What Do N95 and P100 Respirator Ratings Mean?

Posted by PK Safety Team on Mar 2nd 2020

What Do N95 and P100 Respirator Ratings Mean?

If you and your team need to wear respirators on the job, it helps to have a means of comparing the relative protection between different respirators and filters. These ratings are designed to help protect you and your workers from different sets of airborne hazards. Sawdust and particles containing asbestos fibers are not the same. Neither should we use the same filter. If you use the wrong type of mask on the job, it could put you and your team at risk.

 Learn more about N-, R-, and P-rated respirators and what they mean for you and your employees.

Respirator Classifications

You’re probably used to seeing respirators with labels such as “N95” or “P100,” but this rating system is actually made up of two parts. The letter denotes the type of material used in the respirator filter media, and the types of hazards it protects against, while the number refers to the filter's ability to remove the most-penetrating particle size while working in the field.

  • N, R and P Ratings

The first part of the rating can either be an N, R, or a P. It may help to understand that the filters used in respirators trap particles by 2 means; first is how tightly the material is woven, which regulates the size of openings for air to pass through. Second is a static electric charge. This may be thought of the static charge generated by rubbing a balloon against your hair. This static electric charge is literally woven in during manufacturing.

The trick is that this charge may be reduced or dissipated by the presence of oil. So the letter designations are meant to convey the relative ability of the filter media to resist that oil.

N-rated respirator masks are not resistant to oil-based substances. They should only be used in environments without oil aerosols. They protect against solid and liquid airborne particles, except those that contain oil.

R-rated respirator masks are somewhat resistant to oil-based substances. They protect against solid and liquid airborne particles, including those that contain oil. When using R-rated filters in oil-filled environments, you should only use the respirator for 8 hours at a time. Dispose of the filter or mask at the end of your shift. You should also replace these filters as they become clogged over time.

P-rated respirators are considered oil-proof. They go above and beyond R-rated respirators when it comes to oil resistance. They protect against all types of solid and liquid airborne particles. Just like R-rated respirators, P-rated respirators tend to degrade more quickly when used in atmospheres with oil-based particles. 

It’s best to replace your filters or disposable respirator as the particle load clogs the filter media. The more dust in the air and the harder you work will have a direct effect on filter life. Also, keeping your reusable respirator clean helps in extending the life of the mask, as well as promoting good hygiene.

  • Numeric Ratings

The numeric half of the rating refers to the percentage of particles the filter will remove from the air. When testing filters for their efficiency, the challenge used is a smoke that has a particle size of 0.3 microns. This is a vanishingly small particle. In a completely still room, it may take 8 hours for such a particle to fall 8 feet.

Against the challenge particle cloud, we look at how much can get through the filter. For example, a “95” rating means the mask will filter out 95% of relevant particles. A mask with a “99” rating will filter out approximately 99% of hazardous particles, and the '100' rating filters out 99.7% which means it is virtually impenetrable.

Choosing the Right Type of Respirator

Now that you understand the respirator rating system, you can choose the right letter and number depending on your work environment. Monitor your work environment for oil-based substances to find out what type of respirator you should be using in the field. If oil-based hazards are present, you’ll need to choose between R- and P-rated respirators.

In practice, 'R' rated filters are not as popular, and may be a little more difficult to find. Most of our customers just opt for the 'P' rated filters and be done with it, as judging the relative amount of oil mist in the air can be problematic.

Consider how much time your employees will need to spend in these spaces before choosing a mask. If your employees only need to be in the field for a few minutes at a time, you may be better off with R-rated respirators. However, if your employees regularly encounter oil-based substances in the field, it’s best to use a P-rated respirator.

In addition to the letter and number of your masks, you also need to make sure your respirator fits comfortably over your face. Look for respirators with adjustable straps, so every member of your team can find the right size and shape for their face. If there are any holes or crevices between the lining of the mask and the sides of your face, toxic particles can easily slip inside, making the mask less effective in the field.

Use respirator fit testing to make sure your equipment is working properly before sending your employees out into the field. Proper fit testing helps ensure that you get all of the protection that your equipment is capable of providing. Test your safety equipment before each and every shift to keep your employees safe on the job.

Keep this information posted around your worksite to remind your employees to double-check their respirators before heading out into the field. One mistake can easily lead to all kinds of unfortunate health outcomes. Stay vigilant and invest in the right safety equipment. Contact us to learn more about choosing the right respirator for your crew. 

SHOP RESPIRATORS & FILTERS