# HEPA Filter material for virus masks, really?… **URL:** \ **Category:** The Quarantine Zone\ **Tags:** covid-quarantine\ **Created:** [April 7, 2020, 12:47am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237 "2020-04-07T00:47:26Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Backwater\_Under\_Duck](https://avatars.discourse-cdn.com/v4/letter/b/ba8739/32.png) [@Backwater\_Under\_Duck](https://boards.straightdope.com/u/Backwater_Under_Duck)\ **Post date:** [April 7, 2020, 12:47am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/1 "2020-04-07T00:47:26Z")
Kind of a straight GQ, but it’s about the virus. Who’s making masks, and out of what? I want to make some masks. I can sew a pattern and have stuff available. The best patterns create a pocket to put a disposable filter in them. What to use. One Doctor develops, with the help of his wife, a mask from a Hoover vacuum cleaner. Traps 99.9% (or something close to that) of all particulates. But the comments all say that HEPA material is some kind of glass product that shouldn’t be near your face. There isn’t much of a consensus. So, HEPA. Safe for mask filter or not? And how about furnace filter material. Filtrite brand says it’s effective, partially, against viruses. Anybody involved in this with some insight? ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [April 7, 2020, 1:01am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/2 "2020-04-07T01:01:11Z")
I was thinking car air filters. This seems a lot like what people during prohibition would have been posting. ---
**Author:** ![Snowboarder\_Bo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowboarder_bo/32/229_2.png) [@Snowboarder\_Bo](https://boards.straightdope.com/u/Snowboarder_Bo)\ **Post date:** [April 7, 2020, 1:22am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/3 "2020-04-07T01:22:57Z")
My mask is made for [these PM2.5 filters](https://www.amazon.com/CHRISLZ-Activated-Carbon-Protective-Replacement/dp/B076Q27336). They are fairly inexpensive. ---
**Author:** ![nelliebly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nelliebly/32/5422_2.png) [@nelliebly](https://boards.straightdope.com/u/nelliebly)\ **Post date:** [April 7, 2020, 1:35am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/4 "2020-04-07T01:35:10Z")
HEPA filters can shed glass fibers that irritate the respiratory system. Supposedly if they’re sandwiched between layers of cloth, it’s not an issue. More to the point, however, is that they are very tough to breathe through, so people tend to push them out of the way or pull them away from their faces now and then–both of which contaminate the hands with any virus on the mask as well as defeating the purpose of the mask. I remain unconvinced masks do much good, but for those who insist on wearing them, the best advice is to make sure they are snug to the face at every single point, which means you should use wire to get them tight to the skin on and around your nose and elastic under the chin. Also, you must still keep at least 6 feet away from people and wash your hands thoroughly after removing the mask. The mask then goes directly in the washer. Do not reuse a mask without washing it first. ---
**Author:** ![Thylacine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thylacine/32/1143_2.png) [@Thylacine](https://boards.straightdope.com/u/Thylacine)\ **Post date:** [April 7, 2020, 4:16am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/5 "2020-04-07T04:16:50Z")
One of our health department folks recommended double paper towel or cut up swimsuit material between cloth layers and definitely no hepa filters because of coatings ---
**Author:** ![RedSky](https://avatars.discourse-cdn.com/v4/letter/r/67e7ee/32.png) [@RedSky](https://boards.straightdope.com/u/RedSky)\ **Post date:** [April 7, 2020, 9:10am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/6 "2020-04-07T09:10:28Z")
I would say furnace filter material would be the most likely type to contain fibreglass to get some heat resistance. HEPA filters come in all shapes and sizes, it seems very unlikely a domestic disposable vacuum filter bag would contain any fibreglass, I couldn’t recommend cutting up some type of permanent industrial filter. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [April 7, 2020, 11:58am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/7 "2020-04-07T11:58:25Z")
This company is making masks/filters using HEPA air filter material. Not yet approved. > [@](#): > > BiOAID’s 2” x 4” strip of commonly available HEPA or MERV13 filter with a boundary layer added at the breathing apparatus offers an alternate to conventional N95 respirators composed of melt-blown polymers. [https://bioaid.us/](https://bioaid.us/). Also see: > **[More of us are now supposed to wear a mask](https://www.cnet.com/health/pill-packs-and-home-furnaces-inspired-this-new-health-mask/)** > > A San Francisco Bay Area startup thinks this is the one to wear. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [April 7, 2020, 3:07pm UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/8 "2020-04-07T15:07:11Z")
There’s also this thread: [Why can’t you use HEPA material to make masks?](https://boards.straightdope.com/sdmb/showthread.php?t=893481) ---
**Author:** ![susan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/susan/32/17537_2.png) [@susan](https://boards.straightdope.com/u/susan)\ **Post date:** [April 7, 2020, 4:15pm UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/9 "2020-04-07T16:15:41Z")
HEPA filters for vacuums, air cleaners, and furnaces all have air sucked through them forcefully, that air then being circulated into habitations. Would having a piece of HEPA filter closer to your face, at a lower air pressure, contain significantly more of any detached fibers or particles? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 7, 2020, 4:16pm UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/10 "2020-04-07T16:16:59Z")
