Gas Piping - Burnham MINUTEMAN II Installation, Operating And Service Instructions

V. Gas Piping
A.
Size gas piping. Design system to provide adequate gas
supply to boiler. Consider these factors:
1. Allowable pressure drop from point of delivery to
boiler. Maximum allowable system pressure is ½
psig. Actual point of delivery pressure may be less;
contact gas supplier for additional information.
Minimum gas valve inlet pressure is stamped on the
rating label located in the boiler's vestibule
compartment.
2. Maximum gas demand. Table 2 lists boiler input
rate. Also consider existing and expected future gas
utilization equipment (i.e. cooking equipment).
3. Length of piping and number of fittings. Refer to
Table 3 for maximum capacity of Schedule 40 pipe.
Table 4 lists equivalent pipe length for standard
fittings.
Table 2: Rated Input
Input Rate
[cubic feet per hour]
Boiler
Model
Natural
Gas
MMII4-70 70
MMII4-105 105
MMII5-105 105
MMII5-140 140
Table 3: Maximum Capacity of Schedule 40 Pipe in CFH For Gas Pressures of 0.5 psig or Less
Length
[Feet]
½
10 132
20 92
30 73
40 63
50 56
60 50
70 46
80 43
90 40
100 38
10
Gas Connection
Size (Inches)
LP Gas
28 ½
42 ½
42 ½
56 ½
0.3 Inch w.c. Pressure Drop
¾ 1
278 520
190 350
152 285
130 245
115 215
105 195
96 180
90 170
84 160
79 150
4. Specific gravity of gas. Gas piping systems for gas
with a specific gravity of 0.60 or less can be sized
directly from Table 3, unless authority having
jurisdiction specifies a gravity factor be applied. For
specific gravity greater than 0.60, apply gravity
factor from Table 5. If exact specific gravity is not
shown choose next higher value.
For materials or conditions other than those listed
above, refer to National Fuel Gas Code, NFPA 54/
ANSI Z223.1, or size system using standard
engineering methods acceptable to authority having
jurisdiction.
B.
Connect boiler gas valve to gas supply system.
1. Use methods and materials in accordance with local
plumbing codes and requirements of gas supplier. In
absence of such requirements, follow National Fuel
Gas Code, ANSI Z223.1.
2. Use thread (joint) compounds (pipe dope) resistant
to action of liquefied petroleum gas.
3. Install sediment trap, ground-joint union and manual
shut-off valve upstream of boiler gas control valve
and outside of jacket. See Figure 8.
4. All above ground gas piping upstream from manual
shut-off valve must be electrically continuous and
bonded to a grounding electrode. Do not use gas
piping as grounding electrode. Refer to National
Electrical Code, ANSI/NFPA 70.
0.5 Inch w.c. Pressure Drop
1¼ ½
1,050 175
730 120
590 97
500 82
440 73
400 66
370 61
350 57
320 53
305 50
¾ 1
360 680
250 465
200 375
170 320
151 285
138 260
125 240
118 220
110 205
103 195
1¼
1,400
950
770
660
580
530
490
460
430
400