GSW 72090 manual Confined Space Air Requirements for Installations

Confined Space Air Requirements for

(a)

U.S. Installations

Refer to Figure 6 (a), (b), (c) or (d) for proper sizing and

location of combustion air ducts and openings. CHECK

LOCAL CODES.

(a) Equipment located in confined spaces; all air from

PERMANENT

OPENINGS

inside the building.

CONFINED

Two permanent openings shall be provided connecting

UNCONFINED

SPACE

the confined space (e.g., closet, small room) with the

SPACE

unconfined space. Each opening shall have a free area

of one square inch per 1,000 BTU/hour input (22

cm²/kW) of all appliances in the confined space, but not

EQUIPMENT LOCATED IN CONFINED SPACES;

less than 100 square inches (645 cm²). The top open-

ALL AIR FROM INSIDE THE BUILDING.

ing shall commence within 300mm (12 in.) of the top of

(b)

COMBUSTION

PERMANENT

space and the bottom opening shall commence within

300mm

VENTILATION

300mm (12 in.) of the bottom of the enclosure.

AIR DUCT

(12 in.)

AIR.

300mm

(b) Basement installation, equipment located in con-

(12 in.)

ABOVE

fined spaces; all air from outdoors.

GRADE

CONFINED

OR

When supplying air directly from the outdoors, each

SNOW

SPACE

opening shall have a minimum free area of one square

LINE

inch per 4,000 BTU/hour input (5.5 cm²/kW) of total

GRADE

input rating of all appliances in the confined space. The

inlets shall be a minimum of 300mm (12 in.) above the

grade (snow) line. The top opening shall commence

BASEMENT INSTALLATION, EQUIPMENT LOCATED

within 300mm (12 in.) of the top of the confined space.

300mm

IN CONFINED SPACES; ALL AIR FROM OUTDOORS

(12 in.)

(c) Equipment located in confined spaces; all air from

(c)

OUTDOORS

outdoors.

AIR DUCT

When supplying air directly from the outdoors using hor-

izontal ducting, each opening shall have a free mini-

300mm (12 in.)

mum area of one square inch per 2,000 BTU/hour (11

cm²/kW) of total input rating of all appliances in the con-

fined space.

(d) Equipment located in confined spaces; all air from

CONFINED

VENTILATION

COMBUSTION

SPACE

outdoors through ventilated attic.

When supplying air directly through vertical ducting,

each opening shall have a free minimum area of one

square inch per 4,000 BTU/hour (5.5 cm²/kW) of total

EQUIPMENT LOCATED IN CONFINED

300mm (12 in.)

input rating of all appliances in the confined space.

SPACES; ALL AIR FROM OUTDOORS.

(d)

ATTIC LOUVERS TO OUTDOORS

OUTLET

AIR

INLET AIR

DUCT

CONFINED

SPACE

Burn Hazard

300mm (12 in.)

Do not touch vent.

EQUIPMENT LOCATED IN CONFINED SPACES; ALL AIR

Doing so can result in

FROM OUTDOORS THROUGH VENTILATED ATTIC.

Figure 6

Combustion Air Supply Openings And Ducts

burns.

(U.S.A.)

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