RV53i & RV53e Operation and Installation Manual
17
Pipe Sizing Procedure - Example
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 location and the maximum BTU usage at full load when all gas products are in use.
Gas Input of all gas products (BTU / HR)
Cubic Feet per Hour (CFH) =
Heating Value of Gas (BTU / FT
3
)
2. Use the table for your gas type and pipe type to 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 1000 BTU/FT
3
. The gas input of the RV53i is
150,000 BTU/HR. Additional appliances at the location require 114,000 BTU/hr. Therefore the cubic
feet per hour = (150,000 + 114,000) / 1000 = 264 FT
3
/HR. If the pipe length is 10 feet then the 3/4 inch
pipe size is capable of supplying 264 FT
3
/HR of natural gas.
Gas Piping
The gas supply must be capable of handling the entire gas load 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
. For Canadian gas pipe sizing, refer to the Natural
Gas and Propane Installation Code CAN/CSA B149.1. The below information is provided as an example. The
appropriate table from the applicable code must be used.
Pipe Size (inches)
Length
3/4
1
1 1/4
1 1/2
10
273
514
1060
1580
20
188
353
726
1090
30
151
284
583
873
40
129
243
499
747
50
114
215
442
662
60
104
195
400
600
70
95
179
368
552
80
89
167
343
514
90
83
157
322
482
100
79
148
304
455
125
70
131
269
403
150
63
119
244
366
175
58
109
224
336
200
54
102
209
313
Length
Pipe Size (inches)
1/2
3/4
1
1 1/4
10
291
608
1150
2350
20
200
418
787
1620
30
160
336
632
1300
40
137
287
541
1110
50
122
255
480
985
60
110
231
434
892
80
101
212
400
821
100
94
197
372
763
125
89
185
349
716
150
84
175
330
677
175
74
155
292
600
200
67
140
265
543
Pipe Sizing Table - Natural Gas
Pipe Sizing Table - Propane Gas
Inlet Pressure: less than 2 psi (55 inches W.C.)
Pressure Drop: 0.3 inches W.C.
Specific Gravity: 0.60
Inlet Pressure: 11.0 inches W.C.
Pressure Drop: 0.5 inches W.C.
Specific Gravity: 1.50
Schedule 40 Metallic Pipe
Capacity in cubic feet per hour
Schedule 40 Metallic Pipe
Capacity in Thousands of BTU per Hour
