Degree Lecture Notes - Building Services by Sheilly Tan

Building Services (BLD60903/ARC2423)

AIR-CONDITIONING SYSTEMS

Lecture by:

Mohamed Rizal Mohamed School of Architecture, Building, Design Taylor’s University, Malaysia

Definition  The control of temperature, humidity, air cleanliness and air movement & heat radiation with mechanical means, to achieve human thermal comfort.

Factors for using air-conditioning system  Comfort (in a room)  Performance (workers, machinery, etc.)  Health (prevent smoke, dust, ect.)  Equipment (computer, electronic equipments, etc.)

Factors related to human comfort  Air temperature Temperature control – supply of cooling or heating (normally between 22ºC – 27 ºC)  Relative humidity Humidity control – humidification or dehumidification  Air movement is controlled to avoid the sensation of cold drafts and at the same time prevent the formation of pockets of stagnant air within the conditioned space.  Air purity Control of air purity – filtration of the supply air

Building Services Other building services related to air-conditioning system: 

Electrical supply



Water supply (for bigger & more complex systems)

Air-cooling principles  As gas is compressed, it will liquefy at a given point and as it liquefies, it will release a large amount of latent heat from within the gas  As the pressure on the liquid is lowered, it vaporizes back to gas, and as it boils through the vaporizing process, it absorbs a large amount of latent heat into the liquid

RELEASE HEAT

LIQUID HI

PRESSURE

LOW

GAS

ABSORB HEAT

How an air-conditioning system works?  Removing heat from the air inside the room and releasing this collected heat into the air outdoors. Two cycles involved:  Refrigerant cycle  Air cycle 1) Refrigerant cycle  A process to remove heat from one place to another  Heat inside a room is transferred through the evaporator and removed to the outside air through a condenser.

Refrigerant cycle 3

Heat is transferred from inside air to refrigerant

EXPANSION VALVE

LOW PRESSURE LIQUID

HIGH PRESSURE LIQUID

EVAPORATOR

CONDENSER

LOW PRESSURE GAS

Heat is transferred from refrigerant to outside air

HIGH PRESSURE GAS

COMPRESSOR

LOW PRESSURE

HIGH PRESSURE

Components in the refrigerant cycle Evaporator  The function is to provide a heatabsorbing surface  A coil of pipe where the refrigerant inside it is vaporizing and absorbing heat.  The air blown over the surface of this pipe is cooled

Components in the refrigerant cycle Condensers  Reject the heat absorbed by the evaporator.  The refrigerant changes from a vapor to a liquid in the condenser.  While this change of state is taking place, a great amount of heat is rejected

Components in the refrigerant cycle Compressors  Compresses the refrigerant vapor from the evaporator and pumps the refrigerant throughout the system.  Refrigerant vapor enters the compressor through the suction valve and fills the cylinder.  This refrigerant is cool but it absorbs heat in the evaporator. Most of this heat is absorbed while it was changing state from liquid to a vapor.

Components in the refrigerant cycle Compressors  The compressor compresses this vapor, causing it to become very warm, as high as 200°F, and pumps it to the condenser. Expansion Valve  A valve or small fixedsize tubing or orifice that meters liquid refrigerant into the evaporator.

2)Air cycle 

A process to distribute treated air into the room that needs to be conditioned.



Latent heat inside the room is removed when the return air is absorbed by the evaporator.



The medium to absorb the heat can be either air or water.



Distribution of air can be either through ducts or chilled water pipes.



Heat inside the room is removed and slowly the internal air becomes cooler.

INLET

OUTLET

ROOM TO BE COOLED

SUPPLY DUCT

RETURN DUCT

AHU FAN

FRESH AIR INTAKE

FILTER

CHILLED WATER CYCLE

AIR DISCHARGE

Example of the air cycle between the room to be cooled and the air handling unit (AHU)

Other components required for air cycle Air Handling Unit (AHU) 

For heating, cooling, humidifying, dehumidifying, filtering and distributing air



Recycling some of the return air from the room 1

Air filter 

Cleaning the air



Reduce the quantity of dust released into the room

Other components required for air cycle Blower fan  To propel the air for distribution 

Centrifugal fan is commonly used in AHU as it can move a small or large quantity of air efficiently



Propeller fan is used especially to remove heat from the condenser

Other components required for air cycle Ductwork & diffusers 

To distribute the air from AHU to the rooms that need to be air-conditioned



Usually the ductwork is hidden inside the suspended ceiling A diffuser is placed at the part where the air comes out



Other components required for air cycle Clean air intake  To renew the contents of air to be distributed 

The air that has been distributed which contains heat and dirt will be returned, therefore some of the return air will be removed to the air while some other will be mixed with fresh air for distribution

Humidifier or dehumidifier  Required only if humidity is an issue.

Types of Air-Conditioning System    

Room air-conditioner (window unit) Split unit air-conditioning system Packaged unit air conditioning system Centralized/plant air-conditioning system

1) Room Air-Conditioner / Window Unit

 Is the simplest form of airconditioning system and suitable only for a small room  Usually installed at window openings or wall  Can be divided into 2 compartments: • the room side • the outdoor side separated by an insulated partition

Room air-conditioner

 The various parts of the AC can be divided into: i) Refrigeration components ii) Air circulation & ventilation components iii) Control system components

i) Refrigeration Components  Comprises the compressor, condenser, expansion valve and the evaporator (cooling coil).  The evaporator and condenser is made up of copper tubing & covered with fins. EXPANSION HIGH VALVE PRESSURE

LOW PRESSURE

INDOOR

LIQUID

EVAPORATOR

CONDENSER

LOW PRESSURE GAS

OUTDOOR

HIGH PRESSURE

COMPRESSOR

GAS

Refrigeration System  During air circulation the room air will be drawn into the AC & then blown over the evaporator and the chilled air is passed into the room.  At the same time the heat from the room air is absorb into the refrigerant and transferred to the condenser  The condenser will release the heat to atmospheric air and the refrigerant will be cooled again

ii) Air Circulation & Ventilation  Comprises the blower, propeller fan/condenser fan, fan motor

 The blower behind the evaporator draws in the air from the room which first passes over the air filter 

The air then passes over the cooling coil then the blower blows this filtered and chilled air, which passes through the grilles of the supply air compartment Room air in

Chilled air out

Air Circulation & Ventilation System  The condenser fan draws in the atmospheric air and blows it over the condenser thus releasing heat from the hot refrigerant to the atmospheric air outdoor

