Page 20
TABLE 10
GAS PIPE CAPACITY - FT
3
/HR (M
3
/HR)
Nominal
Internal
Length of Pipe - feet (m)
Nominal
Iron Pipe Size
inches (mm)
Internal
Diameter
inches (mm)
10
(3.048)
20
(6.096)
30
(9.144)
40
(12.192)
50
(15.240)
60
(18.288)
70
(21.336)
80
(24.384)
90
(27.432)
100
(30.480)
1/4
(6.35)
.364
(9.246)
43
(1.13)
29
(.82)
24
(.68)
20
(.57)
18
(.51)
16
(.45)
15
(.42)
14
(.40)
13
(.37)
12
(.34)
3/8
(9.53)
.493
(12.522)
95
(2.69)
65
(1.84)
52
(1.47)
45
(1.27)
40
(1.13)
36
(1.02)
33
(.73)
31
(.88)
29
(.82)
27
(.76)
1/2
(12.7)
.622
(17.799)
175
(4.96)
120
(3.40)
97
(2.75)
82
(2.32)
73
(2.07)
66
(1.87)
61
(1.73)
57
(1.61)
53
(1.50)
50
(1.42)
3/4
(19.05)
.824
(20.930)
360
(10.19)
250
(7.08)
200
(5.66)
170
(4.81)
151
(4.28)
138
(3.91)
125
(3.54)
118
(3.34)
110
(3.11)
103
(2.92)
1
(25.4)
1.049
(26.645)
680
(919.25)
465
(13.17)
375
(10.62)
320
(9.06)
285
(8.07)
260
(7.36)
240
(6.80)
220
(6.23)
205
(5.80)
195
(5.52)
1-1/4
(31.75)
1.380
(35.052)
1400
(39.64)
950
(26.90)
770
(21.80)
660
(18.69)
580
(16.42)
530
(15.01)
490
(13.87)
460
(13.03)
430
(12.18)
400
(11.33)
1-1/2
(38.1)
1.610
(40.894)
2100
(59.46)
460
(41.34)
1180
(33.41)
990
(28.03)
900
(25.48)
810
(22.94)
750
(21.24)
690
(19.54)
650
(18.41)
620
(17.56)
2
(50.8)
2.067
(52.502)
3950
(111.85)
2750
(77.87)
2200
(62.30)
1900
(53.80)
1680
(47.57)
1520
(43.04)
1400
(39.64)
1300
(36.81)
1220
(34.55)
1150
(32.56)
2-1/2
(63.5)
2.469
(67.713)
6300
(178.39)
4350
(123.17)
3520
(99.67)
3000
(84.95
2650
(75.04)
2400
(67.96)
2250
(63.71)
2050
(58.05)
1950
(55.22)
1850
(52.38)
3
(76.2)
3.068
(77.927)
11000
(311.48)
7700
(218.03)
6250
(176.98)
5300
(150.07)
4750
(134.50)
4300
(121.76)
3900
(110.43)
3700
(104.77)
3450
(97.69)
3250
(92.03)
4
(101.6)
4.026
(102.260)
23000
(651.27)
15800
(447.39)
12800
(362.44)
10900
(308.64)
9700
(274.67)
8800
(249.18)
8100
(229.36)
7500
(212.37)
7200
(203.88)
6700
(189.72)
NOTE-Capacity given in cubic feet (m
3
) of gas per hour and based on 0.60 specific gravity gas.
GROUND
JOINT
UNION
AUTOMATIC
GAS VALVE
(with manual
shut-off valve)
FIELD
PROVIDED
AND INSTALLED
GROUND
JOINT
UNION
Left Side Piping
(Standard)
Right Side Piping
(Alternate)
AUTOMATIC
GAS VALVE
(with manual
shut-off valve)
DRIP LEG
DRIP LEG
MANUAL
MAIN SHUT-OFF
VALVE
(With 1/8 in. NPT
Plugged Tap Shown)
MANUAL
MAIN SHUT-OFF
VALVE
(With 1/8 in. NPT
Plugged Tap
Shown)
FIGURE 18
Leak Check
After gas piping is completed, carefully check all piping
connections (factory- and field-installed) for gas leaks. Use
a leak detecting solution or other preferred means.
CAUTION
Some soaps used for leak detection are corrosive to
certain metals. Carefully rinse piping thoroughly af
ter leak test has been completed. Do not use
matches, candles, flame or other sources of ignition
to check for gas leaks.
NOTE - In case emergency shutoff is required, shut off the
main manual gas valve and disconnect the main power to
the furnace. These devices should be properly labeled by
the installer.
The furnace must be isolated from the gas supply system
by closing its individual manual shutoff valve during any
pressure testing of the gas supply system at pressures
equal to or less than 1/2 psig (3.48 kPa).
IMPORTANT
When testing pressure of gas lines, gas valve must
be disconnected and isolated. See figure 19. Gas
valves can be damaged if subjected to more than 1/2
psig (3.48 kPa).
MANUAL MAIN
SHUT-OFF VALVE
WILL NOT HOLD
NORMAL TEST
PRESSURE
CAP
ISOLATE
GAS VALVE
FURNACE
FIGURE 19