Chapter II. Information
and Restrictions
A. Criteria for Selecting
Respirators
To use this selection logic, the user must first assemble the necessary
toxicologic, safety, and other relevant information for each respiratory
hazard, including the following:
• General use conditions, including determination of contaminant(s);
• Physical, chemical, and toxicological properties of the
contaminant(s);
• NIOSH recommended exposure limit (REL), OSHA permissible
exposure limit (PEL), American Conference of Governmental Industrial
Hygienists (ACGIH) Threshold Limit Value (TLV), State-OSHA exposure
limit, American Industrial Hygiene Association (AIHA) Workplace
Environmental Exposure Limit (WEEL), or other applicable occupational
exposure limit;
• Expected concentration of each respiratory hazard;
• Immediately dangerous to life or health (IDLH) concentration;
• Oxygen concentration or expected oxygen concentration;
• Eye irritation potential; and
• Environmental factors, such as presence of oil aerosols
NIOSH recommends that air sampling be conducted to determine exposure
levels found in the workplace. A combination of air sampling and
exposure modeling is often used to make reasonable estimates of
exposure. Ideally, this determination should be made by a professional
industrial hygienist. Also, OSHA offers free consultation to qualifying
small- and medium-sized businesses to help recognize hazards,
suggest approaches to solving problems and identifying the kinds
of help available if further assistance is required. The OSHA
web sitewww.osha.gov
provides information on compliance assistance and consultation
programs.
Obtaining complete information on all criteria needed to use this
selection logic may be difficult. When conflicting or inadequate
data are found, experts should be consulted before decisions are
made that could affect the proper use of this selection logic. In
addition, the adequacy of the respirator selected is dependent on
the validity of the exposure limit used and the accuracy of the
hazard concentration determination. While the selection logic can
be used with any exposure limit, NIOSH recommends that the more
protective limit of the NIOSH REL or the OSHA PEL, be used in respirator
selection. If no REL or PEL exists, other applicable occupational
exposure limits such as the ACGIH TLV can be used.
The information obtained on general use conditions for respirators
should include a description of the actual job task, including the
duration and frequency, location, physical demands, and industrial
processes, as well as issues affecting the comfort of the respirators.
Some conditions may preclude the use of specific types of respirators
in certain circumstances because the individual must be medically
and psychologically suited (i.e., not claustrophobic) to wear a
given respirator for a given task, particularly if the respirator
is a self-contained breathing apparatus (SCBA).
Employers must establish a cartridge/canister changeout schedule
which is based on the service life of the cartridge/canister under
the conditions of use. The changeout schedule can be determined
with the assistance of the respirator manufacturer (changeout software
or other tools) or by conducting service life tests. Information
obtained on the service life of the cartridge/canister under conditions
of intended use must be evaluated regardless of the odor warning
properties of the chemicals. These evaluations must be based on
all gases and vapors present at the temperature and relative humidity
extremes (high and low) in the workplace. NIOSH recommends that
when the employer or a representative of the employer conducts
service life tests, the challenge concentrations of the gases and
vapors should be at least the maximum use concentration (MUC) of
the respirator and that a safety margin be applied when evaluating
service life data. OSHA provides information on determining change
schedules on their web site (http://www.osha.gov/SLTC/etools/respiratory/change_schedule.html).
In humid workplaces where organic vapor cartridges are used to
protect workers from a single volatile source, software (CD-ROM)
for predicting service life can be ordered from NIOSH by calling
1-800-356-4674. The software can also be downloaded from the OSHA
web site at: http://www.osha.gov/SLTC/etools/respiratory/advisor_genius_wood/breakthrough.html.
This information can be used to set up cartridge replacement schedules
and should be used in conjunction with sensory warning properties.
Although odor should not be relied on for cartridge/canister change
out, workers should be trained to exit the contaminated area whenever
they detect the odor or experience any irritation symptoms of the
contaminant. (See the NIOSH policy statement dated August 4, 1999,
in the Appendix (page 27) for a discussion of the OSHA standard
and NIOSH’s recommendations for change schedules.) If workers
are detecting the odor before the end of the change schedule, the
respirator program administrator should reevaluate this respirator
use; i.e., the change schedule, the workplace concentrations or
the other use conditions (relative humidity (RH), work rate, etc.).
B. Restrictions and Requirements
for All Respirator Usage
The following requirements and restrictions must be considered to
ensure that the respirator selected will provide adequate protection
under the conditions of intended use:
1. Workers are not exposed to a single unvarying
concentration of a hazardous substance, rather, individual exposures
may vary throughout a workshift and between days. The highest anticipated
concentration should therefore be used to compute the required protection
factor for each respirator wearer.
2. Qualitative or quantitative fit tests must
be provided as appropriate to ensure that the tight-fitting facepiece
respirator fits the individual. NIOSH endorses the OSHA standard
29 CFR1910.134 for fit testing except for irritant smoke (see the
Appendix, page 27). Employees must pass a fit test with the exact
model and size that they will wear in the workplace.
3. Respirators with tight-fitting facepieces should
not be used when facial scars or deformities interfere with the
face seal.
4. Respirators with tight-fitting facepieces (including
pressure-demand respirators) should not be used when facial hair
interferes with the face seal.
5. The usage limitations of air-purifying elements,
particularly gas and vapor cartridges or canisters, should not be
exceeded (see NIOSH Certified Equipment List for general limitations
at http://www.cdc.gov/niosh/npptl/topics/respirators/cel).
6. Respirators must be certified by the NIOSH.
A list of certified respirators can be found at http://www.cdc.gov/niosh/npptl/topics/respirators/cel/.
7. A complete written respiratory protection program
must be developed which includes regular worker training; maintenance,
inspection, cleaning, and evaluation of the respirator; use of the
respirator in accordance with the manufacturer’s instructions;
fit testing; medical evaluation; and environmental monitoring. Minimum
respiratory protection requirements for some contaminants can be
found in the OSHA Respiration Protection Standards, 29 CFR 1910.134.
Detailed information on respirator programs can be accessed at:
http://www.osha.gov/SLTC/etools/respiratory.
In addition, the OSHA Small Entity Compliance Guide provides procedures
and checklists that can help small businesses comply with the respirator
standard. This information can be accessed at: http://www.osha.gov/Publications/SECG_RPS/secgrev-current.pdf.
8. The APFs that appear in this respirator selection
logic are based for the most part on laboratory studies. However,
a few APFs have been validated and revised as necessary after consideration
of data obtained from studies of workplace protection factors (WPFs).
OSHA is currently considering setting APFs for respirators.
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