Three numbers
The first is the hazard ratio: measured concentration ÷ exposure limit. The second is the protection factor assigned to the respirator class; it is not derived from an individual's fit test score, it belongs to the class. The third is the maximum use concentration: protection factor × limit. If the airborne concentration exceeds it, that respirator is not suitable; in immediately dangerous atmospheres an independent air supply is required.
Why fit testing is separate
The protection factor assumes the respirator seals to the face. A fit test checks that assumption per person; face shape, facial hair and the model itself change the outcome. Passing a fit test does not raise the protection factor — it only shows that this person can use this model. The record holds person, model, protocol, score and date.
Optifora's protective equipment module keeps the selection calculation and the fit-test record on the same person.