Page:NIOSH DM DFM respirator evaluation draft.pdf/27

4—Strategy used by NIOSH for RAPF determinations.

  It is not feasible for NIOSH to test or evaluate respirator performance over an entire range of typical use conditions that may adversely affect their protection levels. As will be discussed at length in this evaluation,^[1] the strategy for equipment testing is totally consistent with the professional practice used for at least 20 years by respirator experts to determine respirator-class APFs through evaluation of face-seal leakage measurements. That is, it has not been the accepted standard of professional practice to use the makes and models with average or typical face-seal leakage in a class to determine APFs. Instead, it has been the practice to use the makes and model with greater or higher face-seal leakage in the class to determine APFs. This practice has been founded on the rationale that virtually no purchasers nor users know whether their particular respirator model and use conditions may result in hazardous, poor, average, or superior face-seal fit.
  Because the nature and technology of industrial respirators prevents purchasers and users from adequately assessing respirator safety and protection under widely-varying use conditions, NIOSH has determined that demanding-use considerations are necessary when determining APFs in order to protect the health and safety of all respirator users.
  Absent some means of continually assuring a respirator's proper fit every time it is worn, the RAPFs given in this evaluation reflect only the Institute's assessment of the protection potential that can be afforded by the listed masks. The RAPFs do not consider whether certain types of respirators certified by NIOSH can be reliably fit tested periodically and reliably fit checked by a wearer each time they don their mask. The NIOSH RAPFs do not necessarily indicate and do not guarantee the personal protection that will actually be provided every day to every wearer as respirators are used on the job.
  Reliable and effective facepiece-seal tests (both periodic fit tests and fit checks every time a mask is donned) are essential for the likelihood of each wearer achieving the RAPFs given in this report. Thus, when users and purchasers utilize NIOSH RAPFs, they must take into account any questionable efficacy and reliability of those fit tests and fit checks they rely upon. For example, the U. S. Court of Appeals for the District of Columbia Circuit ruled, in 1987, that OSHA had correctly assigned an APF of 5 to those "disposable respirators" that could not be fit checked by wearers