What Does Quantitative Fit Test (QNFT) Mean?
A quantitative fit test (QNFT) is one type of mask fit test used to determine whether a respirator properly fits an individual employee. Mask fits tests are used with tight fitting respirators to ensure that equipment fits the wearer properly. Without a proper fit, ambient air can leak into the mask and expose the wearer to airborne contaminants.
A quantitative fit test (QNFT) is performed by collecting and analyzing air samples from within the respiratory inlet cover of the respirator while it is worn by the intended user. This collection is accomplished through use of a hose inserted into the face piece of the mask, which then delivers the air sample to a separate device for analysis. This testing procedure results in a numeric value for the level of contaminants within the mask.By comparing this number to the concentration of the contaminant outside the mask, a fit factor can be calculated. This number should indicated if and at what level any leakage exists when the worker is wearing the mask.
A quantitative fit test differs from a qualitative fit test because the latter relies on subjective feedback from the wearer to detect potential leaks.