Selecting Respiratory Protection

To select the correct respirator for protection against particulates, the following conditions must be known:

• The identity and concentration of the contaminants in the workplace air
• The permissible exposure limit (PEL) for each contaminant
• The hazard ratio (HR), which is the airborne particulate concentration divided by the exposure limit
• The assigned protection factor (APF) for the class of respirator (the APF should be greater than the HR)
• The immediately dangerous to life or health (IDLH) concentration, including oxygen deficiency
• Any available information about the service life for combination cartridges or canisters

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