comfort systems tom de saulles

Tom de Saulles

AN ILLUSTRATED GUIDETO BUILDING SERVICESComfort Systems

27/99

SUPERSEDED by AG 15/2002

27/99

AN ILLUSTRATED GUIDETO BUILDING SERVICES

Comfort Systems

Tom de Saulles

A Client’s Guide to Defining Building Engineering ServicesDETR ref. 39/3/426 (cc1648)

BSRIA ref. SR 70290

The Building Services Researchand Information AssociationOld Bracknell Lane West,Bracknell, Berkshire RG12 7AHTel: +44 (0) 1344 426511 Fax: +44 (0) 1344 487575e-mail: [email protected] web: www.bsria.co.uk


ISBN 0 86022 543 3 Printed by The Chameleon Press Ltd. BSRIA 70290 March 2000

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any formor by any means electronic, mechanical, photocopying, recording or otherwise without prior written permission of thepublishers.


BSRIA 27/99 An Illustrated Guide to Building Services

ACKNOWLEDGEMENTS

This work was part funded by the Department of the Environment, Transport and theRegions, under the ‘Partners in Innovation’ scheme. BSRIA acknowledges thefinancial support of the Department of the Environment, Transport and the Regions.BSRIA would also like to thank the Chartered Institution of Building ServicesEngineers (CIBSE) for their financial contribution.

The project was undertaken with the guidance of a steering group of industryrepresentatives. BSRIA would like to thank the steering group for their help andguidance. The members of the group were:

Andrew Ford Fulcrum Consulting (Representing DETR)Dr Hywel Davies CIBSE (Representing CIBSE & CCF)John Killey Citibank (Representing CIBSE)John Deal CIBSE (Representing CIBSE)Nicholas Rowe Gardiner & Theobald (Representing BCO)Hans Haenlein Hans Haenlein ArchitectsJohn Armstrong Ove Arup & Partners

Special acknowledgement is given to Gay Lawrence Race (BSRIA), for herconsiderable contribution to this publication.

BSRIA would also like to thank the following organisations who kindly provided thephotographs and additional information which have made this illustrated guidepossible.

Airedale International Air Conditioning Ltd Hudevad LtdAmbi-Rad Limited Illuma Lighting LtdApollo Lighting Ltd Ledger Bennett Advertising LimitedAtlantic 2000 Lightform Special Projects LimitedBluesky Communications Mitsubishi ElectricCaradon Gent Limited Monodraught LimitedCarrier Air Conditioning OSRAM LimitedClockwork Marketing Co Ltd Powrmatic LimitedColt International Ltd Royston Simpson PublicityCovrad Heat Transfer Limited Taylor Alden LimitedCrompton Lighting Limited Temperature LimitedDaikin Europe NV Toshiba Carrier UK LtdDE-VI Electroheat Ltd Translite Systems LtdDisplacement Design Ltd Trox TechnikDravo Environmental Services Ltd Trox (U.K.) LtdFFwd Precision Marketing

The views expressed in this document are not necessarily those of the Secretary ofState for the Environment, Transport and the Regions. Final editorial control of thisdocument rests with BSRIA.

B R I T I S H

C O U N C I L

f o r

O F F I C E S

Construction Clients’Forum (CCF)

Royal Institute ofBritish Architects

(RIBA)



PREFACE

This illustrated guide provides basic reference information on building services systems for construction clients andprofessionals in other areas of the construction industry. The systems covered are:

• Heating• Ventilation• Air Conditioning• Lighting• Controls

For construction clients, the guide provides a simple insight into the main system options discussed during thebriefing process and can consequently assist dialogue with the design team. It can also help clients to identify andraise technical questions which they feel are relevant to their organisation’s specific needs. For constructionprofessionals, the guide provides a quick reference to building services systems and can assist their workingknowledge of the subject.

To ensure the guide is simple and quick to use, a brief overview of each system is provided, followed by a list of keypoints. Photographs and simple drawings are used to help explain the appearance and operation of each system.

