all work has been completed and checked! 6. Once work is complete switch off the machine, the pipe will then thaw in a few minutes and the freeze head(s) can be removed. How to check that an ice plug has been formed A problem when freezing a water pipe is that the water could be moving. If the freeze times specified by the freezer makers are to be achieved, the water must be cold and stationary. One way to check when using a pipe-freezing machine is to use a digital temperature probe to measure the temperature of the pipe close to either end of the freeze head. If the water is moving during the freezing process it will be cooled and this will show as a lower temperature on the down-stream probe, giving an indication of any flow and its direction. In humid atmospheres a coating of ‘frost’ will also form on the freeze head and pipe after a period of time once the ice plug has formed. When using an aerosol spray a small quantity of aerosol can be sprayed on to the pipe immediately next to the freeze jacket to determine if an ice plug has formed. If the pipe is sufficiently cold to have formed the plug, then the spray will condense as a white ‘frost’ on the surface of the pipe whist the spray is applied. Figure 3 Disposable freezer kit

Which method is best? Both methods are effective. The aerosol spray method usually forms the ice plug faster, and copper’s good heat conducting properties mean that the ice plug will form more quickly in a copper tube compared to other materials, but the aerosol spray method has a relatively high cost per freeze (because the volatile fluid is lost). Also, once the aerosol is empty one is working against time, as the ice plug will melt in about 30 minutes unless more fluid can be injected into the freezer jacket. The pipe-freezing machine on the other hand has a higher initial purchase cost but low running costs and, provided the electricity supply to the machine is not interrupted, the ice plug can be maintained more or less indefinitely. The pipe-freezing machine is also more ‘ozone-friendly’ as no greenhouse gases are released into the atmosphere when it is used. Another factor to consider is accessibility: with the aerosol freezer it is necessary to be able to fit the insulation jacket all round the pipe, and this can sometimes be difficult where the pipe is installed tight against a wall surface or in a corner; however, the freezer heads used with a pipe freezing machine are specially shaped to fit on to one side of the pipe and can be used even when the pipe is tight against the wall. So, to try to answer the question ‘which freezing method is best?’: if freezing is often needed due to, for example, ineffective or missing servicing valves, then a pipe-freezing machine would probably be an economical option; if pipe freezing is only rarely required then an aerosol kit will probably be adequate. Brian Curry, December 2004.

Figure 4 Freezer head clamped to pipe

Aerosol spray

Systematic Installation of Copper to Save Money Part 1 - Basic Principles

opper is a marvellous material for the professional installer. Easy to bend and join to produce an installation that looks great and gives us pride in our work. Furthermore, by adopting a systematic approach to tube fabrication and installation methods, considerable savings can be made. Savings will result from better use of our labour. By taking as many measurements as possible in one operation, piecemeal, time consuming installation of individual tubes is reduced and cutting lengths can be optimised to minimise waste. This first of two articles explains basic principles that can be used to produce an efficient top quality tube installation every time.

measure and deduct

Where tube runs along a wall between two obstructions two clip allowances must be deducted to obtain the tube C-C length

measure and add

Where tube runs along the outside of an obstruction two clip allowances must be added to obtain the tube C-C length

measure

Where tube passes an obstruction clip allowances cancel out and can be ignored. Simply measure size of obstruction to obtain the tube C-C length.

Figure 2 Fixing clip allowances ÂŠ European Copper Institute

The method is based on two basic principles. First, the ability to determine accurate cutting lengths for tube - cutting lengths

Clip stand off allowance is equal to the distance from the fixing surface to the centre of the tube allowance

Figure 1 that allow for bends, fittings and clip stand off dimensions. Actual lengths of walls and positions of fixed points, such as taptails and other connections are measured. Tube cutting lengths are then easily worked out. Second, an ability to prepare clear, dimensioned single line sketches of the tubes to be fabricated, either by the measurer or by another operative. A chart to facilitate this is the subject of the second half of the article. To enable accurate fabrication of tubes, either from drawings or from actual structures, it is necessary to have a method of determining the actual tube cutting lengths required.

allowance allowance

fixing surface

By measuring the actual length of the wall and then either deducting, adding or ignoring clips the tube centre to centre length is obtained. Where a tube connects to a fixed point and this has been measured to, only one clip needs to be allowed for. Fitting allowances To allow for a fitting and to obtain the tube cutting length, the operative needs to know the measurement from the centre line of the fitting back to the tubestop, see Figure 3. For a typical 15mm elbow this is about 12mm and for a 15mm equal tee it is about 8mm. These measurements are easily determined by measuring the actual pattern of fittings to be used when installing the tube. They can then be deducted from the centre to centre tube length, see Figure 3.

Fixing clip allowances It is necessary to allow for fixing clips to obtain tube centre to centre lengths. The allowance for a clip is the measurement by which the tube centre line is off the fixing surface, see Figure 1. For a typical plastic spacing clip to hold Note: fitting allowances are ALWAYS 15mm tube this allowance is about C-C measurement required 22mm. When allowing for Allowance for tee Allowance for elbow clips on tube fixed to Cutting length of tube walls or other surfaces there are four possibilities. These depend on whether the tube is passing Tube stop / insertion depth between, going around, going past obstructions or connecting to a fixed point, see Figure Figure 3 Fitting allowance and cutting length 2. 45

deducted. A simple example: Figure 4 shows the plan of a wall along which a 15mm copper tube is to be installed using elbows to change direction. First the tube is sketched and each piece is identified. Next, the actual lengths of the walls are measured accurately. Finally cutting lengths are determined before work on the installation commences, see table 1 for method. Where tube is to be bent a similar technique is used. Walls are measured as before and fixing clips allowed for to determine centre to centre lengths. These are then used to set up the tube accurately in the bending machine to enable multiple bends to be made on one piece of tube. Note: as tube is gained when forming simple 90Â° bends no extra need be allowed.The cutting length is determined by adding the centre to centre lengths of the various sections of the tube run. Once the tube has been bent, one end will need to be trimmed to the correct length due to gains from each bend.This can be done when it is installed. A further worked example and a layout chart that can be used as the basis of a simple prefabrication system are discussed in the following article.

ÂŠ European Copper Institute

Table 1 Tube Tube Measured Clip identity diameter length allowance

Fitting Cutting allowance length

400

-2 @ 22

-2 @ 12

332

300

+2 @ 22

-2 @ 12

320

100

-2 @ 12

100

-2 @ 12

300

-2 @ 22

-2 @ 12

232

500

-1 @ 22

-2 @ 12

454

400

300

100 B

300

E F 500

Fitting allowance for elbow = 12mm Allowance for fixing clips = 22mm

Figure 4

Pipe Sizing for Hot and Cold Water Part 2 - Tabulation Method

n Part 1 we looked at the basic principles of pipe sizing. Now to put them into practice we will determine some of the tube diameters required for a proposed refurbishment of a large house into two flats. Each flat containing a kitchen, bathroom, en-suite shower and cloaks WC. Reference numbers The first thing to do is to make a drawing of the proposed pipe layout, preferably on scale plans so that measurements of pipe lengths and changes in level can be shown. Then, number each branch and discharge point that needs to be sized, from the water main or cistern, to give an easy reference. For example the section of tube from the water main to the branch entering

Table 2 Pipe sizing tabulation chart

flat 1 is referenced 1-2, see Figure 5 hot and cold water systems diagram. The reference numbers are then transferred to column 1 on the tabulation chart, see Table 2.

Cloaks Basin spray tap WC cistern

Loading units Next we have to determine the loading units for each referenced pipe, for example: pipe 2-3 serves all the fittings in flat 2 and so has a value of:

Pipe 1-2 serves both flats so the loading unit value will be twice the above, 90 loading units. Pipe 3-4 serves both hot and cold in the shower and bathroom (to give balanced pressures at the shower) as well as hot only in the kitchen and cloaks giving 37 loading units. See Table 4, column 2 for the remainder.

Bathroom 3/4" bath taps 1/2"basin taps WC cistern En-suite Shower Kitchen 1/2" sink taps 15mm w/machine taps

1@0 = 0 1@2 = 2

Total loading units

2 @ 10 = 20 2 @ 1.5 = 3 1@2 = 2

Design flow rate Using Figure 1, from the previous article, we can convert the loading unit values in column 2 into design flow rates and note these in column 3.

2@3 = 6 2@3 = 6 2@3 = 6

Initial mains head available = 30m

Pipe reference

Loading units

Design flow rate (l/s)

Assume tube diameter (mm)

Velocity (m/s)

Head loss (m/m)

Vertical drop(+) or rise(-)

Available head

Effective

Total head loss

Residual head (11-9)

Residual head required at fitting

Final tube diameter (mm)

