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VENT TERMINATION CLEARANCES
These instructions should be used as a
guideline and do not supersede local codes
in any way. Install venting according to local
codes, these instructions, the current National
Fuel Gas Code (ANSI-Z223.1) in the USA or
the current standards of CAN/CGA-B149.1
in Canada.
Gas Vent Rule – Gas vent caps are not permitted
within 8 ft. (2.4 m) of a vertical wall or similar
obstruction. Gas vent caps that are located 8
ft. or more from a portion of a building which
extends at an angle greater than 45° upward
from the horizontal may terminate in accordance
with Figure 4 , provided that in no case shall
any discharge opening on the cap be less than
2 ft. (.6 m) horizontally from the roof surface
(National Fuel Gas Code ANSI Z223.1 (NFPA
54) (CAN/CGA B149.1).
Multiple Terminations
These appliances may vent adjacent to and at
the same level with any other gas appliances
(including direct-vent appliances) provided that
there is at least 2 ft. (0.6m) between the proximal
edges of the vent caps. These appliances may
be vented adjacent to a chimney vent servicing
a solid fuel fireplace provided the B-vent cap
is at least 2 ft. (0.6m) away from the nearest
point of the chimney opening.
Multiple Terminations
2 ft.
(0.6m)
Minimum
6
12
Roof Pitch is X/12
Minimum Height from Roof to
Lowest Discharge Opening
1" (25 mm)
Minimum
Figure 4 -
Vertical Vent Termination Clearances
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Termination Heights For Vents
Above Flat Or Sloped Roofs
Ref. NFPA 54 / ANSI Z223.1, 7.6
Roof Pitch
X
Flat to 6/12
6/12 to 7/12
7/12 to 8/12
8/12 to 9/12
9/12 to 10/12
10/12 to 11/12
11/12 to 12/12
12/12 to 14/12
14/12 to 16/12
16/12 to 18/12
18/12 to 20/12
20/12 to 21/12
Feet
Meters
1.0
0.3
1.25
0.38
1.5
0.46
2.0
0.61
2.5
0.76
3.25
0.99
4.0
1.22
5.0
1.52
6.0
1.83
7.0
2.13
7.5
2.29
8.0
2.44
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