Desa LHP) (V)L36(EP, LZPR), LEN) (V)L32(HP Ventilation AIR, Ventilation Air From Inside Building

AIR FOR COMBUSTION

AND VENTILATION

Continued

1.Determine the volume of the space (length x width x height).

Length x Width x Height =________ cu. ft. (volume of space)

Example: Space size 22 ft. (length) x 18 ft. (width) x 8 ft. (ceiling height) = 3168 cu. ft. (volume of space)

If additional ventilation to adjoining room is supplied with grills or openings, add the volume of these rooms to the total volume of the space.

2.Multiply the space volume by 20 to determine the maximum Btu/Hr the space can support.

_______(volume of space) x 20 = (Maximum Btu/Hr the space can support)

Example: 3168 cu. ft. (volume of space) x 20 = 63,360 (maximum Btu/Hr the space can support)

3.Add the Btu/Hr of all fuel burning appliances in the space.

Vent-free heater	__________ Btu/Hr
Gas water heater*	__________ Btu/Hr
Gas furnace	__________ Btu/Hr
Vented gas heater	__________	Btu/Hr
Gas fireplace logs	__________	Btu/Hr

Other gas appliances* +		________	Btu/Hr
Total	=	________	Btu/Hr

*Do not include direct-vent gas appliances. Direct-vent draws combustion air from the outdoors and vents to the outdoors.

Example:	40,000
Gas water heater
	__________ Btu/Hr
Vent-free heater	39,000	Btu/Hr
	+ ________
Total	79,000	Btu/Hr
	= ________

4. Compare the maximum Btu/Hr the space can

support with the actual amount of Btu/Hr used.

__________ Btu/Hr (maximum the space

A.Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adjoining room or add ventilation grills between rooms. See Ventilation Air From Inside Building.

B.Vent room directly to the outdoors. See Ven- tilation Air From Outdoors, page 9.

C.Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined.

If the actual Btu/Hr used is less than the maximum Btu/Hr the space can support, the space is an un- confined space. You will need no additional fresh air ventilation.

WARNING: If the area in which the heater may be operated is smaller than that defined as an unconfined space or if the building is of unusually tight construction, provide adequate combustion and ventilationairbyoneofthemethods described in the National Fuel Gas Code,ANSIZ223.1/NFPA54Section

5.3or applicable local codes.

VENTILATION AIR

Ventilation Air From Inside Building

This fresh air would come from an adjoining un- confined space. When ventilating to an adjoining unconfined space, you must provide two perma- nent openings: one within 12" of the ceiling and one within 12" of the floor on the wall connecting the two spaces (see options 1 and 2, Figure 4). You can also remove door into adjoining room (see option 3, Figure 3). Follow the National Fuel Gas Code, ANSI Z223.1/NFPA 54, Section 5.3, Air for Combustion and Ventilation for required size of ventilation grills or ducts.

can support)

__________ Btu/Hr (actual amount of

Btu/Hr used)

Example: 63,360 Btu/Hr (maximum

the space can support)

79,000 Btu/Hr (actual amount of Btu/Hr used)

Ventilation
Grills
Into	Or
Adjoining
	Remove
Room,
	Door into
Option 1
	Adjoining
	Room,
	Option
	3

12"

Ventilation Grills

Into Adjoining Room,

Option 2

The space in the above example is a confined space because the actual Btu/Hr used is more than the maximum Btu/Hr the space can support. You must provide additional fresh air. Your options are as follows:

12"

Figure 3 - Ventilation Air from Inside

Building

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