Return air grille

Supply air grille

wall indoor Control panel

iii) Control System Three important parameters which can be controlled in room AC:

Vertical louvers (inside)

Horizontal louvers

 Room air temperature by regulating the thermostat  Chilled air flow rate by changing the speed of the blower motor  Direction of the air flow by changing the direction of the vertical & horizontal louvers at the front panel

Control panel (inside)

2)Split Unit Air Conditioning System

 The most popular type of AC nowadays: silent operation, elegant looks, & no need to make a hole in the wall  Consist of two units – an outdoor unit (condenser) and one or several indoor units (evaporator/AHU) connected by copper tubing

Indoor unit

Outdoor unit

Outdoor Unit  Sufficient flow of air is required around it to remove heat from compressor and condenser  Contains the important parts of the split AC like compressor, condenser, expansion valve etc.  The condenser is covered with aluminum fins so that the heat from the refrigerant can be removed at faster rate  A propeller fan draws in the surrounding air and blows it over the compressor and condenser thus cooling them Outdoor unit

Indoor Unit  Produces the cooling effect inside the room.  Contains the evaporator (cooling coil), blower fan, supply air louvers, air filter, return air grille, drain pipe & control panel  The blower draws in the warm room air and it passes over the filter and the evaporator which leads to the cooling of the air and the process continues  This air is then blown to the room where the cooling effect is produced.  Direction of air flow can be controlled by the horizontal and vertical louvers

Indoor unit

Copper Tubing  The refrigerant piping is made up of copper tubing and it connects the indoor and the outdoor unit while covered with insulation Connection point of the copper tubing  Consist of 2 pipes: one to supply the refrigerant to the cooling coil and the other to return the refrigerant to the compressor  Distance between the indoor and the outdoor unit should be kept as minimum as possible.

Types of split unit air-conditioning system: i) Split unit without outside air (ductless) ii) Split unit with outside air (ducted) iii) Variable refrigerant flow (VRF)/ variable refrigerant volume (VRV) i) Split unit without outside air (ductless split)  No supply of fresh air to renew the existing indoor air  The existing indoor air is recycled & recirculated  Normally used for small room/area

Types of indoor unit – stand-alone/floor mounted, wall mounted & ceiling mounted/cassette type

Wall mounted type

Ceiling mounted / cassette type Floor mounted type

Power supply

Control panel

Refrigerant cycle

Indoor unit

Supply air

Outdoor unit

Discharge pipe

Return air

Indoor unit

Consideration for placement of the indoor unit a. At the location from where the air can be distributed evenly throughout the room. b. The wall mounted indoor unit should be located not too close to the roof/ceiling (preferably about 2.4m from the floor) c. The indoor unit should be accessible easily so that one can conveniently clean the filter every fortnight and the whole unit. d. If the indoor unit is installed above certain window, make sure that it is in symmetry with the window.

Considerations for placement of the outdoor unit a. Should be located in the open space preferably on the terrace so that air can flow freely over the compressor and the condenser. b. Can also be hung on the external wall or the upper floor slab supported by steel angles and rods

Considerations for placement of the outdoor unit c. The surface on which the outdoor unit is to be installed should be rigid enough to avoid its vibration.

d. There should not be any hindrances in front of the outdoor unit that would block the passage of hot air to the open space. e. Easily accessible for carrying out the maintenance works of the compressor, condenser, and other devices. The installation and gas charging also should be convenient.

ii) Split unit with outside air (ducted split)  Ducting is utilized to distribute the conditioned air

 Sometimes some of the existing indoor air is recycled & re-circulated and mixed with fresh outdoor air  Larger capacity compared to the ductless split system  Evaporator can be placed inside a suspended ceiling or in a closet

Outdoor unit

SECTION

iii) Variable Refrigerant Flow (VRF) / Variable Refrigerant Volume (VRV)  The traditional split unit – one to one split system  VRF/VRV - multi-split system (one external unit is connected to several indoor units ~ 8 units)  Types of indoor units: floor standing, wall mounted, ceiling mounted / cassette units & ducted units mounted above ceiling  Particularly popular because they require less outdoor plant space than conventional systems  Use refrigerant as the cooling medium rather than chilled water

VRV outdoor unit

Example of a VRV system used in a building

Types of VRF/VRV system: a. Master & slave system b. Zoned control units c. Variable refrigerant volume (VRV) system

a)Master & slave system  One outdoor unit is connected to several indoor units  Slave unit control only itself while Master unit can be used to control the individual unit or all units at the same time. All indoor units will therefore function as the master setting  Suitable for single areas, single rooms or even multiple rooms with very similar heat gains

 i.e.: schools, restaurants, offices, etc. where the central control is required.

b)Zoned control units ď&#x201A;§ One outdoor unit is connected to several indoor units ď&#x201A;§ Each indoor unit has its own individual temperature controller ď&#x201A;§ Each unit functions as required to maintain the individual room temperature

ď&#x201A;§ Limitation: if cooling is required in one area it is not possible to provide heating in a different area served by the same system because the compressors will function in only cooling mode or heating mode

c)Variable refrigerant volume (VRV) ď&#x201A;§ One outdoor unit is connected to several indoor units ď&#x201A;§ Able to provide total versatility and each indoor unit may cool / heat independently of each other

Advantages of split system  Individual temperature control and suitable for small areas/ rooms  Installation is less disruptive to other unrelated areas  Easy installation especially for an existing building with little renovation  This system does not contribute much to distribution of smoke in occurrence of fire

Disadvantages of split system  Rarely designed into the fabric of the building & can look unsightly  All split systems have a maximum vertical and total refrigeration pipe work length allowable

Disadvantages of split system

Planning for Placement of Unitary System â&#x20AC;˘ Usually the outdoor unit of a split unit airconditioning system is concealed with louvers, plants, etc.

Planning for Placement of Unitary System â&#x20AC;˘ For a bungalow all the outdoor units can be placed on the rooftop where they cannot be seen from the ground level â&#x20AC;˘ However careful attention should be given to the placement of piping, otherwise it will look unsightly

LECTURE 6

FIRE PROTECTION IN BUILDINGS (Part 1) • • • • • •

Fire triangle Types of fire detection Requirement of Fire Protection i.e. UBBL Travel/running Distance Smoke Control Fire Protection- Design requirement

LIFE SAFETY is the ultimate consideration in Building Design. Life safety of OCCUPANTS of buildings must always be priority and this can be achieved by minimum fire protection in respect of the various basic aspects of: Means of escape for occupants/evacuation Spread of fire within the building, from one building to another/passive containment Means of detection and extinguishment of fire; active intervention & access for fire fighting and rescue

FIRE TRIANGLE

Fire can be easily extinguished by removing one of the factors inhibiting the chemical reaction of the combustion process. For example, we can remove heat by pouring water on the fire or removing the fuel or cutting off oxygen supply by using a fire blanket.

