Modulex EXT Series Piping Application Guide
Page
4
of
7
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
TAG-0096
10/06/2021
Phone: 800-526-0288
4.
GAS PIPING
All gas piping and components must comply with NFPA local codes, and utility requirement minimums.
Only gas approved fittings, valves, or pipe should be utilized.
Standard industry practice for gas piping is Schedule 40 iron pipe and fittings. All high and low gas
pressure piping systems must comply with local utility and building codes.
Assembled piping should be clean of all debris, pipe chips, or foreign material to prevent any from
entering the Modulex boiler gas trains. Piping should be tested as prescribed in NFPA 54. Equipment
should be isolated before testing any piping system over the allowable pressure.
DO NOT EXCEED
10.5
” W. C.
on the inlet side of the Modulex boiler at any time.
5.
GAS SUPPLY MAIN SIZING
The fuel supplier, or utility, should be consulted to confirm that sufficient volume and normal pressure
is provided to the building at the discharge side of the gas meter or supply pipe. For existing
installations with gas equipment, gas pressure should be measured with a manometer to ensure
sufficient pressure is available. Before sizing gas piping, a survey of all connected gas devices should
be made. Gas piping supplying more than one gas device must be able to handle the total connected
input within the allowable gas pressure drop. The allowable minimum and maximum gas pressure for
each device should be considered. Whenever the minimum and maximum gas pressures vary
between devices, gas pressure regulators at each unit should be installed to allow regulation at any
individual unit. Gas pressure must never exceed the maximum allowable rating of any connected
device.
The total length of gas piping as well as fitting pressure drop must be considered when sizing the gas
piping. Total equivalent length should be calculated from the meter or source location to the last unit
connected. Gas piping
Table 1
, containing data extracted from NFPA 54, should be used as
a minimum
guideline.
Gas pipe size should be selected on the total
equivalent
length from the table. The gas
volume for cfh flow will be the input divided by the calorific value of the fuel to be supplied.
TABLE 1: Gas Supply Main Piping Minimum Size Requirements
Nominal
Iron Pipe
Size
Maximum Capacity of Pipe in Cubic Feet of Gas / Hour
(Gas pressure = 0.5 psig or less, pressure drop = 0.5 inches of W.C.)
(Natural Gas with Specific Gravity of 0.60)
Length of pipe in feet
10’
20’
30’
40’
60’
80’
100’
1.1/4”
1,390
957
768
657
528
452
400
1.1/2”
2,090
1,430
1,150
985
791
677
600
2”
4, 020
2,760
2,220
1,900
1,520
1,300
1,160
2.1/2”
6,400
4,400
3,530
3,020
2,430
2,080
1,840
3”
11,300
7,780
6,250
5,350
4,290
3,670
3,260
4”
23,100
15,900
12,700
10,900
8,760
7,490
6,640
5”
41,800
28,700
23,000
19,700
15,800
13,600
12,000
NOTE:
For further information refer to National Fuel Gas Code Handbook, ANSI Z223.1.
