Before using any type of personal protective equipment, employers and employees should use the hierarchy of controls which includes elimination, substitution, engineering controls, and administrative controls. If there is a chemical or particulate exposure hazard where these controls are not feasible or effective, respiratory protection may be used. The Occupational Safety and Health Administration (OSHA) respiratory protection standard 1910.134 is the regulation that governs the use of respirators for general industry and 1926.103 does the same for construction.
The standards delineate what should be in a respiratory program. These include:
- A written respiratory program with assigned personal.
- Selection
- Medical evaluation.
- Fit testing.
- Scheduling, cleaning, disinfecting, storing, inspection, repairing, discarding, and other maintenance
- Training
- Evaluation of the respiratory protection program.
Before choosing a respirator, it is important to determine the hazard and select the right respiratory protection for the job. OSHA has given various respirators an assigned protection factor (APF) to help in the selection process. These are can be found under respiratory standard 1910.134(d)(3)(i)(A). An N95 “dust mask” with an APF of 10 may be adequate or a self-contained breathing apparatus with an APF 10,000 may be needed. The APFs have been in place for decades although the rule was revised and published in 1998.
APFs indicate the level of workplace respiratory protection that a class of respirators is expected to provide. With a clear understanding of the standards, employers must select the appropriate type of respirator based upon the exposure limit of a contaminant and the level of that contaminant in the workplace. Think of APFs as the divisor in a division problem. If the APF of a respirator is 10 and the concentration of a workplace contaminant is 100 PPM, then the concentration inside the respirator should be at or lower than 10 PPM.
OSHA requires that a qualitative or quantitative fit test be used to determine that the respirator does not leak. When using a quantitative fit tester an actual APF of the respirator of the test subject can be determined. It measures the concentration of the test aerosol inside and outside of the subject’s respirator while doing specified activities. The concentrations are averaged and an APF is determined.
It is vital for employers and employees to select the appropriate respirator for the job to better protect employees against contaminants in the workplace. Using the APFs is one tool to bring the levels of contaminant inhaled to a safer limit.
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