Nature and Structure of Fire Fire is a kind of oxidation as combustion. In combustion, oxidation takes place rapidly producing a mixture of gases and energy. Energy is released as heat and light, and some gases become visible as smoke. Fire has its triangle needs : Fuel, High Temperature, Oxygen Deprived of any of the above needs, building fires will be extinguished

Influence of Triangle of Needs of Building Design

Growth of Fire • Ignition Combustion can be very fast, ie gas explosion or ot can be a small smouldering process • Growth A fire once started can grow rapidly as it creates conditions for growth • Development The fire passes through a development stage after the initial rapid growth. During this stage the fire temperature increases more slowly. However if it goes to another new area (spreads), the cycle will begin again.

Growth of Fire â&#x20AC;˘ Decay In the final decay stage, the fire will burn itself out due to lack of fuel and oxygen. But a sudden rush of oxygen like breaking a window can reignite the fire with explosive violence. â&#x20AC;˘ Fire Load The total amount of combustible materials available to fire. Certain combustible materials release more heat than others when they burn therefore contribute more fire load.

Purpose of Fire Protection The protection aims are :

Protection of Human Lives

Preservation of material assets

Environmental protection

Wood Wood is most prevalent material used in homes Wood frame house will not withstand much heat and will have little structural integrity However, heavy timbers can resist fire very well

Steel  Most common material for larger buildings  Non combustible and does not add fuel to the fire, but loses its strength when exposed to high temperatures  Normal critical temp 593 celcius, 1 100 Farenheit  Buildings made of steel will collapse relatively quick when exposed to extreme heat of fire  The lighter the steel, the quicker it will fall  Walls can collapse from the movement caused by expansion of steel framing  Encasement has become a very common and effective way of insulating steel to increase its resistance to fire

Concrete ď ś Resistance to fire attach will depend on the type of aggregate used, fire loading and moisture content ď ś Usually reinforced concrete buildings resist fire very well however, high temperatures will cause some damage and effect its strength

Glass  Modern highrise buildings commonly contain large amounts of glass – Glazing, Fibre Glass Insulation, Fibre Glass reinforced plastic products  Glass used for windows and doors have little fire resistance

Masonry ď ś Masonry (bricks, tiles and some concrete) provides good resistance to heat and usually will retain its integrity

Plastics ď ś Plastic products are increasing in use by the building industries, Lower cost and aesthetic considerations make the use of plastic building materials desirable ď ś However, all plastics are combustible

Types of Fire Protection Passive Fire Protection â&#x20AC;˘ Planning matter â&#x20AC;˘ Must be considered at the planning design stage in the building design â&#x20AC;˘ Selection of fire resisting materials , sub-division of building into fire-tight cells or compartments both vertically and horizontally to contain fire outbreak and spread of fire

Effective passive fire precautions represent good planning, good design and sound construction which could complement other basic functions of the building

Types of Fire Protection Active Fire Protection • Manual and automatic fire protection systems such as fire alarms, detector (heat/ smoke), rising mains, hose reels, fire telephones, CO2 fixed installation, automatic sprinklers and smoke spills systems to a warning of an outbreak of fire and the containment and extinguishment of fire • Provision of adequate and suitable facilities to assist rescue and fire suppression operations are also within the active fire defence strategies The overall fire defence for development projects in Malaysia are based on the ‘Fire Safety Philosophy’ of the Malaysian Uniform Building By Law 1984 (UBBL) where life safety is the first consideration.

How Fire Spreads Convection More than 75% of the combustion products of a fire eg. Smoke, burning brands, toxic gases are dissipated in rising convection currents if hot gases at temperatures of 8001000 deg centigrate which heat anything in their path It will create a â&#x20AC;&#x2DC;mushroom effectâ&#x20AC;&#x2122; when the convection current is blocked by underside floor or ceiling. It can smoke log escape routes and prevent means of escape

How Fire Spreads Radiation Radiant heat is transmitted to buildings or materials not shielded from fire â&#x20AC;&#x201C; it is the transfer of heat energy as electromagnetic waves. Radiation passes through normal glass windows easily, and buildings with many or large windows are more likely to spread fire to other buildings.

How Fire Spreads Conduction The movement of heat through materials eg. Metals are better conductors of heat than stones. Conducted heat can travel through partitions, floors, ceilings, walls, to adjacent rooms, especially through metal piping, metal frames and joists.

Combustible materials or internal linings of adjacent rooms can be heated to their ignition temperature by conducted heat.

Structural Protection in Buildings A total fire safety system for any high rise building must include structural integrity during fire as structural failure while occupants are still in buildings can be catastrophic. Elements of structure can only be effective as fire breaks if they have the necessary degree of fire resistance. There are three criteriaâ&#x20AC;Ś

• Insulation The ability of an element of structures to resist passage of heat through it by convection • Integrity The ability of an element of structure to prevent the passage of flames and hot gases through it • Stability The ability of an element of structure to resist collapse as the load bearing function, to continue support its load

PASSIVE FIRE PROTECTION • Purpose Group and Compartment

• Fire Appliance Access • Walls and Floor • Means of Escape

Seventh Schedule UBBL

Dead end limit : Shall be the distance to a storey exit or to a point where alternative means of escape is available provided that the total travel distance shall not exceed the limit under (2), Seventh Schedule, Uniformed Building By-Law 1984 6 meters 9 meters 10 meters 15 meters Travel distance: The distance required to be traversed from any point in a storey of a building to either â&#x20AC;˘ the fire-resisting door in the staircase enclosure â&#x20AC;˘ if there is no such door, the first stair tread of the staircase

Good Building Design For Fire Safety • Provide adequate fire appliance access, fire hydrants and other facilities to assist fire / rescue personel • Provide adequate fixed installation, where appropriate, for quick and effective detection and extinguishment of fires • Designing and installing building services so that they do not assist the spread of fire or smoke • Designing and providing adequate and safe escape routes for the occupants of the building • Selecting materials for the construction which will not promote the rapid spread of fire or dangerous smoke or gases • Subdividing buildings into compartments of reasonable sizes by means of fire resisting walls and floors, providing fire stops to protect openings between floors and compartments • Designing and constructing the exterior of a building so that fire is unlikely to spread to it from another burning building

Conclusion In considering fire protection measures for buildings, it has become evident that the problem of safety of occupants and fire fighters are interrelated, that they involve smoke as well as fire and the their solutions depends on the design of the buildings as a whole. Thus, special approach is required, incorporating measures that work in harmony to meet safety objectives.

