Respiratory protection , The Half mask VALUAIR medium is designed to work when external concentration allows it .
The type of protection depends on the cartridges connected, gases , particules or combined.
The threshold is depending on a theoretical calculation , based on the facial leakage and the efficiency of the adapted canister . The APF is evaluated from 12 to 50 . It allow the use of the Half mask from an external concentration between 12 time to 50 time the Occupational Exposure Limit .