Trane INTELLIPAK Installation Operation & Maintenance page 33

Table 3-4
Sizing Natural Gas Pipe Mains & Branches
Sizing Natural Gas Pipe Mains & Branches
Gas Input (Cubic Feet/Hour)*
Gas Supply 1-1/4" 1-1/2"
Pipe Run (ft) Pipe Pipe
10 1050 1600 3050 4800 8500 17500
20 730 1100 2100 3300 5900 12000
30 590 890
40 500 760
50 440 670
60 400 610
70 370 560
80 350 530
90 320 490
100 305 460
125 275 410
150 250 380
175 225 350
200 210 320
* Table is based on a specific gravity of 0.60. Use Table 3-1 for
specific gravity of the local gas supply.
Specific Gravity Multipliers
Specific
Gravity Multiplier
0.50 1.10
0.55 1.04
0.60 1.00
0.65 0.96
Figure 3-10
Unit Gas Trains (Natural Gas)
235 and 350 MBH
2" 2-1/2" 3" 4"
Pipe Pipe Pipe Pipe
1650 2700 4700 9700
1450 2300 4100 8300
1270 2000 3600 7400
1150 1850 3250 6800
1050 1700 3000 6200
990 1600 2800 5800
930 1500 2600 5400
870 1400 2500 5100
780 1250 2200 4500
710 1130 2000 4100
650 1050 1850 3800
610 980 1700 3500
Gas Heating Capacity Altitude Correction Factors
Sea Level
To 2000
Capacity
Multiplier 1.00
Note: Correction factors are per AGA Std. 221.30 - 1964, Part VI, 6.12.
Local codes may supersede.
Installation (Continued)
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 (Table 3-1)
Cu.Ft/Hour = 500
Table 3 indicates that a 1-1/4" pipe is required.
Altitude (Ft.)
2001 2501 3501
To 2500 To 3500 To 4500 To 5500 To 6500 To 7500
.92 .88 .84
500 and 850 MBH
33
4501 5501 6501
.80 .76 .72