Gas Installation Technology

Andrew S. Burcham is an Engineering Technician Member of The Institution of Gas Engineers. He has over 40 years of experience in the gas industry, starting as an apprentice Gas Service Engineer with British Gas in 1981. He worked for British Gas for 25 years, later becoming an assessor and trainer. In 2006, he left British Gas and worked as a self-employed heating engineer while also assessing ACS programs at colleges. Since 2014, Andrew has been the ACS Centre Manager at Colchester Institute, delivering training and assessment programs for plumbing and heating engineers. His depth of knowledge and hands-on experience make him an invaluable resource. Stephen J. Denney is a highly respected tutor and assessor in the gas industry, bringing over 30 years of invaluable experience. After graduating as an award-winning plumbing student in 1991, he established a successful business in mechanical services. In 2014, Stephen became a full-time lecturer and assessor and currently holds a pivotal role at Colchester Institute's Gas and Utilities Department. In this position, he oversees quality assurance and develops industry courses, equipping professionals with essential skills for success in the gas industry. His extensive practical experience, combined with his role as an assessor, enables him to provide valuable insights and real-world perspectives to professionals in the gas and utilities sector. Roy D. Treloar was, until his retirement, curriculum development manager for the Professional Training Centre at Colchester Institute.

Introduction xi

Acknowledgements xiii

1 The Gas Industry 1

The Gas Industry 1

Nationally Accredited Certification Scheme for Individual Gas Fitting Operatives (ACS) 4

