A scavenger duct shall be provided for every 2 automatic dry-cleaning machines to provide adequate exhaust ventilation around the machine bases. This duct shall terminate near the floor and shall be directly connected to the exhaust ventilation system. In the case of attendant-operated units in which an internal scavenger duct is an integral part of the total machine unit, the duct shall be connected as above to the exhaust ventilation system.
('69 Code, § 5-20)