What is the "Protection Factor" of a 1/2 face negative pressure, air-purifying respirator?

The "Protection Factor" of a 1/2 face negative pressure, air-purifying respirator is typically defined as 10. This number indicates the level of respiratory protection provided by the respirator in an environment with airborne contaminants.

In practical terms, this means that a person wearing this type of respirator can expect the level of contaminants in their inhaled air to be ten times lower than that in the surrounding atmosphere. This is essential for ensuring worker safety when exposed to hazardous materials such as asbestos, where controlling exposure is critical.

The factor is based on testing and the design of the respirator, which works by filtering out particles from the air. Other types of respirators or higher levels of respiratory protection yield higher protection factors, but for a standard half-mask respirator, the protection factor remains 10, reflecting its effectiveness for most occupational exposures.