Today's topic is on air conditioning filters. These are the tools to control dust particles from entering the air-conditioned space. "Dust" could be a misnomer when we enter into the world of cleanrooms. Even tobacco smoke and bacteria are particles that can be filtered off!

Prefilters

Having efficiencies ranging from 50% to 85%, prefilters are used for protection against accumulations of textile fibres and insects. They are ineffective in separating smoke, pollen and staining particles like soot, oil mist.

Those with efficiencies above 85% are able to collect pollen and have some limited effect against smoke and staining particles. These are used in dehumidification systems.

In textile industries, prefilters are used in air-conditioning systems to protect heat exchangers, humidifiers and fans. Window mounted air-conditioning units use them for protecting the evaporator coils. Those with 85% efficiencies are used to control dusts from entering food handling premises and kitchens.

Fine filters

Fine filters are those with efficiencies ranging from 40% to 98%. Those in the 90% to 98% range are very effective against staining particles like soot and oil mist. They are also very effective against bacteria.

Their users includes air-conditioning for schools, kitchens, filing rooms, light engineering workshops, restaurants, and air curtains for food shops.

The higher ranges are suitable for operating theatres, laboratories, and computers.

Absolute filters

Absolute filters are the most efficient filters around with efficiencies ranging from 85% to more than 99.97%

They are highly efficient in collecting bacteria, radioactive dusts and all kinds of smoke and aerosols.

They are used for constant climate precision measurement or calibrating rooms, special clean air laboratories, operating theatres, sterilization rooms, and clean rooms.