So, you want to grow out your beard, but wear a tight-fitting respirator at work? Ensuring the respirator seal is a vital part of respiratory protection practices. Facial hair that lies along the sealing area of a respirator, such as beards, sideburns, or some mustaches, will interfere with respirators that rely on a tight facepiece seal to achieve maximum protection. Facial hair is a common reason that someone cannot be fit tested.
The reason for this is simple – gases, vapors, and particles in the air will take the path of least resistance and bypass the part of the respirator that captures or filters hazards out. So then, why can't facial hair act as a crude filter to capture particles that pass between the respirator sealing area and the skin? While human hair appears to be very thin to the naked eye, hair is much larger in size than the particles inhaled. Facial hair is just not dense enough and the individual hairs are too large to capture particles like an air filter does; nor will a beard trap gases and vapors like the carbon bed in a respirator cartridge. Therefore, the vast majority of particles, gases, and vapors follow the air stream right through the facial hair and into respiratory tract of the wearer. In fact, some studies have shown that even a day or two of stubble can begin to reduce protection. Research tells us that the presence of facial hair under the sealing surface causes 20 to 1000 times more leakage compared to clean-shaven individuals.