Understanding Respirators

To get the best protection from a respirator, you need to learn about its different parts. When used, maintained, and replaced correctly, the different parts of a respirator can lessen your exposure to nearby hazards.

Anatomy of respirator. Face seal keeps contaminants out of mask. Straps hold mask snugly in place. Filter or prefilter traps particles. Full-face mask adds eye protection. Cartridge captures certain gases and vapors. Valve opens when you exhale and closes when you inhale.

Filtering out the hazards

Cartridges trap gases and vapors. Filters trap particles. All cartridges, filters, and prefilters must be certified by NIOSH (National Institute for Occupational Safety and Health). NIOSH rates filters on a scale of 3 efficiency levels: 95%, 99%, and 99.97%. Within these efficiency levels are 3 filter types: N, R, and P. This classification refers to how effective a filter functions when exposed to oils: 

  • N filters. These are used when no oily particles are present.

  • R filters. These can be used to protect against oily particles. They are somewhat resistant to oils.

  • P filters. These provide the highest level of protection against all particles. They are strongly resistant to oils.

When to replace filters and cartridges

Follow instructions from your supervisor or the respirator manufacturer to learn when to replace your prefilter, filter, or cartridge.