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GASINSTALLATIONTECHNOLOGYSecond Edition

R. D. TreloarColchester Institute

A John Wiley & Sons, Ltd., Publication

iii



ii



GasInstallationTechnology

i



ii



GASINSTALLATIONTECHNOLOGYSecond Edition

R. D. TreloarColchester Institute

A John Wiley & Sons, Ltd., Publication

iii



This edition first published 2010C© 2005, 2010 Roy Treloar

Blackwell Publishing was acquired by John Wiley & Sons in February 2007. Blackwell’s publishingprogramme has been merged with Wiley’s global Scientific, Technical, and Medical business to formWiley-Blackwell.

Registered officeJohn Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ,United Kingdom

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All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, ortransmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise,except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission ofthe publisher.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print maynot be available in electronic books.

Designations used by companies to distinguish their products are often claimed as trademarks. All brandnames and product names used in this book are trade names, service marks, trademarks or registeredtrademarks of their respective owners. The publisher is not associated with any product or vendormentioned in this book. This publication is designed to provide accurate and authoritative informationin regard to the subject matter covered. It is sold on the understanding that the publisher is not engagedin rendering professional services. If professional advice or other expert assistance is required, theservices of a competent professional should be sought.

Library of Congress Cataloging-in-Publication Data

Treloar, Roy.Gas installation technology/R.D. Treloar. – 2nd ed.

p. cm.Includes index.ISBN 978-1-4051-8958-3 (pbk. : alk. paper)

1. Gas-fitting. 2. Gas appliances–Installation. I. Title.

TH6810.T74 2010

696′.2–dc22 2009037337

A catalogue record for this book is available from the British Library.

Set in 10/12 pt Sabon by Aptara R© Inc., New Delhi, IndiaPrinted in Singapore

1 2010

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http://www.wiley.com/wiley-blackwell



v

Contents

Introduction xiAcknowledgements xiiAbbreviations and Acronyms xv

Part 1 The Gas Industry 1The Gas Industry 2Nationally Accredited Certification Scheme for Individual Gas Fitting

Operatives (ACS) 4Required ACS Assessments and Flowcharts 6Legislation Affecting the Gas Installer 1 10Legislation Affecting the Gas Installer 2 12Industry Documents and British Standards 14Gas Safety (Installation and Use) Regulations 16

Part 2 Gas Utilisation 19Gas: Its Origin 20Characteristics and Properties of Gases 22Liquefied Petroleum Gas (LPG) 26The Combustion Process 28Air Requirements for Combustion 30Products of Combustion 32The Gas Flame 34Flame Pattern and Characteristics 36Atmospheric Burners 38Pre-mix Burners 40Gas Pressure and Flow 42Gas Pressure Readings 44Quick Reference Guide to Taking Pressures 46Estimating a Suitable Pipe Size 48Domestic Natural Gas Pipe Sizing 50Commercial Pipe Sizing 52Determining Existing Losses Due to Pipe Size 54Gas Rates and Heat Input 56Quick Reference Tables: Gas Rate/Heat Input 58The Physical Laws Relating to Gas 60Measurement of Gas 1 62Measurement of Gas 2 64

Contents



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Part 3 Gas Controls 69Quarter Turn Gas Control Valves 70Screw Down Gas Control Valves 72Spring Loaded Gas Control Valves 74Electrically Operated Gas Control Valves 76Heat Operated Gas Control Valves 78Pressure Operated Controls Valves 80Low and High Pressure Cut-off Devices 82Pressure Regulators 84LPG Regulators 1 88LPG Regulators 2 90Flame Supervision Devices 92Testing Flame Supervision Devices 98Thermostatic Control 100Multi-functional Gas Valve 1 102Multi-functional Gas Valve 2 104Ignition Devices 106Vitiation Sensing Devices 108Pressure and Flow Proving Devices 110

Part 4 Installation Practices 113Polyethylene Pipe Jointing 114Copper Pipe Jointing 116Mild Steel Pipe Jointing 118Semi-rigid and Flexible Pipe Connections 120Gas Service Pipework 122Connections to High Rise Buildings 126Gas Meter Installations 128Commercial Gas Installations 132Internal Installation Pipework 134Pipework Laid in Floors 136Pipework in Walls 138Pipework Support and Allowance for Movement 140Timber Framed Dwellings 142LPG Supply 144LPG Cylinder Installation 146Storage and Transportation of LPG Cylinders 148LPG Bulk Tank Installation 150Gas Supplies from a Bulk Tank Installation 152LPG Vapour Take-off Capacity 154Pipe Sizing LPG Installations 156

