Testing dictates that all hospital masks must withstand exposure to a burning flame (within a specified distance) for three seconds. Flame Spread: As hospitals contain sources of oxygen, heat, and fuel the ASTM standards include testing for flame resistance. 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.ĥ. The Delta P is measured in units of mm H2O/cm2 and the lower the value the more breathable the mask feels. Delta P (Pressure Differential): Delta P measures the air flow resistance of the medical mask and is an objective measure of breathability. 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.Ĥ. ASTM specifies testing with synthetic blood at pressures of 80, 120, or 160 mm Hg to qualify for low, medium, or high fluid resistance. 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.
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.ģ. 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. The higher the percentage, the better the mask filtration. 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. This method is NOT recommended by ASTM for product comparison or evaluating consistency.Ģ. Some manufacturers use the Modified Greene & Vesley method to determine the BFE rating. Moderate and high protection masks must have bacterial filtration rates greater than 98%. In order to be called a medical/surgical mask, a minimum 95% filtration rate is required. ASTM specifies testing with a droplet size of 3.0 microns containing Staph. BFE (Bacterial Filtration Efficiency): BFE measures how well the medical face mask filters out bacteria when challenged with a bacteria-containing aerosol. ASTM F2100 specifies the performance requirements for Medical Face Masks with five basic criteria:ġ. WHO says people wearing medical masks should “ensure the coloured-side faces outwards”.ASTM standards are referenced by the Food and Drug Administration (FDA), as the endorsed standard in the United States. Versions of the post have been fact checked here, here, here and here. There is no advice that the coloured and white sides are used to indicate the health of the wearer.
Surgical mask blue or white out how to#
In the same video, Dr Wing Hong also stresses the importance of wearing the mask the correct way up, with the metal wired edge running over the nose.Ī WHO infographic details how to wear a medical mask safely with an instruction that says “ensure the coloured-side faces outwards”. “So, if I cough, it absorbs it… so, you gotta wear it like this – blue on the outside, white on the inside.” “You see it (the mask) has the blue colour on the outside because it is waterproof and then you have white on the inside because it is absorbent,” he said. Providing more detail, Dr Seto Wing Hong, co-director of the WHO Collaborating Center for Infectious Disease Epidemiology and Control, addresses the claim in this video. In an instructional video (1min14sec) on March 9, Dr April Baller from WHO’s Health Emergencies Programme explains how to wear a medical mask correctly.ĭr Baller says the inside of the mask is “usually the white side”, advice she reiterates in another video on June 5. The post’s claim goes against advice outlined by the World Health Organization. The Facebook post falsely advises that the “correct” way to use a face mask is to have the coloured side facing out if a person is sick and the white side out if they’re healthy. A post claims the coloured side of a mask should be worn on the outside when a person is sick. The July 29 post has been viewed more than 2.3 million times and shared by more than 160 users. It also claims the white side of the mask is “the filter part” to be worn facing out when the wearer is not sick, to prevent germs getting in. The post shows an infographic headed, “The correct way to use a medical mask” and claims that masks should be worn “colored side out if you are sick and do not want to spread germs around”.
A Facebook post claims medical face masks being used to prevent the transmission of COVID-19 are designed to be worn differently depending on the health of the wearer.