Knowing the differences in particulate filters is important to ensure you're getting an adequate level of respiratory protection in your workplace.
In this article, we'll go over some of the most common types of particle filters you may encounter here in Australia.
Many countries have their own regulatory standards around respiratory protective equipment (RPE) manufacturing and performance standards. Thus the various letters and numbers you see assigned to different filters.
In Australia, the certifying body is the AS/NZS 1716:2012. The National Institute for Occupational Safety and Health (NIOSH) oversees the U.S. standards and it's the EN 149-2001 in Europe.
Generally speaking, Australia recognizes and accepts NIOSH and EN 149 certified RPE so you'll probably come across these in your quest to protect your lungs :-)
Alright, let's get started.
P1, P2 and P3 Filters
The performance of particulate filters is determined using sodium chloride aerosols of 0.02-0.2 micron equivalent diameter and ~0.3-0.6 micron mass median diameter. These sizes are considered the "most penetrating particle size" for filters. Simply put, it means they're better than their smaller and larger particle friends at making their way through the filter material into the breathing zone.
The 'P' stands for particulate and the numbers denote the efficiency levels:
P1 - Filters out ~80% of mechanically generated particles. When performance tested, it must be at least 80% efficient at keeping out the most penetrating particle size (~0.3 to 0.6 microns).
P2 - Filters out ~94% of mechanically and thermally generated particles and biohazards such as viruses. When performance tested, it must be at least 94% efficient at keeping out the most penetrating particle size (~0.3 to 0.6 microns).
P3 - Filters out ~99.95% of mechanically and thermally generated particles. When performance tested, it must be at least 99.95% efficient at keeping out the most penetrating particle size (~0.3 to 0.6 microns).
The level of protection you need depends on the hazard you're trying to protect yourself from and the assigned protection factor (APF) needed based on the concentration of contaminants in the air. You can read more about protection factors here.
You can get single-use P1 and P2 disposable masks or you can attach these filters to reusable respirators. See the photo below.
Disposable masks are called "filtering facepiece" respirators because the entire facepiece is the filter.
P3 disposable masks are not approved by the AS/NZS 1716 (but some countries do have them).
According to Australian standards, P3 is only a P3 when attached to a full-face respirator. P3 filters can be used on half-face respirators, but they're considered a P2 level of protection.
N95 Filters
N95 filters (NIOSH, USA) are the relative equivalent of P2 filters (AS/NZS 1716).
The N stands for "non-oil" meaning it doesn't filter out oil-based particulates. And 95 means it filters out 95% of the most penetrating particle size when performance tested.
You can get disposable N95 masks (filtering facepiece respirators) or N95 filters that attach to reusable respirators.
FFP Filters
There's not much to say about this one. FFP2 stands for filtering facepiece P2. This is the nomenclature used in Europe under the EN 149 certification standards.
FFP2 is the relative equivalent of P2s (AS/NZS 1716) and N95s (NIOSH, USA).
Is N95 Better than P2?
This section pertains to disposable filtering facepiece N95 and P2 masks.
P2 and N95 disposable masks are used in healthcare settings and industries such as construction. The key differences are:
P2/N95 used for healthcare are fluid-resistant without valves and;
P2/N95 used in industry may have an exhalation valve for easier breathing and are not typically fluid-resistant.
Fluid resistance ratings go from Level 1 (least resistant) to Level 3 (most resistant) according to the AS 4381:2015 or ASTM standards.
The reason you won't see healthcare workers wearing valved masks is because there is a potential for the wearer to exhale infectious particles.
We hear a lot, especially from those in the healthcare industry, that N95s are better than P2s. This is not true.
The amount of misinformation out there is understandable but concerning.
We came across an article recently comparing P2s and N95s. The author claims: "By design, an N95 provides a higher level of fluid resistance making it a suitable option for healthcare environments where exposure to bodily fluids is a concern." This article also ascertains: "While P2 respirators may offer adequate filtration, a P2 typically only has a level 2 fluid rating. In healthcare settings, a higher fluid protection of a level 3 grade is required." And goes on to say: "If a P2 respirator has an intent on infiltrating the healthcare sector, it must meet the elevated level 3 fluid resistance standards specifications set by the TGA for acceptance."
Most of this information is incorrect and misleading. It's the reason people are confused and continue to believe they need an N95 instead of a P2, especially in healthcare.
Here are the facts.
First, N95s and P2s are essentially the same as far as filtering out submicron, fine particles There's no real difference.
In fact, N95 and P2 filters have the worst filtration efficiency for particles around 0.3 microns (the "most penetrating particle size"); 95% and 94% respectively. Particles smaller than or larger than 0.3 microns get filtered out at a higher percentage due to the physics behind mask fibers and construction. This is true for N95s and P2s.
Second, P2s can certainly be rated at Level 3 fluid resistance (this is the highest level) and many are. An example is the Trident P2 in Level 3. Softmed has a Level 3 as well. And so does AMD. And Multigate. These are all TGA-approved and widely used in healthcare.
Third, a Level 3 fluid rating is not a general requirement in healthcare settings. The level of fluid protection of any PPE - gowns, drapes, masks, etc. - is based on a risk assessment. For example, if you're performing or assisting in a particularly bloody surgery with the possibility of lots of splashing, Level 3 may be the right choice. If the chances of contact with body fluids are lower or less risky, then a Level 1 may be adequate.
Finally, the TGA doesn't require a respirator to be Level 3 fluid-resistant to be accepted on the ARTG. There are plenty of Level 1 and Level 2 masks included on their register. The popular 3M 1860S is a Level 1 N95 listed on the ARTG.
That was the long answer to get to the short answer: N95s are not better than P2s. They are essentially the same.
How to Select the Right Filters
Click here to read all about that!
And if you're really feeling filter nerdy, read this one too.
Wrapping Up
Okie dokie, there you have it.
In a nutshell:
The AS/NZS 1716 classifies particulate filters as P1, P2 and P3 based on their level of efficiency against the 'most penetrating particle size'.
N95 (NIOSH, USA) and FFP2 (EN 149) are the relative equivalents of P2s (AS/NZS 1716).
In Australia, P3 filters are only considered P3 when attached to full face respirators. If they are on half face respirators, then it's considered P2 level efficiency.
In Australia, you can get disposable P1, P2 filtering facepiece masks but not disposable P3 masks.
N95s are not better than P2s. They are essentially the same.
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