It is acknowledged that the design team’s role includes assessing and recommending appropriate design solutionsfor a given project. This guide makes no attempt to provide a route for system selection other than pointing outtypical applications for many of the systems covered.



CONTENTS PAGE

GLOSSARY ii

INTRODUCTIONIntroduction to building services 1Building design and building services 2Location of building services 3Thermal comfort 4

HEATINGRadiators 7Convectors 8Underfloor heating 8Radiant heating 10Warm air unit heaters 12Boilers 13

VENTILATIONNatural ventilation - The use of windows 17Natural ventilation - Powered window actuators 19Natural ventilation - Single sided and cross ventilation 20Natural ventilation - Stack ventilation 21Natural ventilation - Stack/wind ventilators 22Mechanical ventilation - extract only 23Mechanical ventilation - supply only 24Mechanical ventilation - supply and extract systems 25

AIR CONDITIONINGIntroduction to air conditioning systems 29Constant volume (CV) 32Variable air volume (VAV) 33Displacement ventilation 35Fan coils 36Chilled beams 38Chilled ceilings 39Room based heat pumps (Versatemp systems) 39Split systems 40Variable refrigerant flow systems (VRF) 42Chillers, dry coolers and cooling towers 43Air diffusers 44

LIGHTINGLight quality and lighting levels 47Luminaires 48Lighting systems for work areas 50Lighting systems - design considerations and control systems 51Summary of lamp characteristics 51Standard incandescent lamps 53Tungsten halogen lamps 54Tubular fluorescent lamps 55Compact fluorescent lamps 56High pressure mercury lamps 57Sodium lamps 58Metal halide lamps 59

CONTROLSIntroduction to control systems and components 63Analogue and direct digital control (DCC) systems 65Building management systems 66Integrated control systems 67

ALPHABETICAL LIST OF SYSTEMS & EQUIPMENT 68


An Illustrated Guide to Building Services ii BSRIA 27/99

GLOSSARYThis glossary contains largely non-technical explanations of common terms associated withbuilding services and may differ in phraseology from definitions found in British Standards andother authoritative sources. For detailed system and equipment descriptions use the alphabeticalindex at the back of the guide.

Air change rate The quantity of air supplied to a space, expressed in terms of the number of times the totalvolume of air in the space is replaced in a specific period of time, typically one hour.

Central plant The siting of plant items such as boilers, chillers air handling units etc. in a centralisedplant room/area.

Decentralised plant Plant items located at strategic points throughout the building, serving the local area.

Downdraughts Downward moving draught caused by room air coming into contact with a cold surface inwinter such as a window. The cool air sinks and can create a draught at low level.

Emitters The means of getting the heat or cold from distribution systems into the individual space.Examples of emitters include radiators, convectors and radiant panels.

Exhaust air Air which is exhausted to atmosphere.

Extract air Stale air removed from a space. Some of this air may be re-circulated and someexhausted.

False ceiling Suspended ceiling below the structural slab to give a void that can be used for servicesdistribution, eg ventilation ductwork. Sometimes called the services zone.

Free cooling Cooling that can be obtained without operating chillers, eg by using outside air directly whenit is at a low enough temperature.

Glare Dazzle or excessive contrast which can make it difficult or dangerous to carry out a task.Discomfort glare causes visual discomfort without necessarily impairing the vision of thetask or object eg glare caused by a very bright light in the field of view such as directsunlight or an unshielded light bulb. Disability glare impairs the ability to see detail withoutnecessarily causing discomfort eg glare caused by excessive dazzle or reflection such aslight reflecting from a glossy surface or from water.

High temperaturehot water (HTHW)

Hot water circulated within a pressurised system at a temperature of more than 120oC.Pressurisation is required to prevent the water turning to steam. (Medium temperature hotwater (MTHW) operates between 90oC and 120oC)

HVAC Heating, ventilation and air conditioning.

Illuminance The amount of light reaching a surface such as a desk top. Measured in lux (one lumen perm2) eg 300 - 500 lux for a offices with visual display units (VDU).

Indoor air quality(IAQ)

The quality of the internal air considering freshness, temperature, humidity and pollutants.

