It is important to select the right respirator for the job. There are many types of respirators and each type protects against different hazards. Supply air respirators are necessary in oxygen deficient atmospheres. When using a supply air respirator, have a back-up person with a SCBA standing nearby. Air purifying respirators use ambient air and cannot be used in oxygen deficient atmospheres, IDLH atmospheres, or areas where the identity or concentration of a contaminant is unknown.
Ambient air is purified by a chemical cartridge, canister, or particulate filter.
Cartridges and canisters must be replaced if the user notices an odor, taste, or throat irritation. Disposable or single-use respirators are made of cloth or paper and are primarily used for nuisance dusts. Filter or dust respirator becomes damaged, visibly dirty, wet, or contaminated on the inside. Fullface mask covers the face from the hairline to below the chin. This type of mask provides eye protection.