MERV 101: What is a MERV?
If you’ve spent any time looking for air filters, you’ve probably seen a filter’s Minimum Efficiency Reporting Value (MERV) rating. But what does it mean?
MERV is a testing and rating system developed by the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) for comparing the efficiency of media filters, bags, and cartridges. MERV specifically looks at the efficiency of the filter on particles between 0.3 and 10 microns.
Most industrial systems use filters that have between an 8 and 15 MERV rating. The higher the MERV rating, the more efficient a filter is. But a higher MERV rating doesn’t always mean that a filter is the best option or fit for your system. The MERV rating has nothing to do with filter lifespan, maintenance cycles, or even how the clean the air is after filtration.
The MERV rating is not a proper assessment of mist collectors or filters. Most filters don’t have a binder to hold the fibers in place. So, when a filter gets wet, the fibers move, resulting in microscopic holes and decreased performance. Filters in any mist collector appliance are going to get wet. Unfortunately, a MERV rating does not account for this.
Dust collecting products also can’t use the MERV system as a measure of performance. Most dust collectors reach an optimal operating capacity after a couple hundred usage hours, once a layer of dust has built up on the surface. This creates what is known as a "dust cake." The dust cake will typically remain on the filter throughout its entire lifespan. The dust cake actually makes the filter more efficient and can’t be quantified by a MERV rating.
Having expert input is important when choosing the best filter type and configuration. To find an expert who can assist you, contact your local TRION representative today.