Qualitative fit testing is a subjective pass/fail method used on half-masks that rely on a user’s sense of taste to detect air leakage from the respirator. The test uses Bitrex (a harmless, bitter-tasting chemical) or Saccharin (a sweet-tasting chemical), which will determine whether the mask passes or fails.

Quantitative fit testing measures the precise amount of leakage into any tight-fitting facepieces. Instead of relying on your senses, the test is performed by a machine calculating the measurements.

All facial hair that may impede a tight seal for a facepiece must be shaven. Neatly trimmed, closely shaved facial hair, such as small goatees or mustaches, may be acceptable while wearing a respirator. Full beards are not acceptable.

According to OSHA 29 CFR 1910.134: The employer shall not permit respirators with tight-fitting facepieces to be worn by employees who have:

1. Facial hair interfering with the sealing surface or the value function.
2. Any condition that interferes with the face-to-facepiece seal or valve function.
3. This requirement applies to both negative and positive pressure respiratory protective devices that rely on the principle of forming a face-to-facepiece seal.
4. Beard growth at points where the seal with the face and respirator occurs is a condition that has been shown by numerous studies to prevent a good face seal.