Minimum Efficiency Reporting Value, commonly known as MERV, is a measurement scale designed in 1987 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to report the effectiveness of air filters in more detail than other ratings. For example, often a high-efficiency particulate air (HEPA) filter is impractical in residential central heating, ventilation, and air conditioning (HVAC) systems due to the large pressure drop the dense filter material causes. Experiments indicate that less obstructive, medium-efficiency filters of MERV 7 to 13 are almost as effective as true HEPA filters at removing allergens within residential air handling units.[1]
The MERV scale is designed to represent the worst-case performance of a filter when dealing with particles in the range of 0.3 to 10 micrometers. The MERV value is from 1 to 16. Higher MERV values correspond to a greater percentage of particles captured on each pass, with a MERV 16 filter capturing more than 95% of particles over the full range. The following table is a grouping of MERV values by particle size:
Mold spores, dust mite debris, cat and dog dander, hair spray, fabric protector, dusting aids, pudding mix
Better residential, general commercial, industrial workspaces
9–12
3.0–1.0 μm ("E2")
Legionella, humidifier dust, lead dust, milled flour, auto emission particulates, nebulizer droplets
Superior residential, better commercial, hospital laboratories
13–16
1.0–0.3 μm ("E1")
Bacteria, droplet nuclei (sneeze), cooking oil, most smoke and insecticide dust, most face powder, most paint pigments
Hospital and general surgery
While the lowest MERV value in each row has no minimum requirement for filtering the particle size for that row, it does have stricter requirements for all larger particle sizes than any lower MERV value. For example, MERV 13 has no minimum requirement for removing 0.3–1.0 μm particles (the standard specifies <75%) but has higher minimum requirements for removing 1.0–3.0 μm, 3.0–10.0 μm, and > 10 μm particles than MERV 12 and all lower MERV values. All other MERV values on each row do have minimum removal percentages for that row's particle size.[1]
Similar scalesedit
Two proprietary scales are used to rate sub-HEPA air filters.
The Home Depot scale is known as filter performance rating (FPR), and is reduced from a 1–10 scale to only 4, 7, 9, and 10. It measures ability to capture large particles, small particles, and weight change over the lifetime of the filter.[2]
Although the standards measure slightly different attributes and thus, are not strictly convertible, one retailer reported the following typical equivalents:[3]
minimum, efficiency, reporting, value, minimum, efficiency, reporting, value, commonly, known, merv, measurement, scale, designed, 1987, american, society, heating, refrigerating, conditioning, engineers, ashrae, report, effectiveness, filters, more, detail, t. Minimum Efficiency Reporting Value commonly known as MERV is a measurement scale designed in 1987 by the American Society of Heating Refrigerating and Air Conditioning Engineers ASHRAE to report the effectiveness of air filters in more detail than other ratings For example often a high efficiency particulate air HEPA filter is impractical in residential central heating ventilation and air conditioning HVAC systems due to the large pressure drop the dense filter material causes Experiments indicate that less obstructive medium efficiency filters of MERV 7 to 13 are almost as effective as true HEPA filters at removing allergens within residential air handling units 1 Contents 1 MERV scale 2 Similar scales 3 See also 4 Notes 5 Sources 6 References 7 External linksMERV scale editThe MERV scale is designed to represent the worst case performance of a filter when dealing with particles in the range of 0 3 to 10 micrometers The MERV value is from 1 to 16 Higher MERV values correspond to a greater percentage of particles captured on each pass with a MERV 16 filter capturing more than 95 of particles over the full range The following table is a grouping of MERV values by particle size MERV Minimum particle size Typical controlled contaminant 1 Typical application 1 1 4 gt 10 0 mm Pollen dust mites cockroach debris sanding dust spray paint dust textile fibers carpet fibers Residential window A C units 5 8 a 10 0 3 0 mm E3 Mold spores dust mite debris cat and dog dander hair spray fabric protector dusting aids pudding mix Better residential general commercial industrial workspaces 9 12 3 0 1 0 mm E2 Legionella humidifier dust lead dust milled flour auto emission particulates nebulizer droplets Superior residential better commercial hospital laboratories 13 16 1 0 0 3 mm E1 Bacteria droplet nuclei sneeze cooking oil most smoke and insecticide dust most face powder most paint pigments Hospital andgeneral surgery While the lowest MERV value in each row has no minimum requirement for filtering the particle size for that row it does have stricter requirements for all larger particle sizes than any lower MERV value For example MERV 13 has no minimum requirement for removing 0 3 1 0 mm particles the standard specifies lt 75 but has higher minimum requirements for removing 1 0 3 0 mm 3 0 10 0 mm and gt 10 mm particles than MERV 12 and all lower MERV values All other MERV values on each row do have minimum removal percentages for that row s particle size 1 Similar scales editTwo proprietary scales are used to rate sub HEPA air filters The Home Depot scale is known as filter performance rating FPR and is reduced from a 1 10 scale to only 4 7 9 and 10 It measures ability to capture large particles small particles and weight change over the lifetime of the filter 2 The 3M scale is known as microparticle performance rating MPR and measures the ability to filter particles 0 3 to 1 microns 3 Although the standards measure slightly different attributes and thus are not strictly convertible one retailer reported the following typical equivalents 3 MERV FPR MPR 6 below lowest rating 300 8 5 600 11 7 1000 1200 13 10 1500 1900See also editCorsi Rosenthal Box a do it yourself air purifier Ultra low particulate air ULPA a type of air filter that can remove particles larger than 120 nmNotes edit ANSI ASHRAE Standard 62 1 2007 requires a filter of at least MERV 6 efficiency for residential applications in the U S Sources editM N Rama Rao amp Company Industrial Filters Eurovent and ASHRAE Classifications Retrieved 2007 09 19 Newell Donald February 2006 Interpreting Filter Performance The meaning behind the terminology of ASHRAE standards 52 1 and 52 2 PDF HPAC Engineering Archived from the original PDF on 2009 01 07 Retrieved 2009 05 11 References edit a b c d Residential Air Cleaners 2nd Edition A Summary of Available Information PDF EPA Archived from the original PDF on February 1 2013 Retrieved 2012 08 20 Best Air Filters for Your Home a b MERV vs MPR vs FPR Rating SystemsExternal links editIndoor Air Quality IAQ at EPA gov Retrieved from https en wikipedia org w index php title Minimum efficiency reporting value amp oldid 1214966564, wikipedia, wiki, book, books, library,