Infiltration Air that enters a building through cracks and gaps in the building fabric due to temperaturedifference and/or wind. This air can provide some ventilation but is uncontrolled andunreliable. Infiltration can also contribute to the building heat loss in winter and heat gain insummer.

Low temperaturehot water (LTHW)

Hot water circulated within a system under atmospheric pressure at a temperature ofusually less than 90oC

Luminaire A fitting which houses one or more lamps and controls the distribution of light. An airhandling luminaire is one through which room air is extracted.

Lux Unit of illuminance. One lux is equal to one lumen per square metre.

Mechanical services Term commonly used to describe heating, ventilation and air conditioning systems.

Natural ventilation Ventilation air that enters a building by natural means ie due to temperature differenceand/or wind.

Noise rating (NR) European measure of sound level which relates to the sensitivity of the human ear. Oftenused to specify an acceptable sound level eg NR 35-40 for offices, NR 20 for a concert hall.

Occupied zone The area of a space occupied by people - usually from floor level to a height of 1.8m. Inspaces where the occupants are seated, such as an auditorium, the occupied zone will besmaller.

Passivesystems/measures

Systems or measures which achieve a reduction in the heating or cooling load without theuse of mechanical systems.


BSRIA 27/99 iii An Illustrated Guide to Building Services

GLOSSARYThis glossary contains largely non-technical explanations of common terms associated withbuilding services and may differ in phraseology from definitions found in British Standards andother authoritative sources. For detailed system and equipment descriptions use the alphabeticalindex at the back of the guide.

Plant Large items of machinery and apparatus. In the case of building services this term isusually used to describe major pieces of equipment such as boilers and chillers.

Raised floor Raised floor above the structural floor slab to give a void that can be used for servicesdistribution eg data cabling, small power etc.

Re-circulation air Often more air is required to heat or cool than is needed to provide ventilation. The excesscan sometimes be re-circulated providing a very effective method of heat recovery. Re-circulation may not possible when the air is contaminated with dangerous or unpleasantpollutants such as cigarette smoke.

Relative humidity A term often used to specify the internal design condition for humidity within a space. Aratio, usually expressed as a percentage, indicating how humid the air is. Literally theactual vapour pressure of the air at a given dry bulb temperature divided by the saturationvapour pressure of the air at the same temperature.

Resultanttemperature

A temperature often used to specify a design condition for a space, it combines airtemperature, surface temperature and air velocity into a single index.

Riser A shaft providing vertical distribution of services within a building ie to carry services betweenfloors.

Sealed building Building with non-openable windows.

Solar gain Heat gain caused either by sunshine directly entering a space or by sunshine incident onbuilding fabric which absorbs the heat and then transmits it to the space.

Stratification A vertical temperature gradient in a fluid such as water or air caused by poor circulation.

System An organised arrangement of plant and equipment that works together to provide a functionsuch as heating or cooling.

Terminal The end point of a system run. An air terminal device is the end point of a ductworksystem, such as a grille or diffuser.

Terminal unit A unit at the system outlet which usually provides local control eg a VAV terminal unit.

Thermal response The time taken for a system or emitter to warm up eg how long it takes a radiator to heatup. Also the time taken for the fabric of a building to respond to a change in temperature iefor the fabric to warm up or cool down.

Ventilation Ventilation is primarily the supply of fresh air to a building to meet the needs of theoccupants - to provide oxygen, dilute carbon dioxide and odours to acceptable levels andremove contaminants. The stale (vitiated) air must also be extracted.

Zoning The division of a building into a number of distinct zones for the purposes of system control(see introduction to air conditioning).


Introduction Heating Ventilation Air-conditioning Lighting Controls

BSRIA 27/99 1 An Illustrated Guide to Building Serv ices

INTRODUCTION TO BUILDING SERVICES

What are building services?Building services, also sometimes called engineeringservices, are primarily used to help create acomfortable and safe living or working environment forpeople and processes, by providing warmth, light,water, power, sanitation, transport, communication,sound control, security and fire protection. There area huge range of building services used in everybuilding and also in many other places where acomfortable and usable internal environment must becreated, such as ships, aircraft, trains etc.