7.96

-4

26.00

18.04

Pipe length (m) Actual

1-2

1.15

2.4

0.22

36.2

2-3

0.72

2.5

0.33

20.4

6.73

-3

15.04

8.31

3-4

0.64

2.1

0.25

8.31

5.31

4-5

20.5

0.45

1.5

0.13

3.5

1.17

5.31

4.14

5-6

14.5

0.38

1.2

0.09

0.27

-1.5

2.64

2.37

6-7

11.5

0.32

2.3

0.48

1.44

+0.8

3.17

1.73

0.5

7-8

0.3

2.2

0.43

1.5

2.5

1.08

+0.5

2.23

1.16

0.8

5-9

0.2

1.5

0.24

5.5

1.32

4.14

2.82

0.5

ÂŠ European Copper Institute

uvdhwss

diameters we have assumed will actually give us the flow rate mains pressure system we require. flat 2 wb bath wc The initial mains head available is 30m, subtracting the vertical rise of cold branch after PRV 4m for pipe 1-2 we sink w/m cloaks wc gives balanced pressure put 26m available at shower head in column 11 and then subtract the total head loss of 7.96m from column 9. The residual head flat 1 low pressure system for this pipe is thus 18.04m, this figure then goes in column 12. The available head for pipe 2-3 is now found by subtracting the vertical rise, 3m, from the previous residual head to give the new available head, this now being main at 3 bar minimum pressure 15.04m. Again the total head loss Figure 5 Hot & Cold water systems from column 9 is subtracted to give Assumed tube diameter 15+(2x0.6)+(2x10)=36.2m this can the new residual head. This process is For each referenced section of pipe then be noted in column 8. The process repeated for each pipe. Remember to we have to assume a tube diameter.This is then repeated for each referenced run add any vertical drops to the residual is done using Figure 2 from the previous of tube. head figure. See columns 11 and 12 for article and a ruler, align the ruler with the Note: where it is not possible to the remainder. Column 13 is used to tube diameter and flow rate. Check the forecast the numbers of fittings a indicate the minimum residual head water velocity is below 3m/s for cold or percentage (between 10% and 40% required at a discharge point. A typical 2.5m/s for hot. If acceptable note the depending on the complexity) can be shower will require a minimum of 1m velocity in column 5 and the head loss in added to the actual length of tube. head whilst a basin tap needs 0.5m and a m/m in column 6. For example, pipe The total head loss for each pipe can bath tap 0.8m to give a satisfactory reference 1-2 assuming 28mm diameter now be calculated by multiplying the discharge. flowing at 1.15 l/s would give a velocity of effective length in column 8 by the head about 2.4m/s and a head loss of about loss in column 6. For pipe 1-2 this is: 36.2 Final tube diameter 0.22 metres head per metre run. This is x 0.22 = 7.96m total head loss, the result If the residual head at any discharge repeated for each pipe using the goes in column 9 and is repeated for point is less than that required, or if the appropriate part of Figure 2, see columns each pipe. head becomes negative, it is necessary to 4, 5 and 6 for the results. select a larger diameter tube. If there Changes in level seems to be plenty of head available, as Effective length of tube Using column 10 we can now note is the case with pipe reference 5-6 Next we need to consider the actual any changes in level. Rises are shown as supplying the shower, there is scope to length of tube and the resistances of the negative, because head is lost. Drops are consider reducing the diameter, see installed fittings. Pipe 1-2 is 15m long, this positive, as head is gained. For example column 14. is noted in column 7. It has two pipe 1-2 rises 4m from the main to the stopvalves and two bends fitted. branch at 2, this is shown as -4m. Referring to Table 2 and assuming 28mm diameter tube, the bends have an Head pressure effective length of 0.6m each whilst the Using columns 10, 11, 12 and 13 we stopvalves have an effective length of can now assess the available head and 10m giving a total effective length of: residual head to see whether the tube ÂŠ European Copper Institute

Installing Copper Pipework in Suspended Flooring Systems Copper pipework can be found in all types of buildings that use many different construction techniques. One very important aspect of pipework services installation is positioning in floors and ceilings. Joists span from wall to wall and support the floors/ceilings. They can be made from timber, metal or steel reinforced concrete. Copper pipework systems can easily be installed with the various joist options currently used by the building industry. Traditional sawn timber joists Copper pipework has been installed in homes fitted with timber joists for many years. Notching of joists to accommodate the tube is a simple exercise but a strict set of rules apply as to the width, depth and position of notches. Traditional timber joists are installed using C16 or C24 strength graded timber (timber that has been visually selected so that it does not have large knots, shakes, splits or is warped). This means that the timbersâ&#x20AC;&#x2122; load bearing capacity can be predicted more accurately. Consequently floors and structures that are correctly specified and installed will be safe. Also there is sufficient safety margin that properly designed holes and notches can be cut into the joists without impairing the safety factor significantly (see Figure 1).

Holes must be drilled with their centres on the neutral axis (the horizontal centreline) of the joist. It is acceptable to drill holes in a zone that begins at 0.25 of the span, and extends to 0.4 of the span measured from the edge of the joist bearing surface. The maximum diameter of any hole is 1â &#x201E;4 of the depth of the joist and, where more than one hole is to be drilled, the holes must be at least 3 diameters apart. If the joist is to have notches cut into its top surface, then the maximum depth of any notch is 1/8 of the depth of the joist. It is acceptable to cut notches into the joist in a zone that begins at 0.07 of the span, and extends to 0.25 of the span measured from the edge of the joist bearing surface. Joist clips, which comprise a zinccoated steel plate on top of a plastics moulded body (see Figure 2), can be used to secure tube in the notch and will help to prevent noises due to creaking floorboards, and punctures of the tube due to nails and screws. Note: Notches or holes must NOT be cut or drilled in roof rafters or in joists that are 100mm deep or less, or in the bottom surface of any joist.

Timber-metal-web floor joist system The open web design of timbermetal-web joist systems (see Figure 3) allows for easier and more flexible installation of services than is possible with traditional timber joists. However, it is essential that any copper services are installed without cutting, notching, drilling, or removing any timber or metal web components of the joists or any strongback beams, (which are fitted across the centre of spans of 4 metres or over to stiffen the floor structure). Piped services can be supported by fixing their supports to the timber components of the joist (see Figure 4).

Figure 3: Timber-metal-web floor joist system Brackets screwed to timber

Figure 2:Typical joist clips

Span S

Figure 4: Supporting piped services in timber-metal-web joists

Neutral axis

0.4 S

0.25 S

0.07 S Max depth of notch d/8

Holes in this zone

Depth d

Not less than 3 dia's apart centre to centre. Max dia of holes d/4

Notches should be in this zone.

Engineered timber joist systems Engineered timber joist systems are manufactured from glued wood fibres; the joists comprise a vertical web, which is the main weight carrying component, with rebated laminated timber reinforcing flanges glued along the top and bottom of the web to form an I-beam (see Figure 5).

Figure 1: Recommended location of holes and notches in traditional timber joists ÂŠ European Copper Institute

Where beams or trimmer joists have to be incorporated into the floor, these are solid made from laminated-strand or stronger parallel-strand wood fibres. Joints between the floor components are made by metal joist connectors. When installing copper pipework services into engineered timber joists, do not drill holes in or cut any cantilever reinforcement, or cut or notch the joist flanges. Where possible use the pre-stamped knockout holes to run services through the joists. These knockout holes are 38mm in diameter and located at 300mm centres along the length of the joists. If the knockout holes are not suitable, then further holes can be cut in the joist web provided they fall within the areas as specified by the joist manufacturer, typically as shown in Figure 6. It is also important to check the location of the joists before cutting through the floor covering, otherwise you may inadvertently cut the joist flanges, which could then impair the integrity of the floor!

Steel joists The open web design of lightweight fabricated steel joists (see Figure 7) allows for easier and more flexible installation of services than is possible with traditional timber joists. However, as with timbermetal-web joists, it is essential that any copper services are installed without cutting or removing any metal components.

Figure 7: Typical lightweight fabricated steel joists Cellular steel joists (see Figure 8) are formed with circular holes in the web and copper pipework services can be run through these holes (see Figure 9) but again without cutting or removing any metal components.

Hanger brackets

Figure 9: Supporting piped services in cellular steel joists Pre-cast concrete beam and block floors Pre-cast concrete beam and block floors (see Figure 10) can be used for both ground and upper floors. A typical beam is 150mm deep and is made from high strength concrete reinforced with 5mm diameter pre-stressed steel wires. The space between the beams is infilled with solid or hollow concrete or polystyrene blocks and these are then covered with a screed which is typically 65mm deep. Individual infill blocks can be omitted where vertical services have to pass through the floor and horizontal run–outs can be installed in accordance with regulations in ducts or in certain circumstances directly in the screed. However, the pre-cast beams must not be cut, otherwise the structural integrity of the floor will be damaged!

Figure 8: Typical lightweight cellular steel joists

Figure 5: Engineered timber joist system

Typical laminated strand beam

Maximum 50mm diameter / depth / depth 1/3 depth 1 3

Allowed hole zone

1 3

2 x diameter of the largest hole (minimum)

Maximum 50mm diameter

Parallel strand beam

/ depth / depth / depth

1 3

Allowed hole zone

1 3 1 3

1 3

2 x diameter of the largest hole (minimum)

Typical engineered timber joist 150

150

Maximum hole size 38mm in cantilever

Figure 10: Typical concrete beam and block floor Copper pipework services can be installed in buildings fabricated using modern building techniques and products. Providing the rules relating to each of the joist types are followed, copper pipework can be successfully installed. B Curry, February 2009

Do NOT cut or notch joist flanges

150

Do not cut holes in hatched areas near to joist supports

38mm knockout holes 2 x diameter of the 2 x longest side of largest hole (min) largest rectangular including knockout holes hole (minimum)

See joist manufacturer’s data sheet for minimum distance of hole from joist support

Planning and Positioning of Pipework

hen deciding on the most suitable location for pipe runs the designer / installer will have to take into account the wishes of the client for a reliable, quality installation, usually with (at least in domestic situations) minimum amounts of tube visible, and that the work is carried out at minimum cost. These wishes will have to be balanced against the requirements of the various standards and statutes that govern our work, such as the Water Regulations or the Gas Safety (Installation and Use) Regulations. The

competent installer will also take the trouble to make the work as neat and visually pleasing as possible with even spacings for tube supports and even gaps between different lines and with the tube fixed plumb and level or laid to the correct fall. Regulations and Standards These demand that tube is installed so that it is reasonably accessible for inspection and testing as well as maintenance and repair. They also prohibit the installation of tube in situations where there is a danger of

Solid or cavity wall

Cement mortar

Pipes in solid floors

Flexible mastic

Sleeve Tube Flexible mastic Consider extending sleeve above floor in areas like kitchens

Pipes in walls Pipe in chase

Internal partition Only permitted if water pipe is part of closed circuit heating

Solid wall

Removable cover Pipe in purpose made duct

Surface finish

Pipes run close to panel under bath

Pipes in suspended floors

Insulated if under ground floor Access points required at 2m intervals and at every joint for inspection purposes

Figure 1 Examples of ducts and chases ÂŠ European Copper Institute

Sleeve

Figure 2 Sealing of sleeves

Recommended practice

Only permitted if no joints are enclosed and water pipe can be withdrawn for e xamination

