Talk:HEPA

message: The air purifier article basically says "BEWARE of those that say 'HEPA-type'", but can anything be known about a filter that is labeled as such?  What do they mean by "HEPA-type"?  It seems they would be limited in saying that by false advertising laws unless it had something in common with real HEPA filters.  What is that something? — Omegatron 21:21, 25 October 2006 (UTC)
replies: text: "HEPA-like" or "HEPA-type" filters are just as you said: non-conventional advertising practice. That "something" is maybe only the shape (pleated) and these filters actually yield a lower efficiency. True medical HEPA filters are all laser-tested and should remove 99.97% of all particles greater than 0.3 microns. The test is done using DOP and if not passed, they are not issued a certificate. Usually, "HEPA-like" filters have an efficiency of 95% (as advertised by some "fairer" companies) but no one really knows the actual efficiency unless tested. The Vindictive 08:27, 12 April 2007 (UTC)

text: Blueair has a proprietary brand called HEPAsilent. Its essentially a MERV 8 or 9 filter once the carbon runs out, and the electrostatic charge in the filter medium is depleted. And since their purifiers lacks any form of ionizers, static or any form of ground to the filter medium, quality is going to be different the first 2-3 weeks and rest of the filters lifetime without functional carbon. There is nothing unique about Blueair. The primary sales purpose of a Air Filter for home usage is to get rid of visible floating dust, while the secondary purpose is to get rid of particles of building materials or pollen. A better filter means you need a bigger fan, or make the device silly loud. Skimping on the filter is the simplest way to fix the problem, but it also means you can't trust the device's rating if its not HEPA or MERV.--Stalkerkun (talk) 21:56, 9 August 2021 (UTC)
thread_title:  HEPA-type/HEPA-like 

message: So it picks up particles above and below 0.3 um?  We should have a graph of that, like  — Omegatron 21:41, 25 October 2006 (UTC)
thread_title:  Graph 

message: Perhaps we should delete this link?  It does not provide any information about hepa filters, but seems mostly to be a commercial site. VitaminE 23:35, 17 December 2006 (UTC)
thread_title:  hepafilter.com 

message: Correct expansion of the abbreviation (acronym) is "high-efficiency particulate-arresting" (filter).
Yes, and when I corrected the article to the correct acronym, it was reverted.  What gives?  —Preceding unsigned comment added by 128.2.161.180 (talk) 17:41, 31 October 2007 (UTC)
replies: text: I suggest finding a modern, authoritative reference giving that expansion.  The expansion used most commonly, and therefore most likely correct in the absence of a clearly authoritative source to the contrary, is "High Efficiency Particulate Air." Since "HEPA is commonly followed by the word "filter" this certainly makes sense.  Pzavon 00:20, 1 November 2007 (UTC)
thread_title:   correct expansion of the abbreviation 

message: This is helpful: the CFR that covers N100 filters  http://www.cdc.gov/niosh/pt84abs2.html  comment added by User talk:Quincy8Boy on 20 June 2007 
:Both N/P100 and N/P99 would have been called "HEPA" in the past.  This NIOSH regulation establishes a designation scheme for particulate filters that moves away from, and in fact does not use the term "HEPA" at all.  Pzavon 02:53, 21 June 2007 (UTC)
thread_title:  links 

message: In many cases vacuum cleaner manufacturers add a number after the HEPA designation: 11, 12 or 13. Anyone know what this refers to? Benkeboy (talk) 10:02, 19 December 2008 (UTC)
replies: text: In an email from Electrolux I got the answer that HEPA 12 removes 99.5% of particles larger than 0.03 micron, HEPA 13 filtrates even smaller particles. The extension "W" means washable. But still have not found any standards for this or any other document with same or similar info. Benkeboy (talk) 10:58, 30 December 2008 (UTC)
replies: text: That seems unlikely as a general proposition.  HEPA is defined as a filter that will remove 99.97% of particles 0.03 microns in size.  Since that size is the most difficult to filter, a basic HEPA filter will be more that 99.97% effective at removing particles larger than 0.03 microns AND less than 0.03 microns in size.  This has been confirmed through testing and even seems to hold true into the nanoparticle range.  Perhaps the HEPA 12, HEPA 13, etc., designations are one manufacturer's method of marketing a "not quite HEPA" product.  Pzavon (talk) 20:53, 30 December 2008 (UTC)
replies: text: According to the article a HEPA filter can remove at least 99.97% of particles larger than 0.3 micron. According to the manufacturer HEPA 12 removes particles a factor 10 smaller, although at 99.5 rather than 99.97%. 193.137.16.117 (talk) 21:39, 2 January 2009 (UTC)
replies: text: Thanks.  I read that as sales hype by the manufaturer since all HEPA filters will do that.  Pzavon (talk) 16:42, 3 January 2009 (UTC)
thread_title:  HEPA 11, 12 and 13 

message: I've noticed that some companies are selling washable HEPA filters in their various uses and I'm curious about how they compare to the kind that are disposed of. If anyone can find more info on them I think it should go in the main article.  —Preceding unsigned comment added by 66.27.124.108 (talk) 22:47, 31 December 2008 (UTC)
thread_title:  Washable HEPA 

