Part I. OSHA-Accepted Fit Test Protocols
(a) The employer shall ensure that persons administering
QLFT are able to prepare test solutions, calibrate equipment
and perform tests properly, recognize invalid tests, and
ensure that test equipment is in proper working order.
(b) The employer shall ensure that QLFT equipment is kept
clean and well maintained so as to operate within the parameters
for which it was designed.
2. Isoamyl Acetate Protocol
Note: This protocol is not appropriate to use for the fit
testing of particulate respirators. If used to fit test
particulate respirators, the respirator must be equipped
with an organic vapor filter.
(a) Odor Threshold Screening
Odor threshold screening, performed without wearing a respirator,
is intended to determine if the individual tested can detect
the odor of isoamyl acetate at low levels.
(1) Three 1 liter glass jars with metal lids are required.
(2) Odor-free water (e.g., distilled or spring water) at
approximately 25 deg. C (77 deg. F) shall be used for the
solutions.
(3) The isoamyl acetate (IAA) (also known at isopentyl
acetate) stock solution is prepared by adding 1 ml of pure
IAA to 800 ml of odor-free water in a 1 liter jar, closing
the lid and shaking for 30 seconds. A new solution shall
be prepared at least weekly.
(4) The screening test shall be conducted in a room separate
from the room used for actual fit testing. The two rooms
shall be well-ventilated to prevent the odor of IAA from
becoming evident in the general room air where testing takes
place.
(5) The odor test solution is prepared in a second jar
by placing 0.4 ml of the stock solution into 500 ml of odor-free
water using a clean dropper or pipette. The solution shall
be shaken for 30 seconds and allowed to stand for two to
three minutes so that the IAA concentration above the liquid
may reach equilibrium. This solution shall be used for only
one day.
(6) A test blank shall be prepared in a third jar by adding
500 cc of odor-free water.
(7) The odor test and test blank jar lids shall be labeled
(e.g., 1 and 2) for jar identification. Labels shall be
placed on the lids so that they can be peeled off periodically
and switched to maintain the integrity of the test.
(8) The following instruction shall be typed on a card
and placed on the table in front of the two test jars (i.e.,
1 and 2): "The purpose of this test is to determine
if you can smell banana oil at a low concentration. The
two bottles in front of you contain water. One of these
bottles also contains a small amount of banana oil. Be sure
the covers are on tight, then shake each bottle for two
seconds. Unscrew the lid of each bottle, one at a time,
and sniff at the mouth of the bottle. Indicate to the test
conductor which bottle contains banana oil."
(9) The mixtures used in the IAA odor detection test shall
be prepared in an area separate from where the test is performed,
in order to prevent olfactory fatigue in the subject.
(10) If the test subject is unable to correctly identify
the jar containing the odor test solution, the IAA qualitative
fit test shall not be performed.
(11) If the test subject correctly identifies the jar containing
the odor test solution, the test subject may proceed to
respirator selection and fit testing.
(b) Isoamyl Acetate Fit Test
(1) The fit test chamber shall be a clear 55-gallon drum
liner suspended inverted over a 2-foot diameter frame so
that the top of the chamber is about 6 inches above the
test subject's head. If no drum liner is available, a similar
chamber shall be constructed using plastic sheeting. The
inside top center of the chamber shall have a small hook
attached.
(2) Each respirator used for the fitting and fit testing
shall be equipped with organic vapor cartridges or offer
protection against organic vapors.
(3) After selecting, donning, and properly adjusting a
respirator, the test subject shall wear it to the fit testing
room. This room shall be separate from the room used for
odor threshold screening and respirator selection, and shall
be well-ventilated, as by an exhaust fan or lab hood, to
prevent general room contamination.
(4) A copy of the test exercises and any prepared text
from which the subject is to read shall be taped to the
inside of the test chamber.
(5) Upon entering the test chamber, the test subject shall
be given a 6-inch by 5-inch piece of paper towel, or other
porous, absorbent, single-ply material, folded in half and
wetted with 0.75 ml of pure IAA. The test subject shall
hang the wet towel on the hook at the top of the chamber.
An IAA test swab or ampule may be substituted for the IAA
wetted paper towel provided it has been demonstrated that
the alternative IAA source will generate an IAA test atmosphere
with a concentration equivalent to that generated by the
paper towel method.
(6) Allow two minutes for the IAA test concentration to
stabilize before starting the fit test exercises. This would
be an appropriate time to talk with the test subject; to
explain the fit test, the importance of his/her cooperation,
and the purpose for the test exercises; or to demonstrate
some of the exercises.
(7) If at any time during the test, the subject detects
the banana-like odor of IAA, the test is failed. The subject
shall quickly exit from the test chamber and leave the test
area to avoid olfactory fatigue.
