The Bulletin - August 1998

Journal of the Association for Petroleum and Explosives Administration

C L OSE D I

Scully On·Truck Computer

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D RIP STOP diesel nozzle

Situation Today

Often the area around a diesel dispenser is contaminated by diesel which has fallen onto the forecourt for one reason or the other One of the main reasons is that motorists do not wait that extra second for the nozzle to drain before removing the spout from the car filler pipe.

The Solution

The Z.VA Slimline nozzle is now available with the New Drip Stop spout ER242. 1TMV The patented magnetic closure inside the spout works after refuelling has finished The_Drip Stop operates in two ways. Firstly it closes.to diesel dripping when the spout is removed tror:i filler pipe too quickly and secondly, it retains the rema1_ns left 1n the spout so that the next customer doesn 't spill this diesel onto the forecourt when removing the nozzle from the dispenser.

How does it work?

The Drip Stop functions on the principle of a magn rather than a strong spring. When the nozzle 1s not in use t . floating magnet holds the "valve" closed. Since the magnetic fore€'. is very small when compared with a spring the pressure loss is minimised in such a way that the pressure. drop even at flow rates up to 501pmin is negligible. Also thf'. innovative patented design allows for quick opening and slightly closing , this prevents the Z.VA Slimline from being placed in the dispenser holster with a full spout.

Maintaining ZVA topping up facility

Well known ability of the ZVA Slimline "to the penny dispensing " is as sensitive as eve r and is in no way cornprorni?ed by this new designed spout. The new spout is also supplied as standard with Drip Catcher fitted . How to order: Please con tact our Sales Office for further details .

£8.00

Opinions expressed in this Journal are not necessarily the views (Free to Members) ISSN 0263 4597

of the Association

Talking Point

Hasn't risk assessment started?

When the petroleum Officer drove past the self service site on the front cover he was surprised to find customers serving themselves despite the extensive re-imaging work to the sales building.

The two small holes so carefully cut out by the forecourt contractor were not of sufficient dimension to provide the attendant with adequate vision of the dispensing activities.

The operator decided with some encouragement from the petroleum officer it would be in his best interests to revert to attendants serving until the shop front had been reimaged !

by West Yorkshire Fire Service

Dr Steve Rooker HSE

Steve Rooker died on Friday 31 July following a short illness. He was suffering from cancer. To those in the industry who knew him, the suddeness of his death, and the loss of someone with such energy and commitment has come as a shock. The Association expresses its condolences to his colleagues and family at this difficult time.

Contents

TALKING POINT

NOTES &NEWS

PROSECUTIONS

TANK COATINGS

CHAMBER TESTING

VAPOUR RECOVERY

WHERE DO THE VAPOURS GO?

STAGE 1B WARNING

STAGE 1B MORE PROBLEMS DISCOVERED

photo

and news

APEA 40TH ANNIVERSARY & EXHIBITION

516 OCTOBER TELFORD

This year the APEA are holding the Exhibition and Conference at Telford in Shropshire at the Telford International Centre on October 5 & 6th 1998.

The Conference will be held this year over two days in the Gallery Suite situated above the Exhibition halls, with the Conference dinner being held on the evening of 5th October in the Moat House Hotel which is close to the centre.

The Exhibition is also being held over the two days and already a substantial number of Exhibitors have booked places for the event.

Should you need infmmation on the Exhibition please contact Chris Knight on

This year the Conference will be free to all members registering before September 20th but will cost £20 after that date.

The APEA has reserved a number of Hotels this year at reasonable rates all situated close to the venue and bookings can be made direct through Jane Gwilt of The Accommodation Booking Centre

Underground Tank Management Programmes

Asger Erricson

In addition the APEA is running a pmtner programme on both days which will enable pmtners to enjoy a trip to Jronbridge Gorge, Bliss Hill Museum with lunch which must be booked prior to the event and is free to overseas visitors.

The Conference will commence on Monday October 5th at 14:00 hours and will feature the following presentations:John Hazledean HSE

The New Regulations Sites for Leaks

Dr Warren Rogers US

Requirements for Monitorino "'

Methods of Operational Pe1t'ormance & Integrity of Storage Systems

Thomas Haar Germany & Dave Wilson US

Full Fuel Control Terminal to the Nozzle

Phil Whitehead Veeder Root

Simplicity -A Solution to Regulatory Compliance

T .,l·iy 6th Octoher at 10: 30am ues '

Henry Clayton Shell Gas Europe

Dispensing LPG at the Petrol Station

Mike Baach US

PI · & P1·1·111·itisation for Economic Proper an n mg.

Hydrocarbon Contamination Surveys

Using Non Intrusive Methods

Exhibition and Conference packs are being distributed to members to provide registration and other details but should you wish to reserve a place at the Conference, the Exhibition or at the Conference Dinner please contact Barbara Jacketts on 01473 828539 or fax 828538.

MIND YOUR TANK!

An Esso site in Taunton had a rather nasty surprise when contractors Drillsafe drilled a new entry hole for a contents gauge through the tank lid .. The drill not only went through the tank lid, but it also dnlled down the neck of the tank, ak a lono hole Investigators discovered that not all m mg o · tanks have the same size neck.

Fortunately the contractors were fully insured and repairs b ·ed out they have now adopted methods to have een cam ' h d ·111·no close to the lid edge does not repeat this ensure t at n "' type of incident.

LONDON LEAKS!

F . B . oade have reported that within a two The London Ire n,,, h b t oe tanks m London ad een th Period five s ora,,, mon . h ldest was 26 years old and the discovered leakmg, t e 0 t ks were all sincrle skin steel t JO years old These an "' younges · 1· Id failure in one to a large hole in and suffered from eit 1er ".'e Tile i·esults of the tanks leaking d b orros10n · L another cause Y c · . e when water entered one .d bly from nmsanc vaned cons1 eia t over 30.000 litres of d . . Id to customers, o . . . tank an was so 1 tank causing a maJor mc1dent petrol escaping from anot 1e1 in central London.

1 storaoe tanks in London the data Of about 8000 petro ·.t'.0 lled before the war. h t 1091 were ms a base shows t a <'

k , ·e still single wall with 21 % over 40 82% of the tan s m L ·iderable nsk of le,1k111g. years old and at cons

· 1 lhtions are under 20 years old. The good 45% of the ms c1 ' • , • L 1 t "iu:e requtnng all new steel t<lnks to be news bem 0 t 1a SI . · . "'L I 1 n to be double wall 111 199 I. 18% ol the 111stalled 1n om t k · 11-e now double skm and will alarm hdore storage tan s 111 ' product leaks out.

NEW SECRETARY FOR AFSC'

At a recent mel'ling. Marlene Williamson. of (. 'anwron Technical Sen ices was appnintl'd of ThL' Association of h)J'L'l'Ourt Systems Contntl'l\lr.., follo\\tng. tlw retirement of Denni-.; Fox All lllL'll1hl'I' companie.., \\l'\n,nw

Marlene, and wish Dennis, who has been secretary since the formation of the organisation, a long and happy retirement.The AFSC, a non profit making organisation is committed to developing and promoting good safe working practices and procedures within the industry. The association is currently establishing Risk Assessments and Safety Method Statements for many tasks, including:-

Tank and pipework installation

Pump installation

Submersible pump installation and testing Equipment servicing and commissioning

Tank and pipework testing

Members of the association is open to any company who actively install and service forecourt systems, provided they can demonstrate they operate and strictly observe good Health & Safety procedures.

For more information please

I.

DURAPIPE FITTING FIRE (Bulletin Vol 36 No 2)

After reading the article on the fitting fire technical experts came up with a number of comments that may be of interest.

Gross overheating of this type of electrofusion fitting can arise due to excessive wire movement within the molten polyethylene material. This wire movement can occur if the gap between the pipe and the fitting is excessively large or if the pipe is not fully pushed home in the fitting. It is also more likely to occur in fittings where the wires are not well embedded in the fitting bore and are not electrically insulated. If two unprotected wires touch then a short circuit occurs which will educe the overall resistance of the fitting.

