Trane Voyager Commercial Installation, Operation And Maintenance Manual page 41

Table 19. Specific gravity multiplier
Specific Gravity
0.5
0.55
Table 20. Sizing natural gas pipe mains and branches
Gas Supply Pipe
Run (ft) 1-1/4" Pipe
10
20
30
40
50
60
70
80
90
100
125
150
175
200
Notes:
1. If more than one unit is served by the same main gas supply, consider the total gas input (cubic feet/hr.) and the total length when determining
the appropriate gas pipe size.
2. Obtain the Specific Gravity and BTU/Cu.Ft. from the gas company.
3. The following example demonstrates the considerations necessary when determining the actual pipe size. Example: A 40' pipe run is needed to
connect a unit with a 500 MBH furnace to a natural gas supply having a rating of 1,000 BTU/Cu.Ft. and a specific gravity of 0.60. Cu.Ft/Hour =
[(Furnace MBH Input) / (Gas BTU/Cu.Ft.)] X Multiplier. Cu.Ft/Hour = 500. This table indicates that a 1-1/4" pipe is required.
(a) Table is based on a specific gravity of 0.60. Use previous table or the specific gravity of the local gas supply.
Figure 35. Gas train configuration for low heat units
(high heat units utilize two gas trains.)
RT-SVX34R-EN
Multiplier
1.1
1.04
1-1/2" Pipe
1050 1600
730 1100
590 890
500 760
440 670
400 610
370 560
350 530
320 490
305 460
275 410
250 380
225 350
210 320
Table 19. Specific gravity multiplier (continued)
Specific Gravity
0.6
0.65
Gas Input (Cubic Feet/Hour)
2" Pipe 2-1/2" Pipe
3050 4800
2100 3300
1650 2700
1450 2300
1270 2000
1150 1850
1050 1700
990 1600
930 1500
870 1400
780 1250
710 1130
650 1050
610 980
I I n n s s t t a a l l l l a a t t i i o o n n P P i i p p i i n n g g
Multiplier
1
0.96
(a)
3"Pipe
8500
5900
4700
4100
3600
3250
3000
2800
2600
2500
2200
2000
1850
1700
4"Pipe
17500
12000
9700
8300
7400
6800
6200
5800
5400
5100
4500
4100
3800
3500
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