(8) If the test is failed, the subject shall return to
the selection room and remove the respirator. The test subject
shall repeat the odor sensitivity test, select and put on
another respirator, return to the test area and again begin
the fit test procedure described in (b) (1) through (7)
above. The process continues until a respirator that fits
well has been found. Should the odor sensitivity test be
failed, the subject shall wait at least 5 minutes before
retesting. Odor sensitivity will usually have returned by
this time.
(9) If the subject passes the test, the efficiency of the
test procedure shall be demonstrated by having the subject
break the respirator face seal and take a breath before
exiting the chamber.
(10) When the test subject leaves the chamber, the subject
shall remove the saturated towel and return it to the person
conducting the test, so that there is no significant IAA
concentration buildup in the chamber during subsequent tests.
The used towels shall be kept in a self-sealing plastic
bag to keep the test area from being contaminated.
3. Saccharin Solution Aerosol Protocol
The entire screening and testing procedure shall be explained
to the test subject prior to the conduct of the screening
test.
(a) Taste threshold screening. The saccharin taste threshold
screening, performed without wearing a respirator, is intended
to determine whether the individual being tested can detect
the taste of saccharin.
(1) During threshold screening as well as during fit testing,
subjects shall wear an enclosure about the head and shoulders
that is approximately 12 inches in diameter by 14 inches
tall with at least the front portion clear and that allows
free movements of the head when a respirator is worn. An
enclosure substantially similar to the 3M hood assembly,
parts # FT 14 and # FT 15 combined, is adequate.
(2) The test enclosure shall have a 3/4-inch (1.9 cm) hole
in front of the test subject's nose and mouth area to accommodate
the nebulizer nozzle.
(3) The test subject shall don the test enclosure. Throughout
the threshold screening test, the test subject shall breathe
through his/her slightly open mouth with tongue extended.
The subject is instructed to report when he/she detects
a sweet taste.
(4) Using a DeVilbiss Model 40 Inhalation Medication Nebulizer
or equivalent, the test conductor shall spray the threshold
check solution into the enclosure. The nozzle is directed
away from the nose and mouth of the person. This nebulizer
shall be clearly marked to distinguish it from the fit test
solution nebulizer.
(5) The threshold check solution is prepared by dissolving
0.83 gram of sodium saccharin USP in 100 ml of warm water.
It can be prepared by putting 1 ml of the fit test solution
(see (b)(5) below) in 100 ml of distilled water.
(6) To produce the aerosol, the nebulizer bulb is firmly
squeezed so that it collapses completely, then released
and allowed to fully expand.
(7) Ten squeezes are repeated rapidly and then the test
subject is asked whether the saccharin can be tasted. If
the test subject reports tasting the sweet taste during
the ten squeezes, the screening test is completed. The taste
threshold is noted as ten regardless of the number of squeezes
actually completed.
(8) If the first response is negative, ten more squeezes
are repeated rapidly and the test subject is again asked
whether the saccharin is tasted. If the test subject reports
tasting the sweet taste during the second ten squeezes,
the screening test is completed. The taste threshold is
noted as twenty regardless of the number of squeezes actually
completed.
(9) If the second response is negative, ten more squeezes
are repeated rapidly and the test subject is again asked
whether the saccharin is tasted. If the test subject reports
tasting the sweet taste during the third set of ten squeezes,
the screening test is completed. The taste threshold is
noted as thirty regardless of the number of squeezes actually
completed.
(10) The test conductor will take note of the number of
squeezes required to solicit a taste response.
(11) If the saccharin is not tasted after 30 squeezes (step
10), the test subject is unable to taste saccharin and may
not perform the saccharin fit test.
Note to paragraph 3. (a): If the test subject eats or drinks
something sweet before the screening test, he/she may be
unable to taste the weak saccharin solution.
(12) If a taste response is elicited, the test subject
shall be asked to take note of the taste for reference in
the fit test.
(13) Correct use of the nebulizer means that approximately
1 ml of liquid is used at a time in the nebulizer body.
(14) The nebulizer shall be thoroughly rinsed in water,
shaken dry, and refilled at least each morning and afternoon
or at least every four hours.
(b) Saccharin solution aerosol fit test procedure.
(1) The test subject may not eat, drink (except plain water),
smoke, or chew gum for 15 minutes before the test.
(2) The fit test uses the same enclosure described in 3.
(a) above.
(3) The test subject shall don the enclosure while wearing
the respirator selected in section I. A. of this appendix.
The respirator shall be properly adjusted and equipped with
a particulate filter(s).
(4) A second DeVilbiss Model 40 Inhalation Medication Nebulizer
or equivalent is used to spray the fit test solution into
the enclosure. This nebulizer shall be clearly marked to
distinguish it from the screening test solution nebulizer.
(5) The fit test solution is prepared by adding 83 grams
of sodium saccharin to 100 ml of warm water.
(6) As before, the test subject shall breathe through the
slightly open mouth with tongue extended, and report if
he/she tastes the sweet taste of saccharin.
