If you engage in activities which expose you to noxious fumes or other harmful substances, you likely already know the importance of wearing a good-quality mask or RPE (respiratory protective equipment). A well-designed permeable barrier, whether a disposable mask or a heavy-duty “respirator”, can provide vital protection to your respiratory system and overall health. However, it doesn’t matter how well the mask blocks harmful particles if you don’t wear it correctly. If a mask does not fit your face “like a glove,” pockets of air may allow harmful substances to pass between the mask’s edges and your skin. As a result, you may expose yourself to the very risks your mask should prevent.
If you’re required to wear a mask to perform your job, it’s likely that “face fit testing”, also known as “fit testing”, will also be mandated by law. The face fit test checks for an unbroken seal between your face and the mask’s face seal. A professional testing agency can use computerized equipment to assess how well the mask sits on your face. In many places, professionals who rely on masks for their work are required to regularly engage accredited “fit testers” to check how well their masks’ fit. Depending on the company and the equipment used, face fit testing may be carried out either at the tester’s facility or at a designated location of your choosing.
Prior to the fitting test, a testing company usually subjects the mask in question to a battery of general tests. This first stage establishes whether there are any internal structural problems with the mask, aside from fit. Any perishable parts are replaced; an inward leakage test may be performed; and the motor and the battery are tested for functionality.
At the beginning of the face fit testing, an engineer will inspect whether you are wearing the mask correctly. You may receive tips on how to adjust the mask for a more secure fit. Should your mask pass this initial visual inspection, you will then undergo the actual fitting test, itself. This stage of the test may be quantitative, using computerized equipment.
In other cases, a qualitative test may be used, assessing any mask fit failure through the wearer’s perception of taste. Initially, the wearer must assess his or her sensitivity to taste by atomizing a small amount of saccharine or bitrex into the air. At this stage, the test subject does not wear a mask. The tester then records the degree to which the test subject reported having tasted the saccharine or bitrex solution. Following this initial stage, it is imperative to wait at least five minutes and possibly longer, until the subject can no longer detect any of the saccharine or bitrex flavor. Next, with the mask on, the wearer again atomizes a small amount of the same solution. If the subject is able to taste any of the solution this time, with the mask in place, then the mask has not passed the test. If the subject is unable to taste the solution, the mask is properly fit to the subject’s face. Afterwards, the subject opens the mask’s seal to check again whether she or he can in fact taste the atomized solution, thereby confirming the mask’s fit.