25
Gas Piping
NATURAL GAS
Pipe Sizing - Natural Gas
Refer to Table 1 for schedule 40 metallic pipe
length and diameter requirements for natural
gas, based on rated PRESTIGE Excellence
input (divide by 1,000 to obtain cubic feet per
hour).
- Table 1 is based on Natural Gas with a spe-
cific gravity of 0.60 and a pressure drop
through the gas piping of 0.30”w.c..
- For additional gas piping sizing informa-
tion, refer to ANSI Z223.1. For Canadian
installations refer to B149.1 or B149.2.
Natural Gas Supply Pressure Requirements
1. Pressure required at the gas valve inlet
supply pressure port:
- Maximum 13”w.c. at flow or no flow
conditions to the burner.
- Minimum 5”w.c. during flow conditions
to the burner. Must be verified during
start up and with all other gas appliances
operating within the building.
2. Install 100% lockup gas pressure regulator
in the gas supply line if inlet pressure can
exceed 13”w.c at any time. Adjust the lock-
up pressure regulator for 13”w.c maximum.
DO NOT adjust or attempt to measure
gas valve outlet pressure. The gas valve
is factory-set for the correct outlet pres-
sure. This setting is suitable for natural
gas and propane and requires no field
adjustment. Attempts by the installer to
adjust or measure the gas valve outlet
pressure could result in damage to the
valve, causing potential severe personal
injury, death or substantial property
damage.
WARNING
Table 1: Gas Piping Sizing - Natural Gas
Length of Pipe in
Feet
Capacity of Schedule 40 Metallic Pipe in Cubic Feet of Natural Gas Per
Hour (based on 0.60 specific gravity, 0.30" w.c. pressure drop)
SCH 40
1/2"
3/4"
1"
1-1/4"
1-1/2"
10
132
278
520
1050
1600
20
92
190
350
730
1100
30
73
152
285
590
890
40
63
130
245
500
760
50
56
115
215
440
670
75
45
93
175
360
545
100
38
79
150
305
460
150
31
64
120
250
380