Required ACS Assessments and Flowcharts 9

Legislation Affecting Gas Operatives 10

Specific Legislation Affecting Gas Operatives 15

Industry Documents and British Standards 17

Gas Safety (Installation and Use) Regulations 21

The Future of Gas 24

2 Gas Utilisation 27

Gas: Its Origin 27

Characteristics and Properties of Gases 29

Liquefied Petroleum Gas (LPG) 33

The Combustion Process 34

Air Requirements for Combustion 37

Products of Combustion 39

The Gas Flame 41

Flame Pattern and Characteristics 44

Atmospheric Burners 46

Pre-mix Burners 48

Gas Pressure and Flow 50

Gas Pressure Readings 52

Quick Reference Guide to Taking Pressures 54

Estimating a Suitable Pipe Size 56

Domestic Natural Gas Pipe Sizing 58

Domestic LPG Pipe Sizing 62

Commercial Natural Gas Pipe Sizing 67

Gas Rates and Heat Input 69

Electronic and Smart Meters 72

Quick Reference Tables: Gas Rate/Heat Input 73

The Physical Laws Relating to Gas 76

Measurement of Gas 78

3 Gas Controls 87

Quarter Turn Gas Control Valves 87

Screw Down Gas Control Valves 90

Valve Application 93

Spring-loaded Gas Control Valves 94

Electrically Operated Gas Control Valves 96

Heat-operated Gas Control Valves 98

Pressure-operated Controls Valves 100

Low- and High-pressure Cut-off Devices 102

Pressure Regulators 105

LPG Regulators 108

Flame Supervision Devices 113

Testing Flame Supervision Devices 120

Thermostatic Control 120

Multi-functional Gas Valve 122

Air/Gas Ratio Valve 125

Ignition Devices 127

Vitiation-sensing Devices 129

Pressure and Flow Proving Devices 132

4 Installation Practices 135

Polyethylene Pipe Jointing 135

Copper Pipe Jointing 138

Mild Steel Pipe Jointing 141

Semi-rigid and Flexible Pipe Connections 143

Gas Service and Installation Pipework 145

Connections to High-rise Buildings 150

Gas Meter Installations 153

Commercial Gas Installations 158

Internal Installation Pipework 160

Pipework Laid in Floors 162

Pipework in Walls 165

Pipework Support and Allowance for Movement 168

Timber-framed Dwellings 170

LPG Supply 173

LPG Cylinder Installation 174

Storage and Transportation of LPG Cylinders 176

LPG Bulk Tank Installation 178

Gas Supplies from a Bulk Tank Installation 181

LPG Cylinder Sizing 184

5 Testing and Purging 187

Testing and Purging 187

Tightness Testing With Air (Domestic) 193

Tightness Testing Natural Gas Installations (Domestic) 194

Tightness Testing LPG Installations (Domestic) 199

Purging Domestic Gas Installations 204

Commercial Strength and Tightness Testing (TPCP1A) 209

Commercial Strength and Tightness Testing (TPCP1) 217

Direct Purging Commercial Pipework 230

Indirect Purging Using Nitrogen (N2) 239

6 Flues and Chimneys 243

Flue/Chimney Classification 243

Chimney/Flue Material and Specification 244

Natural Draught Open-Flue Systems 248

Installation of an Open-Flue Chimney 250

Minimum Open-Flue Heights Domestic ≤70 kW 252

Minimum Open-Flue Heights Commercial >70 kW 254

Open-Flue Terminal Design and Location 258

Condensation within Open-Flue Systems 262

Brick Chimneys 264

Flexible Stainless Steel Flue Liners 267

Pre-cast Flue Blocks 270

Pipes Used for Chimneys 272

Fan Draught Open-Flue Chimney Systems 274

Shared Open-Flue Chimney Systems 276

Checking and Testing Open-Flue Systems 279

Room-Sealed Flue Chimneys 282

Fan-Assisted Room-Sealed Flue Appliance 284

Room-Sealed and Fan Flue Terminal Locations ≤70 kW 288

Room-Sealed and Open-Flue Terminal Locations >70 kW 293

Shared Room-Sealed Flue Systems 295

Fan Dilution System 301

Concealed Flues 302

7 Ventilation 305

Need for Ventilation 305

Ventilation Location 308

Effective Ventilation 311

Purge Ventilation (Rapid Ventilation) 315

Ventilation Sizing and Tables 316

Domestic Ventilation Tables 319

Commercial Ventilation Tables 321

Worked Examples for Domestic Premises 325

Worked Examples for Commercial Premises 330

Domestic Ventilation Ready Reckoner 334

8 Gas Installer Responsibility 337

Working on Gas Installations and Appliances 337

Commissioning 339

Servicing Gas Appliances/Installations 346

Installation of Second-hand Appliances 348

Landlords’ Gas Safety Responsibilities 348

Gas Industry Unsafe Situations 351

Gas Escape Procedures 357

Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (riddor) 359

Carbon Monoxide Detection 361

Gas Operative’s Response to an Activated CO Alarm 362

Determining the Ambient Level of CO in a Room (CO Build-up Test) 364

Ambient Air Testing for CO2 in a Non-Domestic Setting 367

Combustion Performance Analysis 368

9 Domestic Appliances 375

Gas Fires and Space Heaters 375

Component Parts of a Gas Fire 377

Open-Flued Radiant Convector Gas Fires 379

Open-Flued Solid Fuel Effect Fires and Heaters 381

Installation of Open-Flued Gas Fires 384

Decorative Fuel Effect (DFE) Gas Fires 391

Fan Flued and Room-Sealed Space Heaters 393

Flueless Space Heaters 396

Commissioning and Servicing Space Heaters 398

Domestic Gas Cookers 401

Installation of Cooking Appliances 406

Domestic Flued Cooking Range 408

Commissioning and Servicing Cookers 410

Instantaneous Gas Water Heaters 413

Instantaneous Water Heater Operation 416

Components and their Operation 419

Installation of Water Heaters 421

Commissioning and Servicing of Water Heaters 422

Domestic Gas Boilers 426

Conventional or Traditional Gas Boilers 428

The Combination Boiler 430

The Condensing Boiler 431

Installation of Domestic Gas Boilers 435

Commissioning and Servicing Gas Boilers 437

Domestic Ducted Warm Air Heaters 441

Installations of Warm Air Heaters 444

Commissioning and Servicing Warm Air Heaters 447

Domestic Tumble Dryers 450

Installation of Domestic Tumble Dryers 453

Domestic Gas Refrigerators 455

Leisure Appliances 456

Greenhouse Heaters and Gas Pokers 460

10 Commercial Appliances 463

Commercial Boilers 463

Commercial Boiler Gas Control Systems 465

Commercial Warm Air Heaters 467

Commercial Direct Fired Air Heaters 470

Commercial Indirect-Fired Air Heaters 471

Commercial Hot Water Storage Heaters 473

Commercial Instantaneous Water Heaters 475

Overhead Radiant Heaters 477

Ventilation for Overhead Radiant Heaters (Type A – Flueless) 482

Gas Boosters 485

11 Commercial Laundry 493

Commercial Laundry Equipment 493

Tumble Dryer and Rotary Ironer 494

Make-up Air 494

Exhaust and Ducting Systems 496

Commissioning and Maintenance 497

Gas Washing Machine 498

12 Commercial Catering 501

Commercial Catering 501

Catering Establishments 503

Ventilation/Extraction in Commercial Kitchens 506

Commercial Catering Appliances 515

Mobile Catering Units 532

13 Educational Establishments 535

Educational Establishments 535

General Considerations 535

Gas Pipework 535

Isolation Valves and Interlocks 537

Boiler Rooms and Plant Rooms 538

Ventilation and Flues 539

Appliances 541

Commissioning, Testing and Maintenance 541

14 Non-permanent Dwellings 543

Residential Park Homes 543

Leisure Accommodation Vehicles – General Requirements 545

Leisure Accommodation Vehicles – Caravan Holiday Homes 548

Leisure Accommodation Vehicles – Caravans and Motor Caravans 551

Gas Supply on Boats 553

Pipework Installation on Boats 556

Tightness Testing on Boats 557

Appliances and Ventilation for Boats 559

15 Electrical Work 563

Electricity 563

Electrical Safety 565

Bonding 567

Safe Isolation 571

Inspection and Testing 576

Fault Diagnosis of Basic Electrical Controls 577

16 The ACS Assessment Process 581

The ACS Assessment Process 581

Matters of Gas Safety Criteria 583

Your ACS Assessment (CCN1) 584

Glossary 591

Appendix A Abbreviations, Acronyms and Units 605

Index 609