Chapter III. Respirator Selection
Logic Sequence
After all criteria have been identified and
evaluated and after the requirements and restrictions of the
respiratory protection program have been met, the following sequence
of questions can be used to identify the class of respirators that
should provide adequate respiratory protection. Note that if OSHA
has promulgated a substance – specific standard for a contaminant
found in your workplace, respirator selection must meet or exceed
the respirators required in that standard. (OSHA General Industry
Air Contaminants Standard, 29 CFR 1910.1000).
Step 1. Is the respirator intended for use
during fire fighting?
a. If yes, only a full-facepiece,
pressure-demand, self-contained breathing apparatus (SCBA) meeting
the requirement of the NFPA 1981, Standard on Open-circuit
Self-contained Breathing Apparatus for Fire and Emergency Services
(2002 edition) is required. Information on NFPA 1981 can be found at
http://www.nfpa.org/.
b. If no, proceed to Step 2.
Step 2. Is the respirator intended for use in an
oxygen-deficient atmosphere, i.e., less than 19.5% oxygen?
a. If yes, any type of SCBA other than escape
only, or supplied-air respirator (SAR) with an auxiliary SCBA is
required. Auxiliary SCBA must be of sufficient duration to permit
escape to safety if the air supply is interrupted.
If
yes, and contaminants are also present, proceed to Step 3 to
determine if the hazard requires the SCBA or SAR/SCBA to meet a
specific APF level.
b. If no, proceed to Step 3.
Step 3. Is the respirator intended for entry
into unknown or IDLH atmospheres (e.g., an emergency situation)?
a. If yes, one of two types of respirators are
required: a pressure-demand SCBA with a full facepiece or a
pressure-demand SAR with a full facepiece in combination with an
auxiliary pressure-demand SCBA. Auxiliary SCBA must be of sufficient
duration to permit escape to safety if the air supply is
interrupted.
b. If no, proceed to Step 4.
Step 4. Is the exposure concentration of the
contaminants, as determined by acceptable industrial hygiene
methods, less than the NIOSH REL or other applicable exposure limit?
a. If yes, a respirator is not required for
routine work. For escape respirators, determine the potential for
generation of a hazardous condition caused by an accident, spill or
equipment failure. See Section IV. Page 17, for a discussion and
selection of escape respirators. Proceed to Step 6.*
b. If no, proceed to Step 5.
* If respirators are required by the employer to
be worn (even if below the occupational exposure limit), OSHA
requires that the employer establish and implement a written
respiratory protection program with worksite specific procedures. If
an employer provides respirators at the request of employees or
permits employees to use their own respirators when exposure levels
are below the applicable limits, this is considered voluntary
respirator use. OSHA requires that employers provide to their
employees the information contained in Appendix D of 29 CFR
1910.134, that they establish and implement those elements of a
written program necessary to ensure that any employee using a
respirator voluntarily is medically able to wear the respirator
(except that medical evaluation is not required for voluntary use of
filtering facepieces) and that the respirator is cleaned, stored,
and maintained so that it does not represent a health hazard to the
wearer.
Step 5. Are conditions such that a worker who is
required to wear a respirator can escape from the work area and not
suffer loss of life or immediate or delayed irreversible health
effects if the respirator fails, i.e., are the conditions not
immediately dangerous to life or health (IDLH)? IDLH values for
certain compounds can be found in the NIOSH Pocket Guide for
Chemical Hazards. This document can be accessed at http://www.cdc.gov/niosh/npg/npg.html.
IDLH values for some substances can also be found on the NIOSH
internet at
http://www.cdc.gov/niosh/idlh/idlh-1.html.
a. If yes, conditions are not considered to be
IDLH. Proceed to Step 6.
b. If no, conditions are considered to be IDLH.
Two types of respirators are recommended: a pressure-demand,
full-facepiece SCBA or a pressure-demand, full-facepiece SAR in
combination with an auxiliary pressure-demand, full-facepiece SCBA.
The auxiliary SCBA must be of sufficient duration to permit escape
to safety if the air supply is interrupted. An auxiliary unit means
that the SAR unit includes a separate air bottle to provide a
reserve source of air should the airline become damaged. The
auxiliary unit shares the same mask and regulator, and enables the
SAR to function as an SCBA if needed.
Step 6. Is the contaminant an eye irritant, or
can the contaminant cause eye damage at the workplace concentration?
