Filter or Treat
Ventilation Air Supplies
Efficient
filtration of ventilation air supplied to occupied spaces
(and treatment when toxic compounds are present) can help
greatly to ensure occupant health.
Particulate
filters or air cleaners with a minimum efficiency of 30%*
are recommended for mechanically supplied ventilation air
to most occupied spaces, especially if it includes return
air from spaces without unusual contaminant sources. These
include residential rooms (except bathrooms or kitchens),
offices, retail spaces, conference rooms, classrooms, lobbies,
hotel or motel rooms, etc.
Air recirculated
from dusty spaces or spaces containing mild contaminants requires
95% dust spot efficiency filtration* and often gas phase air
cleaning to remove odors and pollutants. Such spaces include
dedicated copy and printer rooms, dining areas, break rooms,
kitchens or other areas with cooking or food-dispensing equipment,
cafeterias, laundry rooms, locker rooms, bathrooms and toilet
rooms closed to the general public.
Air from
spaces with more severe contaminants should not be recirculated,
but should be equipped with exhausts and kept under negative
pressure. In Santa Monica, outdoor air filtration or treatment
is typically unnecessary unless there are nearby air pollution
sources, such as loading bays, traffic, etc.
*Filter
efficiencies should be rated according to ASHRAE Standard
52.1 Atmospheric Dust Spot Method.
Caution
- Unitary
equipment may require supplementary filters to meet these
efficiencies, and must be specified with appropriate static
pressures.