Solid floor

damage or of leaks failing to be discovered. Damage could be either to the structure, through weakening or by reducing its fire resistance; or the tube, by movement; or its contents, by contamination. The customersâ&#x20AC;&#x2122; demands that minimum amounts of tube are visible means that hidden pipework often has to be installed in chases and ducts and typical details of recommended practice for water services are illustrated in Figure 1. The basic principles behind the design of chases and ducts are that: any leaks, however unlikely, will become apparent, and in the case of gas services, that a dangerous build-up of gas/air mixture cannot develop; where a leak could remain undetected for long periods more particular care has to be 51

Sleeving Where tube passes through brick or block walls or solid floors it should be sleeved. When installing copper tube in these situations it is normal practice to use another piece of copper tube as the sleeve. For tubes up to 80mm diameter the internal bore of the sleeve should be at least 6mm larger than the outside diameter of the tube. For tubes over 80mm diameter the sleeve bore should be at least 25mm greater. It is important to ensure that the sleeve is correctly built into the structure and the annular gap between the sleeve and the tube is concentric and that at least one end of the gap between the tube and sleeve is sealed with approved mastic.This should permit the tube to move whilst at the same time maintaining the fire resistant properties of the structure and preventing water, gas or vermin passing through the gap. See Figure 2 for details. Servicing and appliance shut-off valves Where regular maintenance of equipment and fittings has to take place the regulations require that servicing valves are fitted, this is both to facilitate maintenance and to reduce the loss of water when draining down. Obviously, these must be readily accessible for operation. Screwdriver operated servicing valves are required on service pipes feeding float operated valves such as in WC cisterns and storage cisterns. Servicing valves must also be installed on cistern fed supplies if the cistern is over 18 litres capacity. On combination cylinder units it is not normally possible to fit the servicing valve between the cistern and cylinder. In this case the servicing valve is required on the outlet pipe(s) from the cylinder. Using servicing valves with swivel outlets will enable easy disconnection on water services. An appliance shut-off valve is required on the inlet to gas appliances. ÂŠ European Copper Institute

Installation pipe

Screwdriver operated

Appliance connector

taken, for example, where pipes are installed under ground-floor level; where continuous flooring is used, such as flooring chipboard, properly formed openings with covers that are easily removable should be provided at changes of direction, including tees; where pipes have to be insulated then they should be insulated in accordance with laid down standards.

Cistern over 18L capacity

Gas Appliance Union Appliance shutoff valve

servicing valve

Servicing Valves

Circulator

Figure 3 Servicing Valve Locations This is usually a plug cock with a union to enable disconnection for servicing. Make sure you install these the correct way round, with the union on the outlet and always remember to cap or plug the outlet when it is disconnected! Use of plastic coated copper tube Where gas pipes or closed circuit central heating pipes are to be buried in solid floors it makes sense to use plastic coated copper tube. This is available in half-hard temper straight lengths as well as soft coiled. The plastic coating gives a degree of insulation as well as protecting the tube. Use yellow ochre coloured plastic coated tube for gas and green or blue for water as an aid to tube identification.

Plastics Covered and Chrome-Plated Copper Plastics covered copper tube Plastics covered copper tube has many uses in plumbing and heating systems and is specified in EN 13349. It comprises either half hard (R250 condition) or hard (R290 condition) straight lengths, or soft condition (R220) coiled copper tube, to EN 1057 covered with either Low Density Polyethylene or Polyvinyl chloride. The complete impermeability of copper tube and the external protection of the plastics covering means that water supply pipes can pass through contaminated ground without compromising the quality of the water. Where solid floor or wall construction is encountered, plastics covered tube can be installed in the structure in accordance with the Water Regulations, either buried in the walls or in the screed (with few or no joints) by using coiled soft copper tube, which is available in lengths up to 50m. The plastics covering is formed around the copper without a seam, this provides a reliable continuous protective coating.The covering is available in either solid or castellated pattern, see Figure 1. The castellated pattern gives a number of advantages: noise transmission is reduced, some lateral expansion can be

Plain covering

accommodated and a lower surface temperature than that of the fluid being transported. This can be particularly useful on jobs where low surface temperature heat emitters are specified. As well as providing a tube suitable for buried services in corrosive environments, the plastics covering can be colour coded to aid fluid identification: blue or green for water, yellow ochre for fuel gases and white as a neutral colour for other services, such as central heating lines.

Bending plastics covered copper tube Normal internal bending springs can be used to support the tube walls for hand bending, and formers and guides are also available that accommodate the increased overall tube diameter to enable plastics covered tube to be machine bent easily using standard techniques. The suitability of tooling depends on the size and temper of the tube to be manipulated. Machine bending on castellated covered tube is not recommended above 15mm. For detailed advice consult the relevant tube manufacturerâ&#x20AC;&#x2122;s literature.

Castellated covering

Jointing plastics covered copper tube Whether using capillary, compression, push-fit or press fittings, the tube should be cut with a pipe cutter (or with a fine tooth hacksaw) and then deburred both inside and outside as necessary. When jointing using capillary fittings, the plastics covering should be slit lengthways with a sharp knife and folded back about 100 to 150mm, see Figure 2. When heating, care should be taken not to allow the flame of the blowtorch to come into contact with the plastics covering. It is recommended that the end of the plastic and part of the exposed copper be wrapped with a wet rag, to prevent over-heating and possible damage. As usual, when soldering capillary fittings, the use of excess flux should be avoided. Flux the outside surface of the tube only (not the inside of the fitting), twist the tube slightly as the fitting is pushed on to it, and remove any residual flux both to prevent unsightly stains, or in extreme cases corrosion of the pipework, which could occur if the excess flux were to run down the tube and into the spaces between the copper and the castellated plastics covering.

Fold back covering and protect with a wet cloth whilst capillary soldering

Copper tube Air spaces Copper tube Figure 1 ÂŠ European Copper Institute

Slit plastics covering Figure 2 53

When using compression fittings the plastics covering should be cut all round and removed, see Figure 3. This is to permit entry of the copper tube up to the tube stop in the body of the fitting; and, for manipulative (type B) fittings, for the tube end to be flared. Do not slit the covering lengthwise when using compression, push-fit or press fittings as this may create a lengthwise score along the copper’s surface and this could prevent the ‘O’ ring from making a complete seal. When jointing is complete it is essential that any cut and folded plastics coverings are returned to their original positions and the lengthways cut and any exposed tube and fitting are carefully and completely protected by spirally wrapping the joint with self-adhesive Figure 3

generally half hard copper; R250, to EN 1057 - chrome plated in accordance with EN ISO 1456, usually to Service Condition 2. Matching chrome plated capillary, compression, push-fit and press fittings are also available. To maintain the decorative finish of the product the copper tube is not always engraved. As chromium cannot be directly electrodeposited on to copper with satisfactory adhesion, a preparatory layer (10µm nominal thickness) of nickel is deposited before the finishing layer of chromium (0.3µm) is applied. Bending chrome plated copper tube Chrome plated tubes are suitable for cold bending in the ‘as supplied’ condition using appropriately sized springs or

Figure 4

Slit all round plastics covering and remove

Wrap with tape to prevent moisture entering through cuts in plastics covering

polyethylene or PVC waterproof tape, see Figure 4. Moisture should be prevented from entering the channels in castellated plastics coverings at positions where the covering has been terminated. Particular care should be taken to prevent run-off water from fresh concrete (concrete latency water) from entering the spaces as this can corrode or crack copper. Moisture can be prevented from entering the gap by the application of a suitable waterproof adhesive plastic tape over the last 25mm or so of plastics covering and a similar length of the immediately adjacent bare copper tube, see Figure 5.

bending machine formers and guides. Chrome plated tube must not be annealed as the heating process will damage the finish. When using a bending machine, care should be taken not to damage the chrome surface, by ensuring that the equipment used is in good condition. A lubricant (thin oil) can be used on the former and guide to ease bending. The inside surfaces of both the

former and guide should also be clean and unmarked by scratches or dents, otherwise surface marks will occur when the tube is bent. Capillary jointing chrome plated copper tube It is essential to remove the chrome plating in order to solder capillary fittings. This is not an easy task as care must be taken not to remove too much metal; otherwise the capillary gap may become too large for a leak-tight joint to be made.The most effective tool to use is a fine-toothed flat file. Carefully file off the chrome until bare copper is visible all the way round the tube for the full insertion depth of the fitting.The remainder of the jointing process is the same as for plain tube and capillary fittings except that a damp rag should be wrapped around the tubes close to the fitting so that the heat of the blowtorch flame does not damage the chrome plating. Compression jointing chrome plated copper tube When making hand-tightened compression joints with chrome plated tubes, the relatively hard nature of the chrome plating, compared to plain copper tube, means that it is necessary to increase the torque (pressure) used when tightening the fitting with spanners to ensure a sound joint. Push-fit fittings with chrome plated copper tube It is sometimes necessary to use a special scribing tool to create a scored mark in the correct position all around the tube, see Figure 6. This is to enable the grab ring to grip effectively on to the tube. © B Curry, July 2005.

