Desa CGP6L, CGP10L Determining FRESH-AIR Flow for Heater Location, Ventilation AIR

10,000 AND 6,000 BTU/HR PROPANE/LP GAS HEATER

FRESH AIR FOR COMBUSTION AND VENTILATION

Continued

DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION

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 heater 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 20 ft. (length) x 16 ft. (width) x 8 ft. (ceiling height) =

2560 cu. ft. (volume of space)

If additional ventilation to adjoining room is supplied with grills or open- ings, 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: 2560 cu. ft. (volume of space) ÷ 50 cu. ft. = 51.2 or 51,200 (maximum Btu/Hr the space can sup- port)

3.Add the Btu/Hr of all fuel burning ap- pliances 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

Example:
Gas water heater	44,000	Btu/Hr
Vent-free heater	+ 10,000	Btu/Hr
Total	= 54,000	Btu/Hr

*Do not include direct-vent gas appli- ances. 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:

51,200 Btu/Hr (maximum the space can support)

54,000 Btu/Hr (actual amount of Btu/ Hr used)

The space in the above example is a con- fined 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 ventila- tion grills between rooms. See Ventila- tion Air From Inside Building.

B.Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 5.

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 unconfined 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, provide ad- equate combustion and ventila- tion air by one of the methods described in the National Fuel Gas Code, ANSI Z223.1, 1992, Section 5.3 or applicable local codes.

VENTILATION AIR

Ventilation Air From Inside Building

This fresh air would come from an adjoin- ing unconfined space. When ventilating to an adjoining unconfined space, you must provide two permanent 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 2). You can also remove door into adjoining room (see option 3, Figure 2). Follow the Na- tional Fuel Gas Code NFPA 54/ANSI Z223.1, Section 5.3, Air for Combustion and Ventilation for required size of ventila- tion grills or ducts.

WARNING: Rework work- sheet, adding the space of the adjoining unconfined space. The combined spaces must have enough fresh air to supply all appliances in both spaces.

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