Bryan Boilers FREE FLEX, Installation & Operation Manual, Page: 61 / 100

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Bryan Steam, LLC www.bryanboilers.com
Phone: 765-473-6651 783 N Chili Ave, Peru, IN 46970 sales@bryansteam.com
Appendix A: Sizing Gas Piping
Design the gas piping system to provide an adequate gas supply to the boiler. Refer to Table 18 for minimum
and maximum gas supply pressures and boiler capacities. Also consider existing and expected future gas utilizing
equipment (
i.e., water heater, cooling equipment
). Refer to Table 32 for maximum capacity of schedule 40 pipe.
Table 33 lists equivalent pipe length for standard fittings. Given the specific gravity of gas at the boiler’s location,
a correction factor can be found on Table 34 and multiplied by the “Capacity in Cubic Feet of Gas Per Hour” in
Table 32. For gas piping material other than schedule 40 pipes, refer to the National Fuel Gas Code, NFPA 54/
ANZI Z223.1 and/or CAN/CGA B149 Installation codes. Use methods and materials in accordance with Local
Codes and requirements of gas supplier. In the absence of such requirement follow National Fuel Gas Codes,
NFPA /ANSI Z 223.1 and/or CAN/CGA B149 Installation Codes.
Table 32: Maximum Gas Capacity Of Schedule 40 Pipe
Pipe Length
in Equivalent
Feet
Pipe Size (NPT)
¾ 1 1-1/4 1-1/2 2 2-1/2 3 4
10 273 514 1060 1580 3050 4860 8580 17500
20 188 353 726 1090 2090 3340 5900 12000
30 151 284 583 873 1680 2680 4740 9660
40 129 243 499 747 1440 2290 4050 8270
50 114 215 442 662 1280 2030 3590 7330
60 104 195 400 600 1160 1840 3260 6640
70 95 179 368 552 1060 1690 3000 6110
80 89 167 343 514 989 1580 2790 5680
90 83 157 322 482 928 1480 2610 5330
100 79 148 304 455 877 1400 2470 5040
125 70 131 269 403 777 1240 2190 4460
150 63 119 244 366 704 1120 1980 4050
175 58 109 224 336 648 1030 1820 3720
200 54 102 209 313 602 960 1700 3460
Based on gas pressures less than 2 psig and a pressure drop of 3.0 iwc and 0.6 specific gravity.