Assessments - 4, GPA: 4 ( )

Fabricante : Gas-Fired Products Arquivo Tamanho: 1.33 mb Arquivo Nome : Língua de Ensino:

Other venting references are in the equipment volume of the ASHRAE Handbook. Form #43155010 Feb-04 -13- SINGLE HEATER VENTING (VERTICAL THROUGH THE ROOF) 1. When venting the heater to outside of building through a roof, use single-wail metal pipe. This is to be constructed of galvanized sheet metal or other approved noncombustible corrosion-resistant material as allowed by state or local codes. 2. A vent passing through a combustible roof shall extend through a 2-inch clearance roof thimble. Double-wall, Type B vent must be used for the portion of the vent system which passes through the roof. An approved vent cap (Leslie “VersaCap”-Type B) must be attached to end of the flue. 3. The maximum equivalent length of vent pipe should be carefully observed. A safety switch in the heater is designed to shut the heater off before excessive flue restriction causes bad combustion. Refer to the Vent Sizing Table at the end of this section for required vent pipe diameter. ■ Minimum Equivalent Length - 5 ft. of Pipe ■ Maximum Equivalent Length - 100 ft. of Pipe Use the following correction factors to obtain the equivalent length: a. Subtract 15 ft. if the run is horizontal. b. Subtract 10 ft. for an approved vent cap. c. Subtract 10 ft. for each elbow beyond 15 ft. from the heater. d. Subtract 15 ft. for each elbow within 15 ft. of the heater. 4. Avoid locating elbows in the first 5 ft. of vent pipe whenever possible. Limit to (2) 90° elbows. When vent pipe is in a horizontal run, it must have 1/4 inch per foot rise. 5. Joints between sections of piping shall be fastened by sheet metal screws or other approved means and should be sealed to prevent leakage of flue gas into building. Aluminum or Teflon tape suitable for 550°F (3M Company tapes 433 or 363) or silicone sealant is recommended. 6. All portions of the vent pipe shall be supported to prevent from sagging. 7. When the vent pipe passes through areas where the ambient temperature is likely to induce condensation of the flue gases, the vent pipe should be insulated and a condensation drain should be provided. 8. Minimum clearance for single-wall flue pipe to combustible material shall be 6 inches. This may be reduced when the combustible material is protected as specified in the National Fuel Gas Code or the authority having jurisdiction. 9. Single-wall metal pipe shall not originate in any unoccupied attic or concealed space and shall not passthrough any attic, inside wall or concealed space, or through any floor. For the installation of a single-wall metal pipe through an exterior combustible wall, refer to latest edition of the National Fuel Gas Code or the authority having jurisdiction. 10. A venting system shall terminate at least 3 ft. above any forced air inlet located within 10 ft. SINGLE HEATER VENTING (HORIZONTAL THROUGH SIDEWALL) When venting the heater horizontally through a combustible outside sidewall, the same requirements listed previously for venting Vertical Throug...

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