message: The Air Transport Association would like to add a section about how HEPA filters remove airborne contaminants on airline flights.  In the interest of ensuring the page's neutrality, we would like to know if any other editors would like to work with us to update this article. If there is no interest, we will work to ensure that our revisions fall in line with Wikipedia's standards of neutrality, no original research and verifiability.
Lanekedc3 (talk) 20:59, 4 May 2009 (UTC)
replies: text: I googled about this subject and it seems that the info, that I deleted, was from a Boeing website and exaggerated how safe airplane air is. Read this WSJ article: http://blogs.wsj.com/middleseat/2009/05/01/swine-flu-and-travel-qa-on-infectious-diseases-in-airline-cabins/ Airplane air is not as safe as air in your home or in an industrial "clean room", this is corporate propaganda. Read from that link about all those flights where SARS or the flu for example spread among lots of passengers even on flights as brief as 3 hours. Wicksteed100 (talk) 15:46, 22 February 2012 (UTC)
thread_title:  Airline Usage 

message: Please note also that in NIOSH filter definitions (http://www2.cdc.gov/drds/cel/cl.htm), the N-class filters are particulate, oil-free *only*, whereas the P-class filters are for all particulates, including oil droplets (why they're so much more expensive than "mere" N-class), and the newer R-Class seem to be also against all particulates but with a time limit (due possibly to degradation?).  This is the 1st I've heard of an R-class; last time I checked filters was in 2003-04, and never saw a mention, so they must be rather new? 
MERV ratings seem to refer to furnace/central air conditioner filters,  (http://www.furnacefiltercare.com/merv-ratings.php).  Per my referencing web page, a MERV furnace filter comparable to a HEPA filter would actually be about a MERV 16, or higher, to meet HEPA's 99%+ efficiency of 0.3 micron particulates.
Ryoverde (talk) 20:08, 9 September 2009 (UTC)
thread_title:  NIOSH Filter Definitions N, P, and R and MERV Information

message: when hepa filter has to b replaced?  —Preceding unsigned comment added by 59.92.188.250 (talk) 10:23, 10 December 2009 (UTC)
thread_title:  hepa replacement 

message: I like the diagram, but the explanation of the different mechanisms doesn't make sense. < 0.1 micron = < 100 nm. So which mechanism predominates? Consider correcting this and sorting the mechanisms on particle size.  —Preceding unsigned comment added by 85.149.64.49 (talk) 10:12, 27 March 2010 (UTC)
thread_title:  diagram 

message: I put them under separate headings. Seems more readable to me that way. Paragraph about the European Norm (copied from German Wikipedia) could do with some references.It appears that the EN is only available for purchase.  —Preceding unsigned comment added by 213.23.163.134 (talk) 17:41, 5 July 2010 (UTC)
thread_title:  Function and Specifications 

message: A micrometer is 1000th part of a millimeter ( or 1000 000 th part of a meter) and is known as micron. There is another unit , which is very commonly used i.e. 1/1000 th part of one inch. This unit is commonly called as mil.
Relationship between these units can be easily seen. 
one mil is equal to 25.4 microns.
39.37 (approx 40) mils are equal to 39.37x25.4 microns = 1000 microns or 1 millimeter.
Devkumarbansal (talk) 11:50, 18 October 2013 (UTC)
thread_title:  Microns or Micrometers? 

message: US Department of Energy HEPA website
US Department of Energy Specification for HEPA Filters Used by DOE Contractors, 1997 Onerock (talk) 04:01, 15 September 2011 (UTC)
thread_title:  Broken links 

message: I've just looked at a Honeywell home HEPA filter, and it looks a lot like an air cleaner for a car engine: basically of the same gross structure.  I suppose the difference is in the material used.  Could we get some text in the article explaining how the two are the same and how they are different?  Thanks.CountMacula (talk) 07:17, 23 April 2014 (UTC)
thread_title:  How the same and how different from automotive engine air cleaners? 

message: At various times, the expansion of HEPA has been given as "high-efficiency particulate arrestance", "high-efficiency particulate arresting", or "high-efficiency particulate air", among others. The article currently features two of the alternative names. Please do not change or remove any of them without first discussing the choices here. I don't hold a dogmatic position on the names, but think that all commonly-seen names should be given in the article. If you believe that a given one is more "correct" or others are "erroneous", please cite some WP:RS to back your claim. Do not remove an alternative name without discussing it with other editors.  Reify-tech (talk) 23:07, 14 July 2015 (UTC)
thread_title: Acronym expansion

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thread_title:  External links modified 

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thread_title:  External links modified 

message: SKay (talk) 11:19, 3 March 2019 (UTC)
thread_title:  Copied Portion of Intro to [[Air filter]] 

message: The following Wikimedia Commons files used on this page or its Wikidata item have been nominated for deletion:
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thread_title:  Commons files used on this page or its Wikidata item have been nominated for deletion 

message: I’m not certain if “material” is the best word… “matrix” might be more accurate. I changed “matra” to “material”, but I’m wondering if “matrix” might not be more accurate… thoughts anyone? Jd.varner44 (talk) 22:23, 30 September 2021 (UTC)
thread_title:  HEPA filter image/description