Sears N8MPN050B12B1 SoffitVen, Indoor Combustion Air, ThisinstallationNOTapprovedin Canada

Outside Air (This is ONLY a guide. SubJect to codes of country having jurisdiction.)

ThisinstallationNOTapprovedin Canada

GasVent

,GableV_/)

(1)

Soffit Vent

Inlet

Air (1)

MinimumOne Inlet and OneOutlet Air Supply is Required May be in andCombination Shown

Inlet Air Opening Must beWithin12"(300mm)of floor

Outlet Air OpeningMust be Within12"(300mm)of ceiling

(1)1 Square Inch (6cm2) per 4000 BTUH

(2)1 Square Inch (6cm2) per 2000 BTUH

Vent

G Vent _j_.Gable

ba_ventilated Attic'_

I Top Above Insulation_

I/	I	1		€_:;;_l TM
				SoffitVen,
I_		utletAir (1)			Outlet/1_
II		_.			Air(1)
F		NG_
_,,		_	r-_	Inlet
			--	Air (2)	Inlet

Air (1)

........Air (2)

The opening shall commence within 12" of the top of the enclo- sure. Appliances shall have clearances of at least 1" from the sides and back and 6" from the front. The opening shall directly commu-

nicate with the outdoors or shall communicate through a vertical or

horizontal duct to the outdoors or spaces (crawl or attic) that freely

communicate with the outdoors.

4.Combination of Indoor and Outdoor Air shall have:

a. Indoor openings that comply with the Indoor Combus- tion Air Method below and

b.Outdoor openings located as required in the Outdoor

Combustion air Method above and

c.Outdoor openings sized as follows.

1)Calculate the Ratio of all Indoor Space volume divid-

ed by required volume for Indoor Combustion Air Meth- od. Outdoor openings sized as follows.

2)Outdoor opening size reduction Factor is I minus the Ratio in 1) above.

3)Minimum size of Outdoor openings shall be the size

required in Outdoor Combustion Air Method above multiplied by reduction Factor.

FreeArea

BTUH			MinimumFree Area Required for EachOpeningor Ductto Outdoors
Input		Two HorizontalDucts		SingleOpening		TwoVerticalDuctsor Openings	Round Duct
Rating		(sq.inJ2,000 BTUH)		(sq. in./3,000BTUH)		(sq.inJ4,000 BTUH)	(sq. in./4,000
							BTUH)
50,000		25 sq, in.			16.7sq. in.	12,5sq. in.	4"
75,000		37,5 sq. in.			25 sq, in,	18.75sq. in.	5"
100,000		50 sq. in.			33.3 sq. in.	25 sq. in,	6"
125,000		62,50 sq. in.			41,7 sq. in.	31.25sq, in.	7"
150,000		75 sq, in.			50 sq, in,	37,5 sq. in.	7"
EXAMPLE:	Determining	Free Area
Furnace		Water Heater	Total Input
100,000	+	30,000	(130,000	+ 4,000)	32.5 Sq. In. Vertical
Furnace		Water Heater	Total Input
100,000	+	30,000	(130,000	+ 2,000)	65 Sq. In. Horizontal

Indoor Combustion Air

Standard and Known-Air-Infiltration Rate Methods

© NFPA & AGA

Indoor	air is permitted	for combustion	and ventilation,	if the
Standard	or Known-air-lnfiltration		Rate Method is used,

CARBON MONOXIDE POISONING HAZARD.

Failure to supply adequate combustion air could result in death or personal injury.

Most homes will require additional air from outdoors for combustion and ventilation. A space with at least 50 cubic feet per 1,OOOBTUH input rating or homes

with tight construction may need outdoor air to supplement air infiltration for proper combustion and ventilation of flue gases.

441 O1 261302