Section R. 325.17401 - Dry cleaning machine exhaust systemsRule 401.
(1) A dry cleaning machine which uses a solvent and is designed to be installed and operated without a loading door exhaust system as specified in subrule (2) of this rule shall be approved for operation only if the machine is constructed and operated in a manner to limit the peak work area concentration of the solvent vapors.(2) Except as provided in subrule (1) of this rule, dry cleaning machines and recovery units or dryers shall be equipped with an exhaust system capable of providing an indraft velocity across the entire loading door opening which averages 100 feet per minute. The exhaust from the blower shall be tightly piped to a point not less than 5 feet above the roof of the building, any adjacent parapet wall, or adjacent building, whichever is applicable, and a minimum of 25 feet away from any return air opening. The stack shall be soldered or taped to prevent vapors from entering the work area and shall be equipped with a vertical discharge cap. Exhaust ducts from dry cleaning machines and recovery units or dryers shall be sized and joined in a manner to maintain the required air flow from each unit.Mich. Admin. Code R. 325.17401