(7) The nebulizer is inserted into the hole in the front
of the enclosure and an initial concentration of saccharin
fit test solution is sprayed into the enclosure using the
same number of squeezes (either 10, 20 or 30 squeezes) based
on the number of squeezes required to elicit a taste response
as noted during the screening test. A minimum of 10 squeezes
is required.
(8) After generating the aerosol, the test subject shall
be instructed to perform the exercises in section I. A.
14. of this appendix.
(9) Every 30 seconds the aerosol concentration shall be
replenished using one half the original number of squeezes
used initially (e.g., 5, 10 or 15).
(10) The test subject shall indicate to the test conductor
if at any time during the fit test the taste of saccharin
is detected. If the test subject does not report tasting
the saccharin, the test is passed.
(11) If the taste of saccharin is detected, the fit is
deemed unsatisfactory and the test is failed. A different
respirator shall be tried and the entire test procedure
is repeated (taste threshold screening and fit testing).
(12) Since the nebulizer has a tendency to clog during
use, the test operator must make periodic checks of the
nebulizer to ensure that it is not clogged. If clogging
is found at the end of the test session, the test is invalid.
4. BitrexTM (Denatonium Benzoate) Solution Aerosol Qualitative
Fit Test Protocol
The BitrexTM (Denatonium benzoate) solution aerosol QLFT
protocol uses the published saccharin test protocol because
that protocol is widely accepted. Bitrex is routinely used
as a taste aversion agent in household liquids which children
should not be drinking and is endorsed by the American Medical
Association, the National Safety Council, and the American
Association of Poison Control Centers. The entire screening
and testing procedure shall be explained to the test subject
prior to the conduct of the screening test.
(a) Taste Threshold Screening.
The Bitrex taste threshold screening, performed without
wearing a respirator, is intended to determine whether the
individual being tested can detect the taste of Bitrex.
(1) During threshold screening as well as during fit testing,
subjects shall wear an enclosure about the head and shoulders
that is approximately 12 inches (30.5 cm) in diameter by
14 inches (35.6 cm) tall. The front portion of the enclosure
shall be clear from the respirator and allow free movement
of the head when a respirator is worn. An enclosure substantially
similar to the 3M hood assembly, parts # FT 14 and # FT
15 combined, is adequate.
(2) The test enclosure shall have a \3/4\ inch (1.9 cm)
hole in front of the test subject's nose and mouth area
to accommodate the nebulizer nozzle.
(3) The test subject shall don the test enclosure. Throughout
the threshold screening test, the test subject shall breathe
through his or her slightly open mouth with tongue extended.
The subject is instructed to report when he/she detects
a bitter taste
(4) Using a DeVilbiss Model 40 Inhalation Medication Nebulizer
or equivalent, the test conductor shall spray the Threshold
Check Solution into the enclosure. This Nebulizer shall
be clearly marked to distinguish it from the fit test solution
nebulizer.
(5) The Threshold Check Solution is prepared by adding
13.5 milligrams of Bitrex to 100 ml of 5% salt (NaCl) solution
in distilled water.
(6) To produce the aerosol, the nebulizer bulb is firmly
squeezed so that the bulb collapses completely, and is then
released and allowed to fully expand.
(7) An initial ten squeezes are repeated rapidly and then
the test subject is asked whether the Bitrex can be tasted.
If the test subject reports tasting the bitter taste during
the ten squeezes, the screening test is completed. The taste
threshold is noted as ten regardless of the number of squeezes
actually completed.
(8) If the first response is negative, ten more squeezes
are repeated rapidly and the test subject is again asked
whether the Bitrex is tasted. If the test subject reports
tasting the bitter taste during the second ten squeezes,
the screening test is completed. The taste threshold is
noted as twenty regardless of the number of squeezes actually
completed.
(9) If the second response is negative, ten more squeezes
are repeated rapidly and the test subject is again asked
whether the Bitrex is tasted. If the test subject reports
tasting the bitter taste during the third set of ten squeezes,
the screening test is completed. The taste threshold is
noted as thirty regardless of the number of squeezes actually
completed.
(10) The test conductor will take note of the number of
squeezes required to solicit a taste response.
(11) If the Bitrex is not tasted after 30 squeezes (step
10), the test subject is unable to taste Bitrex and may
not perform the Bitrex fit test.
(12) If a taste response is elicited, the test subject
shall be asked to take note of the taste for reference in
the fit test.
(13) Correct use of the nebulizer means that approximately
1 ml of liquid is used at a time in the nebulizer body.
(14) The nebulizer shall be thoroughly rinsed in water,
shaken to dry, and refilled at least each morning and afternoon
or at least every four hours.
(b) Bitrex Solution Aerosol Fit Test Procedure.
(1) The test subject may not eat, drink (except plain water),
smoke, or chew gum for 15 minutes before the test.
