Industrial air filtration is rated on the MERV scale according to ASHRAE Standard 52.2. A MERV 8 rating indicates the filter will provide between 30 and 35 percent dust spot efficiency. It also means the filter can remove 70 to 84.9 percent of particles 3 to 10 microns in size such as mold spores and dust.

Industrial air filtration is also used on particle sizes 1.0 to 3.0 microns. The MERV range is 9 through 12. A MERV 9 rated filter will provide less than 50 percent efficiency where a MERV 12 gives greater than 80 percent on this size of particles. This same MERV 12 rated filter will provide greater than 90 percent on particles from 3 to 10 microns.

Differences for Industrial Air Filtration

There are two types of filters basic to HVAC systems. One of these is the mechanical filter. The other is the electrostatic filter. The filters can be made of several different fibers including fiberglass, cotton, polyester, and others. For comparison, a MERV 14 filter will remove droplet nuclei at 95 percent efficiency. This level is required for critical areas in hospitals.

A very important component in deciding on the best industrial air filtration is the number of air changes per hour. If the air circulation is slow, it does not do a sufficient job of cleaning the air. Industrial use is not as critical as a hospital requiring 6 to 12 air changes per hour, but it still should be at least two to three times per hour if the unit runs continuously.