Automatic dry-cleaning machines designed in accordance with the alternate provided for in § 112.12, shall be installed as follows. The front panel of the machine shall be sealed to the floor and to the panel wall between the customer and service areas. The panel wall shall be of such construction as to permit the free flow of air from the sales area to the service area. The ventilation required in §§ 112.16 and 112.17 shall be provided for the service area with a fresh air intake from the outside atmosphere. The intake shall be so sized as to maintain a negative pressure in the service area at all times.
('69 Code, § 5-18)