OSHA requires you to ensure that all of your employees who use tight-fitting respirators (including filtering face pieces like N95) be fit tested prior to initial use, whenever a different respirator facepiece (size, style, model or make) is used, and at least annually thereafter.
A quantitative fit test (QNFT) means "an assessment of the adequacy of respirator fit by numerically measuring the amount of leakage into the respirator."
A QNFT is necessary for respirators that must achieve a fit factor of greater than 100. This includes a full face respirator, or an atmosphere-supplying respirator. When possible, Safety Links recommends using a QNFT for all fit tests including fit tests for half mask respirators!
We have a selection of probed respirator adapters for most types, makes and models.