Section 325.52006. Direct-fired air heaters.

 (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 permissible exposure limits 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: 2005 AACS.