NFPA 54 National Fuel Gas Code Handbook 2006 Edition

Preface ix
History of the National Fuel Gas Code xi

PART ONE

National Fuel Gas Code, with Commentary 1

1.1 Scope 3
1.2 Purpose 9
1.3 Retroactivity 10
1.4 Equivalency 10
1.5 Enforcement 10

2 Referenced Publications (Reserved) 13

3 Definitions 15

3.1 General 15
3.2 (Reserved) 15
3.3 General Definitions 15

4 General 33

4.1 Qualified Agency 33
4.2 Interruption of Service 33
4.3 Prevention of Accidental Ignition 34

5 Gas Piping System Design, Materials, and Components 37

5.1 Piping Plan 37
5.2 Provision for Location of Point of Delivery 38
5.3 Interconnections Between Gas Piping Systems 39
5.4 Sizing of Gas Piping Systems 39
5.5 Piping System Operating Pressure Limitations 43
5.6 Acceptable Piping Materials and Joining Methods 45
5.7 Gas Meters 53
5.8 Gas Pressure Regulators 55
5.9 Overpressure Protection Devices 58
5.10 Back Pressure Protection 61
5.11 Low-Pressure Protection 61
5.12 Shutoff Valves 62
5.13 Expansion and Flexibility 62

6 Gas Piping Installation 65

6.1 Piping Underground 65
6.2 Installation of Piping 71
6.3 Concealed Piping in Buildings 73
6.4 Piping in Vertical Chases 75
6.5 Gas Pipe Turns 76
6.6 Drips and Sediment Traps 77
6.7 Outlets 78
6.8 Branch Pipe Connection 79
6.9 Manual Gas Shutoff Valves 79
6.10 Prohibited Devices 80
6.11 Systems Containing Gas–Air Mixtures Outside the Flammable Range 81
6.12 Systems Containing Flammable Gas–Air Mixtures 81
6.13 Electrical Bonding and Grounding 83
6.14 Electrical Circuits 84
6.15 Electrical Connections 84

7 Inspection, Testing, and Purging 87

7.1 Pressure Testing and Inspection 87
7.2 System and Equipment Leakage Test 91
7.3 Purging 92

8.1 General 96
8.2 Accessibility and Clearance 108
8.3 Air for Combustion and Ventilation 108
8.4 Equipment on Roofs 131
8.5 Equipment Connections to Building Piping 134
8.6 Electrical 137
8.7 Room Temperature Thermostats 138

9 Installation of Specific Equipment 141

9.1 General 142
9.2 Air-Conditioning Equipment (Gas-Fired Air Conditioners and Heat Pumps) 143
9.3 Central Heating Boilers and Furnaces 149
9.4 Clothes Dryers 159
9.5 Conversion Burners 163
9.6 Decorative Appliances for Installation in Vented Fireplaces 164
9.7 Gas Fireplaces, Vented 166
9.8 Non-Recirculating Direct Gas-Fired Industrial Air Heaters 167
9.9 Recirculating Direct Gas-Fired Industrial Air Heaters 169
9.10 Duct Furnaces 171
9.11 Floor Furnaces 173
9.12 Food Service Equipment, Floor-Mounted 175
9.13 Food Service Equipment Counter Appliances 178
9.14 Hot Plates and Laundry Stoves 179
9.15 Household Cooking Appliances 179
9.16 Illuminating Appliances 182
9.17 Incinerators, Commercial-Industrial 183
9.18 Infrared Heaters 183
9.19 Open-Top Broiler Units 185
9.20 Outdoor Cooking Appliances 185
9.21 Pool Heaters 186
9.22 Refrigerators 188
9.23 Room Heaters 188
9.24 Stationary Gas Engines 190
9.25 Gas-Fired Toilets 190
9.26 Unit Heaters 191
9.27 Wall Furnaces 193
9.28 Water Heaters 195
9.29 Compressed Natural Gas (CNG) Vehicular Fuel Systems 199
9.30 Appliances for Installation in Manufactured Housing 200
9.31 Fuel Cell Power Plants 200

10 Venting of Equipment 203

10.1 General 204
10.2 Specification for Venting 206
10.3 Design and Construction 208
10.4 Type of Venting System to Be Used 212
10.5 Masonry, Metal, and Factory-Built Chimneys 215
10.6 Gas Vents 224
10.7 Single-Wall Metal Pipe 232
10.8 Through the Wall Vent Termination 235
10.9 Condensation Drain 237
10.10 Vent Connectors for Category I Gas Utilization Equipment 237
10.11 Vent Connectors for Category II, Category III, and Category IV Gas Utilization Equipment 243
10.12 Draft Hoods and Draft Controls 243
10.13 Manually Operated Dampers 246
10.14 Automatically Operated Vent Dampers 246
10.15 Obstructions 246

11 Procedures to Be Followed to Place Equipment in Operation 249

11.1 Adjusting the Burner Input 249
11.2 Primary Air Adjustment 251
11.3 Safety Shutoff Devices 252
11.4 Automatic Ignition 252
11.5 Protective Devices 252
11.6 Checking the Draft 252
11.7 Operating Instructions 253

12 Pipe Sizing 255

12.1 Pipe Sizing Methods 255
12.2 Tables for Sizing Gas Piping 256
12.3 Sizing Equations 256

13 Sizing of Category I Venting Systems 293

13.1 Additional Requirements to Single Appliance Vent Table 13.1 Through Table 13.5   294
13.2 Additional Requirements to Multiple Appliance Vent Table 13.6 Through Table 13.13(a) and Table 13.13(b)   305

14 Referenced Publications 325

Annexes

A Explanatory Material 327

B Coordination of Gas Utilization Equipment Design, Construction, and Maintenance 328

C Sizing and Capacities of Gas Piping 333

D Suggested Method of Checking for Leakage 356

E Suggested Emergency Procedure for Gas Leaks 359

F Flow of Gas Through Fixed Orifices 360

G Sizing of Venting Systems Serving Appliances Equipped with Draft Hoods, Category I Appliances, and Appliances Listed for Use with Type B Vents 368

H Recommended Procedure for Safety Inspection of an Existing Appliance Installation 395

I Indoor Combustion Air Calculation Examples 397

J Example of Combination of Indoor and Outdoor Combustion and Ventilation Opening Design 404

K Other Useful Definitions 406

L Informational References 410

PART TWO

Supplements 415

1 Development of Revised Venting Guidelines 417

2 Corrugated Stainless Steel Tubing Gas Piping Systems 435

3 Technical Background for Residential Carbon Monoxide Responders 441

4 Revision to American National Standard for Gas Water Heaters—Volume 1—Storage Water Heaters with Input Ratings of 75,000 Btu per Hour or Less 455

5 Procedure to Estimate Infiltration Rate for Residential Structures 461

6 Calculation Worksheets 467

Index 477  

About the Editor 491