References Guide To Fire Protection In Malaysia (published by Fire and Rescue Team Dept Malaysia, PAM, IEM, ACEM, Inst of Fire Engineers (UK) Malaysia Branch (IFE) Malaysian Fire Protection Assc (MFPA) Uniform Building By Law (UBBL) 1984

LECTURE 7

FIRE PROTECTION IN BUILDINGS (Part 2) • Water based fire protection system and equipment • Non-water based fire protection system and equipment • Alarm and detection systems and devices

Class A fires are fires that involve ordinary combustible materials such as cloth, wood, paper, rubber, and many plastics.

UBBL 1984

CLAUSE 227 â&#x20AC;&#x153;Portable extinguisher shall be provided in accordance with the relevant codes of practice and shall be sited in prominent positions on exit routes to be visible from all directions and similar extinguishers in a building shall be of the same method of operation.â&#x20AC;?

External Fire Hydrant Fire hydrant installation consists of a system of pipework connected directly to the water supply mains to provide water to each and every hydrant outlet and is intended to provide water to the firemen to fight the fire.

â&#x20AC;˘ Hydrant pumps draw water from the water storage tank and two sets of pumps, one on duty and the on standby are provided.

UBBL 1984 CLAUSE 225 (2) “Every building shall be served by at least one fire hydrant located not more than 91.5 meters from the nearest point of fire brigade.”

CLAUSE 225 (3) “Depending on the size and location of the building and the provision of access for fire appliances, additional fire hydrant shall be provided as may be required by the Fire Authority.”

2 way Hydrant 3 way Hydrant

Gravity Feed Hose Reel System â&#x20AC;˘ Where the tank is located at the roof or upper floors and the static pressure is adequate to achieve the required pressure, the hose reels may be fed directly from the hose reel tank. â&#x20AC;˘ If pumps are required for the upper floors, a bypass pump is usually provided. Where there is excessive pressure, pressure reducing valves should be installed with a manual by pass in case the pressure reducing valve fails.

UBBL 1984 Clause 230 Installation and testing of dry rising system

UBBL 1984 Clause 231 Installation and testing of dry rising system

10 minutes break

UBBL 1984 Clause 228 1) Sprinkler valves shall be located in a safe and enclosed position on the exterior wall and shall be readily accessible to the Fire Authority 2) All sprinkler system shall be electricity connected to the nearest fire station to provide immediate and automatic relay of the alarm when activated - Tenth Schedule : table of requirement for fire extinguishment alarm systems and emergency lighting

Fire Sprinkler Pumps

Duty Pump

Standby Pump Jockey Pump

Fire Detectors Fire detectors are designed to detect one or more of the three characteristics of fire : • Smoke • Heat • Flame No one type is suitable for all applications and the final choice depends on individual circumstances.

â&#x20AC;˘ Flame Detectors

Maximum response time should not exceed 90 seconds

Fire Alarm Systems System Concept Fire detection and alarm systems are designed to provide warning of the outbreak of fire and allow appropriate fire fighting action to be taken before the situation gets out of control. As all systems are designed primarily to protect life and property, this places a great responsibility on the designer because each building will present a different set of problems in relation to the risk of fire and fire spread. Each fire detection and alarm system therefore must be specially designed to meet the requirements for each building.

Audio And Visual Alarm Concept During fire, if fire alarm system is installed, activation of an alarm sounder is alert the attention of occupants so that evacuation can be carried out without causing harm to the occupants.

END OF FIRE PROTECTION SYSTEM IN BUILDINGS

What are the 3 elements a fire needs to ignite?

What are the 2 types of fire protections?

PASSIVE

ACTIVE

What is PASSIVE fire protection?

System that allows fire to act upon itself by means of compartmentalization to contain its spread, to protect lives and materials (structures, furnitures, valuables etc) It begins at concept and design phase of any construction What is ACTIVE fire protection?

System that is on FULL TIME duty. For example, sprinkler system System is mechanically operated.

What is PURPOSE GROUPS as stated in UBBL?

Categorization of buildings/ compartments within a building in accordance to their intended use as stated in the Fifth Schedule of Uniformed Building By Law (UBBL).

How do you show a PARTY WALL?

Type of systems in ACTIVE fire protection?

Water based Non water based Alarm & Detection System & Devices Smoke Alarm System

Where do you use DRY RISER system?

Buildings which is top most floor higher than 18.3m and less than 30.5m from the fire access level Name the NON-WATER BASED system?

CO2 Dry chemical agent and applications system Aragonite

ARC 2423 BUILDING SERVICES

• Is an integral part of modern buildings; used to move goods and people vertically or horizontally • Common types of transportation systems:  Lifts/elevators  Escalators  Travelators

 An apparatus for raising and lowering people or things to different floors of building  A lift shall be provided for non-residential building which exceeds 4 storeys above / below main entrance (By-Law 124 of UBBL 1984)  Also essential in building less than 4 storeys if access for elderly or disabled is required

 Minimum standard of service – one lift for every four storeys and with a maximum walking distance of 45m to the lift lobby

 Various speeds of lifts based on types/functions: Types of lifts

Car speed (m/s)

Passenger - up to 4 floors 4 to 9 floors 9 to 15 floors over 15 floors paternoster

0.3 – 0.8 0.8 – 2.0 2.0 – 5.0 5.0 – 7.0 Up to 0.4

Goods, to any height

0.2 – 1.0

Hydraulic, passenger or goods (max. 4 to 5 floors)

0.1 – 1.0

ď&#x201A;§ Lift should be positioned at locations which provide easy access for all building users, i.e. central entrance lobby of offices, hotels, apartments, etc.

