Environmental Engineering Reference
In-Depth Information
quantitative test, special instrumentation is used and the test is gener-
ally performed by an industrial hygienist or safety professional who has
extensive training in this area. The special instrumentation and equip-
ment required to perform quantitative fit tests are expensive.
In the qualitative test, which is the test most commonly admin-
istered in general industry, the person performing the fit test knows
the worker has a good it if the worker cannot sense the agent when it
is released in close proximity to the worker's breathing zone (between
the shoulders and top of head). The qualitative fit test is not as accurate
as the quantitative fit test in measuring the worker's ability to wear a
respirator because qualitative fit tests rely on the wearer's subjective
response, so it may not be entirely reliable. The qualitative it test is,
however, much easier to administer, less expensive, and easily per-
formed in the field.
At the minimum, before using a respirator, users must test their
respirators by performing their own pre-use self-fit tests. Workers must
test the positive and negative seal of their masks each time they use
a respirator. This is accomplished by performing positive and negative
pressure tests. During the
positive pressure test
, the user closes the
respirator's exhalation valve and breathes out gently into the facepiece.
This should cause the facepiece to bulge out slightly. If no air leaks out,
the user has a good fit. During the
negative pressure test
, users cover
both filter cartridges with the palms of their hands and inhale slightly
to partially collapse the mask. This negative pressure is held for 10 sec-
onds. If no air leaks into the mask, it can be assumed that the mask is
fitting properly.
To retain their original effectiveness, respirators must be peri-
odically cleaned (disinfected) and properly stored. The provisions for
cleaning and proper storage of respirators must be included in the orga-
nization's written respiratory protection program. Respirators should
be cleaned after each use. When performing the cleaning operation it is
always best to follow the manufacturer's instructions. Keep in mind that
caution must be exercised whenever respirators are cleaned. Certain
detergents and solvents will not only damage the facepieces but could
also damage the respirator casing.
After use and cleaning, a respirator should be properly stored.
Respirators are subject to damage when stored in bright sunlight.
Moreover, respirators can become contaminated or damaged whenever
they are exposed to dirt, grease, oil, solvents, or other contaminants
that can render the respirator useless and create a serious health haz-
ard for the user.
Speaking of the user's health, OSHA states that not everyone can
wear a respirator. Anyone assigned to a job requiring a respirator must
first have a medical examination and be cleared by a medical doctor for
respirator use. OSHA is very straightforward on this issue and states
that no one should be assigned a task requiring the use of respirators
unless found physically able to do the work while wearing the respirator.
Follow-up medical examinations are also required—usually at no longer