For example: Houses have heating, ventilation,lighting, power, hot and cold water, drainage andtelephone systems. They may also have alarmsystems, fire protection or cooling. All these need tobe controlled and to operate efficiently.

More complex buildings and industrial processes mayrequire many building services, which can amount toup to 50% of the total building cost - these caninclude:

• Heating, ventilation, air conditioning, refrigeration• Daylighting and electrical lighting• Electrical power services• Acoustics - control of noise• Hot and cold water• Sanitation and drainage• Transport systems - lifts, elevators, document

handling and mechanical conveyance• Communication systems - telephones, public

address, personal call systems etc• Fire prevention and protection• Security systems• Control for all these systems• Special services - steam, medical gases,

compressed air and vacuum services, wastedisposal, kitchen services, dust and fume extract,drying systems, vibration control, provision ofelectricity supplies at various voltages andfrequencies etc

Building services are not just for offices

Why do I need to know about building services?When all building services are working well they tend to beignored or taken for granted. When did you last visit a largepublic building and comment on how wonderful the heatingor lighting was? Building services play a huge part increating a successful building and are certainly the firstthing noticed when not working well - eg a flickering light orcold draughts.

Building services engineering is a recognised specialistdiscipline within the building process and building servicesengineers can provide design, installation, maintenanceand operation of building services systems. However someknowledge of building services is useful for everybody - weall need to know how to operate systems - whether settinga thermostat or timeclock for the central heating orselecting a lamp to give a good light for reading. For thoseinvolved in the design and operation of buildings it isessential to understand the role that services play increating a productive and comfortable environment, and toappreciate that there are now many choices available insystems and equipment that need to be assessed againstindividual priorities and needs.

Clients in particular need to be able to consider whatconditions they want to achieve in their new or refurbishedbuilding, understand the system choices available andappreciate how the systems will need to be operated.


Introduction Heating Ventilation Air-conditioning Lighting Controls

An Illustrated Guide to Building Services 2 BSRIA 27/99

INTRODUCTION - BUILDING DESIGN AND BUILDING SERVICES

Building design can determine many of the costswhich an operator will encounter during the life of abuilding. The building services can account for around28% of the capital cost and 50% of the operating costfor a typical office. It is therefore important that theservices form an integral part of the overall buildingconcept to help ensure they will operate efficiently.Involving the specialist building services engineer atan early stage in the design process can help achievethis objective.

If the services are not considered until a later stage,problems which could perhaps have been overcomeby simple measures may require a more complextechnical solution. A well designed building may costa little more initially but the overall cost of ownershipshould be reduced. Whole life costs of buildingservices systems should be considered as the cost-in-use element can form a large proportion of the totalcost, outweighing the initial capital cost.

It is not always possible to design a building that canutilise all possible energy and environmentally friendlymeasures. Urban noise and pollution may dictate theneed for ‘sealed’ buildings incorporating a mechanicalventilation or air conditioning system. The activities insome buildings can also necessitate air conditioningto offset a high internal heat gain.

Some basic energy efficient strategies relevant tomost building types are:

• During cold weather useful heat gains should bemaximised and heat losses minimised whilstensuring adequate ventilation.

• Heat gains during warm weather should be

minimised to avoid overheating. Correctorientation, external shading and fenestration canall reduce heat gains.

• Natural ventilation should be used wherever

practicable. Deep plan depths and substantialpartitioning can preclude this. Where naturalventilation alone is not adequate for cooling, amixed mode system (combined natural andmechanical ventilation) may be sufficient asopposed to an air conditioning system.

• Where ever possible, maximum use of daylight

should be made to reduce the energy used byartificial lighting.

High internal heat gains and/or the need to havesealed windows to keep external noise/pollution outmeans that some buildings cannot avoid the use ofmechanical ventilation or air conditioning.

If internal heat gains are sufficiently low and theexternal environment is suitable, natural ventilationcan provide a low energy solution to cooling andventilating a building.


comfort systems tom de saulles

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