Figure: 25 TAC §133.169(a)

Figure: 25 TAC §133.169(d)

TABLE 4
FILTER EFFICIENCIES FOR CENTRAL VENTILATION
AND AIR CONDITIONING SYSTEMS
Area Designation	Number of Filter Beds	Filter Bed No. 1 (Percent, MERV*)	Filter Bed No. 2 (Percent, MERV*)
Orthopedic and organ transplant operating rooms	2	25, 7	99.97, 17
Protective environment rooms	2	25, 7	99.97, 17
IV preparation and chemo-hood rooms	2	25, 7	99.97, 17
General procedure operating rooms, delivery rooms, nurseries, critical care units, patient care areas and treatment, diagnostic and related areas	2	25, 7	90, 14
Laboratories and sterile storage	1	80, 13	----
Administrative, bulk storage, soiled holding areas, food preparation areas, and laundries	1	30, 7	----

* MERV – Minimum efficiency rating value (American Society of Heating Refrigeration and Air-Conditioning Engineers (ASHRAE) Standard 52.2, 1999 edition.

NOTES:

Additional roughing or prefilters should be considered to reduce maintenance required for filters with efficiency higher than 75%.
The filtration efficiency ratings are based on ASHRAE Standard 52.1, 1992 edition.