Since the type of fitting in question operates in a constant voltage control system this reduction of resistance will cause the fitting to draw more current from the welding machine thereby increasing the heat flow into the polymer melt and encouraging more wires to touch and further short circuits to develop. This can create an upward spiral of temperature ultimately resulting in burning of the polymer unless an additional monitoring and control circuit is built into the welding machine.

On the other hand the electrofusion fittings used within other Systems have "built in·· safeguards which prevent this type of incident arising. Jn these fittings the welding control system is based on a constant current which means that the maximum current that can be drawn from the welding machine is limited. This means that the heat input is limited and the upward spiral or temperature will therefore he prevented. Jn addition the wires are electrically insulated one from another using a high temperature lacquer thereby reducing the possibility of short circuits. Further the wires

are well embedded in the bore of the fitting to inhibit wire movement during fusion.

DURAPIPE will comment in the next issue of the Bulletin.

GUIDANCE ON THE USE OF EN954-1 MACIDNE SAFETY STANDARD FOR SAFETY RELATED PARTS OF CONTROL SYSTEMS

As a result of the publication of the EN954-1 standard for safety related parts of control systems, the UK standards body and the Health and Safety Executive considered it necessary to provide a guide on the standard for use in industry. A working group was formed to produce the Guide and the ECA Control Systems Group offered to publish it on their behalf.

The Guide points out some of the pitfalls that can occur if the document is not used correctly. In particular it highlights the fact that all the clauses within the document require attention and not just the requirements for its categories.

!he. Guide is aimed primarily at machine suppliers which mcorporates: In particular it highlights the fact that all clauses within the document require attention and not Just the requirements for its categories.

!he .Guide is aimed primarily at machine suppliers mcorporates: manufacturers, contractors, installers. mtegrators. These may all be involved in some way with the risk assessment of the safety-related parts of a machine control system.

Anyone wishing to obtain a copy of the Guide, should contact the ECA Technical Department at ESCA House, 34 Palace Court, London W2 4HY or telephone OJ 71 229 1266 Th G "d · · £" 50 · e u1 e is free of charge apart from a -· postage charge for multiples of I O or more copies.

EXPLORISK 1999

International Trade Fair for Explosion Safety and Risk Control

. safety is rapidly growing into a major m its own right. It is not a niche market within the wider range of industries. The increasing awareness of companies to _guarantee the safety of their workers an? the environment has partly facilitated this growth. while the changes in European legislation will draw even greater attention to the need for explosive-free products and services. The recognition that this industry commands can be seen in the enormous interest and participation in events such as the ExploRisk trade fair the only event specifically aimed at the industry concerned with explosion safety and the control of related risks.

EXPLORISK 1996

A u\ance back at the results of ExploRisk 1996 confirms b that the fair has hit the right tone. 197 exhibitor'.-. from the entire sector took parl. In 1996. a total uf .1.6.'il) visitors

contact Marlene Williamson at Camerons Technical Services

from 28 countries came to ExploRisk. More than half the v1s1tors occupied managerial pos1t1ons within their companies. The participants represented a broad spectrum of activities with the emphasis on technology and acquisitions. Most visitors appeared to be mainly interested in the electro-mechanical and electronic sectors, although the interest of participants and exhibitors was very similar, which clearly shows that ExploRisk manages to attract the very people the exhibitors want to reach.

EXPLORISK 1999

ExploRisk 1999 will be organised to draw on the strengths of earlier trade fairs. The programmes will again focus on the most important sectors concerned with explosion safety and risk reduction. The emphasis will be on specific themes relevant to electro-mechanics and electronics, the processing of materials and logistics; safety on the shop-floor; services; legislation; legislation and standardisation. For example, information will be available on systems for preventive and post-operative protection against internal and external explosions; on equipment for the transport and handling of goods in dangerous areas; and on insurance, scientific studies, and inspection and certification. As in the past, the trade fair will be organised in parallel with the international industrial seminar.

ExploRisk 99 will however also differ essentially from the past and mark a new start, with Flanders Expo replacing EuropEx as the organiser of the trade fair. Furthermore, it is the intention of ExploRisk to create a fair for an even wider international public.

Internet Conference

Process safety researchers and technical experts will be on hand January 27-29, 1998 at the first international internet conference to discuss the newest research and technical solutions to the problems of process safety. (For more information e-mail ober@prosicht.hamtec.de)

Information

construction or modification work. They aim to improve safety standards of both contractors and site operators and clearly describe the legal responsibilities of both parties. Most frequently occurring accidents and incidents are recreated to emphasise the importance of following the correct procedures and highlighting the risk if you don't.

The videos, which have a running time of 25 mins, are available from:

Fairbanks Media, and cost £13.85 inc p&p and VAT.

Please send cheque with order payable to Fairbanks Media and specify which version you require.

ESSENTIAL

WETSTOCK TRAINING WORKSHOP FOR PETROLEUM REGULATIONS

ENFORCERS

A one day wetstock management training workshop for petroleum regulations officers is to be held on Tuesday J3th October 1998 111 Skelmersdale, Lanes.

The workshop will provide delegates with the ·k·11 · determine the adequacy and accuracy of site S I S .f d .f ·1· t' systeins ·md records to ident1 y an quant1 y reconc1 ia 10n · ' ' losses and determine improvements and c01Tect1ve k h 11 i·efer to the new Petroleum Regulations The wor s op w1 , t f tl1e proposed Groundwater Regulations. and the 1mpdc o The cost per delegate is£ 130 excl. VAT.

· this and other future Ple·1se reaister your interest 111 '· :::- . b k·. E vironmental Ltd by telephonmg courses with Fair an s n . . ·111· ·w·ird 'l rea1strat1on form. 01695 51775 who WI OJ ' ' /::'

SOFITAM PUMP SERVICES APPOINT LEADING INDUSTRY

MANAGER

1e of the UK's leading forecourt Sofitarn Pump Services, 01 , . 1 lnve appomted a well kno'A'n and petroleum specia ists. ' , · , , B " as National s,tles ExeLLlll\C. mdustry t 1gure. Tony oyn:.

I 00 BEF for students I Flanders Expo

Dates: 9th. I Oth and 11 th February. I *999 Hours: daily from 9.30 a.m. to 6 p.m. Admission fee: 350 BEF or on invitation Halls: Organiser: E-mail: Web Site:

CONTRACTOR SAFETY VIDEOS

Following the release of the Institute or Petroleum Code ol Safe Practice for Contractors Wllrking on Petrol Filling St t. 11 s· 1 \ ideP has been crnnrnissioned hy the llKPlA llil , cl JO '

1111·es It is <tvailahlc in two versions: one lor comp, · · · . . contractors -,ite opL'ratin's and one lor petrol l1l1111g statf\111 stall. The videos explain the nL'v\ pron'dures tll he adoplL'd when l'l lJ1traL'!llrs L'aJT\ llUt SCI'\ IL'l'. rna intL'llallL'L'.

·'ble for sellin° the cnmpanv"s full Tony will he rcspons1 , ."' .. . , :, , , I -en·iccs mcludmg Snf1t,m1 s ILLentl) range ot products dl1l s facilities management programme·

T l ·k, I 1n the petroleum industry for m er 20 ony 1as wo1 Cl , tly ·is Reaional Manager at Pniteus. Back years, most 1eccn ' · "' · I · l 1· wl1t'Il t1c worked as a Produl'l Manager !or 111 l 1C e1g 1 !CS .• , ,. another service organisation he helped cPn\'crt the l I K s first 80 BP sites to unleaded fuel.

Said Snfitarn Pump Sen ices Sales DirL'L'll ll' Su1annL' Attrec: 'Tony has a lrL'111Cl1lhlUS kno\\ ledg.L' llf our industn and he will pla) an 1111pPrtant part 111 dnl'lll]linµ uur facilities manag.L'lllL'llt sn\ ice"

Away frnn1 wnrk. Tony is a keen fan 1lt' (Ira ml l'n \ MlllllI Racing tll such an L'\IL'lll that ht' L'\ en lll'lps arranµv ll Htrs ll l man\ lll !-·.urllpL"s kad111µ \L'llUL'S IIkL' [\:\pnan) and l L' l\L1110.

