Gas Installation Technology

Roy Treloar has been involved with the mechanical service industry since leaving school in 1973, becoming a full time lecturer, teaching plumbing in 1985. He is currently the curriculum development manager for the Professional Training Centre at Colchester Institute where he is responsible for various plumbing, heating, gas and electrical training and assessment programmes. Roy is author of several books, including two highly successful textbooks, Plumbing, and Plumbing Encyclopaedia, both published by Wiley-Blackwell.

Introduction xi

Acknowledgements xii

Abbreviations and Acronyms xv

Part 1 The Gas Industry 1

The Gas Industry 2

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

Required ACS Assessments and Flowcharts 6

Legislation Affecting the Gas Installer 1 10

Legislation Affecting the Gas Installer 2 12

Industry Documents and British Standards 14

Gas Safety (Installation and Use) Regulations 16

Part 2 Gas Utilisation 19

Gas: Its Origin 20

Characteristics and Properties of Gases 22

Liquefied Petroleum Gas (LPG) 26

The Combustion Process 28

Air Requirements for Combustion 30

Products of Combustion 32

The Gas Flame 34

Flame Pattern and Characteristics 36

Atmospheric Burners 38

Pre-mix Burners 40

Gas Pressure and Flow 42

Gas Pressure Readings 44

Quick Reference Guide to Taking Pressures 46

Estimating a Suitable Pipe Size 48

Domestic Natural Gas Pipe Sizing 50

Commercial Pipe Sizing 52

Determining Existing Losses Due to Pipe Size 54

Gas Rates and Heat Input 56

Quick Reference Tables: Gas Rate/Heat Input 58

The Physical Laws Relating to Gas 60

Measurement of Gas 1 62

Measurement of Gas 2 64

Part 3 Gas Controls 69

Quarter Turn Gas Control Valves 70

Screw Down Gas Control Valves 72

Spring Loaded Gas Control Valves 74

Electrically Operated Gas Control Valves 76

Heat Operated Gas Control Valves 78

Pressure Operated Controls Valves 80

Low and High Pressure Cut-off Devices 82

Pressure Regulators 84

LPG Regulators 1 88

LPG Regulators 2 90

Flame Supervision Devices 92

Testing Flame Supervision Devices 98

Thermostatic Control 100

Multi-functional Gas Valve 1 102

Multi-functional Gas Valve 2 104

Ignition Devices 106

Vitiation Sensing Devices 108

Pressure and Flow Proving Devices 110

Part 4 Installation Practices 113

Polyethylene Pipe Jointing 114

Copper Pipe Jointing 116

Mild Steel Pipe Jointing 118

Semi-rigid and Flexible Pipe Connections 120

Gas Service Pipework 122

Connections to High Rise Buildings 126

Gas Meter Installations 128

Commercial Gas Installations 132

Internal Installation Pipework 134

Pipework Laid in Floors 136

Pipework in Walls 138

Pipework Support and Allowance for Movement 140

Timber Framed Dwellings 142

LPG Supply 144

LPG Cylinder Installation 146

Storage and Transportation of LPG Cylinders 148

LPG Bulk Tank Installation 150

Gas Supplies from a Bulk Tank Installation 152

LPG Vapour Take-off Capacity 154

Pipe Sizing LPG Installations 156

Part 5 Tightness Testing 159

Tightness Testing and Purging 160

Testing Equipment 162

Tightness Testing with Air (Domestic) 164

Tightness Testing Natural Gas Installations with System Volumes ≤ 0.035 m3 (i.e. Domestic) 166

