On new construction projects or equipment replacement/modification, filtration of air shall be through MERV 13 final filtration (4” thick where possible) with MERV 8 pre-filtration (2” thick) as a minimum (normally occupied areas/equipment with a portion of the air from outdoors).
Where equipment racks are limited to a single filter, provide MERV 13 (4” thick where possible).
Filters for equipment without an outside air component shall be MERV 8. All filters shall be located upstream of coils/furnaces. All filtration media used to satisfy this requirement shall be deemed equivalent in accordance with ASHRAE 52 (current revision).
For renovation projects where fan static is limited (example: masonry air handlers with field erected stainless steel filter racks from 1900 thru 1970) use MERV 8 filtration (2” thick) with a face velocity between 250 and 300 FPM. Design team shall review the site location/sources of contaminant and make recommendations to CPS where additional filtration levels may be required.