Prosecutions

TESCO CONTAMINATION - DRIVER CONTROLLED DELIVERY

Diesel and petrol storage tanks at a Tesco site in Kingston Upon Hull had to be emptied following cross contamination of fuels. Together with the compensation paid to customers to rectify damage to vehicles the insurance claim was subs tantial.

Investigation by the Trading Sta ndards Service reve aled failures by the tanker d1iver and evidence wa s amassed to bring a successful pro secution under Paragraph 23(b )(vii)(aa) of Schedule 12 to the Caniage of Dangerou s Goods by Road Regulations "the delivery hose was not properly connected to the appropriate outlet on the tanker and to the filling point".

The tanker h ad been top loaded for an evening delivery and the driver claimed that he failed to set three compartment indicators correctly. Thi s in turn re s ulted in him discharging three of the compartments into the wrong s torage tanks at the site which canies up to 230,000 litres of product. Had he then followed the standard procedure of rationalising the tank g auge printouts from before and after d e li ve ry he would have immedi ate ly identified a problem. Thi s ty pe of incident wa s sa id by the defence so licitor to be fa irly frequent in this country and that his client was the first that he knew o f to be pro secuted. In mitigation he also said th at hi s client had not done it deliberately!!

A s the ta nke r co mp art ments were variou s ly filled with between 7000 a nd 4000 litres, the overfill in o ne tank of 10600 1itre s for 10000 litre s which occurred was by chance c ontain e d within free ullage . Lu c kily a se riou s s pill age did no t occur on this occas ion.

Only a s mall number of co mpen sa ti o n c laim s from dri ve rs e ns ued clue to the quick ac tions of th e filling s tation s taff in c lo s in g th e s ite ea rly in the m o rnin g up o n re ce ipt of co ns um er co mpl a ints

lt was al so fortunat e th at no cu s tomer ve hi c les we re in vo lved in accid e nt s clu e to s udd e n loss of powe r o r engine fa ilure as th ey we re being driven whe n co nt aminated fu e l reac hed the ir e ng in es

At t he hea rin g befo re mag is tr ates o n 4 Jun e the driv e r, e mpl oyed by Linkman Ta nk e rs ( n ow TOG Nex us) was fin e d £40 0 w ith £ JOO cos ts He had a lread y had to face inte rnal ac tion s from hi s e mpl oye rs.

T H E OPEN DOOR PRilNCIPLE T O §AIFE TY

Lo nd on Ge ne ral Sa les Ltd of Kingsto n Upo n Hu ll p le aded g uil ty to 1wo c harges und e r Sect io n 1(3 ) of the Pe tro le um (C o nso lidation ) act and sect io n 33(1) o f" the he alth a nd sa fe ty a t Work e tc Act broug h t by th e Trad in g S tandard s Serv ice.

Magistrates s1tt111g on 28 May heard how a routine inspection of a licensed store disclosed several breaches of licence.

The fire door to the store was wedged open , combustible material (cardboard) had been used to mop up a spillage and was left on the floor to be walked upon, ventilation openings were obstructed , no bucket of sand was present and no valid electrical test certificate was in force. The officer was presented with a test certificate clearly identifying a list of faults at the time of testing relating to damage to insulation/gaskets and seal s and marked "DOES NOT COMPLY WITH HSG41 REQUIRES IMMEDIATE

ATTENTION"

No remedial work had been done to correct the faults on the electrical equipment.

The managing director contended at interview that he believed the electrical contractors would have replaced any substandard equipment at the time of the inspection. He said he didn't think he needed to have the items re-tested for five years so hadn't realised that only an unsatisfactory certificate was on file. Commentin g on the practice of keeping the door wedged open throughout the day, he said he had placed a 'Keep Closed ' notice on the door to remind staff.

The petroleum officer was not overly impressed as on the second visit, to en s ure all th e faults found with the electrical equipment and the store had been rectified , th e door wa s wedged open yet again and more rubbish wa s left on the floor.

The mag istrate s que stioned whether al 1 th e safety matter s were now (a t the hearing date) correctly in place and being assured they were ordered fines o f £2000 to be paid plu s £460 costs.

One charge was laid coverin g the lack of a va lid electri ca l certificate and a seco nd for hav ing th e door wedged open.

FIREWORKS

On 24 October 19 97 North Lin co ln s hire Council Trading S tandard s Division rece iv ed a n a nonymou s compl a int that a large quantity of sho p goo d s fireworks were be in g stored in co rrect ly at a reta il premise in Scunthorpe Hi g h S tree t.

ln vest igat io ns by th e departm e nt di sc overe d th a t th e fir e wo rk s we re bei ng sto red Ill th e ir tr a ns it packag in g ju s t 1n .-; 1d e th e de li ve ry ba y at th e rea r o f th e pre mi ses Man y boxes we re ope n, othe rs we re sea led. O n top of on e pil e of bo xes we re lwo s mall e r bo xes con ta inin o c 1oaret te li g ht e rs. I':' '-

T he re was in s uffici e nt sto rag e fac iliti e s o n s it e for th e numh e r of fir e work :-, that hacl bee n de li ve re d to th e s ho p.

The quantity delivered, however, was within the registered quantity.

Amongst the fireworks. two boxes of fireworks prohibited from supply to the general public were found; one containing ariel shells, the other celebration crackers.

The officer involved contacted one of the company directors by telephone whilst still on the site, and explained the problem regarding storage and also that the two boxes of prohibited fireworks had been found. He advised the director to forward some substantial receptacles to the store immediately and said that he would be returning the prohibited fireworks back to the central warehous; that afternoon.

Three metal dustbins were delivered to the site within 2 hours, however, these bins were insufficient storage for all the fireworks on site. The officer, still on site, all the remaining fireworks back to the central warehouse along with the prohibited fireworks. Satisfied that storage was now okay, the officer left the site.

3 days later, the same officer visited another premise owned by the same company and purchased an ariel shell which was on display in a glass cabinet. He then introduced himself to the store manageress and carried out a check on the storage facilities at the site.

He discovered a further 15 packs of ariel shells upstairs in the registered store. These fireworks were seized and removed from the premise. On questioning, the store manageress was unaware of the prohibition on ariel shells, even though 3 days previous, her Head Office had been advised about it.

2 summonses were heard, at Scunthorpe Magistrates Court on Wednesday 25 February 1998, under the Explosives Act 1875 and the Fireworks (Safety) Regulations 1997.

The company entered a plea of guilty. The magistrates imposed fines of £1,000 and £1,500 respectively plus £147.99 costs and the forfeiture of all the seized fireworks.

Letters

Dear Editor

I read Bill Warren's letter in the last Bulletin with some amusement, as he slated off Nigel Hester and the petroleum officers up and down the land.

I wondered if Bill remembered when, as a senior construction engineer for Esso, he had a number of problems and he was glad of our professional services?

I recall one such situation when the approved Esso contractor placed rubbish (yes a whole dustcart full of it), around the petrol tanks and capped this off with concrete on the top. It was only after the intervention by a petroleum inspector that this came to light and was finally removed and the installation made good.

1 thought Bill was glad of our services at the time!

N Young (retired PO)

Does the choice of coatings on your Underground Tanks matter?

Tank Coatings who cares?

Most owners of underground tanks regard coatings as a low priority. Generally they consider the coating to be an integral part of the tank and therefore the tank fabricators problem. They have protection from a long-term warranty and if the coating fails the double skin tank will contain the problem until it has been replaced or repaired. For most owners once their new tank is safely in the ground they don't expect to think about them again for more than twenty years (if at all).

Is this complacency justified? The following article explains why these assumptions are seriously flawed. It explains how coatings are the principal factor in determining the life of your tank, describes why warranties are often worthless and explains how regulators redefining what makes good coating systems. It also points out fundamental weaknesses in the quality assurance controls and tries to provide information so that the tank owner gets better value for money.

