Aerco AM 399W Manual de aplicação - Página 5
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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
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.)
Nominal
Iron Pipe
10'
Size
1-1/4"
1,390
1-1/2"
2,090
2"
4, 020
2-1/2"
6,400
3"
11,300
4"
23,100
5"
41,800
For further information refer to the latest edition of the National Fuel
Gas Code Handbook, ANSI Z223.1
6. GAS HEADER SIZING
Main supply gas pipe sizing should be developed for the total plant. Boiler gas manifold piping should be
sized based on the volume requirements and lengths between boilers and the fuel main. Header sizes
can be either full size or stepped in size as units are connected. A typical gas piping header diagram for
two AERCO AM Series boilers is illustrated in Figure 2. Header should be located above or behind
boiler. Gas piping should not be installed directly over top or front of any part of boiler.
PR1 04/08/2014
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
AM Series Gas Supply
Application Guide
(Natural Gas with Specific Gravity of 0.60)
Length of Pipe in Feet
20'
30'
957
768
1,430
1,150
2,760
2,220
4,400
3,530
7,780
6,250
15,900
12,700
28,700
23,000
NOTE
40'
60'
657
528
985
791
1,900
1,520
3,020
2,430
5,350
4,290
10,900
8,760
19,700
15,800
GF-146-G
TAG-0073_0B
80'
100'
452
400
677
600
1,300
1,160
2,080
1,840
3,670
3,260
7,490
6,640
13,600
12,000
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