Understanding Respirator Filter Ratings: N95, P100, and Beyond

When searching for respirator filters on reputable supplier websites like Parcil Safety, you may wonder what all the different filter ratings mean. The most common filter ratings posted for half-face respirators and full-face respirators are as follows:

• N95
• P100
• R95

Respirator filter ratings can be confusing because they combine letters and numbers to indicate the level of protection from the filter. However, you must learn the meanings behind the various letter classes and numbers to help select the right level of protection based on your needs. 

What Do Filter Ratings Mean?

The first thing we will discuss is the letter classifications associated with the filter ratings. The three main letter classifications are N, R, and P. 

Here is a breakdown of what these letters mean for filtration purposes:

N—The letter N in a filter rating means it is “not resistant to oil.” Its only protection is against non-oil contaminants and particulates, such as dust, dirt, viruses, and bacteria. 

R – The letter R in a filter rating means it is “somewhat resistant to oil.” In other words, the filter offers minimal protection against oil-based contaminants and particulates. It can usually protect against sprays, aerosols, solvents, resins, degreasers, and anything else that doesn’t emit harmful vapors or chemicals. 

P – The letter P in a filter rating means it is “oil proof.” The filter can give you maximum protection against most oil and non-oil contaminants and particulates. Some of these might include vapors, chemicals, gases, fumes, mists, and dust. 

Now, let’s talk about the numerical ratings, which are those numbers you see after each letter in the filter rating system. These numbers basically represent the percentage of particles that the filter can block from entering your airways. 

For example, if you see a 95 after a letter, it means it can filter 95% or more of the airborne contaminants and particles from entering your respiratory system. If you see a 99 after a letter, it can filter out 99% of the particles. As for the number 100, it usually indicates that it can filter 99.97% of all airborne particles, which is the High-Efficiency Particulate Air (HEPA) standard. 

Okay, so you understand the letter classifications and numerical ratings. Let’s look at the three most common filter ratings and what they mean:

• N95 - N95 filters block at least 95% of all non-oil particles from entering your airways. They are recommended in healthcare settings or any environment where you want to protect yourself against respiratory viruses floating in the air. For this reason, N95 filters were popularized during the COVID-19 pandemic.
• P100 – P100 filters block a minimum of 99.97% of all oil and non-oil particles from entering our airways. They are perfect for heavy industrial environments where particulate and vapor exposure are common. Commercial painters, welders, and asbestos removers often wear respirators with these filter ratings. 
• R95 – R95 filters block at least 95% of some oil particles and non-oil particles, except for vapors and chemicals. They are best used in environments with some minor oil mist exposure but nothing robust.

The respirator manufacturers usually recommend that you don’t wear the same respirators continuously for more than eight hours at a time. Follow their advice to ensure that your filtration expectations continue to be met based on the filter ratings. 

Choosing the Right Rating

It is imperative to choose a respirator with the right filter rating so that you can receive the most protection possible against the contaminants in your work environment.  

The rule of thumb is to use the N95 filter to protect yourself in environments where you are exposed to dust, dirt, allergens, bacteria, or viruses. Any environment without oil-based particles is good enough for the N95 filter rating. 

If you are performing heavy-duty tasks involving exposure to toxic particles, hazardous vapors, and chemicals, the P100 respirator will offer better protection. It is also better if you plan to wear the respirator consistently for several hours at a time. 

When to Use Higher Ratings

Should you protect yourself against 95% or 99.97% of airborne particles? You might be wondering this question as you consider these filter ratings. 

Keep in mind that each letter classification has multiple numerical ratings associated with them. For instance, the N letter classification has N95, N99, and N100. There is a lot of talk about using N95 respirators to protect against viruses, but what about the higher-rated N99 and N100 filters? Wouldn’t those offer better protection?

Technically, the higher ratings offer more protection against airborne particles and contaminants. However, the ease of breathing is one common reason why someone would choose a lower rating. It all depends on the threat level of the environment and the amount of filtration protection you really need. 

Here are two scenarios where you would wear an N95 respirator vs. an N99 or N100 respirator:

• N95 – A healthcare or woodworking environment with general threat levels against viruses, wood particles, and other airborne particulates. 
• N99 & N100 – Any environment with a high level of viruses, smoke, bacteria, dust, and particulates in the air, such as wildfires and industrial or manufacturing settings. 

Here are two scenarios where you would wear a P95 respirator vs a P100 respirator:

• P95 – An environment where you spray chemicals, such as pesticides, that generate a mild oil mist in the air.
• P100 – A heavy industrial environment where you’re exposed to highly toxic particulates. 

The higher rating gives you added protection that you don’t get from the lower-rated filters. Just note that it will be more difficult to wear higher-rated filters for extended periods due to the breathing difficulties you might encounter. 

Conclusion

Choosing the right filter rating ensures that you’re equipped with the appropriate level of protection for your specific work environment. Hopefully, you now have a better understanding of how to find the right filter rating for the tasks you plan to do.

Do you have questions or need more clarification about filter ratings and their meaning? Contact Parcil Safety at 1 (855) 715-1400 for more information.