(2) The fit test uses the same enclosure as that described
in 4. (a) above.
(3) The test subject shall don the enclosure while wearing
the respirator selected according to section I. A. of this
appendix. The respirator shall be properly adjusted and
equipped with any type particulate filter(s).
(4) A second DeVilbiss Model 40 Inhalation Medication Nebulizer
or equivalent is used to spray the fit test solution into
the enclosure. This nebulizer shall be clearly marked to
distinguish it from the screening test solution nebulizer.
(5) The fit test solution is prepared by adding 337.5 mg
of Bitrex to 200 ml of a 5% salt (NaCl) solution in warm
water.
(6) As before, the test subject shall breathe through his
or her slightly open mouth with tongue extended, and be
instructed to report if he/she tastes the bitter taste of
Bitrex.
(7) The nebulizer is inserted into the hole in the front
of the enclosure and an initial concentration of the fit
test solution is sprayed into the enclosure using the same
number of squeezes (either 10, 20 or 30 squeezes) based
on the number of squeezes required to elicit a taste response
as noted during the screening test.
(8) After generating the aerosol, the test subject shall
be instructed to perform the exercises in section I. A.
14. Of this appendix.
(9) Every 30 seconds the aerosol concentration shall be
replenished using one half the number of squeezes used initially
(e.g., 5, 10 or 15).
(10) The test subject shall indicate to the test conductor
if at any time during the fit test the taste of Bitrex is
detected. If the test subject does not report tasting the
Bitrex, the test is passed.
(11) If the taste of Bitrex is detected, the fit is deemed
unsatisfactory and the test is failed. A different respirator
shall be tried and the entire test procedure is repeated
(taste threshold screening and fit testing).
5. Irritant Smoke (Stannic Chloride) Protocol
This qualitative fit test uses a person's response to the
irritating chemicals released in the "smoke" produced
by a stannic chloride ventilation smoke tube to detect leakage
into the respirator.
(a) General Requirements and Precautions
(1) The respirator to be tested shall be equipped with
high efficiency particulate air (HEPA) or P100 series filter(s).
(2) Only stannic chloride smoke tubes shall be used for
this protocol.
(3) No form of test enclosure or hood for the test subject
shall be used.
(4) The smoke can be irritating to the eyes, lungs, and
nasal passages. The test conductor shall take precautions
to minimize the test subject's exposure to irritant smoke.
Sensitivity varies, and certain individuals may respond
to a greater degree to irritant smoke. Care shall be taken
when performing the sensitivity screening checks that determine
whether the test subject can detect irritant smoke to use
only the minimum amount of smoke necessary to elicit a response
from the test subject.
(5) The fit test shall be performed in an area with adequate
ventilation to prevent exposure of the person conducting
the fit test or the build-up of irritant smoke in the general
atmosphere.
(b) Sensitivity Screening Check
The person to be tested must demonstrate his or her ability
to detect a weak concentration of the irritant smoke.
(1) The test operator shall break both ends of a ventilation
smoke tube containing stannic chloride, and attach one end
of the smoke tube to a low flow air pump set to deliver
200 milliliters per minute, or an aspirator squeeze bulb.
The test operator shall cover the other end of the smoke
tube with a short piece of tubing to prevent potential injury
from the jagged end of the smoke tube.
(2) The test operator shall advise the test subject that
the smoke can be irritating to the eyes, lungs, and nasal
passages and instruct the subject to keep his/her eyes closed
while the test is performed.
(3) The test subject shall be allowed to smell a weak concentration
of the irritant smoke before the respirator is donned to
become familiar with its irritating properties and to determine
if he/she can detect the irritating properties of the smoke.
The test operator shall carefully direct a small amount
of the irritant smoke in the test subject's direction to
determine that he/she can detect it.
(c) Irritant Smoke Fit Test Procedure
(1) The person being fit tested shall don the respirator
without assistance, and perform the required user seal check(s).
(2) The test subject shall be instructed to keep his/her
eyes closed.
(3) The test operator shall direct the stream of irritant
smoke from the smoke tube toward the faceseal area of the
test subject, using the low flow pump or the squeeze bulb.
The test operator shall begin at least 12 inches from the
facepiece and move the smoke stream around the whole perimeter
of the mask. The operator shall gradually make two more
passes around the perimeter of the mask, moving to within
six inches of the respirator.
(4) If the person being tested has not had an involuntary
response and/or detected the irritant smoke, proceed with
the test exercises.
(5) The exercises identified in section I.A. 14. of this
appendix shall be performed by the test subject while the
respirator seal is being continually challenged by the smoke,
directed around the perimeter of the respirator at a distance
of six inches.
(6) If the person being fit tested reports detecting the
irritant smoke at any time, the test is failed. The person
being retested must repeat the entire sensitivity check
and fit test procedure.
