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).
Nominal Iron Pipe |
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| Length of Pipe, Feet |
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Size, in. 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 100 125 150 175 200 |
1/2 | 132 | 92 | 73 | 63 | 56 |
3/4 | 278 | 190 | 152 | 130 | 115 |
1 | 520 | 350 | 285 | 245 | 215 |
1050 | 730 | 590 | 500 | 440 | |
1600 | 1100 | 890 | 760 | 670 | |
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50 | 46 | 43 | 40 | 38 | 34 | 31 | 28 | 26 |
105 | 96 | 90 | 84 | 79 | 72 | 64 | 59 | 55 |
195 | 180 | 170 | 160 | 150 | 130 | 120 | 110 | 100 |
400 | 370 | 350 | 320 | 305 | 275 | 250 | 225 | 210 |
610 | 560 | 530 | 490 | 460 | 410 | 380 | 350 | 320 |
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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:
Cu. Ft. Per Hr. Required= 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/FT3) may be determined by consulting the local natural gas utility.
Additional tables are available in the latest edition of the "National Fuel Gas Code", ANSI Z223.1.
Combustion Air Supply and Ventilation
WARNING
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.
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
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.
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