Figure 5

Figure 6

Wrap all exposed ends of plastics covering with tape to prevent moisture entering

Score all round chrome with scribing tool to enable grab ring to bite

Chrome plated copper tube Chrome plated tube is usually used on surface fixed applications where a decorative finish is required. It is © European Copper Institute

Copper Pressure Piping Systems

opper tube for Table 1 Design stress values (N/mm 2 ) for solid drawn copper tubes (See BS 1306 for copper alloy tubes) domestic water Values of design stress for metal temperatures services at temp- Material Designation EN 12449 Condition Tensile not exceeding strength eratures up to 110°C (min.) -200 to is manufactured to EN 1057. 100 C 150 C 175 C 200 C +50 C However, 110°C is not the 2 Annealed O 200 41 40 34 26 18 maximum temperature to which copper can be subjected Light drawn 2 250 62 59 55 34 18 in service. Indeed, copper tube, Copper Cu-DHP 1/2H (EN 12449) and copper alloys, 2 As drawn M 280 70 69 55 34 18 correctly installed and jointed, are ideal materials to use for all irrespective of wall thickness generally These do not require the use of a flux as the following industrial and marine allow for a variance of ±10% of any the phosphorus content will remove the pressure piping systems: oxide film. If 1/2H, or as drawn M, specified wall thickness. Where copper tube is to be used for condition tube is heated to temperatures - steam boiler, feed and hot water; steam or condenser water services at >600°C during fabrication or jointing the - hydraulic (water or oil); temperatures of up to 205°C and annealed, O condition values for design - oil fuel; working pressures of up to 17bar, stress should be used. - pneumatic and gas; suitable thicknesses are shown in Table 2. - refrigeration and cryogenic; Table 2 Copper tube for steam services with plain Joints at temperatures from -200°C to Tube can be joined by ends EN12449 +200°C where required. welding, brazing, soldering High pressure Low pressure range or mechanical methods, range The specification for copper and copper provided the type of joint Working pressure Working pressure alloy pressure piping systems is BS 1306. used is suitable for the up to and including up to and including This standard covers the design, tube material, pipeline fluid 7 bar, max working 17 bar, max o installation and inspection of the systems carried, its pressure and temperature 205 C working Size of mentioned above. temperature, and has temperature 205 oC tube the mechanical strength (mm) Thickness (mm) Thickness (mm) Design pressure required under service 6 0.8 0.8 To determine the required wall thickness conditions. 8 0.8 0.8 for a particular diameter of straight tube, Brazing is often used the formula is: where the maximum 10 0.8 0.8 pd working temperature does 12 0.8 0.8 t = ----not exceed 200°C. Socket 15 1.0 1.0 p+20F type capillary joints and 18 1.0 1.0 Where: flanges made from copper t is the minimum tube wall thickness alloy are brazed with 22 1.2 1.2 (mm); EN 1044 group AG silver 28 1.2 1.5 p is the design pressure (bar); brazing alloys as the filler 35 1.5 2.0 d is the outside diameter of the tube metal. This requires the 42 1.5 2.0 (mm); use of a suitable flux. F is the design stress (N/mm2), at the Where both fittings and 54 2.0 3.0 maximum working temperature, and is tube are made from 67 2.0 3.5 obtained from Table 1. copper, EN 1044 group 76.1 2.0 4.0 It should be noted, however, that CP copper-phosphorus 108 2.5 5.0 tube manufacturers’ tolerances brazing alloys can be used. © European Copper Institute

Pressure Testing Piping Systems Where water is unacceptable in the pipework, then a pneumatic leak test followed by a pneumatic pressure test could be carried out, but both employers and employees must be aware of their statutory duties with regard to the Health and Safety at Work Act. This requires employers to provide sufficient information, instruction, training, supervision and a safe working environment, and employees not to carry out the test in a way that endangers themselves or others.

ressure testing of pipelines should normally be carried out using water. Only in exceptional circumstances should pneumatic pressure testing using compressed inert gas or air be used, and then only under carefully controlled conditions. The reason for this is because water is virtually incompressible (as are other liquids) and only a small quantity of energy needs to be introduced to increase the pressure significantly. Air, however, (like all gases) is compressible and, as a result, much more energy has to be put into the gas to raise its pressure. In fact, at the pressure ranges normally used for testing water-piping systems 200 times more energy is stored in compressed gas compared to water at the same pressure and volume. So, should a joint, pipe, or any other component fail under test pressure when using compressed gas, the energy can be released with deadly force! However, where water leakage would cause unacceptable damage to property, a pneumatic leak test (at say 5kPA 20mbar) can be used first, followed by a hydraulic leak test.

The test requirement Water Regulation 12 requires that: â&#x20AC;&#x153;The water system shall be capable of withstanding an internal water pressure not less than 11/2 times the maximum pressure to which the installation or relevant part is designed to be subjected in operation.â&#x20AC;&#x153; So, for a water piping system that will operate at 3-bar the test pressure will be 3 x 1.5 = 4.5bar. The regulation goes on to state that this requirement shall be deemed to be satisfied in the case of a water system that does NOT include a pipe made of plastics, where the whole system is subjected to the test pressure by pumping, after which the test continues for one hour without further pumping. The test is passed if the pressure in the system is maintained for one hour and there is no visible leakage throughout the test.

Water regulation requirements for valves and testing The UK Water Regulations require that every supply pipe or distributing pipe providing water to premises be fitted with a stopvalve, and that water supply systems shall be capable of being drained down and fitted with an adequate number of servicing valves and drain taps. A sufficient number of stopvalves are also needed for isolating parts of the pipework. Fitting these valves and drain taps will also facilitate hydraulic pressure testing.

So the test on an all metal piping system is quite straightforward, simply carry out a risk assessment, prepare and

Figure 1 Graphs illustrating relationship between system pressure, test pressure and time, for metal and plastics water piping systems.

No drop during test period

Pumping stops and pressure is reduced

Pumping stops

Max. 0.6bar drop period

Metal piping test A

Max. 0.8bar drop period

Pumping stops

Test pressure

Test pressure System pressure

No drop during reduced pressure period

Test pressure

System pressure

Plastics piping test A

Plastics piping test B

1/3

Test pressure 0

0 0 10 20 30 mins. 60

ÂŠ European Copper Institute

0 10 20 30

mins.

120

0 10 20 30

mins.

120

180

pressurise the system to 11/2 times the normal maximum pressure, stop pumping and wait for 1 hour to see if any pressure loss is indicated whilst checking the system for visible signs of leakage. Where the system DOES contain plastics piping, two acceptable tests are described by the regulations: tests ‘A’ and ‘B’, but both are complex and time consuming. In test ‘A’ the whole system is subjected to the test pressure by pumping for 30 minutes, after which the test continues for 90 minutes without further pumping; at the end of the 30 minutes pumping period the pressure is reduced to one third of the test pressure. Test ‘A’ is passed if the pressure does not drop below one third of the test pressure over the following 90 minutes and there is no visible leakage throughout the test. In test ‘B’ the whole system is subjected to the test pressure by pumping for 30 minutes, after which the pressure is noted and the test continues for 150 minutes without further pumping. Test ‘B’ is passed if the drop in pressure is less than 0.6bar (60kPa) after the following 30 minutes, or 0.8bar (80kPa) after the following 150 minutes, and there is no visible leakage throughout the test. These tests are illustrated in Figure 1. Planning for the test Before carrying out a pressure test a risk assessment must be carried out. This needs to consider hazards associated with stored energy, the possibility of blast and its effects, potential missile formation and brittle fracture. A safe system of work also needs to be established (this may require a permit-to-work system, training, use of written procedures, suitable venting arrangements, proper tools and equipment, safety restraints and personal protective equipment etc).

The following factors also need to be considered: • Is the specified test appropriate for the service and the building environment? • Will it be necessary to divide up vertical pipework to limit pressures in high-rise buildings? • Will a water test leave pockets of undrained water that might cause frost damage or corrosion later? • Can the piping, or any in-line fittings and components (valves, bellows, tanks, cylinders, radiators etc) withstand the proposed test pressure? If not, these need to be blanked-off or removed and ‘make-up’ pieces of tube inserted. • If a water leak occurs what damage might be caused, and could minor faults be checked by carrying out a leak test with air or inert gas at 5kPa (20mbar) before filling with water? • Are sufficient people available to keep a progressive check for problems whilst filling the system? • Can different services be interconnected temporarily to enable simultaneous testing? • How long will it take to fill the system using the water supply available, and what is the best time to start the test bearing in mind the duration and time needed to undertake the necessary preparations?

Figure 2 Typical hydraulic test pump

Test preparation • Check that all high points have a tap or vent to facilitate removal of air during filling and that these are all closed. • Blank, plug or seal any open ends and close all valves at the limits of the test section of the piping. • Remove or blank off any vulnerable in-line fittings and components that may be damaged by the test pressure. • Open any valves within the enclosed test section. • Check that the test gauge is functioning correctly, has been calibrated and has the correct range. Attach the test pump, see Figure 2 (fit a separate gauge if necessary, see Figure 3) using suitable adaptor fittings. • Check that a suitable hose is available for draining the system. Hydraulic pressure test procedure 1. Start to fill the piping and then ‘walk’ the route of the piping under test, continuously visually checking for leaks and by listening for the sound of escaping air. 2. Release air from all the high points systematically through the system to completely fill it with water. 3. Once the system is full, raise the pressure to the test pressure and, if a plastics piping system, continue pumping for the specified period.

Figure 3 Typical pressure gauge

4. If the pressure falls, check that stopvalves are not letting by, then walk the system again for leaks. 5. Once the system is proven sound, have the test witnessed if necessary and obtain a signature on the test certificate. 6. After testing release the pressure. If necessary, ensure that any vents on cylinders, tanks, and pressure-vessels are opened to atmosphere BEFORE draining down and refitting vulnerable items. If the system has to carry fluids other than water, it may be necessary to dry out the piping internally by passing hot air through it, (this can take some time to achieve). Testing underground water mains Underground water mains are jointed using a variety of methods including socket and spigot, push-fit and mechanical fittings. The forces that have to be contained within the piping can be considerable so, in addition to the above procedures, the following items are also recommended when pressure testing underground water mains: and test long mains in •sectionsInstalldetermined by agreement with the contractor.

•

Pressure testing must NOT commence until anchor blocks and antisnaking blocks are in position and the trench partially backfilled and rammed (leaving the joints exposed). This is to prevent any movement causing damage due to the pressure inside the piping. Strutting may also be necessary on blanked ends and branches. Testing against valves is best avoided, but in any case check that the valves can withstand the test pressure, if necessary blanking off any valves that cannot. Fill the main slowly and allow any air to escape before beginning to test, and pressurize slowly. Once the main is proved sound, complete backfilling, then perform a final test and obtain a witness signature as necessary.

Pneumatic leak testing at low pressure followed by hydraulic pressure testing Due to the inherent dangers associated with pneumatic testing using compressed air or inert gas, a responsible person must be in charge of this operation at all times. This person should direct the preparations and supervise the application of the test by working to a pre-prepared written plan based on the risk assessment. A written record of the test showing the system designed working pressure, the test pressure and duration should be kept and, at the conclusion of the test, this person must verify that the system is safely depressurised and ready for safe operation at the design working pressure. Preparation Check that all high points have a tap or vent and that these are all closed.

