TABLE 1

Filter Efficiencies for Central Ventilation and Air Conditioning Systems in Health Care Facilities
Area Designation	No. Filter Beds	Filter Bed No.1 (%)	Filter Bed1 No.2 (%)
All areas for patient care, treatment, and diagnosis, and those areas providing direct service or clean supplies such as sterile and clean processing.	2	30	90
Protective Environment Room	2	30	99.97
Laboratories	1	80	-
Administrative, Bulk Storage, Soiled Holding Areas, Food Preparation Areas, and Laundries	1	30	-

¹

¹ These requirements do not apply to small outpatient clinics or outpatient clinics that do not perform invasive applications or procedures.

Notes: The filtration efficiency ratings are based on average dust spot efficiency per ASHRAE 52.1 1992.

Additional roughing or prefilters should be considered to reduce maintenance required for filters with efficiencies higher than 75 percent.