Quantitative fit testing uses a machine called the Portaccount to measure the actual amount of leakage into the facepiece and does not rely upon your sense of taste, smell, or breathing irritant in order to detect leakage. The respirators used during this type of fit testing will have a probe attached to the facepiece that will be connected to the machine by a hose. There are three quantitative fit test methods accepted by OSHA:

• Isoamyl acetate, which smells like bananas; (also called banana oil test)
• Saccharin, which leaves a sweet taste in your mouth;
• Bitrex, which leaves a bitter taste in your mouth; and
• Irritant smoke, which can cause severe coughing.

Qualitative fit testing is a “pass” or “fail” test method that utilizes your sense of taste or smell, or your reaction to an irritant in order to detect leakage into the respirator facepiece. Whether the respirator you are wearing passes or fails the test is based simply on you detecting the test substance into your facepiece. There are four qualitative fit test methods accepted by OSHA:

• Generated aerosol;
• Ambient aerosol; and
• Controlled Negative Pressure