(2) A mechanical air supply system shall be provided if its absence will result in
building negative pressures sufficient to cause back-drafting of vents from fuel-fired
equipment or ineffective control.
(3) Mechanical air supply volumes shall be heated to maintain a minimum air
temperature of 65 degrees Fahrenheit measured at the point of air discharge to the
space. Exceptions to this requirement are refrigerated storage rooms, special process
rooms, and similar locations where lower air temperatures are essential to the
preservation of the product or service, or, if in the opinion of the director, a lower air
temperature will not be
harmful to the health of the persons affected.
History: 1979 AC; 2003 AACS.
R 325.2435 Direct-fired air heaters.
Rule 35. (1) A direct-fired air heater, wherein combustion products are released in
the supply air stream, may be installed in buildings of industrial occupancy,
garages, laundries, and commercial kitchens. They shall not be installed in offices,
schools, hospitals, and places of public assembly.
(2) A direct-fired air heater shall have an inlet duct connected directly to the out-of-
doors. Room air shall not be circulated across the burner.
(3) A direct-fired air heater shall deliver air which contains not more than 10 ppm
of carbon monoxide and is free from odors of combustion products. Permissible
concentrations of other contaminants in the delivered air may be established by the
director pursuant to their MAC and the degree of exposure to a person.
(4) The air volume supplied to the building by a direct-fired air heater shall not
exceed 110% of the total air volume exhausted. The director may require interlocking
of a heater control system with an exhaust ventilation system if necessary to ensure that
the exhaust systems are operating.
(5) A direct-fired air heater shall have both of the following:
(a) A pre-ignition purge of fresh air.
(b) A positive fuel supply closure in the event of fuel supply failure, ignition
failure, flame failure, power failure or interruption, or air flow reduction below 50% of
its rated capacity.
History: 1979 AC; 2003 AACS.
R 325.2436 Exhaust ventilation systems.
Rule 36. The minimum rate of exhaust ventilation for places of
manufacturing, processing, assembling, maintenance and repair, or storage of material
shall be 1 cubic foot of air per minute per square foot of floor area. This amount of
exhaust ventilation may be provided by local exhaust, general exhaust, or both. The
director may permit a variance if contaminant control can be accomplished at a lesser
rate of ventilation.
History: 1979 AC; 2003 AACS.
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