Part 5 Tightness Testing 159Tightness Testing and Purging 160Testing Equipment 162

Contents



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Tightness Testing with Air (Domestic) 164Tightness Testing Natural Gas Installations with System Volumes

≤ 0.035 m3 (i.e. Domestic) 166Purging Natural Gas Systems with a Volume ≤0.035 m3 (i.e. Domestic) 170Tightness Testing and Purging with LPG (Domestic) 172Strength Testing for Commercial Pipework 176Commercial Tightness Testing 180Direct Purging Commercial Pipework 186Commercial Purging Procedure 192Indirect Purging Using Nitrogen (N2) 194

Part 6 Flues and Chimneys 197Flue/Chimney Classification 198Chimney/Flue Material and Specification 200Natural Draught Open Flue Systems 202Installation of an Open Flue Chimney 204Minimum Open Flue Heights 1 206Minimum Open Flue Heights 2 208Open Flue Terminal Design and Location 210Condensation within Open Flue Systems 212Brick Chimneys 214Flexible Stainless Steel Flue Liners 216Pre-cast Flue Blocks 218Pipes Used for Chimneys 220Fan Draught Open Flue Chimney Systems 222Shared Open Flue Chimney Systems 224Checking and Testing Open Flue Systems 226Room Sealed Flue Chimneys 228Fan Assisted Room Sealed Flue Appliance 230Room Sealed and Fan Flue Terminal Locations 232Shared Room Sealed Flue Systems 234Fan Dilution System 236Flue Gas Analysis 238Test Equipment for Flue Gas Analysis 240

Part 7 Ventilation 243Need for Ventilation 244Ventilation Location 246Effective Ventilation 248Purge Ventilation (Rapid Ventilation) 250Ventilation Sizing and Tables 252Ventilation Calculations 1 256Ventilation Calculations 2 260Domestic Ventilation Ready Reckoner 264

Contents



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Part 8 Gas Installer Responsibility 267Commissioning Gas Installations/Appliances 268Servicing Gas Installations/Appliances 274Installation of Second-hand Appliances 276Gas Safety and Landlord Inspections 278Gas Industry Unsafe Situations 280Dealing with Unsafe Situations 282Gas Escape Procedures 284Reporting of Injuries, Diseases and Dangerous Occurrences

Regulations (RIDDOR) 286Carbon Monoxide Detection 288Ambient Air Measurements for CO 290Combustion Performance Analysis 292Maximum Combustion CO/CO2 Ratios 294

Part 9 Domestic Appliances 297Gas Fires and Space Heaters 298Component Parts of a Gas Fire 300Open Flued Radiant Convector Gas Fires 302Open Flued Solid Fuel Effect Fires and Heaters 304Installation of Open Flued Gas Fires 1 306Installation of Open Flued Gas Fires 2 308Installation of Open Flued Gas Fires 3 310Decorative Fuel Effect (DFE) Gas Fires 312Fan Flued and Room Sealed Heaters 314Flueless Space Heaters 316Commissioning and Servicing Space Heaters 318Domestic Gas Cookers 322Installation of Cooking Appliances 326Domestic Flued Cooking Range 328Commissioning and Servicing Cookers 330Instantaneous Gas Water Heaters 334Instantaneous Water Heater Operation 336Gas Storage Water Heaters 340Installation of Water Heaters 342Commissioning and Servicing of Water Heaters 344Domestic Gas Boilers 348Conventional or Regular Gas Boilers 350The Combination Boiler 352The Condensing Boiler 354Installation of Domestic Gas Boilers 356Commissioning and Servicing Gas Boilers 358Domestic Ducted Warm Air Heaters 362Installations of Warm Air Heaters 364Commissioning and Servicing Warm Air Heaters 366

Contents



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Domestic Tumble Dryers 370Installation of Domestic Tumble Dryers 372Domestic Gas Refrigerators 374Leisure Appliances 376Greenhouse Heaters and Gas Pokers 378

