Mechanical (cont'd), 1 gas piping and pressures (cont'd), Sizing a gas supply line – Reznor B Unit Installation Manual User Manual
Page 14: Figure 12 - supply piping connection
Form I-F/B, P/N 98126 R21, Page 14
Sizing a Gas Supply
Line
Capacity of Piping
Cubic Feet per Hour based on 0.3" w.c. Pressure Drop
Specific Gravity for Natural Gas -- 0.6 (Natural Gas -- 1000 BTU/Cubic Ft)
Specific Gravity for Propane Gas -- 1.6 (Propane Gas -- 2550 BTU/Cubic Ft)
Length
Diameter of Pipe
of
1/2"
3/4"
1"
1-1/4"
1-1/2"
2"
Pipe
Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane
20'
92
56
190
116
350
214
730
445
1100
671
2100
1281
30'
73
45
152
93
285
174
590
360
890
543
1650
1007
40'
63
38
130
79
245
149
500
305
760
464
1450
885
50'
56
34
115
70
215
131
440
268
670
409
1270
775
60'
50
31
105
64
195
119
400
244
610
372
1105
674
70'
46
28
96
59
180
110
370
226
560
342
1050
641
80'
43
26
90
55
170
104
350
214
530
323
990
604
90'
40
24
84
51
160
98
320
195
490
299
930
567
100'
38
23
79
48
150
92
305
186
460
281
870
531
125'
34
21
72
44
130
79
275
168
410
250
780
476
150'
31
19
64
39
120
73
250
153
380
232
710
433
175'
28
17
59
36
110
67
225
137
350
214
650
397
200'
26
16
55
34
100
61
210
128
320
195
610
372
Note: When sizing supply lines, consider possibilities of future expansion and increased requirements.
Refer to National Fuel Gas Code for additional information on line sizing.
FIGURE 12 - Supply
Piping Connection
All piping must be in accordance with requirements outlined in the National Fuel Gas
Code ANSI/Z223.1a (latest edition), published by the American Gas Association or
CAN/CSA-B149.1 and B149.2, published by the Canadian Gas Association (See Para-
graph 1.4). Gas supply piping installation should conform with good practice and with
local codes.
Unit heaters for natural gas are orificed for operation with gas having a heating value of
1000 (±50) BTU per cubic ft. If the gas at the installation does not meet this specifica-
tion, consult the factory for proper orificing.
Pipe joint compounds (pipe dope) shall be resistant to the action of liquefied
petroleum gas or any other chemical constituents of the gas being supplied.
Install a ground joint union and manual shut-off valve upstream of the unit control sys-
tem, as shown in
FIGURE 12. The 1/8" plugged tapping in the shut-off valve provides
connection for supply line pressure test gauge. The National Fuel Gas Code requires
the installation of a trap with a minimum 3" drip leg. Local codes may require a mini-
mum drip leg longer than 3" (typically 6").
Gas connection sizes are included in the Dimension Tables in Paragraph 4.2. After all
connections are made, disconnect the pilot supply at the control valve and bleed the
system of air. Reconnect the pilot line and leak-test all connections by brushing on a
soap solution.
WARNING: All components of a gas supply system must be
leak tested prior to placing equipment in service. NEVER
TEST FOR LEAKS WITH AN OPEN FLAME. Failure to comply
could result in personal injury, property damage or death.
6. Mechanical
(cont'd)
6.1 Gas Piping
and Pressures
(cont'd)
From Gas Supply
(horizontal or vertical)
Manual shutoff
Pipe nipple extending
outside the cabinet.
Drip
Leg
To Gas Valve
(inside the
cabinet)
To Gas Valve
(inside the
cabinet)
Ground
Joint
Union
Drip
Leg
Ground Joint Union
Manual shutoff