(7) Each test subject passing the irritant smoke test without
evidence of a response (involuntary cough, irritation) shall
be given a second sensitivity screening check, with the
smoke from the same smoke tube used during the fit test,
once the respirator has been removed, to determine whether
he/she still reacts to the smoke. Failure to evoke a response
shall void the fit test.
(8) If a response is produced during this second sensitivity
check, then the fit test is passed.
Top
- Quantitative Fit Test
(QNFT) Protocols
The following quantitative fit testing procedures have
been demonstrated to be acceptable: Quantitative fit testing
using a non-hazardous test aerosol (such as corn oil,
polyethylene glycol 400 [PEG 400], di-2-ethyl hexyl sebacate
[DEHS], or sodium chloride) generated in a test chamber,
and employing instrumentation to quantify the fit of the
respirator; Quantitative fit testing using ambient aerosol
as the test agent and appropriate instrumentation (condensation
nuclei counter) to quantify the respirator fit; Quantitative
fit testing using controlled negative pressure and appropriate
instrumentation to measure the volumetric leak rate of
a facepiece to quantify the respirator fit.
1. General
(a) The employer shall ensure that persons administering
QNFT are able to calibrate equipment and perform tests
properly, recognize invalid tests, calculate fit factors
properly and ensure that test equipment is in proper working
order.
(b) The employer shall ensure that QNFT equipment is
kept clean, and is maintained and calibrated according
to the manufacturer's instructions so as to operate at
the parameters for which it was designed.
2. Generated Aerosol Quantitative Fit Testing Protocol
(a) Apparatus.
(1) Instrumentation. Aerosol generation, dilution, and
measurement systems using particulates (corn oil, polyethylene
glycol 400 [PEG 400], DI-2-ethyl hexyl sebacate [DEHS]
or sodium chloride) as test aerosols shall be used for
quantitative fit testing.
(2) Test chamber. The test chamber shall be large enough
to permit all test subjects to perform freely all required
exercises without disturbing the test agent concentration
or the measurement apparatus. The test chamber shall be
equipped and constructed so that the test agent is effectively
isolated from the ambient air, yet uniform in concentration
throughout the chamber.
(3) When testing air-purifying respirators, the normal
filter or cartridge element shall be replaced with a high
efficiency particulate air (HEPA) or P100 series filter
supplied by the same manufacturer.
(4) The sampling instrument shall be selected so that
a computer record or strip chart record may be made of
the test showing the rise and fall of the test agent concentration
with each inspiration and expiration at fit factors of
at least 2,000. Integrators or computers that integrate
the amount of test agent penetration leakage into the
respirator for each exercise may be used provided a record
of the readings is made.
(5) The combination of substitute air-purifying elements,
test agent and test agent concentration shall be such
that the test subject is not exposed in excess of an established
exposure limit for the test agent at any time during the
testing process, based upon the length of the exposure
and the exposure limit duration.
(6) The sampling port on the test specimen respirator
shall be placed and constructed so that no leakage occurs
around the port (e.g., where the respirator is probed),
a free air flow is allowed into the sampling line at all
times, and there is no interference with the fit or performance
of the respirator. The in-mask sampling device (probe)
shall be designed and used so that the air sample is drawn
from the breathing zone of the test subject, midway between
the nose and mouth and with the probe extending into the
facepiece cavity at least 1/4 inch.
(7) The test setup shall permit the person administering
the test to observe the test subject inside the chamber
during the test.
(8) The equipment generating the test atmosphere shall
maintain the concentration of test agent constant to within
a 10 percent variation for the duration of the test.
(9) The time lag (interval between an event and the recording
of the event on the strip chart or computer or integrator)
shall be kept to a minimum. There shall be a clear association
between the occurrence of an event and its being recorded.
(10) The sampling line tubing for the test chamber atmosphere
and for the respirator sampling port shall be of equal
diameter and of the same material. The length of the two
lines shall be equal.
(11) The exhaust flow from the test chamber shall pass
through an appropriate filter (i.e., high efficiency particulate
filter) before release.
(12) When sodium chloride aerosol is used, the relative
humidity inside the test chamber shall not exceed 50 percent.
(13) The limitations of instrument detection shall be
taken into account when determining the fit factor.
(14) Test respirators shall be maintained in proper working
order and be inspected regularly for deficiencies such
as cracks or missing valves and gaskets.
(b) Procedural Requirements.
(1) When performing the initial user seal check using
a positive or negative pressure check, the sampling line
shall be crimped closed in order to avoid air pressure
leakage during either of these pressure checks.
(2) The use of an abbreviated screening QLFT test is
optional. Such a test may be utilized in order to quickly
identify poor fitting respirators that passed the positive
and/or negative pressure test and reduce the amount of
QNFT time. The use of the CNC QNFT instrument in the count
mode is another optional method to obtain a quick estimate
of fit and eliminate poor fitting respirators before going
on to perform a full QNFT.
