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MERV Filters
MERV is an acronym for "Minimum Efficiency Reporting Value". The MERV rating on an air filter describes its efficiency as a means of reducing the level of 3 to 10 micron-sized particles in air which passes through the filter. Higher "MERV" means higher filter efficiency. The purpose of the MERV standard is to permit an "apples to apples" comparison of the filtering efficiency of various air filters.
Air filter efficiency refers to the relative ability of a filter to remove particles of a given size or size range from air passing through the filter. If a filter were 100% efficient, none of the particles in a given size range would escape the filter and air which has passed through such a filter would contain zero particles.
The MREV Efficiency Rating Scale ranges from 1 to 16, with 1 being the lowest efficiency and 16 describing the highest efficiency. The particle size range addressed by the MERV scale is 3 to 10 microns. A logical inference is that if an air filter is removing particles down to 3-10 microns, it is certainly also at least that efficient at removing larger sized particles.
HEPA Filters
HEPA air filters are not MERV rated as they exceed the ASHRAE test protocol 52.2 used in determining the MERV ratings. In fact, HEPA air filters are the ONLY mechanical air filters that are tested and certified to meet a specific efficiency at a specific particle size. All HEPA air filters must meet a minimum efficiency of 99.97% at 0.3 microns. ASHRAE or MERV air filters are tested using the Dust Spot tests that incorporate some fine dust, powdered carbon and some cotton linters. The Dust Spot test particle size range is from .3 microns to 50 microns in size with an average size of approximately 20 microns in size.
HEPA air filters are tested using DOP, Mineral Oil and other materials that generate a mono-dispersed particle that are all .3 microns or smaller in size. In essence, if 10,000 .3 micron sized particles are blown into a HEPA air filter, only 3 particles are allowed to pass through. Thus, you get the 99.97% at .3 micron rating. If you were to use the HEPA test on a 95% ASHRAE air filter they would be about 50% efficient on .3 micron sized particles once they loaded up with dust. So, HEPA air filters are at least 50% more effective at removing respirable sized airborne particles than any of the ASHRAE air filters previously available on the market.
How PP/F/P Filters relate to these standards:
The HC High Capacity filter meets MERV 8 standard; it is recommended for general use and is our longest lasting filter.
This filter is used with Red Dot's PP/F/P.
The DPM filter meets MERV 16 standard and is recommended for applications where Diesel Particulate Matter, Respirable Silica, and other airborne contaminants pose a threat to the operator. This filter is used with Red Dot's DPM-P/F/P, which provides the unidirectional cab airflow design recommended by NIOSH.
The HE High Efficiency filter meets HEPA standard and is recommended when the very highest level of filtration is needed, or where HEPA filters are required by regulatory requirements. This filter is used with Red Dot's PP/F/P.
Go to DPM-P/F/P Product Information
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