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3.
Add the BTU/Hr of all fuel burning appliances in space.
Vent-Free Heater
_________________________BTU/Hr.
Gas Water Heater*
_________________________BTU/Hr.
Gas Furnace
_________________________BTU/Hr.
Vented Gas Heater
_________________________BTU/Hr.
Gas Fireplace Logs
_________________________BTU/Hr.
Other Gas Appliance*
+_________________________BTU/Hr.
Total
= _________________________BTU/Hr.
Example:
Gas water heater
40000 BTU/Hr.
Vent-free heater
+
18000 BTU/Hr.
Total
=
58000 BTU/Hr.
* 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 actual amount
of BTU/Hr used.
_____________BTU/Hr (maximum space can support)
_____________BTU/Hr (actual amount of BTU/Hr used)
Example:
51200 BTU/Hr (maximum space can support)
58000 BTU/Hr (actual amount of BTU/Hr used)
Space in above example is a confined space because actual BTU/Hr used is more than maximum
BTU/Hr the space can support. Additional fresh air must be provided. The following options are
available.
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 15.
B. Vent room directly to outdoors. See “Ventilation Air From Outdoors” page 16.
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 unconfined. You
will need no additional fresh air ventilation.
WARNING
YOU MUST PROVIDE ADDITIONAL VENTILATION AIR IN UNUSUALLY TIGHT
CONSTRUCTION.
