Mask Protection Standards & Medical Face Mask Information For Use
Access PRIMED Medical Products to learn about the latest information on ASTM mask protection standards. Find information on surgical and procedure masks.
The filtration efficiency and protective ability of a face mask is compromised when the mask becomes wet, torn or dislodged. Generally speaking, the higher protection value of a mask the longer it will maintain filtration; however, there is no set rule for how long a mask should be worn as it depends on humidity levels, respiration rate, nasal discharge, talking, etc. A medical face mask should be worn for only one patient procedure or visit. If a mask gets wet or soiled it should be replaced.
ASTM standards are referenced by the Food and Drug Administration (FDA), as the endorsed standard in the United States. ASTM F2100 specifies the performance requirements for Medical Face Masks with five basic criteria:
1. BFE (Bacterial Filtration Efficiency): BFE measures how well the medical face mask filters out bacteria when challenged with a bacteria-containing aerosol. ASTM specifies testing with a droplet size of 3.0 microns containing Staph. Aureus (average size 0.6-0.8 microns). In order to be called a
medical/surgical mask, a minimum 95% filtration rate is required. Moderate and high protection masks must have bacterial filtration rates greater than 98%.
Some manufacturers use the Modified Greene & Vesley method to determine the BFE rating. This method is NOT recommended by ASTM for product comparison or evaluating consistency.
2. PFE (Particulate Filtration Efficiency): PFE measures how well a hospital mask filters sub-micron particles with the expectation that viruses will be filtered in a similar manner. The higher the percentage, the better the mask filtration. Although testing is available using a particle size from 0.1 to 5.0 microns, ASTM F2100 specifies that a particle size of 0.1 micron be used.
When comparing test results it is important to note the size of the test particles used, as use of a larger particle size will produce a misleading PFE rating.
3. Fluid Resistance: Fluid resistance reflects the surgical mask’s ability to minimize the amount of fluid that could transfer from the outer layers through to the inner layer as the result of a splash or spray. ASTM specifies testing with synthetic blood at pressures of 80, 120, or 160 mm Hg to qualify for low, medium, or high fluid resistance. These pressures correlate to blood pressure: 80 mm Hg = venous pressure (Level 1), 120 mm Hg = arterial pressure (Level 2), and 160 mm Hg (Level 3) correlates to potential high pressures that may occur during trauma, or surgeries that include high pressure irrigation such as orthopedic procedures.
4. Delta P (Pressure Differential): Delta P measures the air flow resistance of the medical mask and is an objective measure of breathability. The Delta P is measured in units of mm H2O/cm2 and the lower the value the more breathable the mask feels. The ASTM standard requires that masks have a Delta P of less than 6.0 for moderate and high barrier masks, whereas low barrier masks must have a Delta P of less than 5.0.
5. Flame Spread: As hospitals contain sources of oxygen, heat, and fuel the ASTM standards include testing for flame resistance. Testing dictates that all hospital masks must withstand exposure to a burning flame (within a specified distance) for three seconds. All PRIMED masks meet this requirement.
5.5 ISO Certification: In addition to the above tests, all medical face masks must be tested to an international standard (ISO 10993-5, 10) for skin sensitivity and cytotoxic tests to ensure that no materials are harmful to the wearer. Tests are conducted on materials used in construction of the mask which come in contact with the user's skin
What is the difference between a medical mask and a respirator?
Medical masks (surgical/procedure masks) are loose fitting masks that cover the mouth and nose. They are designed to stop large droplets and splashes or sprays, but are not designed to seal tightly to the face or filter small airborne contaminants.
A respirator is an item of PPE designed to reduce exposure to airborne contaminants. Known airborne pathogens include TB, SARS, Anthrax, and Hanta virus. Respirators must be individually selected to fit the wearers face and shown to provide a good seal. They also must be certified by NIOSH, and used within a comprehensive respiratory program including fit testing and training.
Post-lockdown SARS-CoV-2 nucleic acid screening in nearly ten million residents of Wuhan, China
Large-scale population screening can provide insights to levels of ongoing SARS-CoV-2 transmission. Here, the authors report a citywide screening of ~10,000,000 residents of Wuhan and show that SARS-CoV-2 infection prevalence was very low five to eight weeks after the end of lockdown.
Advantage® 290 Half-Mask Respirator with Source Control
The Advantage 290 Elastomeric half-mask respirator provides cost effective healthcare professionals protection up to P100 level and filters exhaled breath.
Community and Close Contact Exposures Associated with COVID-19 Among Symptomatic Adults ≥18 Years in 11 Outpatient Health Care Facilities — United States, July 2020
The US Centre for Disease Control performed a study which showed that 85 percent of those who contracted Covid-19 during July 2020 were mask wearers. Just 3.9 percent of the study participants never wore a mask.
Original:
https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6936a5-H.pdf
Erratum. correction:
https://www.cdc.gov/mmwr/volumes/69/wr/mm6938a7.htm?s_cid=mm6938a7_w https://www.theblaze.com/op-ed/horowitz-cdc-study-covid-masks
Young children being forced to wear masks is of particular concern.
now of of course i have NOT gone into the murky world of PCR testing accuracy
which also might taint any recent research