OSHA has added approved fit-testing protocol in its respiratory protection standard. Revisions add a new quantitative fit-testing procedure to assist workers and employers in the proper fit and selection of respirators.

The new fit-testing protocol, referred to as the Controlled Negative Pressure (CNP) REDON protocol, requires three different test exercises followed by two redonnings of the respirator. The three test exercises, listed in order of administration, are normal breathing, bending over, and head shaking.

The procedures for administering the new CNP REDON protocol, with three test exercises and the two respirator donnings to an employee, and for measuring respirator leakage during each test, are summarized here:

Facing forward — In a normal standing position, without talking, breathe normally for 30 seconds; then, while facing forward, hold breath for ten seconds during sampling.

Bending over — Bend at waist for 30 seconds and hold breath for ten seconds during sampling.

Head shaking — Shake head back and forth vigorously several times while shouting for approximately three seconds and, while facing forward, hold breath for ten seconds during sampling.

First redonning — Remove respirator, loosen all face-piece straps, and then redon the respirator mask; after redonning the mask, face forward and hold breath for ten seconds during sampling

Second redonning — Remove respirator, loosen all face piece straps, and then redon the respirator mask again; after redonning the mask, face forward and hold breath for ten seconds during sampling.