What is assessed during a fit test for a respirator?

During a fit test for a respirator, the primary focus is on assessing the proper fit to ensure it provides adequate protection against exposure to hazardous substances. A respirator must form a tight seal around the wearer's face to prevent contaminants from bypassing the filter and entering the wearer's breathing zone. The fit test verifies that the respirator is secure and aligns with the wearer’s facial shape, accounting for any variations that may affect the seal.

While comfort level is an important factor in the overall effectiveness of a respirator, particularly for extended wear, it does not replace the necessity of a proper fit for safety. Similarly, the condition of the air supply is crucial for respirators that rely on supplied air, and the durability of the respirator material is important for its overall performance and lifespan, but these aspects do not directly relate to the fit test itself. Thus, the correct answer emphasizes the critical aspect of ensuring the respirator is fitted properly to guarantee protection for the user.