Double Skin Tanks only part of the solution

The introduction of polyurethane-coated double skin tanks into the UK in the late 1980's was a major step forward in the drive to reduce the risk of tank leaks. But most of the confidence these new tanks gave was based on fabrication design improvements. Their ability to contain leaks and alert the owner was a major step forward but the choice of coating was only a secondary factor. In Holland about the same time the Dutch authorities were taking a totally different approach. They were very concerned that underground tanks were a potentially serious risk to the environment. Most of their tanks were sited below sea level, pmtly submerged in ground water for most of their life and subject to attack by pollution, micro-organisms, cathodic disbondment and stray current corrosion. But they chose single skin tanks! Instead of putting their faith in secondary containment with the assumption that coating failure was inevitable they did exhaustive tests on tank coatings and selected a solvent free epoxy. They then implemented a closely controlled inspection regime at the fabricators and during installation. Finally they specified cathodic protection to protect areas of coating damage or breakdown and monitor the condition of the tank every year after it was buried. They are justifiably proud of their incident free record since and point to the fact that oil companies are now digging up and re-siting 12-year-old tanks that are in perfect condition. They say that coating specification and control is the key lo their success.

Why Polyurethane?

Solvent free polyurethanes replaced bitumen as the standard · 1· 1· k · I UK · h I 80\. coa mg or underground tan s Ill t 1e 111 t e ate

Although Bitumen was cheap and easy lo apply il had a number CJf serious performance problems:

Vulnerable to fuel spills it is dissolved by petrol

Some types are toxic

Poor adhesion making it easily damaged

Susceptible to microbiological attack (bugs in the ground like to eat it!)

Needs to be applied 5mm thick (or 3mm with reinforcement) to give reasonable corrosion protection

Solvent gets trapped causing blisters if it is applied too thick or without allowing enough time between coats.

When the UK fabricators adopted double-skin tank technology from France they also included French coating products. The principal reason for the popularity of this French coating was its rapid cure that gave dramatic production benefits for the tank builders. Anxious not to be left behind most of the UK's tank fabricators invested in new coating application plant and special manipulators to rotate the tanks that allows them to apply solvent free polyurethane.

Is there an alternative?

There are two principal alternatives to solvent free polyurethane:

Glass Fibre

This coating usually consists of a polyester resin remforced with chopped fibreglass. Although these systems ha_ve mechanical properties and resistance to. fuel effectiveness is highly dependent on the skill of application and has a number of generic disadvantages:

The adhesion to the steel is poor which can cause catastrophic failure if subjected to heavy impact during shipment or installation. US tests showed that holidays were detected when GRP coatings were subjected to impact from heights as low as 40 inches.

Its poor permeation resistance means it must he applied at least 2mm thick.

When applyjng the coating it is critical that fibres are exposed on the coating surface as this will wick moisture to the steel surface of the tank and cause corrosion.

• tl t are very

Polyester resms contain components ia fl d t() tile al1 pll·c,1tor and the ammahle. hazar ous · environment.

• Damage if very difficult to identify and repair because of delamination between steel and coatmg.

• The US Underwriter Laboratory Tests showed it is vulnerable to attack from polluted soil when chemicals such as sulphuric acid, NaCl, HCI, NaOH leach into the back fill.

These weaknesses have resulted in most European tank fabricators abandoning the use of GRP many years ago.

Epoxy

For many tank fabricators the only realistic alternative to solvent free polyurethane was coal tax epoxies. This

represented a dramatic improvement in coating performance over bitumen but their slow cure, safety hazards and environmental problems have all but excluded them. But in Germany a new generation of solvent free epoxies was becoming established as the first choice of most underground tank owners. Their popularity was based on coating performance rather than advantages to the tank fabricators and there are now thousands of tanks coated with this system (30,000 in Holland alone). The table below shows why tank owners preferred it to solvent free polyurethane:

Advantages Benefit to Tank Owner

Application

• can be applied without rotating tanks

can be applied at higher ambient temperature

less vulnerable to off ratio mixing faults

can be applied at only soo··µm (0.8 Kg/m2) easily repaired longer over-coating interval (+3 hrs) much longer pot life longer shelf life (+ 6 months) curative will not crystallise

Storage/Handling Damage

• very high adhesion to steel substrate

high abrasion resistance S02 resistant resists marine environment (passes 2.000 hr saline mist test)

Porosity

• low structural porosity • tow water adsorption level after _installati.on • can use cathodic protectmn to monitor/protect damaged areas

Safety

• no isocyanate curative with carcinogenic risks

• 110 dangerous hi-products from hurning

Underground Resistance

l "tthodic dishondment Ill long term tests

• no '

highl) resistant to ful'I spills rL'sistant to 111icro-organ1sms to polluted soil (pHX pH-f)

• increases the range sizes that can be coated; removes bottleneck in production • applied in countries where summer temperatures exceed 30°C

reduces risk of uncured patches/layers of coating being missed by QA reduces cost of tank more likely to be repaired properly reduces risk of delamination reduces risk of dry spray which causes porosity and reduces life of the coating reduces costs and the risk of applying out of date material this can damage application equipment causing poor coating prope1ties

resists puckering/delamination which keeps repairs local and simple to repair . resists damage from straps and backfill resists environmental pollutants "d 1 f "ltii·e caused when tanks are stored av01 s car y ai at ports prior to installation

greater corrosion resistance leading to longer coating life . reduces demands on cathodic protection and reduces risk of cathodic disbondment

reduces risks of coating failure caused by undetected transit/installation damage or breakdown caused by failure in quality management

reduces costs of safety and removes the need for indemnity cover avoids on site hazards and disposal problems

• allows cathodic protection and resistance tn stray electrical current

• a\ oids coating damage and extends the life nl tl1L' tan!-.

Will my warranty protect me?

Threatened with an invasion of GRP tanks using US technology many European tank fabricators were forced to match the extravagant 30-year warranties on offer. Although most fabricators have complete confidence that their tanks have the structural strength to contain fuel for this long, can they be as confident about their tank coating? There are so many factors beyond the control of the coating material manufacture he will inevitably include many exclusions in any cover they will offer. These typically include:

• poor preparation of the steelwork (sharp edges, weld spatter etc)

• poor shot blasting

• mix failures caused by spraying equipment

• coating applied less than specified minimum thickness

• coating holidays (pin-holes, misses)

• handling damage (straps, slings, chains)

• installation damage (chips, scratches, dents)

• polluted backfill

• cathodic disbandment

• constant high water table (immersion conditions)

• sulphur reducing bacteria attack

• stray current corrosion (power lines, underground tracks).

The owner of the tank can only ensure that his warranty will not be worthless by carrying out a detailed site survey for each tank. Since these surveys often cost more than the coating there is little likelihood that there will be enough independent evidence to support a claim against the coating manufacturer.

If a tank has been underground for many years before the failure occurs it will be very difficult to establish if the breakdown is caused by a material fault or an application fault and this inevitably leads to disputes that leave the tank owner the only party with material loss.

So what can be done? The following features can reasonably be expected to be included in any tank coating wairanty:

• •

Cover is enough to pay for in-situ tank repairs and not only the cost of coating which is normally less than 10% of the tank price.

There are no exclusions for site conditions or cathodic protection

• The warranty is insurance backed and does not rely on the financial stability of the supplier

• The term should be at least 10 years. Any more than this stretched credibility unless the coating is backed up by cathodic protection.

Ir the coating manufacture cannot monitor the performance or coating operations in the fabricator and offer reasonable Warranty protection the tank buyer should seriously consider restricting the use of these tanks to sites where:

• soil resistivity is high

• the tank can be easily/cheaply removed if the coating fails

• fuel sales are low and disruption will not be significant

Can Cathodic Protection help?

The short answer is yes! It is almost impossible to completely rule out a defect in the coating its application or any damage in transit or. installat_1on No matter how careful the quality assurance 1s there 1s still a significant risk that the coating will not reach its yre. The consequences for the tank owner of the coatmg fmlmg are significant. Although double skin tanks can protect the environment they will not stop the disruption caused to and shop sales when a tanks outer skin has failed. protection provides the only long term of areas of damage or breakdown and momtonng the cond1t1on of the tank after it is buried.

