Fit Testing

Fit testing is a very important part of making sure employees respiratory devices are working properly.  The purpose of the fit test is to ensure that the mask has an airtight seal around the face of the individual wearing it.  If the fit is not right, than whatever material trying to be kept out may be breathed in by the person wearing the mask.  This is a reason for concern, particularly when many dangerous gases don’t have a scent or very many warning signs.  Filtering particulates, gases, or anything else out is a vital task of any filter respirator.  An airtight seal is also vital with a supplied air respirator. Fit tests can be done in a variety of ways.  Either using an electronic machine that detects the particles coming into the mask or simply using a very strong scent/taste test to tell if are leaking in around the seal.  Both test have some similarities but are very different.  The cheaper method of testing is the taste/smell test.  This method does not require the high-end digital equipment that the other test requires. 

That being said it is also less precise but still very effective.  A substance, usually saccharin, is used to tell if any outside air is seeping threw the seal of the mask.  A hood is placed over the subject to keep the saccharin released in the air in the vicinity of the mask so it may be detected.   First the person administering the test releases the saccharin into the hood while the person is not wearing a mask.  This is to see how much saccharin is needed to be administered before it can be detected.  Than the person drinks water to clear the taste from there mouth.  The mask is than fitted onto the persons face.  Saccharin is than added to the closed hood once again.  The person is asked to move their head side to side, and up and down.  The person is asked to read “The Rainbow Passage”.  The subject is asked to bend over or jog in place as well.  If the person at any point detects the scent/taste during the test than you know the seal is not good.  The mask is than either refitted or swapped for another type of respirator.  The process is similar for the other method as well. 

The subject is still asked to read the rainbow passage, move side-to-side, tilt up and down etc.  A hose is fitted to the respirator and than connected to the machine. While the person is performing the tasks previously listed, the machine measures the amount of particulate entering the air the person is breathing within the mask.  The same process is repeated as it is in the smell/taste test.  The mask is either refitted or swapped out if the subject fails the test.  One big reason a person may fail the test is if they have facial hair that prevents the mask from sealing to there face.  Many times the employee may be asked to shave their face to ensure a better fit.  Naturally, this is usually more of a problem with men.