Ventilation shall mean the provision, circulation or exhausting of air into or from an area or space.

Dilution ventilation. Inducing and mixing uncontaminated air with contaminated air in such quantities that the resultant mixture in the breathing zone will not exceed the permissible exposure limit (PEL) specified for any contaminant.

Exhaust ventilation. The general movement of air out of the area or permit-required confined space by mechanical or natural means.

Local exhaust ventilation. The mechanical removal of contaminated air from the point where the contaminant is being generated or liberated.

Tempered make-up air. Air which has been conditioned by changing its heat content to obtain a specific desired temperature.