Where Respiratory Protective Equipment (RPE) is used, it must be able to provide adequate protection for individual wearers. RPE can’t protect the wearer if it leaks. A major cause of leaks is poor fit – tight-fitting facepieces need to fit the wearer’s face to be effective.
As people come in all sorts of shapes and sizes it is unlikely that one particular type or size of RPE facepiece will fit everyone. Fit testing will ensure that the equipment selected is suitable for the wearer.
JSP have put together a video explaining the test: Face Fit Testing