• ends •and useBlank,valvesplugtoorlimitsealtheanytestopen section of piping to about 50 metres in length for up to 50mm bore tube, (to limit the total stored energy). or blank off any vulnerable •in-lineRemove fittings and components that may be damaged by the test pressure. Check that the testing gauge is •functioning correctly, has the correct range, has been calibrated if necessary and connect it to the system using suitable adaptor fittings. Check that all flexible connections •between the compressed air supply (or pump) are securely fastened at both ends to prevent ‘whipping’ should one end become detached. If the compressed air or inert gas is •at a higher pressure than is required for the test (maximum 0.5bar pressure) a pressure reducing valve, pressure gauge and pressure relief valve set to open at the test pressure should be fitted to the connecting pipework. possible, the compressed air •supplyIf should be controlled outside the

Pneumatic leak test procedure 1. Ensure that all rooms through which the piping passes are cleared of people, then pressurise the system to the leak test pressure (normally 20mbar, but a pressure of up to 0.5bar could be used). 2. Wait at least 10 minutes, checking the gauge for pressure drop, and if necessary ‘walk’ the route of the piping under test checking for leaks using leak detecting fluid. 3. Once the leak test is passed, release the air pressure slowly and then carry out the normal hydraulic test as previously described. Pneumatic pressure testing Because pneumatic pressure testing involves higher final pressures, it also involves higher risk, so this method must only be used when hydraulic testing is not practicable. No work should be carried out on the piping during the test. Carry out the test preparations as for the pneumatic leak test, however if the compressed air supply cannot be controlled from outside the test area then the pipework in the test area should be protected (e.g. by use of sandbags) to limit damage if an explosive failure of the piping occurs! Then follow the low-pressure pneumatic leak test procedure as above. After completing the leak test, make sure that all the rooms through which the piping passes are cleared of all people, and gradually increase the air pressure in steps of about 0.5bar up to the required test pressure. Retain the test pressure for 30 minutes and have this pressure and time witnessed. Gradually reduce the pressure through a safe vent point clear of all people to 1.1 times the working pressure, hold this pressure for 30 minutes, then check for leaks (indic-ated by a further fall in pressure) and obtain witness signature on the test certificate. Once the test is complete, gradually release all pressure through a safe vent point clear of all people, refit any vulnerable components and seal the system ready for use. For further information and guidance refer to HMSO publication GS4 Safety in Pressure Testing.

test area. Brian Curry, May 2003.

Copper for Refrigeration Pipelines

opper tube is used on refrigerating systems for the vapour and liquid circulation lines because of its chemical compatibility with refrigerants, (but not ammonia) its total impermeability and ease of jointing, bending and installation. Degreased tube complying with EN 12449 is used, either in soft coiled condition, (for small diameter lines) or half-hard condition in straight lengths. The copper used in tube for refrigerant lines is required to be oxygen-free or de-oxidised.The tube is supplied with its ends fitted with rubber caps to prevent moisture or other contaminants entering and these should be kept in place and used as a temporary seal during installation. Pipe connections EN 378 covers the safety and environmental aspects of the design, construction and installation of refrigeration systems. It requires that joints must not be damaged by the freezing of water on the outside. Soft soldered joints are not suitable for refrigeration pipework. Brazing, carried out to EN 14324 using copper-phosphorous (CP) filler metals complying with EN ISO 17672 is the preferred method for making non-detachable joints. Brazing is necessary to provide strong joints that can withstand the vibration, temperature and thermal cycling stresses imposed. For copper to copper joints, use a low temperature CP brazing alloy. No flux is needed as the vaporised phosphorous will remove the copper oxide film.

Points to note on joint preparation: • use a wheel cutter rather than a hacksaw, (to prevent swarf entering the tube) and remove internal burrs; © European Copper Institute

Throttling valve Freezing compartment

High pressure side

Evaporator coil

Suction line

Liquid line

Compressor

Receiver

Discharge line Condensor coil

Figure 1

•

clean all surfaces with an abrasive plastic scouring pad, (not steel wool as steel particles could enter the tube); • make sure that the tube is properly supported and inserted to the fitting stop and that joint gaps are not too wide, a good close fit is required; • purge the air out of the tube before brazing.

neutral flame. Hold the torch away from the work so that the flame envelope heats the metal evenly keeping the torch moving constantly. This ensures an even heat-up so that when the brazing rod is applied it quickly melts and flows readily to fill the joint. Once the joint is filled remove the flame immediately, do not prolong the jointing operation.

Brazing technique When brazing it is important to heat the whole joint area evenly, so that the filler alloy melts and fills the capillary gap completely to bond the metal surfaces in the joint. Torches designed to burn LPG with air or oxygen are ideal because they give widespread flame. Where an oxyacetylene torch is used, care must be taken to prevent localised overheating, so use a relatively large nozzle set to a soft

Purging refrigerant pipelines whilst brazing When heat is applied to copper in the presence of air, oxides form on the surfaces of the tube. Normally this is not harmful, but oxide scale on the inside of refrigerant pipelines can lead to problems once the refrigerant is circulating in the system. Refrigerants have a scouring effect that will lift the scale from the tubing and this can be 59

carried through the system and help to decompose the compressor lubricating oil and refrigerant - with the result that sludge can form.The formation of oxides when brazing is easily prevented, this is achieved by slowly passing nitrogen through the pipework whilst the heat is being applied. The procedure can be as follows: • connect a nitrogen cylinder to one end of the pipework to be jointed using a regulator set to a low pressure, the far end of the pipework to be open to atmosphere; • turn on the gas and regulate the flow to about 1 to 2 litres per minute, (this flow rate can easily be felt on the back of a moistened hand). The nitrogen should be allowed to flow without building up a pressure in the pipeline. On larger diameter lines a cardboard disk with a small hole punched in it can be fitted into the far end of the line to reduce the volume of gas required; • continue the flow until the joints have cooled.

Table 1 Recommended maximum spacing for single copper tube supports

Tube diameter (mm) and condition

Spacing (m)

15 & 22 soft (R220)

22 to 54 half-hard (R250)

54 to 67 half-hard (R250)

Detachable joints Where detachable joints are used, EN 378 recommends the use of flanges, or non-manipulative compression fittings for tube up to 50mm outside diameter. The Standard suggests that flared, manipulative joints be avoided where reasonably practicable. They are restricted to use on soft condition, annealed tube of a minimum of 9 and a maximum of 19mm outside diameter. Even on tubes in this range they must not be used to connect to expansion valves, (see Figure 1). When tightening any detachable joint make sure that the torque used is correct. It should be sufficient to compress the ring on to the tube to make a leak-proof seal without too much tube deformation. © European Copper Institute

Figure 2

Tie wrap Closed cell foam insulation

Suction line

Liquid line

Rubber lined tube support

Screwed joints The use of other screwed joints is restricted to a maximum of 32mm inside diameter for liquid lines and 40mm inside diameter for vapour lines, PTFE tape can be used to form the seal on the thread. Tube supports All tube needs to be adequately supported, preferably using rubber lined clips to prevent noise and vibration transmission. The maximum recommended spacing for single tubes is shown in table 1. Where small diameter liquid lines are strapped to vapour lines, (see Figure 2) consider reducing the spacings for tube supports.

be carried out using an inert gas to pressurise the system. If the system has only a relatively small number of joints a bubble test on each joint using leak detecting fluid is easy to carry out. If a pressure gauge is used on a large system then sufficient time, (24 hours would not be excessive) must be allowed to enable tiny leaks to show on the gauge.

Strength Pressure Testing Once the refrigeration system installation work is complete EN 378 requires it to be tested for mechanical strength. This can be by means of hydrostatic pressure to between 1 and 1.3 times the system design pressure. Water could be used, but this is not normally desirable and an inert gas such as nitrogen can be employed. Test certificates should be prepared and witnessed by the responsible person. Note: do not use compressed air as oil/air mixtures are extremely dangerous, there will be oil in the compressor crankcase. Refer to the Health and Safety Guidance Note GS4 Safety in Pressure Testing for more detail if necessary. Joint Inspection and Leak Pressure Testing All brazed joints need to be inspected and a leak pressure test has to 60

Systematic Installation of Copper to Save Money Part 1 - Basic Principles

measure and deduct

Where tube runs along a wall between two obstructions two clip allowances must be deducted to obtain the tube C-C length

measure and add

Where tube runs along the outside of an obstruction two clip allowances must be added to obtain the tube C-C length

measure

Where tube passes an obstruction clip allowances cancel out and can be ignored. Simply measure size of obstruction to obtain the tube C-C length.

Figure 2 Fixing clip allowances ÂŠ European Copper Institute

The method is based on two basic principles. First, the ability to determine accurate cutting lengths for tube - cutting lengths

Clip stand off allowance is equal to the distance from the fixing surface to the centre of the tube allowance

allowance allowance

fixing surface

ÂŠ European Copper Institute

Table 1 Tube Tube Measured Clip identity diameter length allowance

Fitting Cutting allowance length

400

-2 @ 22

-2 @ 12

332

300

+2 @ 22

-2 @ 12

320

100

-2 @ 12

100

-2 @ 12

300

-2 @ 22

-2 @ 12

232

500

-1 @ 22

-2 @ 12

454

400

300

100 B

300

E F 500

Fitting allowance for elbow = 12mm Allowance for fixing clips = 22mm

Figure 4

Loose flange in steel with slip on copper alloy collar

Code 307 PN 6,10, PN 16 DN 10-1800 DN 10-250

Hubbed slip-on flange in copper alloy with tube stop

Code 314 PN 6,10, PN 16 DN 10-1800 DN 10-500

Copper alloy

PN 25 DN 10-700

Steel

Figure 1 Typical flanges for brazing Jointing refrigeration tubing Oil, water and dirt should be kept out of the bore of all pipelines during installation.This is especially important in the case of refrigeration (and oxygen) pipelines. The tube used should be specially de-greased by the manufacturer and supplied with its ends sealed. Any temporary open ends need to be blanked with rubber plugs during installation. It is important to prevent the formation of oxide scale inside the tube when brazing refrigeration pipelines. This is achieved by connecting a nitrogen cylinder to one end of the pipeline via a regulator and passing a gentle flow of gas through the tube whilst heating. The

nitrogen flow displaces the air and prevents oxidation. The flow should be continued until the tube has cooled. Silver solder capillary fittings are usually recommended for oxygen and medical gas applications. Brazing should be to EN 14324 and joints should be visually inspected before carrying out a hydrostatic pressure test for strength. This is followed by a pressure test for leakage using nitrogen or other

Locking nut Locking ring Pressure ring Nitrile rubber sealing ring

Figure 3 Ring seal joint 15 to 159 mm diameter.

suitable inert gas following the guidelines set out in HSE guidance note GS4. Refrigeration liquid lines are limited to a maximum of 25mm ID whilst vapour lines can be up to 40mm ID. Screwed compression fittings are limited to a maximum of 16mm ID. Flared fittings are only suitable for use with annealed tubes and are limited to a maximum of 22mm OD in locations where joints remain exposed for visual inspection. Where there is any doubt regarding the suitability of the materials for any given application, reference should be made to the relevant manufacturer.