(3) A reasonably stable test agent concentration shall
be measured in the test chamber prior to testing. For
canopy or shower curtain types of test units, the determination
of the test agent's stability may be established after
the test subject has entered the test environment.
(4) Immediately after the subject enters the test chamber,
the test agent concentration inside the respirator shall
be measured to ensure that the peak penetration does not
exceed 5 percent for a half mask or 1 percent for a full
facepiece respirator.
(5) A stable test agent concentration shall be obtained
prior to the actual start of testing.
(6) Respirator restraining straps shall not be over-tightened
for testing. The straps shall be adjusted by the wearer
without assistance from other persons to give a reasonably
comfortable fit typical of normal use. The respirator
shall not be adjusted once the fit test exercises begin.
(7) The test shall be terminated whenever any single
peak penetration exceeds 5 percent for half masks and
1 percent for full facepiece respirators. The test subject
shall be refitted and retested.
(8) Calculation of fit factors.
(i) The fit factor shall be determined for the quantitative
fit test by taking the ratio of the average chamber concentration
to the concentration measured inside the respirator for
each test exercise except the grimace exercise.
(ii) The average test chamber concentration shall be
calculated as the arithmetic average of the concentration
measured before and after each test (i.e., 7 exercises)
or the arithmetic average of the concentration measured
before and after each exercise or the true average measured
continuously during the respirator sample.
(iii) The concentration of the challenge agent inside
the respirator shall be determined by one of the following
methods:
(A) Average peak penetration method means the method
of determining test agent penetration into the respirator
utilizing a strip chart recorder, integrator, or computer.
The agent penetration is determined by an average of the
peak heights on the graph or by computer integration,
for each exercise except the grimace exercise. Integrators
or computers that calculate the actual test agent penetration
into the respirator for each exercise will also be considered
to meet the requirements of the average peak penetration
method.
(B) Maximum peak penetration method means the method
of determining test agent penetration in the respirator
as determined by strip chart recordings of the test. The
highest peak penetration for a given exercise is taken
to be representative of average penetration into the respirator
for that exercise.
(C) Integration by calculation of the area under the
individual peak for each exercise except the grimace exercise.
This includes computerized integration.
(D) The calculation of the overall fit factor using individual
exercise fit factors involves first converting the exercise
fit factors to penetration values, determining the average,
and then converting that result back to a fit factor.
This procedure is described in the following equation:
Overall Fit Factor = Number of exercises÷
(1/ff1 + 1/ff2 + ... +1/ffn)
Where ff1, ff2, ff3, etc. are the fit factors for exercises
1, 2, 3, etc.
(9) The test subject shall not be permitted to wear a
half mask or quarter facepiece respirator unless a minimum
fit factor of 100 is obtained, or a full facepiece respirator
unless a minimum fit factor of 500 is obtained.
(10) Filters used for quantitative fit testing shall
be replaced whenever increased breathing resistance is
encountered, or when the test agent has altered the integrity
of the filter media.
3. Ambient aerosol condensation nuclei counter (CNC) quantitative
fit testing protocol.
The ambient aerosol condensation nuclei counter (CNC)
quantitative fit testing (Portacount TM ) protocol quantitatively
fit tests respirators with the use of a probe. The probed
respirator is only used for quantitative fit tests. A
probed respirator has a special sampling device, installed
on the respirator, that allows the probe to sample the
air from inside the mask. A probed respirator is required
for each make, style, model, and size that the employer
uses and can be obtained from the respirator manufacturer
or distributor. The CNC instrument manufacturer, TSI Inc.,
also provides probe attachments (TSI sampling adapters)
that permit fit testing in an employee's own respirator.
A minimum fit factor pass level of at least 100 is necessary
for a half-mask respirator and a minimum fit factor pass
level of at least 500 is required for a full facepiece
negative pressure respirator. The entire screening and
testing procedure shall be explained to the test subject
prior to the conduct of the screening test.
(a) Portacount Fit Test Requirements.
(1) Check the respirator to make sure the sampling probe
and line are properly attached to the facepiece and that
the respirator is fitted with a particulate filter capable
of preventing significant penetration by the ambient particles
used for the fit test (e.g., NIOSH 42 CFR 84 series 100,
series 99, or series 95 particulate filter) per manufacturer's
instruction.
(2) Instruct the person to be tested to don the respirator
for five minutes before the fit test starts. This purges
the ambient particles trapped inside the respirator and
permits the wearer to make certain the respirator is comfortable.
This individual shall already have been trained on how
to wear the respirator properly.
(3) Check the following conditions for the adequacy of
the respirator fit: Chin properly placed; Adequate strap
tension, not overly tightened; Fit across nose bridge;
Respirator of proper size to span distance from nose to
chin; Tendency of the respirator to slip; Self-observation
in a mirror to evaluate fit and respirator position.
