Procom SSU320RHL-B Ventilation Air From lnside Building, Ventilation Air From Outdoors

3. Add the Btu/Hr of all fuel burning appliances in the space.
Vent-free heater			Btu/Hr	Example:
Gas water heater*			Btu/Hr
				Gas water heater		30,000	Btu/Hr
Gas furnace			Btu/Hr
Vented gas heater			Btu/Hr	Vent-free heater	+	26,000	Btu/Hr
Gas heater logs			Btu/Hr	Total	=	56,000	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.

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) 56,000 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.

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

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.

NOTE: 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 ventilation air by one of the methods described in the National Fuel Gas Code, ANSI Z223.1, Section 5.3 or applicable local codes.

Ventilation Air From lnside 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 2). You can also remove door into adjoining room (see option 3, Figure 2). Follow the National Fuel Gas Code. NFPA 54/ANSI Z223.1, Section 5.3, Air for Com- bustion and Ventilation for required size of ventilation grills or ducts.

Ventilation Air From Outdoors

Provide extra fresh air by using ventilation grills or ducts.
You must provide two permanent openings: one within
12" of the ceiling and one within 12" of the floor. Connect
these items directly to the outdoors or spaces open to	Figure 2 -Ventilation Air from Inside Building
the outdoors. These spaces include attics and crawl
spaces. Follow the National Fuel Gas Code, NFPA 54/
ANSI Z223.1, Section 5.3, Air for Combustion and Ven-
tilation for required size of ventilation grills or ducts.

IMPORTANT: Do not provide openings for inlet or outlet air into attic if attic has a thermostat-controlled power vent. Heated air entering the attic will activate the power vent.

Rework worksheet, adding the space of the adjoining unconfined space. The combined spaces must have enough fresh air to supply all appliances in both spaces.

Figure 3 -Ventilation Air from Outdoors

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