What is the permissible exposure factor (PF) for a full face piece air purifying respirator?

The permissible exposure factor (PF) for a full face piece air purifying respirator is indeed 50. This means that when properly fitted and used by a trained individual, a full face piece air purifying respirator can reduce the concentration of hazardous airborne contaminants by a factor of 50. The PF quantifies the degree to which the respirator protects the wearer, indicating that the exposure level outside the respirator should be no more than 1/50th of the permissible exposure limit (PEL) set for that specific hazard.

This factor is based on laboratory evaluations that consider the effectiveness of the respirator in filtering out hazardous substances while also taking into account potential leakage that can occur at the face seal or through the filter. The full face piece design offers an added level of protection because it covers both the mouth and nose, as well as the eyes, which may also be exposed to harmful airborne substances.

The values associated with other choices listed are not representative of the PF for a full face piece air purifying respirator, and selecting a PF that is too low would underestimate the level of protection provided, while a value that is too high could mislead users about the respirator's effectiveness. Understanding the permissible exposure factor is crucial for ensuring the