This objective is to investigate the capabilities of new quantitative respirator fit test method that seems to be less complex, more portable and more cost-effective than current methodologies. The new method is based on exhausting air from a temporarily sealed mask, thereby generating a negative pressure that replicates the inspiratory driving force for leakage into the mask. The exhaust flow rate that is required to generate and sustain a pre-selected negative pressure in the mask is a direct measure of the mask leakage flow rate, which can be used as an index of respirator fit.
Specific aims i nclude refining and automating portions of negative pressure fit test system used in a preliminary exploration of the new method. Sensitivity and precision limits of the new method will be determined through comparison with an aerosol fit test system based on corn oil. A test population recruited from Air Force personnel already assigned to a respiratory protection program will be used and anthropometrically compared to a defined respirator test panel. The capability of the new method to measure respirator fit representative of non-rest work rates will be examined by using a computerized open-circuit metabolic technique. Field measurements of respirator fit will also be attempted with the new method.