De-mountable joints Figure 1 illustrates typical flange joints for brazing and use where disconnection is required. Traditional non-manipulative and manipulative compression joints can also be used provided the manufacturers figures for maximum temperature and working pressure are not exceeded. New on the market are rolled-groove mechanical joints for EN 1057 copper tube (formerly table X and Y). The principle having been developed for use on steel tube for sprinkler Ductile iron housing installations. Figure 2 shows a coupling, this EPDM gasket consists of an epoxy coated ductile iron Groove rolled into copper tube housing that compresses an EPDM rubber gasket Figure 2 Rolled groove mechancial joint to form a pressure seal. ÂŠ European Copper Institute

The mechanical strength of the joint is achieved by the housing having tapered sides that enable it to lock into the rolled grooves. Also available to the UK market is an 'O' ring fitting made from dezincification resistant brass, see Figure 3. This uses a locking nut (or bolted flange ring on the larger sizes) to compress a split locking ring on to the tube for mechanical strength whilst a nitrile rubber ring forms the seal. Safety note Remember, all piping systems must be depressurised and drained before disassembly and removal of any fitting! Cost and performance benefits of copper Good corrosion resistance and the ability to carry a wide range of fluids make copper and its alloys suitable for virtually all pipeline services. Furthermore, coppers high thermal conductivity makes it the ideal material for heat exchangers. Its high strength, wear and corrosion resistance and the ability to be formed to close tolerances means that copper tube has a higher carrying capacity when compared to other tube made from other materials. The ease of fabrication of copper tube and the wide range of jointing and bending methods that are available, simplifies the manufacture and installation of pipeline services. Furthermore, the intrinsic properties of copper over its long, proven, working life results in improved cost effectiveness when compared to other materials.63

Systematic Installation of Copper to Save Money Part 2 - Copper Tube Installation Method he previous article explained the basic principles that can be used to produce a cost efficient top quality tube installation.This article builds on those principles to produce a systematic copper tube prefabrication method based loosely on production engineering techniques. Useful savings of both time and materials can be made by using the system. The basic idea behind the system is to take as many measurements as possible in one operation. This is to eliminate the piecemeal preparation of individual pieces of tube and reduce waste from off-cuts. Measurements of the walls or fixing surfaces and positions of fixed points are taken and used to determine accurate tube cutting lengths.

An example Figure 5 illustrates a plan of hot and cold water pipework to supply a washbasin. Typical clip and fitting allowances are shown. For clarity an isometric view of the pipework is shown, see Figure 6. Using the system The square grid at the top of the layout chart is used first to draw a singleline plan, and, if necessary, section of the 40

Figure 6

Existing services

Isometric view

work. Tubes are then numbered and diameters written on the cutting list. Next actual measurements of the structure are taken and added to the cutting list. Clip and fitting allowances are measured and noted on the allowances list at the bottom right of the chart, (familiarity with the system will soon enable the measurer to remember

1125mm

Pipe clips 15mm clip stand off allowance 15mm elbow allowance 15mm tee allowance 15mm passover allowance 15mm tap connector allowance Height of tap tails above floor level Height of cold service above floor level Horizontal tube spacing

Figure 5 ÂŠ European Copper Institute

= 22mm = 12mm = 8mm = 80mm = 18mm = 545mm = 100mm = 40mm

Hot and cold supplies to basin

452 mm

172 mm

common allowances). The tube cutting list can then be completed by allowing for clips and subtracting the fitting allowances. Figure 7 shows the completed chart with cutting lengths for the work. Where tube is to be fabricated using multiple bends, the isometric grid is used to show the relative directions of the various bends and sections of tube. The cutting list can be used to allow for clips to determine centre to centre lengths for bending.These can be added to produce the cutting length required for each section of bent tube. When the cutting list is complete, the tubes can be fabricated. Whether using fittings or a bending machine, good productivity gains can be made when compared to piecemeal production of individual tubes. All tube of a particular diameter can be cut and if necessary bent at one time. This is to minimise the time spent setting up and adjusting machines. Once each piece of tube is 64

fabricated it can be marked with its number for easy identification on site by the fitter. Actual tube installation is quick and efficient.Tubes can be cleaned, fluxed and assembled into the clips and fittings in one operation. The fitter does not have to offer them into position, mark, remove cut, re-check and then assemble. Variability of site work To work effectively, any system must be able to cope with the variability encountered in construction work! On large contracts, where detailed drawings are available, measurements for basic runs of tube, such as risers and run-outs in ducts or false ceilings, can often be scaled-off from the drawings with sufficient accuracy. On jobs that do not have detailed drawings, or where dimensions are critical, measurements of the structure should be taken on site. By using the system, if necessary, hundreds of metres of pipework can be measured in one operation for later fabrication. This can be done either on site or in the workshop by the measurer or another operative. The system also works very well on small individual jobs. Where there are numbers of identical units, such as on housing sites, it is quite easy to fabricate batches of tubes from a single set of measurements. By making use of the tube that is gained when pipes are to be bent, or by the judicious addition of short extra lengths in strategic places, an allowance can be made for the inevitable variations in size that occur from one unit to the next on site. If compression joints are to be used, one end of each joint can be made on to each piece of tube as it is fabricated.

Figure 7

Plot scale = 0.75 : 1

Cost savings Experience with the system has shown that considerable savings can be made by the better use of site labour and materials. Piecemeal, time consuming installation is reduced and tube cutting lengths can be optimised to reduce waste. If necessary, the planning of tube runs and calculation of cutting lengths can be done before materials arrive on site. Also, better control and utilisation of stock can be achieved.

ÂŠ European Copper Institute

Copper in Small Bore Heating Systems

opper is the ideal material for use in small-bore, (Figure 1) mini-bore and micro-bore, (Figure 2) heating systems. Modern boilers use finned copper heat exchangers and copper tube for their internal pipework because of its proven

long term advantages. It also makes sense for the installer to use half-hard and soft condition copper tube to EN 1057 for the installation,Table 1 indicates the wide selection of tube diameters available for use in this type of work.

Figure 1

Flow

Return

Two pipe system

Boiler Tubes usually 15 and 22mm diameter

Figure 2

Manifolds

Microbore tube (6, 8 & 10mm) to each emitter

Boiler

ÂŠ European Copper Institute

System design Choose tube diameters from the wide selection available to give a water flow velocity of between 0.3 and 1.5m/s. By selecting an appropriate tube diameter some of the long term problems associated with heating systems can be avoided. If the tube used in a circuit is too large in diameter, sluggish water flow can allow sludge (formed by slow corrosion of the steel heat emitters) to settle out into the pipework. If the tube used is too small in diameter, in addition to inadequate delivery, flow noises can be created. Bearing these factors in mind, Table 2 gives details of the minimum and maximum heating load that should be connected to any given circuit for a particular tube diameter. In open-vented systems the temperature drop is usually taken as 11Â°C. Sealed systems can be operated at a higher temperature, which allows smaller tubes and heat emitters to be fitted and a temperature drop of 20Â°C to be used.To use the table, select a suitable tube diameter based on emitter heat output and temperature drop. As further emitters are added to the circuit their heat outputs can be totalled to select the diameters of the tubes feeding them. Installation The installation of a copper system is a simple task for the competent operative; satisfying results are achieved in terms of appearance and ease of fixing. End-feed or integral solder ring fittings are normally used for tees, couplings and elbows. Compression fittings are used where disconnection will be required. For example: radiator valve tails, pump valve connections, tank connectors and the copper tails on the boiler. For a quality installation, care and attention will pay dividends. Lengths 66

Table 1 Diameter and wall thickness of EN 1057 copper tube for domestic heating systems Outside diameter

0.6

0.7

Wall thickness 0.8 0.9

1.0

R R

1.2

should be measured accurately so that the tube does not have to be sprung to make a connection. Tube below 12mm in diameter should be cut square with a junior hacksaw, any burrs should be removed with a file. This is to avoid restricting or reducing the diameter of the bore at the tube end, which can be excessive when using a wheel-cutter, particularly on soft condition tube. After cleaning capillary fittings, apply just sufficient amounts of flux on the tube end only, not inside the fitting. Twist the tube in the fitting after insertion, to spread the flux over the two surfaces and wipe off any excess flux. Apply heat, and in the case of end feed fittings, solder until a complete ring of solder appears around the mouth of the socket. Wipe the fitting with a damp rag to remove any flux residues, then examine the joint for

Indicates BS 2871 Part 1 tube a complete visible ring of solder for confirmation of a sound joint. It is essential, for the long term reliability of any heating installation, to prevent contaminants such as: dirt, general debris, excess flux and metal filings, from entering the system during installation. This can be achieved by applying tape over tube ends or squeezing up-stands flat on carcass pipework. Once the system is in service, it is important to prevent air from entering the system. Over-pumping, micro-leaks on the suction side of the pump and certain types of plastics tube can all allow oxygen to enter the system. Copper tube, being totally impermeable, will not. Plastics coated copper tube Plastics coated copper tube has many uses in heating systems. Where solid

Table 2 Heat carrying capacity (kW) of BS EN 1057 copper tube Heat capacity (kW) Temperature drop 11ÂşC 0.3m/s 1.5m/s (minimum) (maximum)

Diameter (mm)