ď&#x201A;§ Grouping of lifts are essential for user convenience

 When a number of lifts are required, it is preferably to group them together • Reduce waiting time • Reduce cost of installation  According to UBBL clause 153, a smoke detector to be provided at the lift lobby  Lift lobby should be large enough to allow traffic to move in two directions

Group of four to six cars

Two groups of five cars

Two groups of six cars

Factors to determine the number of lifts  Population of the building • Population can be estimated by allowing between one person to 9.5 m2 to 11.25 m2 of the building’s floor area

 Type of building occupancy • Bed lift which is commonly located close to the OT is required in a hospital • Residential building required less lift compared to commercial building

 Numbers of floors and height • As the number of floors increased the number of lifts required increased

 Initial cost • As the number of lifts increase, installation cost and capital cost increase  Maintenance cost • As the number of lifts increase, maintenance cost increase Standard lift capacity: 17, 20 & 24 persons The less number of lifts provided, the longer the waiting time

The quality of performance of a group of lifts is determined by:  Hoisting Capacity (or handling capacity) – a measure of how quickly a set of lifts can transport all passengers to their destination at the peak period.

• Affected by the number of lifts and the size of the lift car

 Waiting Interval – maximum time in seconds between call registered in the main lobby during peak traffic condition and the arrival of the lift • Dependent on the – opening and closing speed of the lift car doors – the acceleration rate of the car – the speed of the lift – the time taken to enter and leave the lift

The quality of the ride is determined by:  Smoothness of the ride  The degree of noise  The accuracy of floor leveling  Lift lobby design  Lift car interior

• Ceiling finishes • Floor and walls finishes

 Lighting level

 Sound system  Other emergency escape provision other than the doors of the lift car

 For skyscrapers or super high rise buildings, it is necessary to divide a building into groups of elevator serving floors, called zones, e.g. in low, middle and high zones  To provide every passenger with as equal elevator service as possible.  Recommended number of servicing floors for each group is 10 to 15

 Carrying passengers to their destination zone as fast as possible, express zones are provided to run express or shuttle elevators between the lobby and each zone.

 This will also maximize high speed elevator performance, reduce round trip time, increase passenger handling capacity, and reduce the required number of elevators.  Space above the low and middle zone elevator hoist ways in the building is available for use as offices and other purposes.  The elevator hall space between express elevator serving floors is also available for use as storage. Rentable space in the building will thus be increased.

 There are two main types of elevators commonly used: • Electric lift • Hydraulic lift  However, there are variations on each type.

 Lifted by ropes, which pass over a wheel attached to an electric motor above the elevator shaft  Used for mid and high-rise applications and have much higher travel speeds than hydraulic elevators  A counter weight makes the elevators more efficient by offsetting the weight of the car and occupants so that the motor doesn't have to move as much weight.

 Preferable to be sited at the top of lift shaft • Minimize the length of rope and optimize the efficiency  Should be ventilated (vent opening to be away from equipment)  Machine room at lower level • Longer rope and more pulleys are required • Increase maintenance cost • Reduce structural cost

Geared Traction Elevators  Have a gearbox that is attached to the motor, which drives the wheel that moves the ropes.  Capable of travel speeds up to 152m per minute.  The maximum travel distance for a geared traction elevator is around 76m.

Gear-less Traction Elevators ď&#x201A;§ Have the wheel attached directly to the motor. ď&#x201A;§ Capable of speeds up to 610m per minute and they have a maximum travel distance of around 610m so they are the only choice for high-rise applications.

ď&#x201A;§ Traction elevators that do not have a dedicated machine room above the elevator shaft. ď&#x201A;§ The machine sits in the override space and is accessed from the top of the elevator cab when maintenance or repairs are required. ď&#x201A;§ The control boxes are located in a control room that is adjacent to the elevator shaft on the highest landing and within around 150 feet of the machine.

 Maximum travel distance of up to 76m and can travel at speeds up to 152m per minute.  MRL elevators are comparable to geared traction elevators in terms of initial and maintenance costs, but they have relatively low energy consumption compared to geared elevators. Advantages of MRL Lift: • Improves aesthetic view of the building • Additional saleable space for builder • Construction cost-saving (Civil & Electrical) • Greater design flexibility for Architects

 Size of shaft required depends on the size and speed of the car, also the type of door gear

 Size of shaft required depends on the size and speed of the car, also the type of door gear  Life shaft extended below to form lift pit

 Lift pit must be watertight and drainage to be provided

ď&#x201A;§ Supported by a piston at the bottom of the elevator that pushes the elevator up as an electric motor forces oil or another hydraulic fluid into the piston. ď&#x201A;§ The elevator descends as a valve releases the fluid from the piston.

 Used for low-rise applications of 2-8 stories  Travel at a maximum speed of 61m per minute.

 The machine room is located at the lowest level adjacent to the elevator shaft.  Suitable for goods lifting, lifts for hospital, and old folk’s home

• Operation is simple – lower maintenance cost • The load imposed is lower compared to electric traction lift – reduce structural cost • Brake, ropes, pulleys, driving sheaves or winding gear are not necessary • No counter weight – larger lift • Extremely accurate floor levelling can be achieved • Acceleration and travel is very smooth

Elevator Lobby Controls and Indicators  Three items required in an elevator lobby: • floor designators • the call buttons • the hall lanterns

Elevator Car Controls  Vary widely based on the types of services the owner wants to place on the control panel - All items must have the equivalent braille description  Floor Selection Buttons are used to select floors that the elevator will stop at.  Operation and Emergency Buttons below the floor selection buttons. These buttons include door open, door close, emergency stop, emergency alarm, intercom or telephone, etc.  Key Switch Controls for maintenance, etc.

Elevator Car Controls

Some of the most common uses of lifts:

 Passenger service – normal lifts and bubble lifts  Goods lift/freight elevators

 Vehicle elevators • Sometimes found in buildings with multistorey car park and located in tight areas

 Residential elevators  Dumbwaiter • Small elevators (or lifts) to carry objects rather than people

• Usually found in multi-levels restaurants and hospitals

ď&#x201A;§ Stage lifts â&#x20AC;˘ Specialized elevators, typically powered by hydraulics - used to raise and lower sections of a theatre stage

• Provide an immediate means of transportation

• Continuously conveys to move large number of people • Quick and efficient - no waiting time required • Can be reversible to suit the main flow of traffic during peak times

 Should be located at location easily seen  Carrying capacity of an escalator depends on • Speed – varies between 0.45m/s to 0.7m/s • Width of the tread – varies between 600mm to 1200mm

• Intended for horizontal movements • Can be inclined up to 15 • The moving surface -reinforced rubber belt or series of linked steel plate running on roller • Speed is about 0.6 – 1.33 m/s • The width varies from 0.6m to 1.0m • Usually used at air terminals, railway stations and shopping centers

â&#x20AC;˘ Same concept as travelator but generally used to move goods, foods, etc.

