Fit testing is a method for finding the respirator that fits your face and making sure it provides a tight seal to help keep you protected. It is a test protocol conducted to verify that a respirator is both comfortable and provides the wearer with the expected protection. The fitting characteristic of a respirator is the ability of the mask to separate a workers respiratory system from ambient air. Fit testing is required for employees wearing tight-fitting respirators, such as disposable or reusable respirators, and it helps ensure the user has selected the correct size respirator and that a seal against the face can be made to provide the expected protection.
There are two types of fit test methods: qualitative and quantitative. Qualitative fit test methods use the reaction of workers to the taste or smell of a special material (if it leaks into the mask) - gas, vapors, or aerosols. Quantitative fit testing uses a fit testing instrument(s) to provide numerical measurements of the amount of face seal leakage present when a user wears a respirator.
During a fit test, the common fit test for most respirators uses your sense of smell or taste to see if air is leaking between your face and the respirator. The tester will also ask you to breathe normally, breathe deeply, turn your head side to side and up and down, and speak. The OSHA Respirator Fit Testing video and NIOSH fact sheet provide complete instructions for conducting fit tests with accepted test agents.
Fit testing is mandatory for US employers, and compliance with the OSHA standard is required. The main advantage of qualitative fit test methods is the low cost of equipment, while their main drawback is their modest precision, and that they cannot be used to test tight-fitting respirators that are intended for use in atmospheres that exceed 10 PEL (due to the low sensitivity) .
