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