â&#x20AC;˘ i.e.: baggage conveyor belts in airports, conveyor belts in factories & sushi restaurants

12/05/2016

BUILDING SERVICES (BLD60903/ARC2423)

MECHANICAL VENTILATION Lecture by: Mohamed Rizal Mohamed School of Architecture, Building, Design Taylor’s University, Malaysia

Definition “the process of changing air in an enclosed space”  Indoor air is withdrawn and replaced by fresh

air continuously  Fresh air is supplied by clean external source  Process of supplying and/or removing air by

means of mechanical devices such as fans INDOOR AIR OUT

FRESH AIR IN

12/05/2016

Functions of mechanical ventilation 1.

Expel stale air containing water vapor, carbon dioxide, airborne chemicals and other pollutants.

Draw in outside air, which presumably contains fewer pollutants and less water vapor.

Distribute/circulate the outside air throughout the house.

Basic Ventilation System  



Has two elements: fan & makeup air supply Fan: to pull stale air out generally in high moisture areas (kitchen, utility & bathrooms) Makeup air supply: outside air is delivered around the house The suction (negative pressure) created by the exhaust fan pulls air through the house from supply points to the pickup points

12/05/2016

The importance of mechanical ventilation  preservation of O2 content & removal of CO2  control of humidity for human comfort  prevention of heat concentrations from 

   

machinery, lighting and people prevention of condensation dispersal of concentrations of bacteria dilution and disposal of contaminants such as smoke, dust gases and body odors provisions of freshness as an alternative to the unreliable natural systems.

Comparison Between Natural & Mechanical Ventilation Natural Ventilation

Mechanical Ventilation

Freely available

Controlled

Fresh air

Fresh air + positive ventilation all the time

No maintenance

Maintenance cost

No filter

Filter can be provided

Uncertain and unpredictable

Predictable

12/05/2016

Types of mechanical ventilation system Supply System ii. Extract System iii. Balance/Combined System i.

The systems can be equipped with the following controls: twenty-four hour timers, interval timers, speed controllers, indoor air quality sensors and dehumidistats

i) Supply System 

 

Mechanical inlet & natural extract Boiler plant, factories Outside air supply is provided by mechanical means in order to maintain positive pressure

12/05/2016

ii. Extract System  natural inlet and

mechanical extract

 kitchen, internal toilet

and bathrooms (hotels, hospitals), basement, attic, crawl space

 the fan creates negative

pressure on its inlet side, and this cause air inside the room to move towards the fan and the air is displaced by fresh air from outside the room

 Commonly used devices:

exhaust fan, surface mounted fan, remote mounted inline/multiport fan, ventilator

Surface mounted fan

12/05/2016

Extract system in a toilet

Smoke extraction system (fire protection)

12/05/2016

iii. Balance/ Combined System  Supply fresh air & extract

stale air using fan  Cinemas, theatres, sport

center, basement, attic, crawl space, etc.  Slight pressurization of the

air inside the building is achieved by using an extract fan smaller than inlet fan – to prevent dust, draughts and noise

 It can supply fresh air & pick up stale air

from a multiple point  House pressure - balanced

12/05/2016

Components Involved in Mechanical Ventilation System:     

Fan Filters Ductwork Fire dampers Diffusers

1) Fan

A device for impelling air through inlet point or ducts, forming part of the distribution system

Purpose of Fan  To remove hot, humid and polluted air  To bring in outdoor air to either cool the people (comfort ventilation) or cool the building at night (convection cooling)  Circulate indoor air at those times when the indoor air is cooler than the outer air

12/05/2016

Types of fan 1.

Propeller fan

2. Axial fan 3. Centrifugal fan

Propeller Fan  The main purpose is for free air discharge (wall or

window)

 Commonly used without ducting (placed on wall)  Can remove large volume of air but not allowing air

to be force through long duct

 Low cost of installation & quiet

Propeller fan  Usually found in small/ medium industrial buildings, toilets & kitchens

12/05/2016

Axial Fan  The fan consists of an impeller with blades of

aerofoil section rotating inside a cylindrical casing

 The air flows through the fans in a direction of

parallel shaft

 Usually used in basement & tunnel

Air flow

Axial fan

Axial fan in a tunnel (above) and basement (right)

12/05/2016

Centrifugal Fan  Efficiently move large or small quantities of air over a wide range of pressure  It consists of impeller which revolve inside a casing shaped like a scroll  The direction of air moving through the inlet is 90°  A base is required for the fan  Usually used in basement & rooftop

12/05/2016

2) Filter  To sift the external air before releasing into the room  To trap and prevent dust, smoke, bacteria, etc. from entering the room  Different filter for different application/use  Usually installed at the inlet grille

Filter

12/05/2016

3) Ductwork 

To channel outside air towards the room or the air from the room towards the outside



Usually in round or rectangular section

4) Fire Damper  In occurrence of fire, to avoid the fire from spreading from one room to another  Usually placed at compartment wall

12/05/2016

Fire Damper

5) Grille and Diffuser ď Ž Located at the edge of the ductwork where the air is released into the room

Building Services (ARC 2423)

AIR-CONDITIONING: Packaged & Plant Systems Lecture by: Mohamed Rizal Mohamed School of Architecture, Building and Design Taylorâ&#x20AC;&#x2122;s University, Malaysia

3) Packaged Unit Air Conditioning System

 Similar to room airconditioner but in a much larger size with fixed rate capacities (in tons)

 Used for medium size buildings/rooms i.e. halls, large restaurants, etc.  All the important components are enclosed in a single casing  Two types: ducted and ductless

 Equipment can be installed at the roof top, on the ground, and inside a ceiling or crawl space  Require ducting for the distribution of the conditioned air

Two methods of removing the indoor heat in the larger packaged unit: a) air-cooled & b) water-cooled a) Air-cooled  Indoor heat is removed by the outdoor air  Equipment are located outside the building adjacent to the room to be airconditioned or on the rooftop for easy flow of air

Air-cooled packaged unit

b) Water-cooled  Indoor heat is removed by continuous supply of water (from cooling tower, etc.)  Basic refrigeration components are built into a compact indoor unit  For ducted type, the duct comes out from the top of the unit that extends to the various rooms that are to be cooled. Ductless type Ducted type

Advantages of packaged air conditioning system • Suitable and more economic for medium size building • Elegant look from the inside and the outside as the components can be hidden on the roof top Disadvantages of packaged air conditioning system • Requires dedicated spaces for placement of the outdoor unit and ducting • May not have individual control if the system is used for a number of rooms • May contribute to distribution of smoke in occurrence of fire

4) Plant System

• For large & complex/ multiple blocks (hospitals, hotels, office towers, airports, shopping malls, etc.) • A building can be wholly or partially air-conditioned • The main components of this system are the refrigeration plant, AHU and cooling tower

Plant System • Refrigerant is cooled in the plant room and distributed to the air handling unit (AHU) located in different room(s) at different level(s)/zone(s) • Treated & cooled air is supplied from the AHU to the rooms in the same level/zone via the ducts • Usually this system is installed during the construction of a building & should be integrated with the structure & spaces of a building in the early stage of design 13

Refrigeration Plant • Consists of the chiller, chilled water pump, water pump, control panel, air compressor and automatic temperature controller. • Can be located anywhere but several factors should be considered, i.e. economy of the space, installation & maintenance, vibration & noise control, etc.