Information on eye irritation is included in the International
Programme on Chemical Safety, International Chemical Safety Cards
which can be accessed at http://www.cdc.gov/niosh/ipcs/nicstart.html.
a. If yes, a respirator equipped with a full
facepiece, helmet, or hood is recommended. Proceed to Step 7.
b. If no, a half-mask or quarter-mask respirator
may still be an option, depending on the exposure concentration.
Proceed to Step 7.
Step 7. Determine the maximum hazard ratio (HR)
by the following:
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• Divide the time-weighted average (TWA) exposure
concentration for the contaminant determined in Step 4 by the
NIOSH REL or other applicable exposure limit. If the exposure
limit is an 8 hour limit the TWA used must be on 8 hour
average. If the exposure limit is based on 10 hours, use a 10
hour TWA.
• If the contaminant has a ceiling limit, divide the
maximum
exposure concentration for the contaminant
determined in Step 4 by the ceiling limit.
• If the contaminant has a short term exposure limit
(STEL),
divide the maximum 15 min TWA exposure
concentration for the contaminant determined in Step 4 by the
STEL.
• For escape respirators, determine the potential for
generation of a hazardous condition caused by an accident or
equipment failure.
• If a potentially hazardous condition could occur or a
hazard ratio greater than 1 has been calculated, proceed to
Step 8. |
Step 8. If the physical state of the contaminant
is:
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• a particulate (solid or liquid aerosol) during periods of
respirator use, proceed to Step 9;
• a gas or vapor, proceed to Step 10;
• a combination of gas or vapor and particulate, proceed to
Step 11. |
Step 9. Particulate Respirators
9.1. Is the particulate respirator intended only
for escape purposes?
a. If yes, see Section IV (page 17), for a
discussion and selection of escape respirators.
b. If no, the particulate respirator is intended
for use during normal work activities. Proceed to Step 9.2.
9.2. A filter series (N, R or P) that will
provide protection against exposure to the particulate in question
is recommended.
a. The selection of N-, R-, and P-series filters
depends on the presence or absence of oil particles, as follows:
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• If no oil particles are present in the work environment,
use a filter of any series (i.e., N-, R-, or P-series).
• If oil particles (e.g., lubricants, cutting fluids,
glycerine, etc.) are present, use an R- or P-series filter.
Note: N-series filters cannot be used if oil particles are
present.
• If oil particles are present and the filter is to be used
for more than one work shift, use only a P-series
filter
|
| Note: To help
you remember the filter series, use the following
guide: |
| |
N for Not
resistant to oil,
R for
Resistant to oil
P for oil
Proof | |
b. Selection of filter efficiency (i.e., 95%,
99%, or 99.97%) depends on how much filter leakage can be accepted.
Higher filter efficiency means lower filter leakage.
Additional information on selecting the appropriate filter
certified under 42CFR84 can be found at http://www.cdc.gov/NIOSH/userguid.html
Proceed to Step 9.3.
9.3. Respirators that have not been eliminated
from Table 1 by the previous steps and that have APFs equal to, or
greater than, the maximum hazard ratio determined in Step 7 are
recommended. Note, however, that the maximum use concentration (MUC)
is the maximum atmospheric concentration of a hazardous substance
from which an employee can be expected to be protected by a class of
respirator and is determined by the lesser of:
| |
• APF X exposure limit
• The
respirator manufacturer’s MUC for a hazardous substance (if
any) |
1 If the respirator is intended for use in an
oxygen-deficient atmosphere, only SCBA or SAR with an auxiliary
SCBA, can be selected from the Table.
| |
• The IDLH, unless the respirator
is a pressure-demand, full-facepiece SCBA or combination
pressure-demand SAR with a full facepiece in combination with
an auxiliary pressure-demand SCBA. |
For
multi-component mixtures the MUC can be calculated
by:
C1/MUC1 + C2/MUC2
+…Cn/MUCn= 1
| Step 10. Gas/Vapor Respirators
10.1. Is the gas/vapor respirator intended
only for escape?
a. If yes, refer to escape respirators
Section IV (page 17).
b. If no, the gas/vapor respirator is
intended for use during normal work activities. Proceed to
Step 10.2.
10.2. An air-purifying chemical
cartridge/canister respirator is recommended that has a
sorbent suitable for the chemical properties of the
anticipated gas/vapor contaminant(s) and for the anticipated
exposure levels. Information on cartridges or canisters
approved for use for classes of chemicals or for specific
gases or vapors can be found in the NIOSH Certified Equipment
List http://www.cdc.gov/NIOSH/npptl/topics/respirators/cel/.
