If you’re shopping for respiratory protection, you may notice that respirators often come with a NIOSH rating, such as N-95 or N-99. But what does that even mean, and why should you care?
For starters, NIOSH stands for the National Institute for Occupational Safety and Health, a federal agency that is part of the Centers for Disease Control and Prevention (CDC).
NIOSH has developed a rating system for air filtration that measures how effective a respirator is at filtering particles out of the air. Respirators are tested to see what percentage of particles they filter out of the air that passes through them. The tests look at particles as small as 0.3 microns, or the size of a single virus.
Test are performed under worst-case conditions. Since you’re usually not going to be in a worst-case scenario, respirators will normally perform better than their NIOSH ratings suggest.
If a respirator filters out at least 95% of all particles, it is given a 95 rating. If it filters out at least 99%, it receives a 99 rating. Respirators can earn a 100 rating if they filter out at least 99.97% of all particles.
Besides particle filtration, NIOSH ratings also look at whether a respirator can protect against oils. Respirators are rated “N” (for “Not resistant”) if they are not resistant to oil, “R” (for “Resistant”) if they are somewhat resistant, and “P” (for “oil Proof”) if they are strongly resistant.
That means there are nine different NIOSH ratings:
|Not resistant||Somewhat resistant||Oil proof|
|Particle Filtration||At least 95%||N-95||R-95||P-95|
|At least 99%||N-99||R-99||P-99|
|At least 99.97%||N-100||R-100||P-100|
Which NIOSH Rating Do You Need?
Different jobs will have different requirements, but N-95 is the most common minimum standard, and is recommended by the CDC itself to protect healthcare workers from disease. R-type or P-type respirators are only needed in jobs where oil is an issue, since the oil can affect how well the respirator performs.
However, since we’re talking about minimum requirements, you can still choose a higher-rated respirator than what is required if you want a higher level of protection. For example, if an N-95 respirator is required, an N-99 respirator will also work for the job. An N-99 respirator might be harder to breathe through, or may have to be larger to let the same amount of air in. But, it will definitely do the job.