Any compound used on the threaded joint of the
gas piping shall be a type that resists the action of
liquefied petroleum gas (propane / LPG).
The gas supply line shall be gas tight, sized, and so
installed as to provide a supply of gas sufficient to
meet the maximum demand of the heater and all
other gas consuming appliances at the location
without loss of pressure.
INFORMATION
Refer to an approved pipe sizing chart if in doubt
about the size of the gas line.
Size the gas pipe
The gas supply must be capable of handling the entire
gas load required at the location. Gas line sizing is
based on gas type, the pressure drop in the system,
the gas pressure supplied, and gas line type. For gas
pipe sizing in the United States, refer to the National
Fuel Gas Code, NFPA 54. The below information is
provided as an example. The appropriate table from
the applicable code must be used.
1. For some tables, you will need to determine the
cubic feet per hour of gas required by dividing the
gas input by the heating value of the gas
(available from the local gas company). The gas
input needs to include all gas products at the lo-
cation and the maximum BTU usage at full load
when all gas products are in use.
2. Use the table for your gas type and pipe type to
Cubic Feet
Gas Input of all gas products (BTU / HR)
per Hour =
Heating Value of Gas (BTU / FT
(CFH)
find the pipe size required. The pipe size must be
able to provide the required cubic feet per hour
of gas or the required BTU/hour.
Example:
The heating value of natural gas for your location is
3
1000 BTU/FT
. The gas input of the RL94i is 199,000
BTU/HR. Additional appliances at the location require
65,000 BTU/hr. Therefore the cubic feet per hour =
(199,000 + 65,000) / 1000 = 264 FT
length is 10 feet then the 3/4 inch pipe size is capable
3
of supplying 264 FT
/HR of natural gas.
20
3
)
3
/HR. If the pipe
VC Series Manual
Pipe Sizing Table - Natural Gas
Schedule 40 Metallic Pipe
Inlet Pressure:
less than 2 psi (55 inches W.C.)
Pressure Drop: 0.3 inches W.C.
Specific Gravity: 0.60
cubic feet per hour
Length
3/4
10
273
20
188
30
151
40
129
50
114
60
104
70
95
80
89
90
83
100
79
Pipe Sizing Table - Propane Gas
Schedule 40 Metallic Pipe
Inlet Pressure:
11.0 inches W.C.
Pressure Drop: 0.5 inches W.C.
Specific Gravity: 1.50
Capacity in Thousands of BTU per Hour
Length
1/2
10
291
20
200
30
160
40
137
50
122
60
110
80
101
100
94
Pipe Size (inches)
1
1 1/4
514
1060
353
726
284
583
243
499
215
442
195
400
179
368
167
343
157
322
148
304
Pipe Size (inches)
3/4
1
1 1/4
608
1150
418
787
336
632
287
541
255
480
231
434
212
400
197
372
1 1/2
1580
1090
873
747
662
600
552
514
482
455
2350
1620
1300
1110
985
892
821
763