Part 10 Commercial Appliances 381Commercial Boilers 382Commercial Boiler Gas Control Systems 384Commercial Warm Air Heaters 386Commercial Direct Fired Air Heaters 388Commercial Indirect Fired Air Heaters 390Overhead Radiant Heaters 392Ventilation for Overhead Radiant Heaters 396Commercial Laundry Equipment 398Boosters and Compressors 402Commercial Catering 406Catering Establishments 408Ventilation/Extraction in Commercial Kitchens 410Commercial Cookers and Ovens 412Specialist Ovens and Steamers 414Boiling Pans, Hot Cupboards and Bains Marie 416Grills, Griddles and Fryers 418Drinking Water Boilers 420Mobile Catering Units 422

Part 11 Non-permanent Dwellings 425Residential Park Homes 426Leisure Accommodation Vehicles 428Caravan Holiday Homes 430Touring and Motorised Caravans 432Gas Supply on Boats 434Pipework Installation on Boats 436Appliances and Ventilation for Boats 438

Part 12 Electrical Work 441Electricity 442Electrical Safety 444Bonding 446Safe Isolation 448Inspection and Testing 450Fault Diagnosis of Basic Electrical Controls 452

Glossary 455

Index 475

Contents



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xi

Introduction

This book aims to cover all areas of the gas industry that the operative is likely toencounter. It has purposely grouped together all the various aspects of gas workto include natural gas and LPG with domestic and commercial installations. Thismay seem strange to some, but it overcomes the problem of repeating topics andcross-checking and allows it all to be contained within the one book.

Much of the work undertaken by the gas engineer follows the same generic principles.The gas principles and processes that are used every day and the type of installationhave little or no bearing on the way in which the work is completed. There arevariances, hence the need sometimes to identify specific installation types; this hasbeen done throughout the book, where necessary.

The book is not designed to be read from cover to cover and the reader will invari-ably need to dip into it to retrieve information on a specific problem or interest. Aparticular topic of interest can be found in one of the following ways:� First, by referring to the contents page, which identifies the subject areas of the

book.� Second, by referring to the index (page 475) and choosing a term related to the

subject in question.

Good luck in your chosen profession.

Roy Treloar

Introduction



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Acknowledgements

I would like to thank the following organisations and companies for permission toreproduce photographs and extracts from tables.

British Standards Institution Sales & Customer Services (for various tablesthroughout)

389 Chiswick High Road, London W4 4ALTelephone: 020 8996 9001Email: [email protected]

Institute of Gas Engineers and Managers (for various tables and the Certificates onpage 185)

Charnwood Wing, Holywell Park, Ashby Road, Loughborough, LeicestershireLE11 3GR

Telephone: 01509 282728Email: [email protected]

CORGI (for the labels on page 283)1 Elmwood, Chineham Business Park, Basingstoke RG24 8WGTelephone: 01256 37220Website: http://www.trustcorgi.com

UKLPGUnit 4 Bow Court, Fletchworth Gate, Burnsall Road, Coventry CV5 6SPTelephone: 024 7671 1601Website: http://www.uklpg.org

Society of Laundry Engineers & Allied TradesSuite 7, Southernhay, 207 Hook Road, Chessington, Surrey KT9 1HJTelephone: 020 8391 2266Website: http://www.sleat.co.uk

Alpha Cookers UK LtdUnit 5, Station Road Industrial Estate, Station Road, Thatcham, Berkshire

RG19 4QYTelephone: 01635 876266Website: http://www.alpha-cookers.co.uk

Acknow

ledgements



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Duomo UK LtdUnits 5–6, Judge Court, North Bank, Berryhill Industrial Estate, Droitwich

Worcestershire WR9 9AUTelephone: 01905 797989Website: http://www.duomo.co.uk

Hobart UKSouthgate Way, Orton Southgate, Peterborough PE2 6GNTelephone: 07002 101101Website: http://www.hobartuk.com

Marco Beverages SystemsTelephone: 0207 2744577Website: http://www.marco-bev.co.uk

Miele Company LtdFairacres, Marcham Road, Abingdon, Oxon OX14 1TWTelephone: 01235 554455Website: http://www.miele.co.uk

MGD Gas Direct LtdUnit 1, 459 Uttoxeter Road, Blythebride, Stoke on Trent ST11 9NTTelephone: 01782 394444Website: http://www.mobilegas.co.uk

Powrmatic LtdWinterhay Lane, Ilminster, Somerset TA19 9PQTelephone: 01460 53535Website: http://www.powrmatic.co.uk