Purging Natural Gas Systems with a Volume ≤0.035 m3 (i.e. Domestic) 170

Tightness Testing and Purging with LPG (Domestic) 172

Strength Testing for Commercial Pipework 176

Commercial Tightness Testing 180

Direct Purging Commercial Pipework 186

Commercial Purging Procedure 192

Indirect Purging Using Nitrogen (N2) 194

Part 6 Flues and Chimneys 197

Flue/Chimney Classification 198

Chimney/Flue Material and Specification 200

Natural Draught Open Flue Systems 202

Installation of an Open Flue Chimney 204

Minimum Open Flue Heights 1 206

Minimum Open Flue Heights 2 208

Open Flue Terminal Design and Location 210

Condensation within Open Flue Systems 212

Brick Chimneys 214

Flexible Stainless Steel Flue Liners 216

Pre-cast Flue Blocks 218

Pipes Used for Chimneys 220

Fan Draught Open Flue Chimney Systems 222

Shared Open Flue Chimney Systems 224

Checking and Testing Open Flue Systems 226

Room Sealed Flue Chimneys 228

Fan Assisted Room Sealed Flue Appliance 230

Room Sealed and Fan Flue Terminal Locations 232

Shared Room Sealed Flue Systems 234

Fan Dilution System 236

Flue Gas Analysis 238

Test Equipment for Flue Gas Analysis 240

Part 7 Ventilation 243

Need for Ventilation 244

Ventilation Location 246

Effective Ventilation 248

Purge Ventilation (Rapid Ventilation) 250

Ventilation Sizing and Tables 252

Ventilation Calculations 1 256

Ventilation Calculations 2 260

Domestic Ventilation Ready Reckoner 264

Part 8 Gas Installer Responsibility 267

Commissioning Gas Installations/Appliances 268

Servicing Gas Installations/Appliances 274

Installation of Second-hand Appliances 276

Gas Safety and Landlord Inspections 278

Gas Industry Unsafe Situations 280

Dealing with Unsafe Situations 282

Gas Escape Procedures 284

Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR) 286

Carbon Monoxide Detection 288

Ambient Air Measurements for CO 290

Combustion Performance Analysis 292

Maximum Combustion CO/CO2 Ratios 294

Part 9 Domestic Appliances 297

Gas Fires and Space Heaters 298

Component Parts of a Gas Fire 300

Open Flued Radiant Convector Gas Fires 302

Open Flued Solid Fuel Effect Fires and Heaters 304

Installation of Open Flued Gas Fires 1 306

Installation of Open Flued Gas Fires 2 308

Installation of Open Flued Gas Fires 3 310

Decorative Fuel Effect (DFE) Gas Fires 312

Fan Flued and Room Sealed Heaters 314

Flueless Space Heaters 316

Commissioning and Servicing Space Heaters 318

Domestic Gas Cookers 322

Installation of Cooking Appliances 326

Domestic Flued Cooking Range 328

Commissioning and Servicing Cookers 330

Instantaneous Gas Water Heaters 334

Instantaneous Water Heater Operation 336

Gas Storage Water Heaters 340

Installation of Water Heaters 342

Commissioning and Servicing of Water Heaters 344

Domestic Gas Boilers 348

Conventional or Regular Gas Boilers 350

The Combination Boiler 352

The Condensing Boiler 354

Installation of Domestic Gas Boilers 356

Commissioning and Servicing Gas Boilers 358

Domestic Ducted Warm Air Heaters 362

Installations of Warm Air Heaters 364

Commissioning and Servicing Warm Air Heaters 366

Domestic Tumble Dryers 370

Installation of Domestic Tumble Dryers 372

Domestic Gas Refrigerators 374

Leisure Appliances 376

Greenhouse Heaters and Gas Pokers 378

Part 10 Commercial Appliances 381

Commercial Boilers 382

Commercial Boiler Gas Control Systems 384

Commercial Warm Air Heaters 386

Commercial Direct Fired Air Heaters 388

Commercial Indirect Fired Air Heaters 390

Overhead Radiant Heaters 392

Ventilation for Overhead Radiant Heaters 396

Commercial Laundry Equipment 398

Boosters and Compressors 402

Commercial Catering 406

Catering Establishments 408

Ventilation/Extraction in Commercial Kitchens 410

Commercial Cookers and Ovens 412

Specialist Ovens and Steamers 414

Boiling Pans, Hot Cupboards and Bains Marie 416

Grills, Griddles and Fryers 418

Drinking Water Boilers 420

Mobile Catering Units 422

Part 11 Non-permanent Dwellings 425

Residential Park Homes 426

Leisure Accommodation Vehicles 428

Caravan Holiday Homes 430

Touring and Motorised Caravans 432

Gas Supply on Boats 434

Pipework Installation on Boats 436

Appliances and Ventilation for Boats 438

Part 12 Electrical Work 441

Electricity 442

Electrical Safety 444

Bonding 446

Safe Isolation 448

Inspection and Testing 450

Fault Diagnosis of Basic Electrical Controls 452

Glossary 455

Index 475