Chapter I. Background
and Purpose
The purpose of this respirator selection logic (RSL) is to provide
a process that respirator program administrators can use to select
appropriate respirators for the protection of workers in specific
workplaces. It is not intended to be used for selection of respirators
for protection against infectious agents or chemical, biological,
radiological or nuclear (CBRN) exposures associated with terrorism
events.*
This RSL contains a series of questions regarding situations which
may require the use of respirators. (See Respirator Selection Logic
Sequence, page 5.) In answering these questions, the user of this
selection logic is assisted in identifying specific classes of respirators,
applicable restrictions, and the appropriate respirator selection
table to use. When using one of the tables to identify a suitable
class of respirators, the user must keep in mind the restrictions
identified in the question section of this respirator selection
logic.
This RSL identifies the criteria necessary to determine the classes
of respirators that will provide the minimum acceptable degree of
protection for a chemical at a given concentration. Classes of respirators
offering greater protection can usually be used in place of the
minimum acceptable class of respirators. Respirator classes are
consistent with respirator certification groupings as specified
in 42 CFR 84.
The recommendations in this RSL are based primarily on the physical,
chemical, and toxicologic properties of the contaminant and on the
limitations of each class of respirator, including filtration efficiency,
air supply capability, and face seal characteristics and leakage.
Thus, this selection logic is limited to identifying classes of
acceptable respirators, rather than individual respirator models.
After various classes of respirators are identified as being suitable
for a given situation, an evaluation is made of other factors of
the particular work environment (e.g., job, task, temperature, mobility,
etc.) so that the most appropriate respirator model within the recommended
classes can be chosen. In some situations, the selection of a respirator
classified as providing a higher level of protection may be advisable.
The assigned protection factors (APFs) used in this respirator
selection logic were based on quantitative fit factor data developed
by Los Alamos National Laboratories under contract to NIOSH and
on field and laboratory data gathered by NIOSH and others. A Notice
of Proposed Rulemaking on Assigned Protection Factors was published
by OSHA on June 6, 2003. When this regulation is finalized, NIOSH
will consider the new standard and revise the RSL as necessary.
NIOSH will also modify its certification
.* Note: Selection of respirators for infectious disease and terrorism-related
exposures requires consideration of additional factors in addition
to the traditional exposure assessment approaches described in this
guidance. See the NIOSH respirator topic page http://www.cdc.gov/niosh/topics/respirators/
for additional information and guidance on particular infectious disease
and terrorism issues.
program to assure that NIOSH certified respirators will be capable
of providing the level of protection determined in the OSHA APF rulemaking.
Fit factors determined for the individual wearer of a respirator by
quantitative fit testing or by any other method used to determine
fit should not be substituted for the APF given for each class of
respirators. In addition, the fit factor determined through quantitative
fit testing must be greater than the APF (10X the APF is generally
recommended); otherwise, the respirator cannot be used by the worker.
Note: In order to provide protection at the APF level,
respirators must be used in a complete respirator program
such as the one required by OSHA in 29CFR1910.134. |
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