• The size is roughly 5% of the total floor area of the rooms to be air-conditioned • The height ranges between 3.5 to 4.6m depending on the sizes of the equipment

Two types of chiller: 1. Water-cooled chiller  The chiller is connected to a cooling tower  Usually the chiller is inside the plant room  The cooling tower is outside the room

Chiller

Cooling tower

Refrigeration Plant Example of equipment layout in a plant room with water-cooled chiller Cold water return from cooling tower

Water tank

Hot water supply to cooling tower Chiller

Water supply

Chiller

Water pump

Chilled water supply to AHU Chilled water return from AHU

Chilled water pump

Refrigeration Plant Example of a water-cooled refrigeration plant

Water tank

Plant room

Cooling towers

2. Air-cooled chiller ď&#x201A;§ using air-cooled chiller unit or connected to aircooled condenser

Chiller and air-cooled condenser Air-cooled chiller

Air-cooled condenser.

Hot air out Cool outdoor air in

Pump

Chiller

Chilled water supply to AHU Chilled water return from AHU

Connection between chiller , AHU,and cooling tower

Air Handling Unit (AHU) • Conditions and circulates the air • It is a large metal box containing a blower, heating or cooling elements, filter racks or chambers, sound attenuators, and dampers.

1 Supply duct 2 Fan compartment 3 Vibration isolator (flexible joint) 4 Heating/cooling coil 5 Filter compartment 6 Mixed air duct 5 2 6 3 4 1 Example of an air handling unit inside the AHU room

• Connects to ductwork that distributes & returns the conditioned air • Equipped with switches and thermostat to control the chilled water flow and temperature of the cooling coil

• The room size is roughly 3% of the floor area serviced by the AHU.

Cooling tower • Is a heat removal device to transfer heat from the chiller to the atmosphere • Heat is removed through evaporation of water • The cooling water is pumped to the refrigeration machine where it cools the condenser coil • A cooling tower needs to be connected to a water tank to replace the water lost by evaporation

Examples of cooling tower

Cooling tower • Usually placed on high location or open space to get optimum ventilation

Warm, moist air out

Fan Hot water in

Distribution system Spray nozzles

Dry & cool surrounding air in

Cold water out

Counterflow type design

Plant system and control methods • There are three systems of plant air conditioning, based on how conditioned air is transferred to a room 1. All-air system 2. All-water system 3. Air and water system • The control method varies depending on the system used 1) All-air system There are two types of all-air plant system: • Single duct system • Double duct system

a) Single duct system

Single Zone Method Variable Air Volume Method Terminal Reheat Method

• In a single zone method conditioned air is delivered at a constant temperature through a low velocity duct system to all the served spaces

From AHU

Single duct – single zone

a) Single duct system

Single Zone Method Variable Air Volume Method Terminal Reheat Method

• In variable air volume method, dampers are used at the terminal outlets to control the air flow according to requirements of each space

From AHU

Single duct – variable air volume

A damper

a) Single duct system

Single Zone Method Variable Air Volume Method Terminal Reheat Method

• In terminal reheat method, air is supplied at about 12°C to terminals equipped with hot water reheat coils to compensate for changing space requirements

From AHU

Single duct – terminal reheat

Reheat terminal

b) Double/dual duct system • Separate ductworks deliver warm air and cool air to terminal mixing units • The terminal unit proportions the cold & warm air in response to a thermostat located in the conditioned space

From AHU

Double/dual duct system

• The mixing units may serve individual spaces or a number of zones • This is usually a high-velocity system to reduce duct sizes and installation space

2) All-water system • Pipes deliver chilled water to fan-coil units in the served spaces • The fan-coil units draw a mixture of outdoor and indoor air over the coils of chilled water and then back into the space • One pipe supplies chilled water to each fan coil unit and the other returns it

All water system

Fan-coil unit • Consists of a finned tube coil, a filter and a fan • The fan recirculates air continuously from the space through the coil, which contains either hot or chilled water • The induction unit mixes the return air with the conditioned air (lower temperature) supplied by the plant room through high velocity duct • Thermostat is used to control the amount of chilled water flow in the cooling coil consequently changing the temperature of the supply air

Fan-coil unit Evaporator Chilled water supply

Fresh air Chilled air supply Warm air return

Corridor

A fan coil unit located above the ceiling

3) Air and water system • The air side consists of central air conditioning equipment, a duct distribution system, and a room terminal • High velocity ducts deliver conditioned air from AHU to induction units in the served spaces • The water side consists of a pump as well as the chilled water supply and return pipes to convey water to induction units within each conditioned space.

• Individual room temperature control is by regulation of either the water flow through it or the air flow over it. • A drip tray is located beneath the chiller coil to collect condensation for external discharge

Air & water system

An induction unit

Induction unit • It has a fan to draw in the return air from the conditioned space • The induction unit mixes the return air with the conditioned air (lower temperature) supplied by the plant room through high velocity duct • The mixed air is blown through a chiller coil into the conditioned space • Usually installed at a perimeter wall under a window

Factors to be considered when choosing the most suitable system: 1)Capital and maintenance cost • Energy-saving features should be considered, as the air-conditioning system has a high energy consumption 2)Building function • Period of occupancy for each room, type of activity and any special requirement such as maximum humidity level, maximum temperature, air purity level, etc.