Wall thickness (mm)

0.6

0.24

1.24

0.45

2.25

0.6

0.49

2.48

0.90

4.51

0.7

0.80

4.00

1.45

7.27

0.8

1.17

5.86

2.13

10.60

0.7

2.00

10.00

3.63

18.10

0.9

4.42

22.14

8.05

40.20

0.9

7.43

37.17

13.50

67.50

ÂŠ European Copper Institute

Plastic sheathing Copper tube Air space

22 R = European recommended dimensions

Figure 3

Temperature drop 20ÂşC 0.3m/s 1.5m/s (minimum) (maximum)

floor construction is encountered plastics coated tube can be buried in the screed, but preferably with few or no joints.This is best achieved by using soft coiled copper tube, readily available in lengths up to 50m, installed in accordance with the water regulations.The plastics sheath is formed around the copper without a seam, providing a reliable continuous protective coating. As well as providing a tube suitable for buried services in corrosive environments, it can be colour coded: blue for water, yellow for gas and white for heating lines. Copper is also available with a castellated profile plastics sheath, see Figure 3. This gives a number of advantages, e.g. heat loss is reduced, noise transmission is reduced, some lateral expansion can be accommodated and a lower surface temperature is present on surface fixed tube. This could be particularly useful on jobs where low surface temperature heat emitters are specified. Formers are available to enable plastics coated tube to be machine bent easily. Where joints are to be formed, the plastics sheath can be slit and pulled back. This will prevent heat damage when using capillary joints. Once the joint is completed, the sheath can be pulled back into position and wrapped with adhesive tape to maintain the continuity of protection. Commissioning It is important to thoroughly flush every heating system as soon as possible after installation. Fill and vent the system with cold water and check all connections for leaks before draining. Refill and commission the boiler and heat up the system. Occasionally leaks can be found at this stage, (sometimes due to heat melting grease based fluxes) so check again before draining the system whilst still hot. If corrosion inhibitor is necessary, it should be added during the final filling operation, before venting and balancing the system for a long and trouble free service life for specifiers, installers and customers. 67

Solar Hot Water Systems Radiation from the sun (normal light) can be transformed to useful heat to provide, for instance, hot water. This can be in almost all areas in the world. Copper has by far the highest thermal conductivity of any commercial metal and this factor, together with copper’s good corrosion resistance and its ability to withstand high temperatures, makes it an ideal material to use for many parts of solar thermal systems. Recently in the UK, major political support has been given to all kinds of renewable energy, including the need to support renewable heating and cooling. Correctly designed solar thermal systems have a proven track record in providing dependable hot water and space heating and, as more systems are installed and economies of scale come into play, payback periods will reduce to make them more cost-effective. UK solar irradiation is relatively low in intensity for long periods, ranging on average from about 2.4kWh/m2 per day in Scotland and the North of England to 3.0kWh/m2 per day in the South West. Irradiance also varies from a minimum of about 60W/m2 at the winter solstice to about 1000W/m2 at the summer solstice. It is often intermittent during the day because of cloud cover and also varies in intensity through the day from zero at sunrise, rising to a maximum at noon and back to zero at sunset. During the summer solar energy can meet the entire demand for domestic hot water economically, but in the winter some form of back-up heating may be required. Overall efficiency in a solar thermal system will be maximised if the collector and piping system have the correct water capacity required to carry the collected heat energy to the storage cylinder. If the collector has a high thermal capacity (due to a large water volume), then it will be relatively slow to heat up. An appropriately-sized solar collector will increase the efficiency with which energy is captured, especially on cloudy days. © European Copper Institute

A flow rate of between 0.01 and 0.02kg/s for each square metre of collector area should be used when choosing tube diameters for the circulation piping. Temperatures in the collector can vary from about -20°C at night in winter to +350°C during stagnation periods (when the heat transfer fluid is not circulating, even though the panel is fully irradiated). Therefore, only materials like copper, that can withstand this temperature range and the associated thermal shocks without damage, should be used for the installation. Types of solar collector There are a number of designs of collector, the flat-plate type being the simplest, see Figure 1. These consist of a metal heat-absorber plate, the surface of which is blackened to make it more efficient in absorbing solar energy and to reduce the emission at higher temperatures. Tubes are attached to the absorber plate to enable heat transfer. The heat transfer is usually by means of water (with inhibitors), for systems of the

drain-back concept, or of a food-grade glycol-and-water antifreeze solution, which is circulated to carry heat from the collector plate to the storage vessel. One or two layers of glass or transparent plastic, separated by an air space, are incorporated above the plate to trap the energy. This air space reduces convective and conductive heat losses back to the atmosphere. The glazing also minimises heat re-radiation from the collector. Insulating the back and sides of the collector, as well as the pipes leading to and from the cylinder, further reduces heat losses. Ideally, the collector will be mounted so that the glass absorber surface is south facing but, even if it is west facing, it will still perform at 80% of the ideal, provided it is angled between 30º and 60º. Instantaneous efficiencies of solar collectors can be as high as 80% when they are operating at close to the ambient (surrounding air) temperature. In a typical domestic installation in Northern Europe 1.0 to 1.5m2 of net flat-plate collector area is used per person for heating domestic hot water.

Insulation Air gap Collector plate and pipework

Glazing Flat-plate collector

Figure 1 – Flat-plate collector 68

cylinder from being cooled due to natural convection when the pump is not running. This check valve is not required for drain-back systems.

Coaxial distributor pipe

When water is heated it will expand. It is especially important to cater for this expansion in a solar heated system as, under certain climatic conditions, the heat transfer fluid may boil and vaporise. This situation can be addressed by installing a vented system (one where an open vent pipe discharges into a header cistern) or, more usually, a sealed system with an expansion vessel and safety valve. This means of accommodating expansion is not required for drain-back systems as they have a built-in reservoir and the systems are “drained” at the point that overheating may occur. The copper absorber is then left to stagnate, a state that it can easily withstand.

Coaxial collector tube

Collector plate Coaxial collector tube Evacuated glass-tube Collector plate cut-away to show coaxial tube

Figure 2 – One type of glass-tube collector Evacuated glass-tube collectors are also available, see Figure 2. These comprise a coaxial circulator tube (a tube within a tube) attached to a collector plate fitted within a sealed glass tube. The outermost part of this glass tube has much of the air removed to create a par tial vacuum, which reduces heat losses and makes tube collectors more efficient at the higher temperatures. For the typical temperature to heat domestic hot water, the annual efficiencies are comparable to flat-plate collectors. Individual tube collectors can be connected to a coaxial distributor pipe by means of push-fit or threaded joints. This type of joint enables the tubes to be rotated to optimise the angle of the collector plates with the sun.This means that glass-tube collectors can be fitted either to sloping roofs or horizontally or vertically on roofs or walls and still have their collector plates aligned with the sun for maximum efficiency. A typical system A typical solar domestic hot water system consists of an area of solar collectors, a piping circulation system, controls and water storage, see Figure 3. In southern European countries the collectors can be sited below the storage cylinder (as the potential for freezing problems is low), then the heat can be carried from the collectors by natural © European Copper Institute

convection, see Figure 4. However, in Northern European areas the collector panel or tube will be roof-mounted and so will be above the storage cylinder. As a result, a circulator pump and temperature sensing controls to turn the pump on and off will be required. For fully-filled systems a check valve will also be needed to prevent circulation from the storage cylinder when it is hotter than the collector. This will prevent the

Hot water storage needs to be carefully considered. Between 30 and 50 litres of hot water (stored at 65ºC) daily per person will normally be sufficient, with 20 to 40 litres of pre-heat storage per square metre of collector area. Storage is usually by means of a single or dual-coil vented or unvented domestic hot water cylinder.The lower coil is used for the solar circuit and the bottom half of the cylinder is the pre-heat store, whilst the upper coil is heated by a boiler

Air release valve

Panel sensor Control comparator

Hot water distribution to taps

Twin coil cylinder Check valve Cylinder sensor Circulator

Flow and return from boiler Cold feed

Temporary filling connection

Pressure gauge Pressure relief valve Expansion vessel

Figure 3 – Solar hot water system 69

or immersion. Alternatively, especially when incorporating a solar system into an existing hot water installation, two indirect cylinders can be used. With this arrangement the solar heated cylinder feeds pre-heated water to the second cylinder or to a back-up boiler from where hot water (with auxiliary heat supplied by the boiler if necessary) is fed to the discharge points, see Figure 5.

Cooler more dense water flows down to base of collector lifting hotter less dense water up to heat the cylinder

Figure 4 – Natural convection with collector below storage

Pump control Pump control is achieved by temperature sensors, attached to the solar collector and storage cylinder, and a comparator circuit, see again Figure 3. This measures and compares the temperature of the collector with the temperature of the solar storage cylinder. When the collector is sufficiently hot (say +6°C above the cylinder temperature) the pump will start and will continue to run until the collector temperature cools or, in case of drain-back, there is no further useful contribution from the collector to the storage cylinder. Brian Curry: 2007.

Solar heated feed to cylinder

Pre-heat buffer cylinder Flow and return from solar panel

Hot water distribution to taps Flow and return from boiler

Figure 5 – Twin cylinder installation

Copper for Steam-Condense Pipelines Benefits of Steam as a Heat Carrying Medium

team has been used to carry heat energy since the industrial revolution. It has been a versatile tool for industry wherever heat is needed and can be used in process plant, space and water heating applications, see Figure 1. One reason for steams versatility is that the temperature can be adjusted easily and very accurately by control of pressure using simple valves. Furthermore, steam carries relatively large amounts of energy in a small mass and gives up this energy easily.

