Filter
Top Products
7
Nominal Iron Pipe Length of Pipe, Feet
Size, in.
1/2
3/4
1
1-1/4
1-1/2
132
278
520
1050
1600
92
190
350
730
1100
73
152
285
590
890
63
130
245
500
760
56
115
215
440
670
50
105
195
400
610
46
96
180
370
560
43
90
170
350
530
40
84
160
320
490
38
79
150
305
460
34
72
130
275
410
31
64
120
250
380
28
59
110
225
350
26
55
100
210
320
10 20 30 40 50 60 70 80 90 100 125 150 175 200
Table 1
Natural Gas Pipe Capacity Table (Cu. Ft./Hr.)
Capacity of gas pipe of different diameters and lengths in cu. ft. per hr. with pressure drop of 0.3 in. and specific gravity
of 0.60 (natural gas).
After the length of pipe has been determined, select the pipe size which will provide the minimum cubic feet per hour
required for the gas input rating of the water heater. By formula:
Gas Input of Water Heater (BTU/HR)
Heating Value of Gas (BTU/FT³)
The gas input of the water heater is marked on the water heater data plate. The heating value of the gas (BTU/FT )
may be determined by consulting the local natural gas utility.
3
Cu. Ft. Per Hr. Required=
Additional tables are available in the latest edition of the "National Fuel Gas Code", ANSI Z223.1.
Combustion Air Supply and
Ventilation
IMPORTANT: Air for combustion and ventilation must not
come from a corrosive atmosphere. Any failure due to
corrosive elements in the atmosphere is excluded from
warranty coverage.
The following types of installation (not limited to the
following) will require outdoor air for combustion due to
chemical exposure and may reduce but not eliminate the
presence of corrosive chemicals in the air:
• beauty shops
• photo processing labs
• buildings with indoor pools
• water heaters installed in laundry, hobby, or craft
rooms
• water heaters installed near chemical storage areas
Combustion air must be free of acid-forming chemicals
such as sulfur, fluorine, and chlorine. These elements are
found in aerosol sprays, detergents, bleaches, cleaning
solvents, air fresheners, paint, and varnish removers,
refrigerants, and many other commercial and household
products. When burned, vapors from these products form
highly corrosive acid compounds. These products should
not be stored or used near the water heater or air inlet.
Combustion and ventilation air requirements are
determined by the location of the water heater. The water
heater may be located in either an open (unconfined) area
or in a confined area or small enclosure such as a closet
or small room. Confined spaces are areas with less than
50 cubic feet for each 1,000 BTUH of the total input for all
gas using appliances.
Carbon Monoxide Warning
Follow all the local and state codes or, in
the absence of local and state codes, the
“National Fuel Gas Code”, ANSI Z223.1
(NFPA 54)- latest edition to properly install
vent system.
Failure to do so can result in death,
explosion, or carbon monoxide poisoning.
WARNING