Proceed to Step 10.3.
10.3. Respirators that have not been
eliminated from Table 2 by the previous steps and that have
APFs equal to, or greater than, the maximum hazard ratio
determined in Step 7 are recommended. Note, however, that the
maximum use concentration (MUC) is the maximum atmospheric
concentration of a hazardous substance from which an employee
can be expected to be protected by a class of respirator and
is determined by the lesser of:
|
|
|
• APF X exposure limit
• The respirator
manufacturer’s MUC for a hazardous substance (if any)
• The
IDLH, unless the respirator is a pressure-demand,
full-facepiece SCBA or combination pressure-demand SAR with a
full facepiece in combination with an auxiliary
pressure-demand SCBA.
|
For multi-component mixtures the MUC can be
calculated by:
C1/MUC1 +
C2/MUC2 +…Cn/MUCn=
1 |
1 If the respirator is intended for use in an oxygen-deficient
atmosphere, only SCBA or SAR with an auxiliary SCBA, can be
selected from the Table.
Step 11.
Combination Particulate and Gas/Vapor Respirators
11.1. Is the combination respirator
intended for "escape only" purposes?
a. If yes, refer to escape respirators on
page 17, for a discussion and selection of "escape only"
respirators.
b. If no, the combination respirator is
intended for use during normal work activities. Proceed to
Step 11.2.
11.2 From Table 3, select a respirator
type, not eliminated by the previous steps, and have APFs
equal to, or greater than, the maximum hazard ratio determined
in Step 7. are recommended. Note, however, that the maximum
use concentration (MUC) is the maximum atmospheric
concentration of a hazardous substance from which an employee
can be expected to be protected by a class of respirator and
is determined by the lesser of: |
|
• APF X exposure limit
• The respirator manufacturer’s
MUC for a hazardous substance (if any)
• The IDLH, unless
the respirator is a pressure-demand, full-facepiece SCBA or
combination pressure-demand SAR with a full facepiece in
combination with an auxiliary pressure-demand SCBA.
|
For multi-component mixtures the MUC can be
calculated by:
C1/MUC1 +
C2/MUC2 +…Cn/MUCn=
1 |
1 If the respirator is intended for use in an
oxygen-deficient atmosphere, only SCBA or SAR with an auxiliary
SCBA, can be selected from the Table.
Table 1. Particulate
Respirators
|
Assigned protection1
factor |
Type of
Respirator |
|
5 |
Quarter mask respirator
|
|
10 |
Any air-purifying elastomeric half-mask respirator
equipped with appropriate type of particulate filter.2
Appropriate filtering facepiece respirator.2,3
Any air-purifying full facepiece respirator equipped with
appropriate type of particulate filter.2
Any negative pressure (demand) supplied-air respirator
equipped with a half-mask.
|
|
25 |
Any powered air-purifying respirator equipped with a
hood or helmet and a high efficiency (HEPA) filter.
Any continuous flow supplied-air respirator equipped with
a hood or helmet.
|
|
50 |
Any air-purifying full facepiece respirator equipped
with N-100, R-100, or P-100 filter(s).
Any powered air-purifying respirator equipped with a
tight-fitting facepiece (half or full facepiece) and a
high-efficiency filter.
Any negative pressure (demand) supplied-air respirator
equipped with a full facepiece.
Any continuous flow supplied-air respirator equipped with
a tight-fitting facepiece (half or full facepiece).
Any negative pressure (demand) self-contained respirator
equipped with a full facepiece.
|
|
1,000 |
Any pressure-demand supplied-air respirator equipped
with a half-mask.
|
|
2,000 |
Any pressure-demand supplied-air respirator equipped
with a full facepiece.
|
|
10,000 |
Any pressure-demand self-contained respirator
equipped with a full facepiece.
Any pressure-demand supplied-air respirator equipped with
a full facepiece in combination with an auxiliary
pressure-demand self-contained breathing
apparatus.
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1 The
protection offered by a given respirator is contingent upon (1) the
respirator user adhering to complete program requirements (such as
the ones required by OSHA in 29CFR1910.134), (2) the use of
NIOSH-certified respirators in their approved configuration, and (3)
individual fit testing to rule out those respirators that cannot
achieve a good fit on individual workers.
2 Appropriate means that the filter medium will provide
protection against the particulate in question. See step 9.2 for
information on the presence or absence of oil particulates.
3 An APF of 10 can only be achieved if the respirator is
qualitatively or quantitatively fit tested on individual
workers.