Suitability of copper Copper tube, being made from a tough, easily jointed, heat and corrosion resistant material, is ideal for steamcondense pipelines. The condition and wall thickness of tube that is required for a particular service can be found by using the formula: pd t = ----p+20F where: t = the minimum tube wall thickness (mm) p = the design pressure (bar) d = the outside diameter of the tube (mm)

F = the design stress (N/mm2) at the maximum working temperature, see Table 1. But note that if the tube is to be braze jointed at >600°C use the stress value for condition O (annealed) tube. Table 2 indicates suitable wall thicknesses for tubes for steamcondense services operating at up to 17 bar and 205°C. (Note also that

Pressure reducing valves Steam mains Process plant Space heating

Water heating Steam boiler Steam trap Condensate mains Cold water make up Hot well Boiler feed pump

Figure 1 Two pipe steam system appropriate sizes of copper tube to EN 1057 up to and including 108mm diameter align in all dimensions with the low pressure range of EN 12449. Furthermore such tubes up to 22mm in diameter also align in all dimensions with the high pressure range.) Installation of steam-condense pipelines For efficient use of steam it is necessary to ensure that the condense lines are properly sized in relation to the steam lines, see Table 3. Both steam and condense lines need to be insulated to

Table 1 Design stress values (N/mm2) for solid drawn copper tubes (See BS 1306 for copper alloy tubes) Material

Designation

Condition

Annealed O Copper

Cu-DHP

Tensile strength (min.)

200

Values of design stress for temperature not exceeding -200 to +50°C

100°C

150°C

175°C

200°C

Light drawn 1/2H

250

As drawn M

280

reduce heat loss, correctly laid out to a slight fall and adequately drained, see Figure 2. The pipework also needs to be Table 2 Copper tube for steam services with plain ends EN 12449 Low pressure High pressure range range Working pressure Working pressure Size of up to and up to and tube including 7 bar including 17 bar (mm) max working max working temperature 205°C temperature 205°C Thickness (mm) Thickness (mm) 6

0.8

1.0

1.2

1.5

2.0

1.5

2.0

3.0

2.0

3.5

76.1

2.0

4.0

108

2.5

5.0

Low carbon steel steam main

80 100 125 150

Copper steam main

76 108 133 159

Copper condensate main

installed with adequate provision for expansion. One metre of copper tube will expand by 1.7mm for a 100°C temperature increase, and the stresses imposed can be considerable if no allowance for expansion is made between 'fixed points'.Where long (over 10m) straight runs of tube are to be installed, consideration should be given to the use of expansion loops or bellows at strategic points. Need for condensate return lines As soon as the steam leaves the boiler it starts to give up some of its energy to any surface at a lower temperature. This results in the formation of condensate (hot water). This condensate forms both in the steam pipework system and in the process equipment that uses the steam. It must be drained away to prevent the system becoming waterlogged and, as hot water, it has too much energy to be allowed to run to waste. The condense return lines are used to carry the condensate back to the boiler feed water tank. Jointing methods Copper steam-condense lines can be jointed by means of: • End-feed brazed joints; • 'High-duty' integral solder ring fittings, these have a silver solder filler ring, see Table 4 for typical working pressures; • Compression fittings; • Rolled groove compression fittings. Table 4 Typical maximum working pressures for general high duty brazed capillary fittings (bar)

For temperatures not exceeding

Fitting size (mm)

150°C

175°C

200°C

242

151

202

126

158

15 - 54

the water boils off at 100°C; at about 300°C the flux looks white and puffy and is starting to work; • by 450°C it is starting to melt and looks milky; • when the brazing temperature of about 600°C is reached the flux is clear and looks watery.

• •

Table 3 Suggested diameter of copper condensate mains for various steam main diameters (mm)

Whatever jointing method is to be used to joint the copper tube, check with the manufacturer's data that it is suitable for the working pressure and temperature required.

At this point the brazing rod can be applied to the mouth of the joint. Keep the flame moving, when the correct temperature is achieved the rod will melt and should readily flow into the joint by capillary action. Once the joint is filled a continuous fillet of brazing alloy should be visible all around the joint, and no further rod should be fed in.

Brazed joints Capillary joints brazed with copperphosphorus alloys (CP) or copper-silver alloys (AG) are suitable for steamcondense working temperatures of up to 200°C. Accurate control of the capillary Note: If the rod 'balls up' it indicates joint gap is important with a clearance too little heat, or else oxidation of of between 0.05 and 0.2mm required. the metal due to insufficient flux. Also, if Adequate strength is achieved where the the brazing alloy will not enter the joint has an overlap of 3 to 4 times the joint, it can be that the various parts of wall thickness of the thinner tube.With a the joint are not evenly heated. short cup joint like this it is easier to Properly designed and installed achieve full penetration of filler metal, copper steam-condense pipelines will and no material is wasted. give long-term reliable service. They are CP alloys do not require the use of relatively light weight and can be quickly flux when making copper to copper and easily fabricated and jointed without joints, AG alloys do, as do CP alloys when requiring the use of expensive plant jointing copper tube to brass or and machinery, and the skills necessary gunmetal fittings. Check and adhere to are well within the scope of the the flux manufacturer's recommend- professional installer. ations as to the upper limits of temperature. Only mix sufficient flux for one day's Always take branches off joints by adding a little water top of steam main to the powder to produce a creamy consistency. A very thin coating of flux should be applied before joint assembly. It is important to ensure that close control of temperature Correct use of eccentric reducer is maintained whilst jointing. Steam Incorrect The joint must be heated evenly so that when the brazing temperature is reached the filler alloy melts Condensate and spreads throughout the Full size drain pocket joint, a gas/air torch is ideal. formed using tee Where an oxy-acetylene torch is used, care must be taken to Fall avoid local over-heating, particularly if using filler metals containing cadmium. Use a large flame and keep it moving Fall to heat the tube and fitting Steam trap evenly. Observe the flux for a Figure 2 guide to heating, it passes through four stages: 72

Underground Copper Water Services hen laying underground water services into buildings it makes sense to use copper. Copper's corrosion resistance and long term resistance to degradation, as well as it's excellent protective properties, mean that nothing can be absorbed by it or permeate through it. Because of this it will keep the water supply safe and healthy for the consumer for many years. Copper tube suitable for underground use is made to comply with EN 1057 half hard thick wall formerly Table Y. It is supplied coiled in long lengths in the annealed or soft condition (in sizes 12 to 28mm O.D.) or half-hard in 6M straight lengths (sizes 6 to 108mm O.D.). It can be joined using either capillary joints or flared type 'B' manipulative compression fittings to EN 1254.

ground level

not less than 750 not more than 1350

Normal case

ground level

pipe can be laid under obstruction if this measures less than 1350

Requirements Water Regulations require that underground water services are laid between 750 and 1350mm deep from the finished ground level, see Figure 1. Burying the service pipe 750mm deep gives it adequate frost protection in normal situations and stipulating a maximum depth of 1350mm means that the service pipe is reasonably accessible should the need arise. The installation of pipes and water fittings in foul soil, refuse or ash pits or cesspools, drains etc. is prohibited.Water fittings need to be able to resist damage from: external loads, vibration, stress and settlement, internal water pressure, temperature and corrosion. A correctly installed copper system will meet this requirement in all respects. Trench excavations Trenches should follow a straight route from the boundary stop valve to the service entry point at the building. ThisÂŠ will facilitate easyInstitute location of the European Copper service in the future. Also, joints below

Pipe laid under obstruction

ground level waterproof insulation required if this measures less than 750

Pipe laid over obstruction

Figure 1

Depth of cover for water services. 73

ground should be kept to a minimum, ideally the service should be laid in one length. Surface boxes for valve access must be provided, they should be supported on concrete or bricks so that they do not rest on the tube.The trench bottom should be prepared to give a firm even surface. Any boulders or rock projections or mud patches should be removed and be replaced with selected fill material. Laying the tube When laying the coiled tube into the trench it should be snaked slightly, this is to allow for any shrinkage of the sub-soil. As in Figure 2. Snaking the tube has the effect of adding length which can then allow any movement to take place without placing undue strain on the tube. This is particularly important where the tube connects to the ferrule valve on the water main where a goose neck bend should be formed. Open ends of tube should be crimped or temporarily sealed with tape to prevent dirt entering the tube before joints are made. Any sheathing or wrappings which have to be cut back to enable jointing should be replaced and the sheathing checked for damage before the trench is backfilled. It is important to make sure that the tube is surrounded by selected material

without large stones or sharp objects. This should be consolidated before the remainder of the trench is filled. Aggressive soils The type and nature of the soil through which the tube is to be laid can occasionally have an effect on the tube. For example, where the soil is known to be strongly acidic, in this case the water company might require that polyethylene coated copper tube be used. It makes sense to use coated copper rather than polyethylene tube alone because some plastics can be permeated by gases. Copper is completely impervious and if protected against the aggressive nature of the soil by the plastic will deliver safe water over the long term. Aggressive soils are usually acidic and contain humus, or vegetable matter, or certain minerals, such as sulphur. The flower colour of the Hydrangea bush can give an indication of the acidity of the soil in which it grows. This is because the flower colour varies with the acidity of the soil. In acid soil, blue and mauve-coloured blooms are produced; in alkaline soil, pink. Where the nature of the soil is not known it is quite easy to determine this by testing with an 'Indicator' paper.These are small strips of

white absorbent paper which have been impregnated with small areas of indicator chemicals which change colour when they come into contact with acids or alkali's. The acidity is measured on the 'pH' scale.This runs from 0, the strongest acid, to 14, the most alkaline. Neutral, neither acid nor alkaline, is 7 on the scale. In use the indicator paper is moistened and the resulting colour change can be compared to a scale to indicate the 'pH'. Ideally water should be neutral or slightly alkaline, with a 'pH' of 7 or 7.5. Water quality and brass fittings Certain types of water, either supplied by the water company or ground water in which the tube is laid, can result in a form of corrosion on brass known as dezincification which is the selective removal of zinc from the brass. This can be identified by the formation of a meringue-like whitish coloured growth on fittings. Because of the problem of dezincification the Water Regulations require that copper alloy fittings containing zinc, if laid in the ground, should be made from gunmetal or dezincification resistant brass. The fitting is immune from dezincification and therefore safe for use in the ground, it can normally be identified by a â&#x20AC;&#x2DC;CRâ&#x20AC;&#x2122; mark.

service entry point

Figure 2 Trench Detail

ground level

Plan

depth of cover maintained between 750 and 1350 as ground level varies

copper service snaked in trench

Elevation site curtilage boundary stopvalve box and cover plate gooseneck bend water main ferrule valve

ÂŠ European Copper Institute