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NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
7
Termination Heights For Vents
Above Flat Or Sloped Roofs
Ref. NFPA 54 / ANSI Z223.1, 7.6
Roof Pitch * Feet * Meters
Flat to 6/12 1.0 0.3
6/12 to 7/12 1.25 0.38
7/12 to 8/12 1.5 0.46
8/12 to 9/12 2.0 0.61
9/12 to 10/12 2.5 0.76
10/12 to 11/12 3.25 0.99
11/12 to 12/12 4.0 1.22
12/12 to 14/12 5.0 1.52
14/12 to 16/12 6.0 1.83
16/12 to 18/12 7.0 2.13
18/12 to 20/12 7.5 2.29
20/12 to 21/12 8.0 2.44
The vent / air intake termination clearances above the high
side of an angled roof is as shown in the following chart:
12
X
Roof Pitch is X/12
2 FT
MIN.
2 FT MIN.
Lowest
Discharge
Opening
H*
*H = MINIMUM HEIGHT FROM ROOF TO
LOWEST DISCHARGE OPENING OF VENT
TERMINATION HEIGHTS FOR VENTS ABOVE
FLAT OR SLOPED ROOFS
Horizontal Overhang
Vertical
Wall
Vent
Termination
Storm Collar
Concentric
Vent Pipe
Flashing
1 inch (25.4 mm) Minimum
Clearance to Combustibles
Vertical Vent Termination Clearances
VENT TERMINATION CLEARANCES
These instructions should be used as a guideline and do not supersede local codes in any
way. Install vent 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 and -B149.2 in
Canada.
Terminate multiple vent terminations according to the installation codes listed above.
Terminate single vent caps relative to building components according to Figure 4.
Horizontal Vent Termination Clearances
The horizontal vent termination must have
a minimum of 3" (76 mm) clearance to any
overhead combustible projection of 2 1/2" (64
mm) or less. See Figure 5. For projections
exceeding 2 1/2" (64 mm), see Figure 5. For
additional vent location restrictions refer to
Figure 6 on Page 8.
Figure 5
Side Elevation View
Note - See Figure 34 on
Page 20 for the exterior
wall recess allowances
of the square horizontal
termination.
3"
(76 mm)
12"
(305 mm)
Combustible Projection greater
Horizontal Vent Termination Clearances
Combustible Projection
2-1/2 inches or less in length
18"
(457 mm)
Ventilated
Soffit
Unventilated
Soffit
than 2-1/2 inches in length
Termination Kit
Figure 4 - Gas Vent Rule