(4) Have the person wearing the respirator do a user
seal check. If leakage is detected, determine the cause.
If leakage is from a poorly fitting facepiece, try another
size of the same model respirator, or another model of
respirator.
(5) Follow the manufacturer's instructions for operating
the Portacount and proceed with the test.
(6) The test subject shall be instructed to perform the
exercises in section I. A. 14. Of this appendix.
(7) After the test exercises, the test subject shall
be questioned by the test conductor regarding the comfort
of the respirator upon completion of the protocol. If
it has become unacceptable, another model of respirator
shall be tried.
(b) Portacount Test Instrument.
(1) The Portacount will automatically stop and calculate
the overall fit factor for the entire set of exercises.
The overall fit factor is what counts. The Pass or Fail
message will indicate whether or not the test was successful.
If the test was a Pass, the fit test is over.
(2) Since the pass or fail criterion of the Portacount
is user programmable, the test operator shall ensure that
the pass or fail criterion meet the requirements for minimum
respirator performance in this Appendix.
(3) A record of the test needs to be kept on file, assuming
the fit test was successful. The record must contain the
test subject's name; overall fit factor; make, model,
style, and size of respirator used; and date tested.
4. Controlled negative pressure (CNP) quantitative fit
testing protocol.
The CNP protocol provides an alternative to aerosol fit
test methods. The CNP fit test method technology is based
on exhausting air from a temporarily sealed respirator
facepiece to generate and then maintain a constant negative
pressure inside the facepiece. The rate of air exhaust
is controlled so that a constant negative pressure is
maintained in the respirator during the fit test. The
level of pressure is selected to replicate the mean inspiratory
pressure that causes leakage into the respirator under
normal use conditions. With pressure held constant, air
flow out of the respirator is equal to air flow into the
respirator. Therefore, measurement of the exhaust stream
that is required to hold the pressure in the temporarily
sealed respirator constant yields a direct measure of
leakage air flow into the respirator. The CNP fit test
method measures leak rates through the facepiece as a
method for determining the facepiece fit for negative
pressure respirators. The CNP instrument manufacturer
Occupational Health Dynamics of Birmingham, Alabama also
provides attachments (sampling manifolds) that replace
the filter cartridges to permit fit testing in an employee's
own respirator. To perform the test, the test subject
closes his or her mouth and holds his/her breath, after
which an air pump removes air from the respirator facepiece
at a pre-selected constant pressure. The facepiece fit
is expressed as the leak rate through the facepiece, expressed
as milliliters per minute. The quality and validity of
the CNP fit tests are determined by the degree to which
the in-mask pressure tracks the test pressure during the
system measurement time of approximately five seconds.
Instantaneous feedback in the form of a real-time pressure
trace of the in-mask pressure is provided and used to
determine test validity and quality. A minimum fit factor
pass level of 100 is necessary for a half-mask respirator
and a minimum fit factor of at least 500 is required for
a full facepiece respirator. The entire screening and
testing procedure shall be explained to the test subject
prior to the conduct of the screening test.
(a) CNP Fit Test Requirements.
(1) The instrument shall have a non-adjustable test pressure
of 15.0 mm water pressure.
(2) The CNP system defaults selected for test pressure
shall be set at -- 15 mm of water (-0.58 inches of water)
and the modeled inspiratory flow rate shall be 53.8 liters
per minute for performing fit tests.
(Note: CNP systems have built-in capability to conduct
fit testing that is specific to unique work rate, mask,
and gender situations that might apply in a specific workplace.
Use of system default values, which were selected to represent
respirator wear with medium cartridge resistance at a
low-moderate work rate, will allow inter-test comparison
of the respirator fit.)
(3) The individual who conducts the CNP fit testing shall
be thoroughly trained to perform the test.
(4) The respirator filter or cartridge needs to be replaced
with the CNP test manifold. The inhalation valve downstream
from the manifold either needs to be temporarily removed
or propped open.
(5) The employer must train the test subject to hold
his or her breath for at least 10 seconds.
(6) The test subject must don the test respirator without
any assistance from the test administrator who is conducting
the CNP fit test. The respirator must not be adjusted
once the fit-test exercises begin. Any adjustment voids
the test, and the test subject must repeat the fit test.
(7) The QNFT protocol shall be followed according to
section I. C. 1. of this appendix with an exception for
the CNP test exercises.
(b) CNP Test Exercises.
(1) Normal breathing. In a normal standing position,
without talking, the subject shall breathe normally for
1 minute. After the normal breathing exercise, the subject
needs to hold head straight ahead and hold his or her
breath for 10 seconds during the test measurement.
(2) Deep breathing. In a normal standing position, the
subject shall breathe slowly and deeply for 1 minute,
being careful not to hyperventilate. After the deep breathing
exercise, the subject shall hold his or her head straight
ahead and hold his or her breath for 10 seconds during
test measurement.