The two main reasons why Cathodic Protection has failed to establish itself in the UK on underground petrol tanks are concerns about cost and doubts about its effectiveness. The early attempts to establish its use proposed impress current systems because of misplaced concerns about earthing arrangements specified by HSE. In most of the UK the soil resistivity is between 10 to 50 ohm m and sacrificial magnesium anodes can provide very effective protection. The anodes are cheap, simple to install and will provide protection for more than 20 years. By installing two low-cost sensing electrodes the tank owner can also monitor the performance of the system at any time.

New Regulations and Controls

The implementation of the EU Ground Water Directive and the changes to introduce a consent scheme for petrol stations rather than licensing are already influencing the choice of coatings for tank owners. In several EU countries they are implementing new legislation to insist that Cathodic Protection be installed on new tank installations. If the US model is followed then there could be new requirements to retrofit cathodic protection on old sites. At the very least the importance of coatings to the protection of the environment and the owners investment is clearly established. In the latest draft of the Guidance for Design, Construction, Modification and Maintenance of Petrol Filling Stations it states "the most effective corrosion protection is when high quality coatings and the appropriate cathodic protection system are used in combination"

Conclusion

In the past the choice of tank coatings in the UK has largely been driven by the priorities of the tank fabricators. It is clear that Solvent Free Epoxy Coatings offer significant benefits to tank owners especially when used in combination with cathodic protection. The time is right for change. the technology is well established (over 20 years). the performance benefits are demonstrably proven hy independent tests and the UK tank buyer can now specify an alternative coating with confidence.

Author Martin McTague. Projection Manager Tank Coatings Permatcx GmbH. Yaihingen. Germany

TESTING SYSTEM IS WATER- TIGHT SOLUTION FOR PROTECTING SUB SOIL ENVIRONMENT

By Chris Cooper of Fibrelite Composites Ltd

Of these different components of the underground system , the tank access chamber/sump is a recoanised weak link but it is also where a solution is now available.

Regulations world-wide call for access chambers/sumps to be kept free from water and provide a secure installation for petrol sp illages.

Before the use of GRP or polyethelene , mo s t c hambers were built from brickwork or concrete. While they were structurall y sound , they were incapable of providing a chamber that contained petroleum spirit and prevented the access of sub-soil water.

Cunent chambers a nive on site preformed with exte ns ions and pipe kits designed to provide a se cure installation but these are still associ a te d with problems. So what goes wron g ? In some c ases the equipment m a y be faulty but , more often , the installation is to bl a m e.

Some times thi s m ay not ev e n be the inst a ller ' s fault: components c an chan ge and in struction s vary. How e ver, th e b asic probl e m has been th at there are no sta nd ard s or c heck s the in stall e r ca n cany out to ve nfy the mtegnt y of the in stallation.

A s a result , when ac cess covers are pulled back , they o ft e n reve al poor installation s affec ted w a te r, co llaps in g wall s o r bo th In a bid to combat thi s, th e ta nk s and · k ·e te sted w hy not al so tes t the access ch a mbers? p1pe w or ' a1

1 · e 1tal pi·otec ti o n -and busine ss there is n o n e nv1ronm 1 < • . t d· 11 0 sti.11 Fibrelite C om pos ites , which operates ro o m 101 s an 1 o · I b II l , de elo ped a Ch a mb er Tes tm g S ys te m (CTS ) g 0 a y, m s v • l · 1 tl at tl1e in staJl e r a nd th e co ntra c to r c an w 1tc 1 mea ns 1< . l h w o rk with acc urac y and confid e nce co mp e te t e 11

When a n expe ns ive underg round environment al pipe w o rk s yste m 1s purchased for a petrol station the c u stom e r naturally e xpec ts it to me e t tll · d e require spec 1f1cattons a nd sta ndard s a t the ve ry leas t Otl · < 1e rw1 se , w hat is the pomt ?

Pro tec tin g a ll as pec ts of the e n v ironme nt has beco me o ne o f the world ' s mos t univ e rsa ll y s upported iss ues a nd is backe d by rig orou s g lo bal leg is la ti o n. Large s um s of mo ne y are be in g s pe nt 111te rnat1 o nally by o il c o mpan ies a nd o th e r bodi es to furth e r e n vironm e nt a l protec ti o n a nd thi s includ e s preve ntin g co nta min ation of th e s ub -so il a nd w ate rc o urs es

M a n y a nc illar y meas ure s a nd mo nit o rin g dev ices alread y e x is t to co pe w ith spilla ge s and lea ks Howeve L des pite thi s. fund a me nta l, unreso lved probl e m s o f pe tro l a nd wa te r see pag e still e xist a ro und the und e rgro un d ta nks. pipewo rk a nd acces s c ha mb e rs w it h po te ntia ll y seve re con se qu e nces bo th in cos t ly re medi a l wo rk a nd possibl e la nd valu e pe na lti es

C TS. fo r w hi c h inte rn a tional pate nt s hav e b.een a p p li ed , is f .· dl y tes tin a sys te m des ig ne d to ve nfy th e v ari o u s a use r- 11en · o sta a es of c hamb e r asse mbl y. b

Fibrelite , w hi c h was found ed 14 ye ar s ag o a n d fac tlll ed th e worl d ' s fir st co mpo s ite tan k acc e ss m a nu < c ha mb e rs a nd cove rs, ha s deve loped th e sys te m w ith th e k no wl edge tha t sub so il w ate r pos e s th e m a in p ro bl e m for access c ha mb e rs/s ump s T he re 1s dire c t co rre la ti o n be t we e n t he c ha m be r 's buri a l de pth a nd th e pote n tia l w ate r pre ss ure th a t may be e xe rted o n it s j o in ts. pe ne tra ti o n s a nd wa ll s.

In s ta ll e rs need to b e a wa re th a t. eve n w he n ta nk in s ta ll a ti o ns ar e see n to be dr y a ll equipm e nt e le m e nt s mu s t still be se cure to preve nt th e fl ow o f a n y pe trol intu t he sub so il. A lso, it is not un co mm o n fo r th e ex c a v a ti u n it sel f tu bec ome a wat e r s um p fo r th e s ur rou nd in g a rect afte r c om p le ti on . T h is m u st a lwa y s be acn1unte cl for durin o "" co n st ru c ti o n

Th e Chamb e r Te sti n g S y stem is d e sign e d t o b e u se r.fri e ndl y E ac h te st tak es o nly 10-15 mins d ep e ndina o n chamb e r ..., vo lu me

A chamber unit comprises the base, round or square, extension pieces where appropriate, pipe seal kit and cable entry kit, all designed and manufactured by Fibrelite. Ideally, the unit must be watertight from tank to finished forecourt level. Dimensions vary from lOOOmm to 1400mm in exceptional circumstances, to allow access for servicing/maintenance equipment.

The principal of the CTS is to check all joints during assembly and on completion before and after backfilling.

The CTS simulates water pressure by applying a vacuum to the chamber. The equipment allows for flexibility in the size of chambers and whether they are round or square. Each test takes only 10-15 minutes depending on the chamber volume.

When using the CTS, the installer will arrive on site and assess the installation whether new or 'live'. If existing tanks are 'live', he would operate the CTS remotely at a distance of at least 5m from any tank chamber or classified equipment.

The chamber is then connected to the tank. The first task is to test the horizontal joint between the tank and chamber. The depth below finished forecourt level is measured; the test plate is located on the chamber and connected to the CTS module.

Power is connected to the CTS enabling the depth of the tank/chamber joint to be selected on the panel. The test button starts the removal of air from the chamber (shown by a series of lights) until it is evacuated to a predetermined level. The chamber is then on test.

At this stage the vacuum level will relate directly to the depth setting and the anticipated level of water pressure. The test module calculates the test period after which a pass or fail light appears.