Reznor UK LtdPark Farm Road, Park Farm Industrial Estate, Folkestone, Kent CT19 5DRTelephone: 01303 259141Website: http://www.reznor.co.uk

TrackpipeOmegaFlex Ltd, Apollo House, Desborough Road, High Wycombe, Bucks HP11

2QWTelephone: 0870 286 8585Website: http://www.omegaflex.com

Truma LtdTruma House, Eastern Avenue, Burton on Trent, Staffordshire DE13 OBBTelephone: 01283 511092Website: http://www.truma.com

Acknow

ledgements



xiv

Sugg Lighting LtdSussex Manor Business Park, Gatwick Road, Crawley, West Sussex RH10 9GDTelephone: 01293 540114Website: http://www.sugglighting.co.uk

Yorkshire FittingsPO Box 166, Leeds LS10 1NATelephone: 0113 270 1104Website: http://www.yorkshirefittings.co.uk

Photographic Workshop Colchester143 Hythe Hill, Colchester, Essex CO1 1NFTelephone: 01206 790221

Acknow

ledgements



xv

Abbreviations and Acronyms

± plus or minus< less than≤ less than or equal to> greater than≥ greater than or equal to∴ therefore∑

sum total� ohma.c. alternating currentACOP Approved Code of PracticeACS Nationally Accredited Certification Scheme for Individual Gas Fitting

OperativesAR At RiskASD atmospheric sensing deviceBS British StandardBS EN British Standard Europaische Norm (European Standard)CE Conformity to Europe (see p. 14)CO carbon monoxideCO2 carbon dioxideCORGI Council of Registered Gas InstallersCOSHH Control of Substances Hazardous to HealthCV calorific valued.c. direct currentDFE decorative fuel effect firedm decimetresECV emergency control valvee.m.f. electromotive forceFFD flame failure deviceFSD flame supervision deviceGRP glass reinforced plasticH2O waterHEL higher explosive limitHSE health and safety executiveHz hertzID Immediately DangerousIGE/UP Institute of Gas Engineers/Utilisation ProceduresIGEM Institute of Gas Engineers and Managers

Abbreviations

andA

cronyms



xvi

ILFE inset live fuel effect fireLAV leisure accommodation vehicleLCD liquid crystal displayLDF leak detection fluidLEL lower explosive limitLFL lower flammable limitLPCO low pressure cut-offLPG liquefied petroleum gasLPGA LP Gas AssociationMAM meter asset manager (gas supplier)MIP maximum incidental pressureMIV meter inlet valveMOP maximum operating pressureMPLR maximum permitted leak rateN2 nitrogenNCS Not to Current StandardsNOx nitrogen dioxide and nitric oxide mix (NO2 NO)O2 oxygenODS oxygen depletion systemOPSO overpressure shut-offPCB printed circuit boardPE polyethylenePME protective multiple earthing (another name for TNCS)ppm parts per millionPTFE polytetrafluoroethylenePVC polyvinyl chlorideRIDDOR Reporting of Injuries Diseases and Dangerous Occurrence RegulationsRPH residential park homeSAP standard assessment procedureSEDBUK Seasonal Efficiency of Domestic Gas Boiler in the UKSG specific gravityTNCS terra neutral combined separated (basically earth and neutral com-

bined at supply but separated at the building); see also PMETTD tightness test durationUPSO under-pressure shut-offUV ultraviolet

Abbreviations

andA

cronyms

P1: IFM/FFX P2: FAW/FFX QC: FAW/FFX T1: FAW


Part 1The Gas Industry

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The Gas Industry

The gas industry has gone through major changes in the past few decades. Prior to and duringthe early 1960s most gas installation work in the UK was undertaken by British Gas. In 1968,a 22-storey block of flats in Canning Town, East London, was devastated by a major gasexplosion, which persuaded the industry that a body was needed to oversee this kind of work.As a result, in 1970 a voluntary gas body was formed, called the Confederation of RegisteredGas Installers (CORGI).

During the early 1970s, plumbers and heating engineers began to take a greater interestin undertaking gas work, thanks to central heating systems becoming a requirement in theaverage home. In 1972 the first Gas Safety Regulations were introduced, which identified thelegal responsibilities to which the installer had to adhere.

With the introduction of the Approved Code of Practice (ACOP) in 1990, gas installers startedto take update training and assessment in gas working practices and, by 1991, anyone workingin the gas industry for financial gain had to be registered with a Health and Safety Executive(HSE)-approved body.

