HEPA & MERV Ratings, material thickness, mask re-use A still common specification for final filters in hospitals the 95% filter could refer to MERV 14, MERV 15, or MERV 16 high efficiency air filters under ASHRAE 52.2/MERV Here’s Why: These filters are used primarily to protect equipment. For reference, a typical dust particle is between .2 and 8 microns, while pollen starts at … Dirt, dust, smoke, and pollen-size particles are trapped "The WEB vent filter in your photo appears to be a synthetic fabric that can be easily cut, but it's filtration effectiveness and efficiency may not be the best product to use if you are cutting and making your own face masks to protect workers from the COVID-19 virus. The test is made of six cycles. It shows particle size ranges. MERV 9 MERV 10 MERV 11 MERV 12 - - - - > 90% > 95% > 95% > 95% 40 - 45% 50 - 55% 60 - 65% 70 - 75% Better Residential Better Commercial Buildings Hospital Laboratories Bag Filters Pleated Filters Better Rigid Style Box Filters F i l t e r e d A i r b o r n e C o n t a m i n a n t s ODOR * POLLEN PET DANDER DUST/LINT DUST MITE MOLD SPORES SMOG + What MERV means when buying air filter for re-purposing for DIY face masks. A high-MERV-rated material in the range of MERV 12 and above is far more effective, but you will need to make a closer examination of the air filter material to be sure that it is not too thick or dense to use as a face mask: too-thick or too-dense a mask can be so difficult to breathe-through that it may be unsafe for the wearer.

not as good at 99.97% (see HEPA filtration discussed below) remember that in a heating or air conditioning system air is being So if each pass is removing 75% of There are other superior ratings including N98, N99, and N100. These dust particles fall into three size groups.The amount of E1, E2 and E3 dust particles that are captured and missed is calculated. The poorest performance is used. This is an industry standard rating system. MERV 10 and MERV 11 filters remove the most common types of indoor pollution. The MERV rating on an air filter describes its efficiency as a means of reducing the level of 0.3 to 10 micron-sized particles in air which passes through the filter. They discourage N95 respirators in order to reserve for medical personnel.However, contractors working at such sites (ie.
They require special blowers to pull the air through them. It is an acronym for "high efficiency particulate … A still common specification for final filters in hospitals the 95% filter could refer to MERV 14, MERV 15, or MERV 16 high efficiency air filters under ASHRAE 52.2/MERV  Here’s Why:So what 95% filter do you need? Any filter, high MERV or HEPA, can be expected to filter out larger particles with an efficiency above its rating. NIOSH, thank you for posting this important information. The test begins with a clean filter. NIOSH makes a clear case in the following statement: "When worn by healthcare professionals, the N-95's (NIOSH calls this class of respirators Filtering Facepiece Respirators (FFR's), are designed to protect the wearer and surgical masks are designed to protect the patient. These filters include HEPA and UVGI. Subject: NIOSH Posting: Respiratory Protection During Outbreaks: Respirators versus Surgical Masks One side is slightly smoother than the other. These filters should not be used in home HVAC or furnace systems.
On average, a 4.5-log reduction was observed across all 41 surfaces tested  – Cleaned and disinfected (neutral detergent and disinfectant) 