Table 2. Gas/Vapor
Respirators
|
Assigned protection1
factor |
Type of
Respirator |
|
10 |
Any air-purifying half mask respirator equipped with
appropriate gas/vapor cartridges.2
Any negative pressure (demand) supplied-air respirator
equipped with a half mask.
|
|
25 |
Any powered air-purifying respirator with a
loose-fitting hood or helmet equipped with appropriate
gas/vapor cartridges.2
Any continuous flow supplied-air respirator equipped with
a hood or helmet.
|
|
50 |
Any air-purifying full facepiece respirator equipped
with appropriate gas/vapor cartridges2 or gas
mask (canister respirator).2
Any powered air-purifying respirator equipped with a
tight-fitting facepiece (half or full facepiece) and
appropriate gas/vapor cartridges or
canisters.2
Any negative pressure (demand) supplied-air respirator
equipped with a full facepiece.
Any continuous flow supplied-air respirator equipped with
a tight-fitting facepiece (half or full facepiece).
Any negative pressure (demand) self-contained respirator
equipped with a full facepiece.
|
|
1,000 |
Any pressure-demand supplied-air respirator equipped
with a half-mask.
|
|
2,000 |
Any pressure-demand supplied-air respirator equipped
with a full facepiece.
|
|
10,000 |
Any pressure-demand self-contained respirator
equipped with a full facepiece.
Any pressure-demand supplied-air respirator equipped with
a full facepiece in combination with an auxiliary
pressure-demand self-contained breathing
apparatus.
|
1
The protection offered by a given respirator is contingent upon (1)
the respirator user adhering to complete program requirements (such
as the ones required by OSHA in 29CFR1910.134), (2) the use of
NIOSH-certified respirators in their approved configuration, and (3)
individual fit testing to rule out those respirators that cannot
achieve a good fit on individual workers.
2 Select a cartridge/canister certified to be
used for the specific class of chemicals or the specific gas/vapor
found in your workplace.
Table 3. Combination Gas/Vapor
and Particulate Respirators
|
Assigned protection1
factor |
Type of
Respirator |
|
10 |
Any air-purifying half-mask respirator equipped with
appropriate gas/vapor cartridges2 in combination
with appropriate type of particulate filter.3
Any full facepiece respirator with appropriate gas/vapor
cartridges2 in combination with appropriate type
of particulate filter.3
Any negative pressure (demand) supplied-air respirator
equipped with a half-mask.
|
|
25 |
Any powered air-purifying respirator with a
loose-fitting hood or helmet that is equipped with an
appropriate gas/vapor cartridge2 in combination with a
high-efficiency particulate filter .
Any continuous flow supplied-air respirator equipped with
a hood or helmet.
|
|
50 |
Any air-purifying full facepiece respirator equipped
with appropriate gas/vapor cartridges2 in
combination with an N-100, R-100 or P-100 filter or an
appropriate canister2 incorporating an N-100,
P-100 or R-100 filter.
Any powered air-purifying respirator with a tight-fitting
facepiece (half or full facepiece) equipped with appropriate
gas/vapor cartridges2 in combination with a
high-efficiency filter or an appropriate
canister2 incorporating a high-efficiency
filter.
Any negative pressure (demand) supplied-air respirator
equipped with a full facepiece.
Any continuous flow supplied-air respirator equipped with
a tight-fitting facepiece (half or full facepiece).
Any negative pressure (demand) self-contained respirator
equipped with a full facepiece. |
|
1,000 |
Any pressure-demand supplied-air respirator equipped with
a half-mask. |
|
2,000 |
Any pressure-demand supplied-air respirator equipped with
a full facepiece. |
|
10,000 |
Any pressure-demand self-contained respirator
equipped with a full facepiece.
Any pressure-demand supplied-air respirator equipped with
a full facepiece in combination with an auxiliary
pressure-demand self-contained breathing
apparatus.
|
1
The protection offered by a given respirator is contingent upon (1)
the respirator user adhering to complete program requirements (such
as the ones required by OSHA in 29CFR1910.134), (2) the use of
NIOSH-certified respirators in their approved configuration, and (3)
individual fit testing to rule out those respirators that cannot
achieve a good fit on individual workers.
2 Select a cartridge/canister certified to be
used for the specific class of chemicals or the specific gas/vapor
found in your workplace.
3 Appropriate means that the filter medium will
provide protection against the particulate in question. See step 9.2
for information on the presence or absence of oil
particulates.
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Chapter
III. Respirator Selection Logic Sequence
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