FMI CDCFNRB-1 Indoor Fireplace User Manual


 
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124979-01C 7
AIR FOR COMBUSTION AND VENTILATION
Continued
All spaces in homes fall into one of the three
following ventilation classications:
1. Unusually Tight Construction
2. Unconned Space
3. Conned Space
The information on pages 6 through 8 will help
you classify your space and provide adequate
ventilation.

The air that leaks around doors and windows
may provide enough fresh air for combustion
and ventilation. However, in buildings of un-
usually tight construction, you must provide
additional fresh air.

construction where:
 -
side atmosphere have a continuous




2

and
 
openable windows and doors and
  

and door frames, between sole plates

between wall panels, at penetrations


If your home meets all of these three criteria,

Ventilation Air From Outdoors
If your home does not meet all of the three
criteria above, proceed to Determining
Fresh-Air Flow For Fireplace Location

The National Fuel Gas Code, ANSI Z223.1/
NFPA 54 denes a conned space as a space
whose volume is less than 50 cubic feet per
1,000 Btu/hr (4.8 m
3
per kw) of the aggregate
input rating of all appliances installed in that
space and an unconned space as a space
whose volume is not less than 50 cubic feet per
1,000 Btu/hr (4.8 m
3
per kw) of the aggregate
input rating of all appliances installed in that
space. Rooms communicating directly with the
space in which the appliances are installed*,
through openings not furnished with doors, are
considered a part of the unconned space.
* Adjoining rooms are communicating only if
there are doorless passageways or ventilation
grills between them.
DETERMINING FRESH-AIR FLOW



Use this work sheet to determine if you have
a conned or unconned space.
Space: Includes the room in which you will install
replace plus any adjoining rooms with door-
less 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 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 20 to determine
the maximum Btu/Hr the space can support.
________ (volume of space) x 20 = (Maxi-
mum Btu/Hr the space can support)
Example: 1792 cu. ft. (volume of space) x
20 = 35,840 (maximum Btu/Hr the space
can support)
3. Add the Btu/Hr of all fuel burning appliances
in the space.
Vent-free replace __________Btu/Hr
Gas water heater* __________Btu/Hr
Gas furnace __________Btu/Hr
Vented gas heater __________Btu/Hr
Gas replace logs __________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.
Example:
Gas water heater ________Btu/Hr
Vent-free replace ________Btu/Hr
Total ________Btu/Hr
4.
Compare the maximum Btu/Hr the space can
support with the actual amount of Btu/Hr used.
________Btu/Hr (maximum space can support)
______ Btu/Hr (actual amount used)
Example: 35,840 Btu/Hr (maximum the
space can support)
40,000 Btu/Hr (actual amount of
Btu/Hr used)
30,000
+ 10,000
= 40,000