> [@RedSky](#): > > I would say furnace filter material would be the most likely type to contain fibreglass to get some heat resistance. Can’t imagine why. The filter is on the inlet side of the furnace - before the air is ever exposed to any heat exchanger. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [April 7, 2020, 4:55pm UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/11 "2020-04-07T16:55:28Z")
It seems pretty easy to tell if one can breath though such a filter? Anyone got one to test? ---
**Author:** ![nelliebly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nelliebly/32/5422_2.png) [@nelliebly](https://boards.straightdope.com/u/nelliebly)\ **Post date:** [April 7, 2020, 9:07pm UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/12 "2020-04-07T21:07:55Z")
If you’ve got one and want to test it, make sure you sandwich it between layers of cloth and fit it tightly around your nose and mouth–no gaps. Masks are good if you’re trying to ensure you won’t spread COVID that you already have, and that’s about it. From [National Geographic](https://www.nationalgeographic.com/science/2020/04/coronavirus-what-you-should-know-diy-masks-and-ventilators/) (all bolding mine): > [@](#): > > But are homemade devices safe? So far, the evidence is scant and mixed, and while a few ideas show promise, **there is some concern that stopgap measures could make things worse**. A study published April 2 in The Lancet found that the coronavirus could survive on cloth for at least a day and on surgical masks for up to seven days. And on April 7, The World Health Organization said **there is currently no evidence that wearing any kind of mask can prevent healthy people in their communities from getting a respiratory infection, including COVID-19.** > [@](#): > > A separate study, from 2015, casts additional doubt on homemade masks. In a randomized trial in Vietnam, healthcare workers **who wore cloth masks acquired more respiratory infections and influenza-like illnesses than their colleagues who wore surgical masks**. Lab tests showed that 97 percent of particles got through the cloth masks, compared to 44 percent with surgical masks. > [@](#): > > Regardless, Davies wrote in a recent summary of her team’s findings that social distancing, hand-washing, and the avoidance of face touching are by far the most effective ways to protect society, adding that **masks should be a last resort that is meant to prevent “an unavoidable risk of exposure.** ” Since the CDC gave the green light on homemade masks, people have been making and wearing them like crazy, convinced they protect them from COVID. They don’t, but the CDC, operating as it is in Full Desperation Modes, is hoping widespread mask use would slow transmission rates. Wear them for that reason, not out of a misplaced sense of protection. ---
**Author:** ![WhyWhyWhy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whywhywhy/32/7539_2.png) [@WhyWhyWhy](https://boards.straightdope.com/u/WhyWhyWhy)\ **Post date:** [April 8, 2020, 7:05am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/13 "2020-04-08T07:05:47Z")
Wife’s Kotex maxipad (new not used), dog’s charcoal pee pad, a 2016 Honda oil filter, cofee filters, or the pink attic insulation material? Need answer fast. Sent from my SM-N920P using Tapatalk ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 8, 2020, 10:08am UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/14 "2020-04-08T10:08:56Z")
> [@WhyWhyWhy](#): > > Wife’s Kotex maxipad (new not used), dog’s charcoal pee pad, a 2016 Honda oil filter, cofee filters, or the pink attic insulation material? Need answer fast. pink attic insulation material (i.e. fiberglass) is a poor choice. People who work with it wear actual respirators to avoid inhaling particles from it. Oil filters often have a one-way valve to prevent backflow. Even assuming reasonable pressure drop characteristics during inhalation through it, you’d need another passage in your mask with a checkvalve on it to allow exhalation. Like an actual respirator. ---
**Author:** ![elucidator](https://avatars.discourse-cdn.com/v4/letter/e/8edcca/32.png) [@elucidator](https://boards.straightdope.com/u/elucidator)\ **Post date:** [April 8, 2020, 1:50pm UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/15 "2020-04-08T13:50:17Z")
My understanding is that the “mask” purpose is to block particles and especially droplets of water, like when somebody sneezes. Filtering out virus is a daunting standard. Understatement of the Year Award. ---
**Author:** ![Damuri\_Ajashi](https://avatars.discourse-cdn.com/v4/letter/d/898d66/32.png) [@Damuri\_Ajashi](https://boards.straightdope.com/u/Damuri_Ajashi)\ **Post date:** [April 8, 2020, 7:20pm UTC](https://boards.straightdope.com/t/hepa-filter-material-for-virus-masks-really/851237/16 "2020-04-08T19:20:45Z")
> [@elucidator](#): > > My understanding is that the “mask” purpose is to block particles and especially droplets of water, like when somebody sneezes. Filtering out virus is a daunting standard. Understatement of the Year Award. I have given up on the HEAP filter thing. It’s not cheap and I generally avoid situations that might warrant a filter. I’m just using a regular old mask so noone thinks i’m gonna get them sick.