From 1991 through to 2009 CORGI (renamed the Council for Registered Gas Engineers) heldthe register which all gas engineers needed to be a member of. Currently, however, this registeris maintained by Capita, and is called the Gas Safe Register.

Since 1991 all gas engineers have needed to be assessed as competent in the aspect of gaswork that they wish to undertake; undertaking any work without this assessment would meanthat they are in breach of the law. The assessment that an individual undertakes is calledthe Nationally Accredited Certification Scheme for Individual Gas Fitting Operatives (ASC).There are many different assessments, and these are listed in the next section.

Working in the Gas IndustryToday, if you wish to work in the gas industry you need to belong to a company registeredwith Capita. Becoming a member is no easy task, and the following activities are necessary togain registration:

1. You will need to gain training through a registered company and be given the opportunityto undertake activities in the type of gas work in which you wish to be assessed. During thisperiod of employment, you will need to complete a portfolio with authenticated evidenceto show that you have undertaken ‘on the job’ work under the guidance of a registeredinstaller and completed several installations yourself.

2. You will need to undertake and be able to show evidence that you have completed ‘off thejob’ training at an established training centre.

3. You will need to demonstrate the skills obtained from (1) and (2) above, and pass thewritten and practical ACS assessment.

4. Only after completing (1)–(3) above can you obtain work with a registered gas business.Alternatively, you may apply to become registered in your own right.

The contact details for the gas registration scheme are:Gas Safe Register, PO Box 6804, Basingstoke, RG24 4NBPhone: 0800 408 5577 Email: www.GasSafeRegister.co.uk



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Gas Safe RegisterNot every individual gas operative is registered in their own right. It is the businesses that areregistered. A business, however, must list all the gas engineers that it employs on its list ofnamed gas fitting operatives. As proof that the operative is maintained on the register, Capitaissues a card-type certificate annually. The operative should carry this as proof of competence.On the back of the card is a list of the work categories that the operative is allowed to perform.

Working without RegistrationBy carefully studying the Gas Safety (Installation and Use) Regulations you will find that it ispossible to undertake gas work, but with a certain degree of limitation. For example, DIY workis an area that may be practised without the need for registration. However, a word of caution,this does mean ‘for yourself’, or possibly for very close family, and without financial gain. Thework must still be completed competently and in compliance with the Gas Regulations andassociated industry documents, such as manufacturers’ instructions and British Standards. Atthe time of writing, certain work within factories and mines, etc. was outside the scope ofthe Gas Regulations but, under the Health and Safety at Work Regulations, this must still becompleted competently and safely.

An example of the Gas Safe Register ID card courtesy of Gas Safe RegisterTM



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Nationally Accredited Certification Scheme forIndividual Gas Fitting Operatives (ACS)

In order for gas operatives to work in a particular aspect of the profession they need tohave undertaken the appropriate ACS gas assessment in the specific area of work. Thereare many different assessments that are applicable to domestic, commercial, naturalgas and liquid petroleum gas (LPG) installations; there are also some specialist andservice provider assessments. In addition to the list of assessments identified below, thereis a range of changeover assessments, providing conversions between the various coreassessments, e.g. domestic to commercial (CCN1 to COCN1). These are given in the nextsection.

Specific Assessment Categories (in alphabetical order)CABLP1 – Domestic LPG fired mobile cabinet heatersCBHP1 – Boosters/compressors and high pressure pipesCCCN1 – Core commercial catering safetyCCLNG1 – Core commercial laundry gas safetyCCLP1B – Core domestic LPG gas safety: Boats, yachts and other vesselsCCLP1EP – Core domestic LPG gas safety: External pipework and gas vessel connectionsCCLP1LAV – Core domestic LPG gas safety: Leisure accommodation vehicles (caravans

and motor homes)CCLP1MC – Core domestic LPG gas safety: Mobile cabinet heaters (limited scope)CCLP1PD – Core domestic LPG gas safety: Permanent dwellingsCCLP1RPH – Core domestic LPG gas safety: Residential park homesCCN1 – Core domestic natural gas safetyCCP1 – Commissioning indirect fired commercial plant and equipmentCDGA1 – Commercial direct fired heating appliancesCEN1 – Domestic central heating/hot water boilers (<70 kW net input)CESP1 – Natural gas core emergency service providerCGFE1 – Gas fuelled enginesCGLP1 – Commercial catering vehicle gas generatorsCIGA1 – Commercial indirect fired heating appliancesCKHB1 – Domestic range cookers/boilersCKR1 – Domestic natural gas cookersCLE1 – Commercial laundry equipmentCMA1 – Specific core meter installationsCMA2LS – Limited core domestic gas safetyCMCALP1 – Commercial LPG mobile catering appliances (boiler rings, bains marie, hot