Factors to be considered when choosing the most suitable system: 3) Efficiency of service • This is especially for buildings with special requirement 4) Building layout and planning • Consideration towards distribution and zoning of areas inside the building and suitability of the system to be used 5) Economy of space • For example: several rooms can share the same equipment and air distribution system

District Cooling System (DCS) • The most sophisticated air-conditioning system due to its size and complexity

• The system distributes chilled water or other media to multiple buildings for air conditioning or other uses. • A DCS consists of three primary components: the central plant, the distribution network and the consumer system • The central plant may include the cooling equipment, power generation and thermal storage

• The central plant consist of refrigeration equipment • The distribution or piping network is located underground • The consumer system would usually comprise of air handling units and chilled water piping in the building. • Widely used in downtown business districts and institutional settings such as college campuses

• Examples of district cooling plants

â&#x20AC;¢ Examples of developments that use district cooling systems in Malaysia: KLCC, KLIA, UNITEN, Putrajaya Government Administration Center, Universiti Teknologi Petronas THERMAL STORAGE CHILLER PLANT ROOM

HOT & COLD WATER PIPES

COOLING TOWERS

District cooling plant in KLIA complex

District cooling plant for KLCC development behind the KLCC mosque

Basis for planning and selecting a system – What architects should know • Evaluating and choosing the most suitable system • Providing sufficient space for placement of all AC system components • Considering the orientation and placement of building on site

Basis for planning and selecting a system – What architects should know • Determining the quantity and location of the AC system components and its effect on the appearance of the building • Considering the economic factor

• Minimizing the noise caused by the equipment through planning and design

a)Selecting the most appropriate and practical AC system • Determined by: - Activities, - Size of space, - Type of organization, - Period of use, - Control method and - Special requirements • There may be more than one system required in a building to serve different functions and requirements

Office tower

Hotel rooms

Podium

Conference

Shopping mall

Restaurants

Office & shopping mall

Hotel

Different AC systems to serve different functions of spaces in a building

Sufficient space • Spaces required for AC system should be allocated during the design stage • An architect should understand the concept & arrangement of AC system components • Usually the spaces are the plant room, AHU room, risers & spaces for ductwork • Circulation space around the equipment for maintenance purposes should also be provided

Planning for the orientation and placement of building on site • Individual systems (unitary & packaged type) are more suitable for developments with several small buildings on a single site (resort, chalet, etc.) • Central system is more common in larger single & high-rise buildings • Orientation of a building towards sunlight (more openings should be directed northsouth) to reduce the cooling load • Location of AC system components should not interfere with other activities on site

Effects on the appearance of a building On the exterior an architect should consider: • How to conceal or to expose the components to achieve certain design effect • Where to place the components that require special needs (i.e. cooling tower & evaporator) • How to get the best placement or arrangement for smaller system (unitary, split type)

Effects on the appearance of a building

On the interior: • Whether to conceal or expose the piping, ductwork, indoor unit, etc.

Economic factor • In terms of installation cost, lifespan, energy consumption • Can be divided into capital cost (installation) and maintenance cost (running & servicing)

Noise • Generated by AC system components such as condenser, high-velocity duct, chiller, evaporator & cooling tower • Divided into air-borne & structure-borne noise • Can be reduced by: a) Installing insulation panels in the equipment room b) Isolating the equipment or rooms which cause the noise from user areas during the design & planning stage

c) By separating the equipment from the floor or roof. i.e.: using cork, rubber sheet or springs to absorb the vibration generated by the equipment

Planning for the placement of AC machine rooms • To get the optimum system operation • Location of the machine rooms are determined by several factors such as economic, by-laws, technical requirements and building use • The rooms are usually located at the back side, basement and the rooftop • Other equipment should be placed close to the machine rooms to reduce the cost for ductworks and piping

Plant room There are several ways and locations to place the plant room with their own advantages and disadvantages a) Rooftop Advantages: • No wastage on primary spaces which normally found on the ground floor. • The length of piping from the cooling tower to the plant room can be reduced if both are placed on the rooftop. • Excellent ventilation.

Plant room Disadvantages: • Increased loading on the building structure. • Noise generated by the vibration of equipment. • Problem during maintenance

b) Intermediate floor level (high-rise) Advantages: • Less wastage on primary spaces. • The length of piping from the cooling tower Upper zone to the plant room can be reduced if both are placed on the same level. • Good ventilation. Lower zone • Easy zoning for air distribution

b) Intermediate floor level (high-rise) Disadvantages: • Noise & vibration problems • Increased loading on the building structure (medium)

c) Ground floor level Advantages: • Easy maintenance & replacement of equipments • Reduced loading on the building structure • The plant room & cooling tower can be isolated from the building or user spaces to minimize noise problem

c) Ground floor level Disadvantages: • Wastage on primary spaces (higher rental rate) • Increased length of piping if the cooling tower is located on the rooftop • Ventilation problem if the cooling tower is located on the ground floor

d) Basement level Advantages: • Less wastage on primary spaces • Reduced loading on the building structure • Easy maintenance and replacement of equipments • Noise & vibration problems can be minimized

d) Basement level Disadvantages: • Increased length of piping if the cooling tower is located on the rooftop • Damages to the equipment if flood occurs • Reduced parking spaces • Mechanical ventilation should be utilized for the plant room

Other possible location Far from the building or user spaces to reduce noise & vibration problems, easy supply of water, excellent ventilation & easy maintenance

AHU room • Can cause noise & vibration problems • Factors to be considered when planning for the location of AHU rooms:  Usually located close to services or noisy zone for easy maintenance  It should get the supply of fresh air (directly or via ductwork).  Try to avoid placing an AHU room next to a toilet

AHU room • Factors to be considered when planning for the location of AHU rooms:  It should be stacked on top of one another in high-rise building (for easy distribution of piping system)

 It should be placed next to the rooms to be air-conditioned to reduce the length of ductwork

Cooling tower • It should get excellent ventilation to remove heat • Usually placed at an open or unobstructed space, however it can be concealed with screenings (aluminium louvers, etc.)

Possible locations: a) Rooftop Advantages: • Excellent ventilation • No wastage on primary spaces • Unsightly outlook can be reduced Disadvantages: • Problems during maintenance & replacement of equipments • Increased loading on the building structure. • Vibration problem

b) Podium level Advantages: • Excellent ventilation • Less wastage on primary spaces. Disadvantages: • Poor outlook if the podium level is viewed from the upper floor of the tower • The heat from the cooling tower will rise upward which causes extra heat load to the tower

c) Ground level Advantages: • Easy maintenance & replacement of equipments • Reduced loading on the building structure • The cooling tower can be placed far from the building Disadvantages: • If it’s not located properly then wastage on primary spaces might happen • The surroundings will be hotter due to the heat released from the cooling tower • Unsightly view & noise problem