If the test fails, this indicates that there has been vacuum decay and that there is a leak. The leak is found by spraying a liquid soap solution onto the outside of the tank/chamber joints and the test re-applied. By using the test plate viewing panels. the location of the leak can be seen and appropriate action taken.

On completion of the test the pipework can be completed and then all pipe outlet joints can he tested as descrihed b f e ore. It would usually be assumed that the pipe outlets would be tested at the same depth as the tank/chamber joint.

As work moves up the chamber to the extensions and c_lectrical ducts, appropriate reductions in depth test and simulated water pressure can be accommodated. When the installer has confidence in their ahility and the CTS. they n1ay cl111 h · osc to c eck the chamher once only on completion 01 the installation.

In every case we recommended that tests are carried out on completion of the chamber and after backfilling of n1atcri-t1 w . ' · ork can continue on the top ol the chamber and allow c<11n1JI ,. · I · · · I · l t·· I e ion ol t 1e surtacmg matena s w1t 1 con 1c ence and tlw ·11111· ·1· I ·' 1opnate cert1J1calion 1 requll'ec.

At present, of course, it is necessary to wait until the site is concreted and finished to look and see if a watertight installation has been achieved with all the inconvenience and inadequacies this involves.

Various added-value tests are incorporated within the basic chamber test and can be used, as necessary, as part of the testing procedure.

By closing the chamber with the test plate, the existing tank, lid and pipework can be tested in the same way as the chamber. This may reveal defective tank gaskets, leaking suction lines and holes in offset fills and vents. The test also checks the final joint between pipework and tank connector (never previously checked) and it has been known to detect holes where manufacturers name-tag rivets are missing allowing water into the tank.

The Fibrelite CTS, which is being exhibited at three international exhibitions this autumn, will be offered as a 'user friendly', good-practice product from which everyone the customer, operator and installer benefits.

1. Equipment Quality

The CTS checks the chamber for adequate wall thickness (deflection), porosity, quality and design of pipe entry kits.

2. Performance Related

Offers the opportunity for the installer to be confident that all materials and joints are secure and that he has done the job correctly.

3. Certification

Chambers can be certified to the main contractor/customer is required.

4. Disputes

Arguments between various parties about payment on sub-standard installations can be avoided.

When the CTS is used, one topic that will require resolution is ownership of the project. The original installer ?f the chamber and pipework may not be the one who mstalls the extensions and electrical ducts and completes the project. This type of detail will require some management attention but it should be possible to reach a solution when the benefits are so great.

There can he no doubt that those in the international petrol station industry will recognise that the clevelopment of the CTS presents a ·water tight" environmental solution t'. 1 a potentially very expensive and certainly a highly-emotive predicament which. when things do go wrong. can have massive implications.

Chris Cooper is Tech11irnl Sales Manager 1\'ith Fi/Jrelite Co111posite1· Ud, Skipto11. North Yorkshire. tel 01756 799773.

The exhibitions at which the Fibrelite l 'ham her Testing System can be seen are Convex '98 USA and Automechanika '98, Frankfurt, both m September and APEA, Telford, in October.

Where do all the vapours go?

If the vapour recovery system integrity is complete from tanker loading, distribution and offloading at the retail site, then the vapours should be safely returned to the terminal for subsequent processing.

What can go wrong during this cycle known as Stage 1a and Stage 1b vapour recovery?

Previous articles in the Bulletin have addressed Stage lb and Stage 2, (automobile refuelling) so what interest is it for Petroleum Officers to be made aware of Stage 1a which is the loading, transport and terminal operation?

Well, the road tanker is the "common denominator" between loading and offloading, and is the transport medium for product and vapours. If this transport medium is not "product and vapour tight" then it can reflect on the offloading efficiency and recovery of vapours at the retail site.

If there is a vapour leak path on the road tanker, then air can be drawn in during offloadig, and this can affect the free collection of returned vapours from the underground tank. The consequences of this could cause problems which might appear to be retail site related, but in fact could be due to a malfunction in the road tanker vapour recovery equipment, which is quite complicated.

It is important therefore to be aware that the latest requirements call for periodic testing of the road tanker PN valves every 24 months, and the tanker shell and other equipment every 36 months.

A new tanker test record plate needs to be fitted, and this is shown in Fig 1, with typical dates added, and the tankers test validity can be readily checked by a Petroleum Officer.

Requirement

There is a requirement to test petroleum road tankers for may not be appreciated by all those concerned 111 obta111111g certification of their fleet Th · e1e 1s confusion in the market place as it was the 1 · t t' t • · . n en 10n o adopt ADR 111 the UK from the I st Jan 1999 aild · t · • 111corpora e appropnate CEN standards when approved and · . . . issued .

However, with the best of intentions the ·I tt. · . . . s o mg 111to place of all the 1eleva'.1t_ documentation in the correct time scale seems fail: and elates will have to be revised to take account ol this. It 1s now suggested that ADR will be delayed in being implemented from 1/1/99 to l/l/200I, due to lack of approved standards.

We seem to he faced with some problems and yet at the same time have to comply with current legislation. This article attempts to clarify the status as of mid year 1998.

The requirement for testing is as a direct result of the European Parliament & Council Directive on the control of volatile organic compounds l VOC l emissi1ms.

In order to meet the mandaton requirt•mcnt!-. nf the \i( )( ·

By Kevin Dawson

directive, the HSC produced the Approved Tank Requirements 1996, which in combination with the S.I. 2095. Carriage of Dangerous Goods by Road Regulations 1996, spell out the need to test the PV valves, the tanker shell and other associated fittings on a periodic basis.

The problems

Leakproofness implies that the tanker has to be not just product tight, but vapour tight, and it is the vapour tightness integrity that would in the main appear not to be currently incorporated into testing methods commonly in use.

The equipment failure modes

Leaks of either product or vapour can occur through the tanker shell caused by stress during operational use, and the shell itself being of welded construction can fail at the weld joints, the inter-compartment baffles, the vapour coaming manifold, run off piping or of course through collision and accident damage.

The operational equipment such as:a) footvalves b) PN valves c) vapour collection vent d) vapour recovery connection f) manlid seating g) dip cap seating can fail or exceed their designed operational limits through wear and tear or possible misuse.

The static pmts such as gaskets can "relax" over ti_me. and l d hl.gh level cut off probe has been lound to even a rep ace . · · · o "O" nno seal leak vapours passmg a m1ssmo e

fl 'bi our· coamino hoses between the manifold The ex1 e vap • e llection vents are pmt1cularly susceptible and the vapom co · 1 "b .· d" d . desions of hose wit 1 a u11e e.u th to leaks. an newe1 o · 1 d 1 anised into a tluck end flange makes for contmmty ea , vu c · t ·dy aild leak ti"ht connection. a much more s m • o

d I k Pl 11 o cm avoid many potential leaks. and Goo 10use ee o • 1 · e ·ti'on of the rubber seals 111 openable the reou ar msp c I.de d' t bes the tiohtcmng down ol flanges on gasket man 1 s. 1p u · · "" . _ . . f 1· plus the attention to the seal on the flexible seat1110 1t mgs · 0 h ·es will help to eradicate vapour leaks. coammg os

Confusion of Documentation

The following are the fundamental documents which are relevant to the requirement to test.

References:-

1/ European Parliament and Council Directive 94/63/E(' 1994

The control of volatile organic compound l VOl') emissions rt'sulting from thl' storage of petrol and it-. distribution from terminals to sen ice -;tatiom

2/ Thr ( 'arriagr of Dangrrous Goods Road Regulations. Instruments No: 2095 l 199()

Purfleet Commercials

The Carriage of Dangerous Goods by Road Regulations 1996 S.I. No. 2095. Reg ll(l)(a) & Schedule 3

Tank Serial No:- SN I Tank Chassis No:- CN

ITANK I T01/07/97 l I I ITANK TI OI/07/2000 11 I IPN.V 11 11 I I 11 11 I

Fig 1

Manhole cover assembly complete with PN breather valve and emergency venting

Vapour collection vent interlocked with foot valve or HLCO operation

Vapour collection line from coaming through tank to low level Dipstick access

API openable adaptor

Pneumatic controls within cabinet

Coaming manifold

Vapour collection connection interlocked to loading rack controls

Locking bar with interlock to trailer brakes

Highlevel

cut off (HLCO) connection interlocked into loading rack controls

3/ RSC Approved Tank Requirements L93 1996

The provisions for bottom loading and vapour recovery systems of mobile containers carrying petrol. (Approved Requirements)

4/ PrEN 12972 Tanks for the Transport of Dangerous Goods 1997 Testing, Inspection and Marking of Metallic Tanks (Draft for Public Comment)

5/ RSC Proposal for Approved Tank Requirements; and appointing Bodies to carry out examination of tanks. 1998 (Consultative Document)

Analysis

For the purpose of this article, we can consider that the two issued and legally binding documents directly relevant to the petroleum tanker industry are the following.