(3) Turning head side to side. Standing in place, the
subject shall slowly turn his or her head from side to
side between the extreme positions on each side for 1
minute. The head shall be held at each extreme momentarily
so the subject can inhale at each side. After the turning
head side to side exercise, the subject needs to hold
head full left and hold his or her breath for 10 seconds
during test measurement. Next, the subject needs to hold
head full right and hold his or her breath for 10 seconds
during test measurement.
(4) Moving head up and down. Standing in place, the subject
shall slowly move his or her head up and down for 1 minute.
The subject shall be instructed to inhale in the up position
(i.e., when looking toward the ceiling). After the moving
head up and down exercise, the subject shall hold his
or her head full up and hold his or her breath for 10
seconds during test measurement. Next, the subject shall
hold his or her head full down and hold his or her breath
for 10 seconds during test measurement.
(5) Talking. The subject shall talk out loud slowly and
loud enough so as to be heard clearly by the test conductor.
The subject can read from a prepared text such as the
Rainbow Passage, count backward from 100, or recite a
memorized poem or song for 1 minute. After the talking
exercise, the subject shall hold his or her head straight
ahead and hold his or her breath for 10 seconds during
the test measurement.
(6) Grimace. The test subject shall grimace by smiling
or frowning for 15 seconds.
(7) Bending Over. The test subject shall bend at the
waist as if he or she were to touch his or her toes for
1 minute. Jogging in place shall be substituted for this
exercise in those test environments such as shroud-type
QNFT units that prohibit bending at the waist. After the
bending over exercise, the subject shall hold his or her
head straight ahead and hold his or her breath for 10
seconds during the test measurement.
(8) Normal Breathing. The test subject shall remove and
re-don the respirator within a one-minute period. Then,
in a normal standing position, without talking, the subject
shall breathe normally for 1 minute. After the normal
breathing exercise, the subject shall hold his or her
head straight ahead and hold his or her breath for 10
seconds during the test measurement. After the test exercises,
the test subject shall be questioned by the test conductor
regarding the comfort of the respirator upon completion
of the protocol. If it has become unacceptable, another
model of a respirator shall be tried.
(c) CNP Test Instrument.
(1) The test instrument must have an effective audio-warning
device, or a visual-warning device in the form of a screen
tracing, that indicates when the test subject fails to
hold his or her breath during the test. The test must
be terminated and restarted from the beginning when the
test subject fails to hold his or her breath during the
test. The test subject then may be refitted and retested.
(2) A record of the test shall be kept on file, assuming
the fit test was successful. The record must contain the
test subject's name; overall fit factor; make, model,
style and size of respirator used; and date tested.
5. Controlled negative pressure (CNP) REDON quantitative
fit testing protocol.
(a) When administering this protocol to test subjects,
employers must comply with the requirements specified
in paragraphs (a) and (c) of Part I.C.4 of this appendix
("Controlled negative pressure (CNP) quantitative
fit testing protocol"), as well as use the test exercises
described below in paragraph (b) of this protocol instead
of the test exercises specified in paragraph (b) of Part
I.C.4 of this appendix.
(b) Employers must ensure that each test subject being
fit tested using this protocol follows the exercise
and measurement procedures, including the order of administration,
described below in Table A-1 of this appendix.
Table A-1. -- CNP REDON Quantitative Fit Testing Protocol
Exercises(1) |
Exercise Procedure |
Measurement Procedure |
Facing Forward |
Stand and breathe normally, without
talking, for 30 seconds. |
Face forward, while holding breath for
10 seconds. |
Bending Over |
Bend at the waist, as if going to touch
his or her toes, for 30 seconds. |
Face parallel to the floor, while holding
breath for 10 seconds |
Head Shaking |
For about three seconds, shake head
back and forth vigorously several times while shouting. |
Face forward, while holding breath for
10 seconds. |
REDON 1 |
Remove the respirator mask, loosen all
facepiece straps, and then redon the respirator mask. |
Face forward, while holding breath for
10 seconds. |
REDON 2 |
Remove the respirator mask, loosen all
facepiece straps, and then redon the respirator mask
again. |
Face forward, while holding breath for
10 seconds. |
1 Exercises are listed in the order in which they are
to be administered.
(c) After completing the test exercises, the test administrator
must question each test subject regarding the comfort
of the respirator. When a test subject states that the
respirator is unacceptable, the employer must ensure that
the test administrator repeats the protocol using another
respirator model.
(d) Employers must determine the overall fit factor for
each test subject by calculating the harmonic mean of
the fit testing exercises as follows:
Overall Fit Factor = N ÷ [1/FF1 + 1/FF2 +...+ 1/FFn]
Where:
N = The number of exercises;
FF1 = The fit factor for the first exercise;
FF2 = The fit factor for the second exercise; and
FFN = The fit factor for the nth exercise.
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