Briggs & Stratton 206484GS manual Natural Gas LP Vapor, Fuel Consumption, Fuel Pipe Sizing

The manometer port permits temporary installation of a manometer to ensure that the engine receives the correct fuel pressure to operate efficiently throughout its operating range.

NOTE: A digital manometer, P/N 19495, is available at your local Briggs & Stratton service center.

When the initial test runs are completed, the manometer is removed and the port is plugged. A typical final fuel connection assembly is shown here, where (A) is the fuel supply and (B) goes to the home generator.

A

B

Fuel Consumption

Estimated fuel supply requirements at half and full load for natural gas and LP vapor fuels are shown below.

Natural Gas		LP Vapor
1/2 Load	Full Load	1/2 Load	Full Load
80 C	137 C	33 C	56 C
80,000 B	137,000 B	82,500 B	140,000 B

C = Cubic feet per hour

B = BTU’s per hour

Fuel Pipe Sizing

The tables below 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.

NPT	10ft	15ft	20ft	30ft	40ft	50ft	60ft	70ft	80ft	90ft	100ft
1/2”	168	146	115	93	79	70	63	59	55	51	48
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 Pipe Size - Gas Flow chart, in cubic feet per hour, specific gravity=0.65

NPT	10ft	15ft	20ft	30ft	40ft	50ft	60ft	70ft	80ft	90ft	100ft
1/2”	110	96	76	61	52	46	42	38	36	33	32
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) Gas Pipe Size - Gas Flow chart, in cubic feet per hour, specific gravity=1.50

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