cupboards, toasters)CMCALP2 – Commercial LPG mobile catering appliances (fryers, fish and chip ranges,

grillers, griddles, doughnut fryers)CMCALP3 – Commercial LPG mobile catering appliances (pressure/expansion boilers,

tea urns, cappuccino machines)CMCALP4 – Commercial LPG mobile catering appliances



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CMCLP1 – LPG commercial core mobile catering gas safetyCMDDA1 – Carbon monoxide/dioxide investigation and combustion performance

testingCMET1 – Diaphragm RPD >6 m3/h and <107 m3/hCMET2 – Diaphragm RPD and turbine metersCMIT1LS – Gas meter instrumentation operativesCOCLP1 – LPG core commercial gas safetyCOCN1 – Natural gas core commercial gas safetyCOCNPI1LS – Natural gas core commercial gas safety pipework (installer/commissioner)COMCAT1 – Commercial catering (freestanding stoves/ovens, boiling tables, hot plates,

bains marie, hot cupboards)COMCAT2 – Commercial catering (pressure/expansion boiler, steaming ovens, boiling

pans, dishwashers, urns)COMCAT3 – Commercial catering (deep fat and pressure fryers, brat pans, griddles,

under- and over-fired grills)COMCAT4 – Commercial catering (fish and chip ranges)COMCAT5 – Commercial catering (conveyor type ovens and forced draught burner

appliances)CORT1 – Commercial radiant heatersCPA1 – Combustion performance analysisDAH1 – Natural gas domestic ducted air heaters (<70 kW net)DFDA1 – Domestic forced draught burning appliancesEFJLP1 – Poly-electro fusion jointingHTR1 – Domestic gas fires and wall heatersHTRLP2 – LPG caravan gas firesHTRLP3 – LPG caravan heatersHWB1 – Hot water boilers 15–140 kW (swimming pool boilers)ICAE1LS – Limited scope commercial first fix appliances and equipmentICPN1 – Commercial pipework first fix >35 mmICPN1LS – Limited scope commercial pipework first fixLAU1 – Natural gas domestic laundry appliancesLEI1 – Natural gas leisure and miscellaneous appliances (barbeques, greenhouse heaters,

gas lights)LEILP1 – LPG leisure and miscellaneous appliances (barbeques, greenhouse heaters, gas

lights)MET1 – Domestic natural gas meters (install/exchange primary and secondary meters)MET2 – Domestic natural gas meters for service providers (install/exchange primary and

secondary meters)MET3LS – Meter installations gas safetyMET4 – Diaphragm gas meter installationsREFLP2 – LPG caravan gas refrigeratorsTPCP1 – Testing and purging low pressure commercial gas pipework >1 m3

TPCP1A – Testing and purging low pressure commercial gas pipework <1 m3

VESLP1 – Single LPG gas pipework above and below ground <0.1 m3

VESLP2 – Multiple LPG gas pipework above and below ground >0.1 m3

WAHLP1 – LPG warm air heaters in boatsWAT1 – Domestic natural gas instantaneous water heatersWATLP2 – LPG caravan gas water heaters



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Required ACS Assessments and Flowcharts

In order to undertake an assessment in the particular work category that you require,e.g. CEN1 (domestic boilers), you also need to hold the specific core assessment. Thisis because the core assessment is a prerequisite to all appliance assessments.

There are several core assessment categories and many have similar assessment cri-teria. Therefore, it is not always necessary to undertake the complete core for a specificrange of appliances as a changeover assessment can be obtained. These include:

CoCATA1 – Changeover COCN1 to CCCN1CoDC1 – Changeover CCN1 to CCCN1CoDNCML1 – Changeover CCN1 to CMCLP1CoDNCO1 – Changeover CCN1 to COCN1CoDNESP1 – Changeover CCN1 to CESP1CoLPNG1 – Changeover CCLP1 to CCN1CoNGLP1 – Changeover CCN1 or COCN1 to CCLP1CoNGLP1B – Changeover CCN1 to CCLP1BCoNGLP1LAV – Changeover CCN1 to CCLP1LAVCoNGLP1PD – Changeover CCN1 or COCN1 to CCLP1PDCoNGLP1RPH – Changeover CCN1 to CCLP1RPH

