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Venting continued – Bradford White TW4-75S-76B-3N User Manual

Page 9

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9

Venting continued-

Canadian

Installations

1

US Installations

2

A=

Clearance above grade, veranda,
porch, deck or balcony

12 inches

(30 cm)

12 inches

(30 cm)

B=

Clearance to window or door that may
be opened

12 inches

(30 cm)

4 feet (1.2 m) below or

to the side of opening;

12 inches (30 cm) above

opening

C=

Clearance to permanently closed
window

*b *b

D=

Vertical clearance to ventilated soffit
located above the terminal within a
horizontal distance of 2 feet (.6 m)
from the center line of the terminal

*b *b

E=

Clearance to unventilated soffit

*b

*b

F=

Clearance to outside corner

*b

*b

G=

Clearance to inside corner

*b

*b

H=

Clearance to each side of center line
extended above meter/regulator
assembly

3 feet (.9 m)

within a height

15 feet (4.6 m)

above the

meter/regulator

assembly

*b

I=

Clearance to service regulator vent
outlet or oil tank vent

3 feet (.9 m) *b

J=

Clearance to non-mechanical air
supply inlet to building or the
combustion air inlet to any other
appliance

12 inches

(30 cm)

4 feet (1.2m) below or to

side of opening;

12 inches (30 cm) above

opening.

K=

Clearance to a mechanical air supply
inlet

6 feet

(1.83 m)

3 feet (91 cm) above if

within 10 feet

horizontally

L=

Clearance above paved sidewalk or
paved driveway located on public
property

7 feet

(2.13 m)†

7 feet

(2.13 m)†

M=

Clearance under a veranda, porch,
deck, or balcony

12 inches
(30 cm) ‡

*b

1

In accordance with the current CAN/CGA-B149 Installation Codes.

2

In accordance with the current ANSI Z223.1-(Latest edition)/NFPA 54 National Fuel Gas Code.

† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single-family
dwellings and serves both dwellings.
‡ Permitted only if a veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor.
*a) A minimum clearance value determined by testing in accordance with section 2.20.
*b) “Clearance in accordance with local installation codes and the requirements of the gas supplier”.

The vent system must terminate so that proper clearances are maintained as
cited in local codes or the latest edition of the National Fuel Gas Code, ANSI
Z223.1.73.4e and 7.8a, b as follows:
1. Do not terminate near soffit vents or crawl space or other area where

condensate or vapor could create a nuisance or hazard or cause property
damage.

2. Do not terminate the exhaust vent terminal where condensate or vapor

could cause damage or could be detrimental to the operation of regulators,
relief valves, or other equipment.

3. Do not terminate the exhaust vent terminal over public area or walkways

where condensate or vapor can cause nuisance or hazard.

4. The vent shall terminate a minimum of 12 inches (25.4 cm) above expected

snowfall level to prevent blockage of vent termination.