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Gas-Fired Boiler Installation
10
Gas Piping
Note: Install a sediment trap (drip leg) and a union
connection ahead of the primary manual shutoff valve
on the boiler. Gas piping should be installed in accor-
dance with National Fuel Gas Code, ANSI Z223.1,
latest edition, and any other local codes which may
apply; in Canada see CAN/CGA-B 149.
Note: See chart below for required pipe size, based on
overall length of pipe from meter plus equivalent
length of all fittings. Approximate sizing may be based
on 1 cubic foot of natural gas per 1,000 Btu per hour
input, i.e., 900,000 Btu per hour requires about 900
cubic feet per hour. (See Typical Boiler Operating
Conditions, Section 4.3, for more information.)
WARNING!
All threaded connections must be made using a pipe
compound that is resistant to the action of liquefied
petroleum gases. Do not use Teflon tape on gas line
threads.
Pipe Capacity for Natural Gas
Equivalent Pipe Length Maximum Capacity in Cubic Feet of Natural Gas per Hour
Pressure Drop of 0.5 inch Water Column/Equivalent Length of
Pipe (in feet)
Nominal
Iron
Pipe
Size
(Inches)
Internal
Diameter
(Inches)
90º Ell
(Feet)
Tee
(Feet)
20
40
60
80
100
150
200
1-1/4 1.380 3.45 6.9 950
1-1/2 1.610 4.02 8.04 1,460 990 810
2 2.067 5.17 10.3 2,750 1,900 1,520 1,300 1,150 950 800
2-1/2 2.469 6.16 12.3 4,350 3,000 2,400 2,050 1,850 1,500 1,280
3 3.068 7.67 15.3 7,700 5,300 4,300 3,700 3,250 2,650 2,280
4 4.026 10.1 20.2 15,800 10,900 8,800 7,500 6,700 5,500 4,600
By Installer
Remote Gas
Shutoff (not
supplied)
Drip Leg
Union
Shutoff (on
boiler)
Gas Meter (not
supplied)