Importance of Maintaining a Current Core AssessmentBecause the core is a mandatory requirement for any further appliance assessment itmust always be maintained as a valid and current assessment certificate. Assessmentsare valid for five years from the date of issue. Should the core certification run out,then the validation of all other certificates received after the date of the core, includingchangeover cores, ceases, even though they may have time to run. As soon as thecore category has been re-assessed and the assessment passed, the other certificatesbecome valid again.

Individual ACS RequirementsAt first sight the vast list of ACS assessment criteria can look quite daunting andit is difficult to choose which assessment to undertake. However, this is can beapproached by using the following flowcharts.

Points to consider� You must hold the specific core for the area of gas work in which you wish to

work, e.g. commercial, domestic or LPG, and have any prerequisite assessments.On the flowcharts these are the assessments through which the line flows.

� If you have a domestic natural gas core and, say, CKR1 you can work on naturalgas cookers only. However, if you also have the LPG core, you can also work onLPG cookers. It is the core that denotes the type of installation into which thecooker is installed.



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Domestic Appliances in Commercial PremisesWhere operatives hold the domestic ACS qualifications for a specific appliance (e.g.CEN1 boilers <70 kW net) they can work on that appliance in commercial premises,providing the pipework, including a local isolation valve, does not exceed 35 mmin diameter. Should an operative hold the commercial core and wish to work on adomestic type appliance, they do not need to obtain the domestic core to acquire adomestic appliance assessment, such as CEN1 above. However, they cannot workin domestic premises unless they also obtain the domestic core.

Commercial Assessments

CBHP1gas

boosters

CORT1overhead heaters

COCN1commercial natural gas core safety

TPCP1Atightness testing <1 m3

CCP1commission

plant & equipment

ICPN1pipework >35 mm

diameter *

this assessment is only requiredif the operative works on pipes bigger than 35 mm

CDGA1directfired

appliances

CIGA1Indirect

fired appliances

CGFE1gas

fuelled engines

CoDNCO

TPCP1tightness testing >1m3

COCLP1commercial

LPG core safety

CoNGLP1

*

Continued over the page:



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CKR1cookers

CEN1boilers

CPA1combustionperformance

HTR1fires

DAH1warm air

DFDA1forced

draught appliances

EFJLP1electro- fusion

welding

HWB1swimming

poolboilers

CKHB1range

cookers

MET1gas

meters

LEI1leisure

appliances

LAU1tumble dryers

WAT1water

heaters

CCLP1LPG core

safety

CoDNCO1

CoLPNG1

CoNGLP1

CCN1natural

gas core safety

Domestic Natural Gasand LPG Assessments

VESLP2multiple

LPG pipes

WAHLP1Warm air on boats

REFLP2caravan

refrigerators

CCLP1LPG core

safety

Specific LPG Assessments

CABLP1cabinet heaters

HTRLP3caravan heaters

WATLP2caravan water

heaters

VESLP1single LPG pipes

HTRLP2caravan

fires

* Note CCLP1 is followed by the letters denotingthe core work area applicable, e.g.:

PD - permanent dwellingsLAV - leisure accommodation vehiclesRPH - residential park homesB - boatsEP - external pipeworkMC - mobile cabinet heaters (limited scope)



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Commercial Catering in Mobile Units

COMCAT1open & solid top ranges

Commercial Catering

COMCAT3grills

griddles & fryers

COMCAT5forced

draught appliances

COMCAT4fish & chip

ranges

COMCAT2pressure- expansion

boilers

CCCN1catering

core safety

CMCALP1open & solid top ranges

CMCALP3pressure- expansion

boilers

CMCLP1mobile

catering core

GCLP1vehicle

generators

CMCALP4water

heaters

CMCALP2grills

griddles & fryers

ICAE1LS1st fix

appliances

ICPN1LSpipework >35 mm

diameter *

Limited Scope Operative

CLE1commercial

laundry *

CCLNG1core

commercial laundry

Commercial Laundry

Meter Installer/Exchanger

CMA1meter core

safety

MET2domestic meters up

to U 6CMET1

commercial RPD

meters *

CMET2RPD & turbine

meters *

MET4meters up

to U 40 Emergency Service Providers

CESP1gas safety

core *

same as MET1

COCNP1LSlimited

scope core safety

TPCP1Atightness testing <1 m3

TPCP1tightness testing >1 m3

ICPN1pipework >35 mm diameter

Nat gas only

Limited Scope Operative(pipe installer/commissioner)

This operative does not make a connectionto a live gas supply and is involved in 1st fixpipework and appliances only.

