What is the primary requirement for negative pressure respirators regarding fit testing?

Negative pressure respirators are designed to provide personal respiratory protection by filtering out contaminants from the air. For these respirators to function effectively, it is crucial that they create a proper seal between the facepiece and the user's face. This is where fit testing comes into play.

Qualitative fit testing involves performing a test to determine if the respirator provides an adequate seal through the use of a substance (like a bitter aerosol) that can be detected by the wearer. The process helps to identify whether any leakage occurs, indicating an insufficient fit. This method is particularly useful because it is straightforward and can be conducted relatively quickly.

On the other hand, quantitative fit testing typically provides a more precise measurement of the fit by using equipment to measure the amount of leakage, but for many applications and types of negative pressure respirators, qualitative testing suffices.

Understanding the importance of fit testing helps ensure that users are adequately protected against airborne hazards. Regular fit testing can identify improperly fitting respirators that could otherwise compromise the safety of individuals working in environments where asbestos and other hazardous materials might be present.