leakage resulting from the second type of point-of-use factors occurring after initial fit testing and mask selection. These include, but are not limited to,
- airborne contaminants that can leak through filters
- incorrect mask position on the user's face
- incorrect headstrap tension
- incorrect headstrap position on and behind the user's head
- failure to use all the headstraps
- changes in a user's facial surface such as facial stubble and perspiration
- mask damage
- improper mask maintenance.
A major respirator manufacturer has correctly noted:
neither QNFT nor QLFT can guarantee that the wearer will don the respirator in the same fashion in the workplace as when being fit tested and, therefore, that the same respirator fit factor will be achieved under actual working conditions. Control of fit is primarily up to wearer himself. Consequently, in a real sense, neither QNFT nor QLFT by themselves have a direct bearing in assuring proper employee health protection, but rather can only assure that the respirator selected by the employee can fit properly.[1]
This statement supports the critical importance of adequate training for each user so they will know how to properly don, adjust, and wear their respirator. It also emphasizes that adequate fit testing must be performed by an employer so that a user will not have to wear a mask that leaks at the face seal.
Point-of-use factors can create a considerable risk of undetected excessive leakage at the face seal or through the filter when a mask is worn in a hazardous environment. Even for those minimal number of particulate contaminants with "adequate warning properties," there is risk to the wearer. By the time a user has smelled or tasted a hazardous contaminant, it may already have done some damage to the user's health. Thus, each wearer must have the capability of reliably and effectively fit checking his or her mask for proper fit each time the mask's protection must be depended on. This is the purpose of fit-check tests that must be performed by users each time they don their respirator.
- ↑ 3M Company: Comment of Minnesota Mining and Manufacturing Company with Respect to the Permanent Lead Standard Quantitative Fit Test Provision, OSHA Docket No. H-049A, Exhibit 6-16, (July 1, 1981), p. 3.