* in addition to the above ICPN1 andTPCP1/1a may be required

(same as COMCAT1)

(same as COMCAT3)

(same as COMCAT2)

(same as WATLP1)



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Legislation Affecting the Gas Installer 1

Legislation places a mandatory/legal responsibility on the gas operative, who mustcomply with it in order to work within the industry. The piece of legislation thataffects the gas engineer most is the Gas Safety (Installation and Use) Regulations.However, this is not the only legislation that needs to be observed. In fact, in thisarea most actions undertaken as general work activities are affected by some pieceof legislation.

Referring to the flow diagram opposite, which only represents a very small percentageof the legislation that must be observed, it will be seen that the law is divided into twoparts, the Acts of Parliament and the Regulations. The Regulations are drawn up bygovernment and often following an Act of Parliament. Regulations are usually policedby an authority such as the Health and Safety Executive (HSE), local authoritiesand their building control officers (BCOs) or water authority inspectors. Acts ofParliament and Regulations are updated as necessary and care needs to be taken toensure that the latest version is referred to.

Below the dotted line opposite falls the industry guidance documentation. Thesedocuments do not have legal status as such. However, compliance with thesedocuments is generally deemed to indicate good working practices and shows thatthe minimum standards have been maintained. Industry guidance documentationmay also form part of a specification for a contract and, as such, non-compliancemay lead to a civil action being taken against the gas fitting company.

Criminal and Civil LawEnglish law is divided into criminal law and civil law and different courts and pro-cedures are followed for each.

Criminal law is penal law involving a crime against the State and is punishable byimprisonment and/or a fine. Action is taken by the police or by such bodies as theHSE or local authority.

Civil law pertains to the rights of private individuals and to the legal proceedingsinvolving those rights. In a civil case the aim of a trial is to establish facts, basedon evidence, and to determine liability. Civil law provides for compensation for theinjured party, usually in the form of damages or an injunction demanding certainaction to be taken.

Examples of the legislation given opposite are described in more detail over the page.



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12

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Legislation Affecting the Gas Installer 2

Gas ActThe Gas Act has seen many changes over the years and is responsible for putting inplace the following Regulations, to name a few:� Gas Safety (Installation and Use) Regulations

These are the main regulations that are applicable to the gas fitting operative, butit must be emphasised that they amount to only a few of many regulations that areapplicable. The Gas Regulations are described in more detail on page 16.

� Gas Safety (Rights of Entry) RegulationsUnder these regulations the gas supplier may, with police assistance if necessary,enter a property to make an installation safe.

� Gas Safety (Management) RegulationsUnder these regulations the gas supplier must submit a ‘safety case’ identifyingtheir procedures. They must operate a full emergency gas service, to include acentral telephone emergency number and must investigate any major gas incident,such as a poisoning or gas explosion.

In 1995 this Act was updated to include new licensing provisions enabling competi-tion in the domestic gas market for the sale of gas.

Health and Safety at Work ActThis Act, first issued in 1974, includes a large number of regulations for workingoperatives. There are possibly hundreds of regulations that fall under this Act. Someexamples are cited below.� Control of Substances Hazardous to Health (COSHH) Regulations

These contain the statutory duties designed to protect operatives and all othersfrom the effects of working with substances that may cause harm to their health.The COSHH Regulations make it a requirement that you maintain a list of all haz-ardous materials and substances used, and have to hand the necessary protectionadvice and first aid information.

� Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RID-DOR)These Regulations apply to the reporting of dangerous and unsafe situations andare covered in depth on page 286.

� Management of Health and Safety at Work (MHSW) Regulations and Construc-tion (Design and Management) (CDM) RegulationsThese Regulations place a wide range of duties on employers, contractors, designersand clients, etc. to ensure that health and safety is maintained throughout theconstruction process. This includes ensuring that adequate risk assessments arecarried out.

There are many, many more regulations falling within the Act and the Regulationsoutlined above. It must be understood that they are only part of the whole picture.