Rheem RESIDENTIAL GENERATOR SYSTEM GEN12S - Manual (Page 12)

Fuel Consumption
See Figure 7 for estimated fuel supply requirements at half
and full load for both natural gas and LP vapor.
Fuel Pipe Sizing
Figures 8 and 9 provide the maximum capacity of pipe in
cubic feet of gas per hour for gas pressures of 0.5 psi or
less and a pressure drop of 0.3 in. water column. Specific
gravity of gas is shown.
Listed values compensate for a nominal amount of
restriction from bends, fittings, etc. If an unusual number of
fittings, bends, or other restrictions are used, please refer to
federal and local codes.
10
NPT 10ft 15ft 20ft 30ft 40ft 50ft 60ft 70ft 80ft 90ft 100ft
3/4” 277 192 158 126 107 95 87 79 74 69 65
1” 428 360 293 236 202 180 164 151 139 129 123
Liquid Propane (LP) (sg=1.50)
Figure 9 — LIQUID PROPANE (LP) GAS Pipe Size - Gas Flow Chart, in cubic feet per hour
Natural Gas* LP Vapor**
1/2 Load Full Load 1/2 Load Full Load
12kW 102 195 41 79
15kW 140 218 66 96
* = Natural Gas is in cubic feet per hour
** = LP Vapor is in cubic feet per hour
Figure 7 — Fuel Supply Requirements
NPT 10ft 15ft 20ft 30ft 40ft 50ft 60ft 70ft 80ft 90ft 100ft
3/4” 346 293 240 192 163 145 132 120 113 106 99
1” 653 549 446 360 307 274 250 230 211 197 187
Natural Gas (sg=0.65)
Figure 8 — NATURAL GAS (NG) Pipe Size - Gas Flow Chart, in cubic feet per hour