21 Statutory Instruments 1006 NO 2095. 1996 Regulation J 1(I )(a) Schedule 3 refers to:-

SPECIAL REQUIREMENTS RELATING TO TANK CONTAINERS AND THE TANKS OF ROAD TANKERS CONSTRUCTED BEFORE I JANUARY 1999. (This document revokes the earlier document dated 1992)

3/ RSC Approved Tank Requirements 1996 are LAW and are directly as a result of the VOC Directive. It specifies the following:-

Clause 34 Pressure vacuum vent valves shall be tested at intervals not exceeding 24 months to ensure the following

(a) the maximum leakage rate of the valve when it is in any orientation shall not be more than 15 ml in 30 minutes

(b) the valve will commence to open when the pressure or vacuum in the tank is within 20% of the appropriate nominal set pressure of the valve.

Clause 35 The tank fittings (notwithstanding paragraph 34) shall be subjected to a leakproofness test at intervals not exceeding 3 years.

The Approved Tank Requirements 1996 have been in force since the I st September 1996, and requires that any petroleum cat1"ying road tankers built after the 31 st August 1996 or any tankers converted to bottom loading after the 31 st August 1996 must hy law comply.

A road tanker vapour collection system should be tested W ta nkers and then comply with the Leakproof11ess on ne , · requirements as prescnhed m ATR 1996. but only _in the following manner would appear to be able to venty this. especially for vapour leak paths.

The future rEN12972 is understood to be almost through its final stage. and could be issued during 1998. This will describe test methods and marking of metallic tanks. and will probably he incorporated eventually into ADR.

HSC Approved Tank Requirements 1998 (Consultative document) may be delayed due Ill a proposal from liN Ill change the implementation date to l/2/2(l(l I dut' lo lack of appnived standards.

Compliance

It is considered that compliance with the legally binding requirements can only be verified by testing, and Purfleet Commercials have introduced a Precision Leak Detection System for Pressure and Vacuum testing which has many benefits:-

• minimum tanker off road time, typically 4 hrs

• test can be combined with other service work

• eliminates the requirement to (i) de-gas (ii) remove any parts (iii) fill with water

• portable to facilitate testing at customers premises

• checks product & vapour leak sources

• record sheet, approval certificate and new chassis plate

• commercially attractive pricing

• competent person status (approved body pending)

In fact, a complete Reg ll(l)(a) (old Reg y) test, certification and compliance with the ATR 1996 and SI 2095 requirements can now be completed in typically 4 hours with the Purfleet PSL approach rather than the more typical 2 days, without any of the consequences of having to fill/empty each compartment with some form of liquid product, and if water is used. having to "safely'" dispose of contaminated water after the test. A new inspection record plate is required to reflect the latest regulations. (See Fig I)

The system uses low pressure, oxygen free nitrogen gas operating up to +/- 200 Mb. Precise and control can test all equipment at its specified operat10n test hm1ts.

Petroleum tankers were considered to be non-pressure vessels, but in fact are low pressure transport tanks. and low pressure will be defined as less than '.!2 the _Pressure Equipment Directive through DTI. This dtrect1ve will be the Transpmtable Pressure Directive and could be 2 or 3 years from being issued.

The PSL system testing is therefore more appropriat_e for petroleum road tankers (and fixed tanks) than higher pressure pneumatic and hydrostatic methods. and other systems which are faced with the requirements to degas. with associated extra cost implications.

Conclusion

The industry has to operate in a proven safe and environmentally friendly manner. and comply with legislation. This can imply ever spiralling costs. but with innovative systems such as the Purtleet PSL approach. then safety. precision and certification at optimum cost is achieved with lower downtime for the vehicle.

Purtleet use fully trained '"Competent Persons·· to carry out the tests. and can have a fitter to rectify any faults found. (Mnst faults arc readily rectifiable as the test prm·ccds l

Eventually '"Apprmnl Bodies"" \viii he appointed lo out the tests on an independent hasi and PurtkL't han· registered with llKAS tu initiate apprm·ed statu hut thi.., cannot he finalist'd until t'ither tlw nl'\\ :\l'R j.., 111\ uk.cd. nr ADR j.., irnpk111L't1led in .Ian tl)l)l or latL'r

IThe is that the to test for Le;kpruofness is with us now!

STAGE 1 B - LET THIS BE A WARNING FOR EVERYONE

By R. Carter Petroman, Cambridge

We are all well aware that Stage I B has its little idiosyncrasies that vary from site to site but we would like to take this opportunity to highlight a potential hazard that could be waiting to surprise an unsuspecting dealer or tanker driver.

Throughout our involvement with vapour recovery and in particular Stage I B, we have encountered many problems. Thankfully, most of these we have managed to resolve but there still remain a few for which solutions have yet to be found.

Many of these problems are due in part to the programming of the installation of Stage I B and of course later this year we will see installations of the smaller and older sites. Some of these will be borderline cases with regard to volume and others will require substantial work in order to facilitate the installation.

This promotes the question of defining if a site is compatible with Stage I B and perhaps more importantly, how much the dealer is prepared to invest in order to meet the necessary requirements.

These may be the subject of a much broader discussion but one point that must be emphasised is the potential danger and risk that is waiting within many sites. This risk must be brought to the attention of all dealers. operators and tanker drivers.

One must hopefully assume that any Stage I B installation. whether already fitted and in operation, or yet to he fitted. is of the highest quality. Nevertheless on how many forecow1s had a detailed site survey been carried out and specific measurements taken to ensure a quality installation'? How many contractors measure the length of suction lines in relation to the length of fill pipe or drop tube within the storage tank'! Probably not all!

The danger is now apparent that if a storage tank is run very low and the suction line is below the level of the fill pipe or drop tuhe. then the lic1uid seal wiH he broken. The result is that an open circuit is created w1th111 the Stage I B system. allowing the tank ullage space Lo he open to atmosphere. Under these circumstances. If two pots of spirit are hcing off-loaded from the deli very tanker. _carncovcr is released from the empty tank. II w1 lJ f ly-otf at a considerable force reJca;,ing vapour directly from that fillpipc onto the forecourt at an alarming rate of volume'

In thl' unfortunate event that these circu111stances should occur. the delivery must he stopped and the ca111-cmer refitted onto the relevant fill pipe Any cars on the forecourt

must stop and switch off their engines until the vapour has dispersed. Meanwhile as the pressure in the Stage I B system decreases, resume delivery by off-loading to the empty tank. These principles will also apply to any newly commissioned sites or on sites where grade and tank changes have taken place.

We would therefore strongly advise that when a storage tank has run out of product, that tank must be off-loaded with product first. In the event of more than one tank being empty, then both should be supplied simultaneously with product to recreate the liquid seal in the storage tanks.

It is therefore paramount that all cam-covers be retained with a webbing or strap as this situation could be very dangerous to an unsuspecting tanker driver and more so with Driver Controlled Deliveries. The only way to avoid this situation is to measure the length of the suction lines in relation to that of the fill pipe or drop tube. If this is not possible, then the suction lines must be removed and measured and refitted at the shortest length.

