New Buck Corporation 329B Manual page 32

1. Determine the volume of space (length x width x height).
Length x Width x Height =_________cu.ft.(volume of space)
EXAMPLE: 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 openings, add volume of
these rooms to t total volume of space.
2. Divide space volume by 50 cubic feet to determine maximum BTU/Hr space can
support.
_________(volume of space)/50 cu. ft. =maximum BTU/Hr space can support)
EXAMPLE: 2560 cu. ft. (volume of space /50 cu. Ft .= 51.2 or
51200 (maximum BTU/Hr space can support)
3. Add BTU/Hr of all fuel burning appliances in space.
Vent-free heater
Gas water heater*
Gas furnace
Vented gas heater
Gas fireplace logs
Other gas appliances*
Total
Example: Gas water heater 40000 BTU/Hr
Vent-free heater + 18000 BTU/Hr
Total
*Does not include direct-vent gas appliances. Direct-vent draws combustion air
from outdoors and vents to outdoors.
4. Compare the maximum BTU/Hr space can support with
used.
____________BTU/Hr (maximum space can support)
____________BTU/Hr (actual amount of BTU/Hr used)
Example: 51200 BTU/Hr (maximum the space can support)
58000 BTU/Hr (actual amount of BTU/Hr used)
The space in above example is a unusually tight construction because actual BTU/Hr used is
more than maximum BTU/Hr space can support. You must provide additional fresh
air. Your options are as follows: A. Rework worksheet, adding space of an adjoining room.
If extra space provides an unconfined space, remove door to adjoining room or add ventilation
grills between rooms. See "Ventilation Air From Inside Building", page 34.
B. Vent room directly to outdoors. See "Ventilation Air From Outdoors", page 35.
C. Install a lower BTU/Hr heater, if lower BTU/Hr size makes room unconfined.
If actual BTU/Hr used is less than maximum BTU/Hr space can support, space is an
unconfined space. You will need no additional fresh air ventilation.
WARNING:
YOU MUST PROVIDE ADDITIONAL VENTILATION AIR IN A
ALLY TIGHT CONSTRUCTION.
= 58000 BTU/Hr
Page 29
_______________BTU/Hr
_______________BTU/Hr
_______________BTU/Hr
_______________BTU/Hr
_______________BTU/Hr
+ _______________BTU/Hr
= _______________BTU/Hr
actual amount of BTU/Hr
UNUSU-