Qualitative Fit-Testing (QLFT) may be used to fit test negative pressure air-purifying respirators under which condition?

• A. If they are used in atmospheres less than ten times the PEL
• B. In any atmosphere
• C. Only for positive pressure respirators
• D. Never for negative pressure respirators

Answer: (A)

Qualitative fit testing is used to see if a negative-pressure air-purifying respirator seals properly by having the wearer detect a test agent when there’s a leak. This method is appropriate for negative-pressure respirators only when the surrounding atmosphere is not more than ten times the permissible exposure limit. In environments below that threshold, a leak will be detectable by taste or smell without exposing the wearer to dangerous concentrations, making the test reliable and safe. If the atmosphere exceeds ten times the PEL, the test becomes unsafe or unreliable, and a quantitative fit test is preferred to objectively measure leakage.