Vanguard Heating VMH10TN Combustion, Determining Fresh-Airflow For Fireplace Location, Continued

AIR FOR	DETERMINING FRESH-AIR FLOW FOR FIREPLACE LOCATION
COMBUSTION	Determining if You Have a Confined or Unconfined Space
	Use this worksheet to determine if you have a confined or unconfined space.
AND
	Space: Includes the room in which you will install fireplace plus any adjoining rooms
VENTILATION	with doorless passageways or ventilation grills between the rooms.
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 16 ft. (length) x 14 ft. (width) x 8 ft. (ceiling height) =
		1792 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 1000 Btu/Hr per 50 cubic feet to determine the maximum
	Btu/Hr the space can support.
	______________ (volume of space) x 1000 Btu/Hr = (Maximum Btu/Hr the space can support)
				50 Cubic Feet
	Example: 1792 Cubic Feet (volume of space) x 1000 Btu/Hr = 35,840 Btu/Hr
							50 Cubic Feet
	This is the maximum Btu/Hr the space can support.
	3. Add the Btu/Hr of all fuel burning appliances in the space.
		Vent-free fireplace				___________________ 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
	Example:	Gas water heater				30,000			Btu/Hr
		Vent-free fireplace		+		10,000			Btu/Hr
				=
		Total				40,000			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: 35,840	Btu/Hr (maximum the space can support)
40,000	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 8.

B.Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 9.

C.Install a lower Btu/Hr fireplace, 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 unconfined space. You will need no additional fresh air ventilation.

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