United States Stove VF30IL, VF30IN manual Determining if You Have a Confined or Unconfined Space

AIR FOR COMBUSTION AND VENTILATION

Determining if You Have a Confined or Unconfined Space

Use this worksheet to determine if you have a confined or unconfined space.

Space: Includes the room in which you will install the firebox plus any adjoining rooms with doorless passageways or ventilation grills between the rooms.

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.Divide the space volume by 50 cubic feet to determine the maximum BTU/Hr the space can support.

_________ (volume of space) 50 cu. Ft. = (Maximum BTU/Hr the space can support)

Example: 3168 cu. Ft. (volume of space) 50 cu. Ft. = 63.3 or 63,300 (maximum BTU/Hr the space can support)

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

Vent-free Firebox		__________________	BTU/Hr
Gas water heater*		__________________	BTU/Hr
Gas furnace		__________________	BTU/Hr
Vented gas heater		__________________	BTU/Hr
Gas firebox logs		__________________	BTU/Hr
Other gas appliances*	+ __________________		BTU/Hr
Total	= __________________		BTU/Hr
Example: Gas water Heater		40,000	BTU/Hr
Vent-free firebox with log heater	+	39,000	BTU/Hr
Total	=	79,000	BTU/Hr

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

4.Compare the maximum BTU/Hr the space can support with the actual amount of BTU/ Hr used.

______________	BTU/Hr (maximum the space can support)
______________	BTU/Hr (actual amount of BTU/Hr used)

Example: 63,300 BTU/Hr (maximum the space can support) 79,000 BTU/Hr (actual amount of BTU/Hr used)

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:

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, page 10.

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