N95 Fit Testing.
Fit tests are essential to insuring that a respirator forms a good seal against the user’s face and prevents contaminants from leaking into the mask. Manufactures provide fitting instructions and use limitations on the product package. Respirator face pieces are made in various sizes to fit a wide variety of face shapes and sizes.
What is a respirator user seal check? It is a procedure conducted by the respirator wearer to determine if the respirator is properly seated to the face. The user seal check can be either a positive pressure or negative pressure check, which are generally performed as follows: The positive pressure user seal check is where the person wearing the respirator exhales gently while blocking the paths for exhaled breath to exit the facepiece. A successful check is when the facepiece is slightly pressurized before increased pressure causes outward leakage. The negative pressure user seal check is where the person wearing the respirator inhales sharply while blocking the paths for inhaled breath to enter the facepiece. A successful check is when the facepiece collapses slightly under the negative pressure that is created with this procedure. A user seal check is sometimes referred to as a fit check. A user seal check should be completed each time the respirator is put on (donned). It is only applicable when a respirator has already been successfully fit tested on the individual.
When should a user seal check be done? Once a fit test has been done to determine the best model and size of respirator for a particular user, a user seal check should be done by the user every time the respirator is to be worn to ensure an adequate seal is achieved.
How do I do a user seal check on a particulate respirator? A user seal check may be accomplished by using the procedures recommended by the manufacturer of the respirator. This information can be found on the box or individual respirator packaging. There are positive and negative pressure seal checks and not every respirator can be checked using both. You should refer to the manufacturer’s instructions for conducting user seal checks on any specific respirator .