Which fit test measures the respirator's effectiveness numerically?

The fit test that measures a respirator's effectiveness numerically is the quantitative fit test. This method utilizes a calibrated instrument to measure the actual amount of leakage around the respirator during use. It provides a numerical value known as the fit factor, which expresses the ratio of the concentration of a substance in the air outside the respirator to the concentration inside. This quantifiable data allows for a clear assessment of how well the respirator fits the wearer and can inform decisions about the adequacy of the fit for protecting the individual from airborne contaminants.

In contrast, the qualitative fit test evaluates the fit based on the wearer's sensory response to a test agent, such as sweet or bitter substances, which does not provide numerical data. Similarly, visual and practical fit checks focus on qualitative observations and do not quantify the fit effectiveness in the same manner as a quantitative test. Thus, the quantitative fit test stands out as the method that offers measurable data ensuring the proper fit and protective capability of the respirator.