ASTM Level 3 surgical masks are being described as an FDA-approved heavy-weight in a field full of questionable fabric masks, or even as a lightweight alternative to medical-grade respirators like the N95. So what is the truth? Keep reading to find the answer!
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ASTM Level 3 surgical masks are being described as an FDA-approved heavy-weight in a field full of questionable fabric masks, or even as a lightweight alternative to medical-grade respirators like the N95. So what is the truth? Keep reading to find the answer!
N95 masks are the workhorse of respirators, and that’s because they work. A certified N95 respirator must filter at least 95% of particulates in that same ultra-fine aerosol range. The tradeoff with this consistently high degree of protection is reduced airflow, so people with certain pre-existing conditions are not advised to use medical-grade respirators on an ongoing basis.
By now you’ve probably heard the refrain that surgical masks are designed as barriers against fluids, not as barriers against airborne particles. Traditionally this is true. From a regulatory perspective, FDA-approved surgical masks, even the mighty ASTM F2100 Level 3s, are not guaranteed to filter the same degree of fine aerosols as N95 or F3502-type masks. For your upper-level mask nerds, a certified Level 3 mask is tested against particles 600 nm (0.6 microns) in diameter, around 10 times the size of the particles used in the N95/F3502 test.
There’s now plenty of evidence that COVID can spread via much smaller particles than the kind surgical masks are designed to protect against. As a result, surgical mask manufacturers are racing to get their scrubs tested to the more rigorous levels required by the N95 standards. In fact, some level 3 masks score impressively well on these tests, achieving filtration efficiency comparable to N95 (or KN95) respirators in the ultra-fine aerosols range (75nm / .075 microns).* The caveat? These are the pre-fit scores.
N95 masks are in a league of their own when it comes to fit, and this is by design. Under the NIOSH standards, N95 respirators must be fitted to the individual wearer in order to minimize gaps and create a seal between the wearer’s face and the outside world. When correctly fitted, an N95 mask achieves a filtration efficiency practically impossible to achieve with a Level 3 Surgical Masks or cloth mask and PM2.5 filter.
On the other hand, studies strongly suggest that because N95-type masks are rigid, even the very smallest gaps can cause them to lose a disproportionate amount of filtration compared to more flexible fabric masks. If you needed another reason to stay away from N95s - besides the fact that medical respirators are still in short supply and needed by health care professionals - this fact should be reason enough!
When considering Level 3 Surgical Masks, the most important factor to know and understand is how well these masks work when you factor in fit. Remember, unlike N95 and PM2.5 masks, Level 3 certification for surgical masks measures only the material itself, and doesn't account for how well the mask filters when worn on your face.
The ASTM F2100 specification offers up this caveat clearly, saying it “only evaluates the materials used in the construction of the medical face mask and not the seal." The testing language under ASTM F2299 is even more explicit, stating: "the integrity of the seal to the wearer's face is not evaluated in this test".
To illustrate how much fit impacts a Level 3 Surgical Mask’s true filtration efficiency, let’s go back to the Level 3 masks mentioned above. These were the ones that scored similarly to a KN95 or N95 mask on a materials-only basis.
In one case, a popular FDA-approved Level 3 mask that scored 92% prior to fit testing, dropped to 77% when measured to account for fit. In another case, a well-known Level 3 mask that surpassed 90% on a materials-only basis filtered only 11% of particulate matter when worn by a real human being. This shows the dramatic difference between a surgical mask with a good fit and one with too many gaps.
Here ends the sharing, and we hope this article was helpful to you! We are an N95 particulate respirator supplier, please feel free to contact us if you need them!