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UV36RN/RP Vent-Free Gas Fireplaces
20007436
WARNING: Do not allow fans to blow directly into the
fireplace. Avoid any drafts that alter burner flame pat-
tern.
WARNING: Any glass doors on an unvented room
heater shall be opened when the appliance is in opera-
tion.
Provisions for Adequate
Combustion and Ventilation Air
Today’s homes are built more energy efficient than
ever. New materials, increased insulation and new
construction methods help reduce heat loss in homes.
Home owners weather strip and caulk around windows
and doors to keep the cold air out and the warm air in.
During heating months, home owners want their homes
as air tight as possible.
While it is good to make your home energy efficient,
you need fresh air. All fuel-burning appliances need
fresh air for proper combustion.
Supplying Adequate Ventilation
This appliance must be installed in an unconfined
space.
The National Fuel Gas Code’s definitions for confined
and unconfined spaces are as shown below.
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 passage-
ways or ventilation grilles 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 25’ (length) x 25’ (width) x 8’
(ceiling height) = 5,000 cu. ft. (volume of space)
If additional ventilation from adjoining room(s) is
supplied with grilles or doorless openings, add the
volume of these rooms to compute the total volume
of the applicable space.
2. Divide the space volume by 50 cubic feet to deter-
mine the maximum BTU/Hr the space can support.
________(volume of space) ÷ 50 cu. ft. = (Maximum
BTU/Hr the space can support.
Example: 5,000 cu. ft. (volume of space) ÷ 50 cu. ft.
= 100 or 100,000 (maximum BTU/Hr the space can
support)
3. Add the BTU/Hr of all gas burning appliances in the
space.
Gas range _________________ BTU/Hr
Vented gas heater __________ BTU/Hr
Gas fireplace logs ___________ BTU/Hr
Other gas appliances* + _____ BTU/Hr
Total = _____ BTU/Hr
Example: Gas range 60,000 BTU/Hr
Vent-free logs + 29,000 BTU/Hr
Total = 89,000 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 sup
-
port with the actual amount of BTU/Hr used.
_______ BTU/Hr (maximum the space can support)
_______ BTU/Hr (actual amount of BTU/Hr used)
Example: 100,000 BTU/Hr (maximum the space can
support) 89,000 BTU/Hr (actual amount of BTU/Hr
used)
The space in the above example is an unconfined
space because the actual BTU/Hr used is less than the
maximum BTU/Hr the space can support. If the space
had been confined, your options would be as follows:
A. Rework worksheet, adding the space of an adjoin
-
ing room. If the extra space provides an unconfined
space, remove door to adjoining room or add venti-
lation grille between rooms. See Ventilation Air From
Inside Building.
B. Install a lower BTU/Hr heater, if lower BTU/Hr size
makes room unconfined.
Converting Confined Space
to Unconfined Space
Additional volume to convert a confined to an un-
confined space could come from an adjoining space.
When using an adjoining space, you can 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 3, Figure 2), or remove
the door into the adjoining room.
The National Fuel Gas Code, ANSI Z223.1/NFPA
54 defines a confined space as a space whose
volume is less than 50 cubic feet per 1,000 Btu
per hour (4.8 m
3
per kw) of the aggregate input
rating of all appliances installed in that space and
an unconfined space as a space whose volume is
not less than 50 cubic feet per 1,000 Btu per hour
(4.8 m
3
per kw) of the aggregate input rating of all
appliances installed in that space. Rooms com-
municating directly with the space in which the
appliances are installed, through openings not
furnished with doors, are considered a part of the
unconfined space.