The Annals of Occupational Hygiene have published in their recent Volume an
article on the role of fit testing in respiratory protection.
Workplace performance measurement of respiratory protective equipment (RPE) is
fundamental to the understanding of how well wearers are protected. It forms
the basis for guidance on which the selection of appropriate equipment is
based. However, the measurement of this performance is open to many sources of
interference and inaccuracy, reducing the value and relevance of the results,
and is most difficult for devices providing the highest levels of protection.
In this paper, a method for critically assessing collected workplace protection
factor (WPF) data is validated. This method rejects unreliable data, using
criteria based on the detection limits of the analytical measurement system. An
iterative approach is also described which arrives at a supportable estimate of
given non-parametric percentiles of the distribution of measured WPFs [such as
the fifth percentile, conventionally taken to be the assigned protection factor
(APF)]. Further pragmatic criteria, based on a combination of experimental
experience and consideration from first principles, are suggested as the basis
for any future studies of RPE performance. These will maximize the chances of
valid measurements being made, and also provide insight into the level of
confidence which can be placed on any of the results. A consequence of these
criteria is that typical working environments and measurement methods are
incapable of generating WPF data which can be considered reliable.
AplusA-online.de - Source: Annals of Occupational Hygiene