Ventilating systems that serve anaesthetizing rooms, intensive care rooms, patient rooms, operating rooms, nurseries, delivery rooms and similar health care rooms shall have at least 2 banks of air filters and shall meet the following requirements:
1. Filter Bank No. 1 shall be installed in the suction side of the supply fan and shall have a minimum air cleaning efficiency rating of 30 percent.
2. Filter Bank No. 2 shall be installed on the pressure side of the supply fan and shall have a minimum air cleaning efficiency rating of 90 percent.
3. All air cleaning efficiencies shall be based on the National Bureau of Standards Dust Spot Test Method and Atmospheric Dust.