EXTERIOR HORIZONTAL VENT TERMINATION CLEARANCE REQUIREMENTS
*See Item D in the Text Below.
| Exterior Wall | Center Line |
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| *18” |
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| Horizontal | V |
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| Termination |
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| 18” | Ventilated Soffit |
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| Inside Corner |
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| Detail D |
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| V |
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L |
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| Fixed |
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| Closed |
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| F | V | Window |
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| C | C |
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| A |
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| X = Air Supply Inlet | V |
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| NOTE: Local Codes Or Regulations |
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| May Require Different Clearances. |
Inside |
| NOTE: Location Of The Vent Termination |
Corner Detail |
| Must Not Interfere With Access To The |
| Electrical Service. | |
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G |
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V |
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A |
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A | = 9” in U.S. | |
= 12” in Canada | ||
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| 3 ft. |
B |
| X |
| A | |
| A |
VOperable
| Window | 3 ft. |
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B |
| J |
B |
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I
= Vent Termination = Area where Termination is not Permitted
N P N
O
V
Q
D
V
M
V
| Canadian Installation* | US Installation** |
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A = Clearance above grade, veranda, porch, deck, or balcony. | 12 inches (30cm)* | 12 inches (30cm)** |
B = Clearance to window or door that may be opened. | 6 inches (15cm) for appliances | 6 inches (15cm) for appliances |
| < 10,000 Btuh (3kW), 12 inches (30cm) | < 10,000 Btuh (3kW), 9 inches (23cm) |
| for appliances > 10,000 Btuh (3kW) | for appliances > 10,000 Btuh (3kW) and |
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| < 50,000 Btuh (15kW), 12 inches (30cm) |
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| for appliances > 50,000 Btuh (15kW)** |
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C = Clearance to permanently closed window | 12 inches (305mm) recommended to | 9 inches (229mm) recommended to |
| prevent window condensation | prevent window condensation |
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D = Vertical clearance to ventilated soffit located above the | 18 inches (458mm) | 18 inches (458mm) |
termination within a horizontal distance of 18 inches (458mm) |
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from the center line of the termination |
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E = Clearance to unventilated soffit*** | 12 inches (305mm) | 12 inches (305mm) |
F = Clearance to outside corner | 5 inches (12.7cm) minimum | 5 inches (12.7cm) minimum |
G = Clearance to inside corner | 6 inches (15.2cm) minimum | 6 inches (15.2cm) minimum |
H = Clearance to each inside of center line extended above | 3 feet (91cm) within a height of 15 feet | 3 feet (91cm) within a height of 15 feet |
meter/regulator assembly | above the meter/regulator assembly* | above the meter/regulator assembly** |
I = Clearance to service regulator vent outlet | 3 feet (91cm)* | 3 feet (91cm)** |
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J = Clearance to nonmechanical air supply inlet to building or | 6 inches (15cm) for appliances | 6 inches (15cm) for appliances |
the combustion air inlet to any other appliance | < 10,000 Btuh (3kW), 12 inches (30cm) | < 10,000 Btuh (3kW), 9 inches (23cm) |
| for appliances > 10,000 Btuh (3kW) | for appliances > 10,000 Btuh (3kW) and |
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| < 50,000 Btuh (15kW), 12 inches (30cm) |
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| for appliances > 50,000 Btuh (15kW)** |
K = Clearance to a mechanical air supply inlet | 6 feet (1.83m)* | 3 feet (91cm) above if within 10 feet |
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| (3m) horizontally** |
L = Clearance above paved sidewalk or paved diveway located | 7 feet (2.13m)‡ | 7 feet (2.13m)‡ |
on public property |
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M = Clearance under veranda, porch, deck or balcony | 12 inches (30cm)*‡ | 12 inches (30cm)‡ |
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N = Depth of Alcove (Maximum) | 6 feet (1.83m)* | 6 feet (1.83m)** |
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O = Clearance to Termination (Alcove) | 6 inches (15.2mm)* | 6 inches (15.2mm)** |
P = Width of Alcove (Minimum) | 3 feet (91cm)* | 3 feet (91cm)* |
Q = Clearance to Combustible Above (Alcove) | 18 inches (457mm)* | 18 inches (457mm)** |
* In accordance with the current |
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** In accordance with the curent ANSI SZ223.1/NFPA 54 National Fuel Gas Codes. |
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*** Clearance required to vinyl soffit material - 30 inches (76cm) minimum. |
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‡ A vent shall not terminate directly above a sidewalk or paved driveway which is located between two single family dwellings and serves both | ||
dwellings. |
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*‡ Only permitted if veranda, porch, deck or balcony is fully open on a minimum 2 sides beneath the floor: |
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Figure 8 |
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NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE. | 7 |