How is Assigned Protection Factor (APF) used to determine respirator adequacy?

How is Assigned Protection Factor (APF) used to determine respirator adequacy?

• A. Compare workplace concentration to APF: C / APF <= PEL ensures adequate protection
• B. APF determines the length of sampling duration
• C. APF sets the PEL value
• D. APF is unrelated to respirator effectiveness

Answer: (A)

APF expresses how much a respirator can reduce the amount of contaminant that reaches the wearer. It is used to estimate the breathing-zone concentration that would occur when the respirator is worn: C_in = C_out divided by the APF. If that estimated inhaled concentration is at or below the permissible exposure limit (PEL), the respirator is considered adequate for that exposure, assuming a proper fit and regular use. For example, if the workplace concentration is 100 units and the APF is 10, the breathing-zone concentration would be about 10 units. If the PEL is 25 units, this would meet the adequacy criterion. APF does not set the PEL, and it does not determine sampling duration; those are addressed by regulatory limits and monitoring plans, respectively.

APF expresses how much a respirator can reduce the amount of contaminant that reaches the wearer. It is used to estimate the breathing-zone concentration that would occur when the respirator is worn: C_in = C_out divided by the APF. If that estimated inhaled concentration is at or below the permissible exposure limit (PEL), the respirator is considered adequate for that exposure, assuming a proper fit and regular use.

For example, if the workplace concentration is 100 units and the APF is 10, the breathing-zone concentration would be about 10 units. If the PEL is 25 units, this would meet the adequacy criterion. APF does not set the PEL, and it does not determine sampling duration; those are addressed by regulatory limits and monitoring plans, respectively.