Desa VMH26NRA, EFS26PR, VMH26PRA, VMH10TNB Ventilation AIR, Ventilation Air From Inside Building

AIR FOR COMBUSTION AND VENTILATION

Determining Fresh-Air Flow for Fireplace Location (Cont.) Ventilation Air

7

AIR FOR COMBUSTION AND VENTILATION

Continued

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

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

Example:		30,000
Gas water heater
		_____________ Btu/Hr
Vent-free fireplace	+	10,000
		_____________ Btu/Hr
Total	=	40,000
		_____________ Btu/Hr

VENTILATION AIR

Ventilation Air From Inside Building

This fresh air would come from an adjoining 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 5). You can also remove door into adjoining room (see option 3, Figure 5). 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.

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:

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

12"

Ventilation Grills

Into Adjoining Room,

Option 2

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 Ventilation Air From Out- doors, page 8.

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.

12"

Figure 5 - Ventilation Air from Inside Building

WARNING: If the area in which the fireplace may be operated is smaller than that defined as an uncon- fined space or if the building is of unusually tight construction, provide adequate combustion and ven- tilation air by one of the methods described in the National Fuel Gas Code, ANSI Z223.1/NFPA 54 Sec- tion 5.3 or applicable local codes.

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