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Page
-Natural gas supply piping-
Maximum delivery Capacity in Cubic Feet of Gas per Hour (based on IPS Pipe carrying Natural Gas with 0.60 Specific
Gravity with a Pressure Drop of 0.5" W.C.).
Based on Energy Content of 1,000 BTU/Cubic ft: The water heater requires 199 Cubic ft/hr for the 540P model.
The following tables are from NFPA 54.
-Propane (LP) supply piping-
Maximum Capacity of Propane (LP) Based on 11" W.C. supply pressure at a 0.5" W.C. pressure drop
Pipe Size
Length
Diameter
10'
(3 .0 m)
20'
(6.1 m)
30'
(9.1 m)
40'
(12.2 m)
50'
(15.2 m)
60'
(18.3 m)
70'
(21.3 m)
80'
(24.4 m)
90'
(27.4 m)
100'
(30.5 m)
125'
(38.1 m)
150'
(45.7 m)
200'
(61.0 m)
1/2"
(13 mm)
172
118
95
81
72
65
60
56
52
50
44
40
34
3/4"
(19 mm)
360
247
199
170
151
137
126
117
110
104
92
83
71
1"
(25mm)
678
466
374
320
284
257
237
220
207
195
173
157
134
1
1/4"
(32mm)
1,390
957
768
657
583
528
486
452
424
400
355
322
275
1
1/2"
(38mm)
2,090 1,430 1,150
985
873
791
728
677
635
600
532
482
412
2"
(51mm)
4,020 2,760 2,220 1,900 1,680 1,520 1,400 1,300 1,220 1,160 1,020
928
794
Unit: Cubic feet per hour
Installation
Installation Manual
Water
heater
199,000 BTU/h
Dryer
35,000 BTU/h
Gas meter
Furnace
120,000 BTU/h
Range
65,000 BTU/h
A
B
C
10' (3 m)Length
1/2" (25 mm)
Pipe size
15' (4.6 m)Length
1/2" (25 mm)
Pipe size
15' (4.6 m)Length
1" (25 mm)
Pipe size
10'(3 m)Length
3/4" (19 mm)
Pipe size
10' (3 m )Length
1" (25 mm)
Pipe size
5' (1.5 m) Length
1-1/4" (32 mm)
Pipe size
10' (3 m)Length
3/4" (19 mm)
Pipe size
5' (1.5 m)Length
1-1/4"(32 mm)
Pipe size
Gas sizing example
(Natural Gas)
Unit: kBTU per hour
Pipe Size
Length
Diameter
10'
(3 .0 m)
20'
(6.1 m)
30'
(9.1 m)
40'
(12.2 m)
50'
(15.2 m)
60'
(18.3 m)
70'
(21.3 m)
80'
(24.4 m)
90'
(27.4 m)
100'
(30.5 m)
125'
(38.1 m)
150'
(45.7 m)
200'
(61.0 m)
1/2"
(13 mm)
268
184
148
126
112
101
93
87
82
77
68
62
53
3/4"
(19 mm)
567
393
315
267
237
217
196
185
173
162
146
132
112
1"
(25mm)
1,071
732
590
504
448
409
378
346
322
307
275
252
213
1
1/4"
(32mm)
2,205 1,496 1,212 1,039
913
834
771
724
677
630
567
511
440
1
1/2"
(38mm)
3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023
976
866
787
675
2"
(51mm)
6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811 1,606 1,496 1,260
Based on Energy Content of 1,000 BTU/Cubic ft:
Divide each appliance's BTU/h requirement by 1,000 BTU/ft
3
to get the appliance's ft
3
/h requirement.
Take into account the distance the appliance is from the gas meter, look in the above gas chart to properly size the line.
For sections of the gas line supplying gas to more than one appliance (Ex: Point A to Point B), add up the cubic ft per hour
requirements of the appliances that are being supplied by that section, and size to the farthest appliance.
For Example: The section from A to B supplies gas to the furnace, range and dryer. Adding up the BTU/h requirements and
dividing by 1,000 yields a cubic ft per hour requirement of 220 cubic ft of gas per hour. The farthest appliance is the range, which
is 50 ft away from the meter. Looking at the above chart, and under the column of 50 ft, Section A to B needs to be 1" in order
to supply 220 cubic ft.
