Navien NFC-175, Installation & Operation Manual

Page: 49 / 124

49 Connecting the Gas Supply
4.1 Gas Pipe Sizing Tables
The following tables are referenced from the 2012 National Fuel Gas Code and 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. This table is recommended for supply pressures less than 6 in WC.
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
In Cubic Feet (ft
3
) per Hour (0.60 Specific Gravity; 3.0 in WC Pressure Drop). Contact your gas supplier for BTU/ft
3
ratings. Use 1,000 BTU/ft
3
for
simplified calculations. This table is recommended for supply pressures of 6 in WC or greater.
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)
1 /
2
in 454 312 250 214 190 172 158 147 138 131 116
3
/
4
in 949 652 524 448 397 360 331 308 289 273 242
1 in 1,787 1,228 986 844 748 678 624 580 544 514 456
1
1
/
4
in 3,669 2,522 2,025 1,733 1,536 1,392 1,280 1,191 1,118 1,056 936
1
1
/
2
in 5,497 3,778 3,034 2,597 2,302 2,085 1,919 1,785 1,675 1,582 1,402
2 in 10,588 7,277 5,844 5,001 4,433 4,016 3,695 3,437 3,225 3,046 2,700
2
1
/
2
in 16,875 11,598 9,314 7,971 7,065 6,401 5,889 5,479 5,140 4,856 4,303
3 in 29,832 20,503 16,465 14,092 12,489 11,316 10,411 9,685 9,087 8,584 7,608
4 in 43,678 30,020 24,107 20,632 18,286 16,569 15,243 14,181 13,305 12,568 11,139