Gas Line Leak Testing; Purging - Polaris PG10/GHX Instruction Manual

Capacity of gas pipe of different diameters and lengths in cu. ft. per hr. with pressure drop of 0.3 in. and specific gravity of 0.60 (natural gas).
Nominal Iron
Pipe Size, in.
10
1/2 132
278
3/4
1 520
1-1/4 1050
1600
1-1/2
After the length of pipe has been determined, select the pipe size which will provide the minimum cubic feet per hour required for the
gas input rating of the water heater. By formula:
The gas input of the water heater is marked on the water heater data plate. The heating value of the gas (BTU/FT
by consulting the local natural gas utility.
Maximum capacity of pipe in thousands of BTU per hour of undiluted liquefied petroleum gases (at 11 inches water column pressure).
Based on a Pressure Drop of 0.5 Inch Water Column.
Nominal Iron
Pipe Size, in.
10
1/2 275
3/4 576
1 1071
1-1/4 2205
Example: Input BTU requirement of the water heater, 199,000 BTUH
Total pipe length, 80 feet = 1" IPS required.
Maximum capacity of pipe in thousands of BTU per hour of undiluted liquefied petroleum gases (at 11 inches water column pressure).
Based on a Pressure Drop of 0.5 Inch Water Column.
Copper Tubing
O.D. Size, in.
10
206
5/8
3/4 348
7/8 536
Example: Input BTU requirement of the water heater, 199,000 BTUH
Total pipe length, 50 feet = 7/8" IPS required.
Additional tables are available in the current edition of the "National Fuel Gas Code", ANSI Z223.1

GAS LINE LEAK TESTING

Any time work is done on the gas supply system perform a leak test
to avoid the possibility of fire or explosion.
Table 7. Natural Gas Capacity (Cu. f t/hr)
20 30 40 50
n/a n/a n/a n/a
190 152 130 115
350 285 245 215
730 590 500 440
1100 890 760 670
Cu. Ft. Per Hr. Required =
Table 8. L .P. Gas Capacity
30 40
20
189 152 n/a
393 315 267
732 590 504
1496 1212 1039
Table 9. L .P. Gas Capacity
20 30
141 n/a
239 192
368 296
Fire and Explosion Hazard
Use joint compound or Teflon tape
compatible with propane gas.
Leak test gas connections before
placing water heater in operation.
Disconnect gas piping at main
gas shutoff valve before leak
testing heater.
Install sediment trap in
accordance with NFPA 54.
Length of Pipe, Feet
60 70 80 90
n/a n/a n/a n/a
105 96 n/a n/a
195 180 170 160
400 370 350 320
610 560 530 490
Gas Input of Water Heater (BTU/HR)
Heating Value of Gas (BTU/FT
Length of Pipe, Feet
50 60 70
n/a n/a n/a
237 217 196
448 409 378
913 834 771
Length of Pipe, Feet
40 50
n/a n/a
164 146
253 224
1. For test pressures exceeding 1/2 psi (3.45 kPa) disconnect
the water heater and its Main Gas Shutoff Valve from the gas
supply piping system during testing, see Figure 36 on page
30. The gas supply line must be capped when disconnected
from the water heater.
2. For test pressures of 1/2 psi (3.45 kpa) or less, the water
heater need not be disconnected, but must be isolated from
the supply gas line by closing the Main Gas Shutoff Valve
during testing.
3. Paint all supply gas line joints and connections upstream of
the water heater with a rich soap and water solution to test
for leaks. Bubbles indicate a gas leak. Do not use matches,
candles, flame or other sources of ignition for this purpose.
4. Repair any leaks before placing the water heater in operation.

PURGING

Gas line purging is required with new piping or systems.
Purging should be performed per the current edition of NFPA 54 the
National Fuel Gas Code.
31
100 125 150
n/a n/a n/a
n/a n/a n/a
150 130 120
305 275 250
460 410 380
3 )
3
) may be determined
80 90 100
n/a n/a n/a
185 173 162
307
346 322
724 677 630
60 80 100
n/a n/a n/a
132 n/a n/a
203 174 154
175 200
n/a n/a
n/a n/a
110 100
220 210
350 320
125 150
n/a n/a
146 132
275 252
567 511
125
n/a
n/a
137