Section 333.13313 - Preventing escape of vapors; ventilation; exception(1) A class IV installation shall be constructed and installed so as to prevent the escape of substantially all vapors into the atmosphere of the dry cleaning room.(2) Ventilation shall be installed in a class IV installation to meet the requirements of rules promulgated pursuant to this part.(3) A class IV installation shall not be installed in a basement or other location difficult to ventilate. An exception may be granted when due to special construction, location, or use the class IV installation will not create injury or hazard to health as determined by the department.1978, Act 368, Eff. 9/30/1978 .