28
DX2
Series
*Consult the NFPA ANSI Z223.1 Gas
Vent Termination criteria if roof pitch
exceeds 9:12.
Vent Termination
United States:
• Vent must terminate a minimum of 4 ft. (1.2 m) below, 4 ft. (1.2 m) horizontally from, and 1 ft.
(30 cm) above any window or door that may be opened or gravity air inlet into the building.
• Vent must terminate a minimum of 3 ft. (.9 m) above any forced air inlet that is located within
10 ft. (3.1 m).
• The bottom of the vent terminal must be located a minimum of 12 in. (30 cm) above grade level
and must extend beyond any combustible overhang. Vents adjacent to public walkways must
terminate a minimum of 7 ft. (2.1 m) above grade level.
• The vent terminal must be installed to prevent blockage by snow and protect building materials
from degradation by flue gases.
• The vent cap must be a minimum of 6 in. (15.2 cm) from the sidewall of the building.
• Vent must be a minimum of 36 in. below or extend beyond any combustible overhang.
• Consult the NFPA ANSI Z223.1 Gas Vent Termination criteria if roof pitch exceeds 9:12.
Canada:
• Vents must terminate a minimum of 3 ft. (.9 m) from a window or door that may be opened, and
non-mechanical air supply inlet or combustion air inlet into the building.
• Vents must terminate a minimum of 6 ft. (1.8 m) from a mechanical air supply inlet.
Rooftop Venting
Guidelines:
Vent Locations and Clearances
• Separate air intake duct from vent pipe a minimum of 4 ft. (1.2 m) by placing vent pipes higher
than adjacent air intake duct.
• Venting may utilize standard B-vent cap.
• The vent terminal must extend a minimum of 2 ft. (.6 m) above the roof.
Figure 3.23
•
Rooftop Venting - Side View
Vent Cap
Roof
Double-Wall B Vent Pipe
Firestop Spacer
Single-Wall Elbow or Alternate Tee Fitting
B to C Adapter
Roof
24 in. Min.*
Heater
3.0
Installation
•
Sidewall Venting
•
Roof Venting