This situation is rarely going to occur on a site with a high volume and large storage facilities, but the sites with smaller storage facilities and increasing sales volumes are more susceptible. This is a situation that could apply to any site with Stage 1B, so operators with this installation must be made aware of these facts as well as the tanker drivers who should be warned prior to the delivery of an empty storage tank and advised accordingly.

Even where there is pe1fect liquid seal of the fill-pipe or drop tube in the storage tank there will always be a certain release of pressure when the cam-covers are removed. This is due to product rising in the fill-pipe due to the increasing pressure within the storage tank compressing the air between the product level and the cam cover. This pressure will rnry from tank to tank and from one off-loadino order to another as well as from site to site.

We hope that this warning will be well heeded and that these potentially dangerous situations can be avoided.

VAPOUR BALANCING PROBLEMS

DISCOVERED

By Tim Foster, Chem Safe

Chem Safe Tank Testing (UK) Limited were recently asked to undertake investigations on a number of petrol filling stations, to determine why these sites were experiencing problems during tanker deliveries. The sites all had one thing in common, they were all fitted with vapour balancing systems of various types.

It has long been believed that problems occurring on sites fitted with vapour balancing systems, such as vapour lock, excessive pressure and product blow back following delivery hose disconnection, were associated with pressure drops caused by long and convoluted tank vent pipes and vapour return pipes. These pressure drops would reduce the speed at which the pressure built up in a tank during delivery, could dissipate and balance with the delivery tanker. Since the product being delivered is gravity fed and not pumped from the delivery tanker a stage occurs where the produce head is equal to the back pressure in the tank thus crating a vapour lock situation.

This being the case it is hard to understand how on sites with large tank farms, where all the tanks are situated in the same vicinity and the probability is that all the vent lines run through the same pipe trench, that problems may occur on a single tank. Why not on all the tanks?

At Chem Safe we had a theory abo t 1 u an a ternatlve cause for these problems. It became app·ti· t h 1 < en t at t 1ese problems were more prevalent on sites that 1 d M vapour balancmo systems mcorporatmg vapour retei1t· d . "' S ion ev1ces such as the Vapa- ava. ·

In such a case the principle is t . . "bi · · 0 1etam as much of the V'liJour as poss1 e w1th111 the site 1 < · · · · s oraoe system TI · · · · ·l · ved hy mamtmn1110 a .· '=' • • • 11s 1s ac ue '=' posit1ve p1·esst11·e 'tl 'd . . 1 . V'' · · w1 1111 sa1 storaoe system o - .•mb, by utilis' · I "'. 1e the valves will on! · mg pressure actuated va ves. · · Y open tl) II I d I. a ow vapours to escape hack to t 1e e Ivery tanker on, I : · ce t 1e whole of the sites storage system exceeds the 35mh 1wess . h • · • · LIJ e t resho Id.

It was initially thought that this posi·t1 · · · ve pressur 'hi t' · problems " · · e Wds I·es11ons1 e 01 • c<1used dur1·110 d 1· · · t , , • i=- e 1venes. especially on s1tcs that h<1d h<1d the Yapa-S·tva i·et. f" · < 1o 1ttecl to an existing stage Ib v<1pou1 balancmg system with which Pl·eviously there had heen no problems. Howevei· • 111 some C·tses tllese problems appeared to he storaoe t·iilk .f <. · · '=' < spec1 ·1c. that is they when de.hvenes were heing made to one tank w1thm the of _tanks. What one factor would make this tank d1t1erent trom the others in the system·)

Chem Safe Tank Testing carried out tests at thirteen sites over a two week period. Some of these sites had heen rittcd with vapour balancing systems. some incorporating the Vapa-Sa\ a dl'\ ice and were experiencing problems sud1 as hack pressure in the rill pipes. sl\l\\ delinTies and \apour

escaping from the fill pipes both during and following deliveries. Other sites were tested prior to the installation of vapour balancing systems, i.e. the vents were open to atmosphere. The tank installations varied, some tanks had direct fill pipes, whilst others had off-set fills.

The results we achieved seemed not only to confirm our theory but were also quite incredible. Out of the thirteen sites tested only one site passed, having leak free internal fill pipes and therefore so called 'liquid seals', the other twelve sites had tanks that failed our test, these tanks had leaking internal fill pipes and therefore these tanks had no liquid seals. (See Charts)

What you may wonder is the relevance of these findings to the problems that occur during delivery? The answer is two fold:

I. It is part of the licence petroleum storage tanks have a liquid seal, this 1s the _mam I · · terTial fill pipe The reasonmg behmd this mvmg an 111 • • · t · tllat in the unlikely event of a fire. m close reqmremen 1s · · t th ·toraoe tank only the vapours m the fill proxurnty o e s "' · ,. . f 1 t k .11 ionite makmo the tue eas1e1 to cont101. pipe o t 1e an WI e "' h · 11 ·qui'd se·1J on the mternal fill pipe. 1.e. the Where t ere 1s no < 1 fill leaks allowin" vapours from the ullage mterna 1 pipe < i=- • f h t k back into the fill pipe. the whole of the space o t e an k I d ionite under the same scen<1no. storage tan wou "'

f I I ak s found on internal fill pipes were in 2 Most o t 1e e< · · If f th tank mainly at its J0111t with the tank the upper ha o e , . . . . bi h . . d 1 ·ed into a tank with such c1 p10 em. t e hd As fuel is e ive1 · · . d . the tank, the vapours 111 the ullage Pressure bm I s up Ill · · · k it escape via the tank vent at a last space of the tan , canm < t··11 d I fore escape back mto the ' pipe. enough rate an t 1e1e

f l d livery this may not cause a problem At the st·irt o t 1e e · < · e for the pressure to reach a critical 't 1 ·11 t·1ke some tnn · as 1 w < · roduct in the delivery tanker 1s such Point ·1\so the head of p 1 1··11 · < · mur tnpped 111 the 111terna 1 pipe tl at it C'\11 force any Vclf ' 1 ' 1 d f' fuel in the storage tank. However as t tl ·ouoh the 1ea o ou 11 e tl iJressure mcreases 111 the I I 1· ·y pnwresses so 1e tie te 1ve1. , d l .i1ead of product on the delivery tanker storage tank dn slows or stops as the vapour build up decre·1ses the de 1 ' ei Y· · · I ·1 1· <- 1nd the head of Juel 111 t 1e le l\'ery I fll pine inc1eases ' 111 tie .' t ••. .- , t t 1 force the trapped \·apour out of thL' t·rnk ·r is msuthc1en ( ' c · · 11 ·kl When the delivery hose Is fill IJine (vapou1 lL . . .. . ... 1· , . . t 1 , ·. tranned m tht' 11'1pipe1s <th L to L Xp<1nd disconnected tic dll t t • • ·k it of the hll pipe. tlm. L,\ltsLs p1od11L t ·md escape h<LL 01 · < · · 1 , , 1nliur pockets to surge back out lll the C'llloht above tie 't ..' "".. ,. 11 V· )llr will continue to he forced haL·k llUl ot fill/off SCI f 1 · <ipl · til either ·1 "as cap is titled lll' tlK the 1111 pipe un ' "" ' pressure in the tank decrt•ases.

Further investigatinns b\ our test ,·nginL'l't"' l'L'\ eakd " I )I L"ttISl'S for thi.., 11roblc111. l'nll\1. no "L'als num )L'r l , · · · , ,

fitted on removabl e internal fill pipes, poor installation of internal fill pipes , to non vapour tight overfill prevention devices and even holes in th e wall of the internal fi ll pipes.

Indions are that once these problems have been remedied deliveries are ach ieved wit h no problems.

These problems wou ld not manifest themselves during normal tank and line test procedures, as the leakage is within the sys tem Chem Safe now offer a very quick and

inexpensive internal te st service, which sho uld we find a fai lure inclu des furt her investigatio n to determine w here the fail ure li es. We can a lso remedy many of the problems on site or if this is not possible offer advice as to ho w such situations can be overcome .

If

have any questions or require further information ca ll now on: 0990 133111 , fax us o n 0990 1331 I 0 or e-mail us on chemsafe @force-group plc.demon.co .uk

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