22 Installing the Water Heater
3.3.1 Gas Pipe Sizing Tables (Referenced from 2012 National Fuel Gas Code)
These tables are for reference only. Please consult the gas pipe manufacturer for actual pipe capacities.
Maximum Natural Gas Delivery Capacity
In cubic feet (ft
3
) per hour (0.60 specific gravity; 0.5 in WC pressure drop). Contact your gas supplier for BTU/ft
3
ratings. Use 1,000 BTU/ft
3
for simplified calculations.
Pipe
Size
Length (including fittings)
10 ft
(3 m)
20 ft
(6 m)
30 ft
(9 m)
40 ft
(12 m)
50 ft
(15 m)
60 ft
(18 m)
70 ft
(21 m)
80 ft
(24 m)
90 ft
(27 m)
100 ft
(30 m)
125 ft
(38 m)
3
/
4
in
360
247
199
170
151
137
126
117
110
104
92
1 in
678
466
374
320
284
257
237
220
207
195
173
1
1
/
4
in 1,390
957
768
657
583
528
486
452
424
400
355
1
1
/
2
in 2,090
1,430
1,150
985
873
791
728
677
635
600
532
2 in
4,020
2,760
2,220
1,900
1,680
1,520
1,400
1,300
1,220
1,160
1,020
2
1
/
2
in 6,400
4,400
3,530
3,020
2,680
2,430
2,230
2,080
1,950
1,840
1,630
3 in
11,300
7,780
6,250
5,350
4,740
4,290
3,950
3,670
3,450
3,260
2,890
4 in
23,100
15,900
12,700
10,900
9,660
8,760
8,050
7,490
7,030
6,640
5,890
Maximum Liquefied Propane Delivery Capacity
In thousands of BTU/H (0.5 in WC pressure drop)
Pipe
Size
Length (including fittings)
10 ft
(3 m)
20 ft
(6 m)
30 ft
(9 m)
40 ft
(12 m)
50 ft
(15 m)
60 ft
(18 m)
80 ft
(24 m)
100 ft
(30 m)
125 ft
(38 m)
150 ft
(45 m)
175 ft
(53 m)
200 ft
(60 m)
250 ft
(76 m)
1
/
2
in
291
200
160
137
122
110
101
94
89
84
74
67
62
3
/
4
in
608
418
336
287
255
231
212
197
185
175
155
140
129
1 in
1,150
787
632
541
480
434
400
372
349
330
292
265
243
1
1
/
4
in 2,350
1,620
1,300
1,110
985
892
821
763
716
677
600
543
500
1
1
/
2
in 3,520
2,420
1,940
1,660
1,480
1,340
1,230
1,140
1,070
1,010
899
814
749
2 in
6,790
4,660
3,750
3,210
2,840
2,570
2,370
2,200
2,070
1,950
1,730
1,570
1,440
