Appendix A to § 1910.134: Fit Testing Procedures
(Mandatory)
Part I. OSHA-Accepted Fit Test
Protocols
A. Fit Testing Procedures -- General
Requirements
The employer shall conduct fit testing using the
following procedures. The requirements in this appendix apply to all
OSHA-accepted fit test methods, both QLFT and QNFT.
1. The test
subject shall be allowed to pick the most acceptable respirator from a
sufficient number of respirator models and sizes so that the respirator is
acceptable to, and correctly fits, the user.
2. Prior to the
selection process, the test subject shall be shown how to put on a
respirator, how it should be positioned on the face, how to set strap
tension and how to determine an acceptable fit. A mirror shall be
available to assist the subject in evaluating the fit and positioning of
the respirator. This instruction may not constitute the subject's formal
training on respirator use, because it is only a review.
3. The
test subject shall be informed that he/she is being asked to select the
respirator that provides the most acceptable fit. Each respirator
represents a different size and shape, and if fitted and used properly,
will provide adequate protection.
4. The test subject shall be
instructed to hold each chosen facepiece up to the face and eliminate
those that obviously do not give an acceptable fit.
5. The more
acceptable facepieces are noted in case the one selected proves
unacceptable; the most comfortable mask is donned and worn at least five
minutes to assess comfort. Assistance in assessing comfort can be given by
discussing the points in the following item A.6. If the test subject is
not familiar with using a particular respirator, the test subject shall be
directed to don the mask several times and to adjust the straps each time
to become adept at setting proper tension on the straps.
6.
Assessment of comfort shall include a review of the following points with
the test subject and allowing the test subject adequate time to determine
the comfort of the respirator:
(a) Position of the mask on the nose
(b) Room for eye protection
(c) Room to talk
(d)
Position of mask on face and cheeks
7. The following criteria shall be used to help
determine the adequacy of the respirator fit:
(a) Chin properly placed;
(b)
Adequate strap tension, not overly tightened;
(c) Fit across nose
bridge;
(d) Respirator of proper size to span distance from nose
to chin;
(e) Tendency of respirator to slip;
(f)
Self-observation in mirror to evaluate fit and respirator
position.
8. The test subject shall conduct a user seal check,
either the negative and positive pressure seal checks described in
Appendix B-1 of this section or those recommended by the respirator
manufacturer which provide equivalent protection to the procedures in
Appendix B-1. Before conducting the negative and positive pressure checks,
the subject shall be told to seat the mask on the face by moving the head
from side-to-side and up and down slowly while taking in a few slow deep
breaths. Another facepiece shall be selected and retested if the test
subject fails the user seal check tests.
9. The test shall not be
conducted if there is any hair growth between the skin and the facepiece
sealing surface, such as stubble beard growth, beard, mustache or
sideburns which cross the respirator sealing surface. Any type of apparel
which interferes with a satisfactory fit shall be altered or removed.
10. If a test subject exhibits difficulty in breathing during the
tests, she or he shall be referred to a physician or other licensed health
care professional, as appropriate, to determine whether the test subject
can wear a respirator while performing her or his duties.
11. If
the employee finds the fit of the respirator unacceptable, the test
subject shall be given the opportunity to select a different respirator
and to be retested.
12. Exercise regimen. Prior to the
commencement of the fit test, the test subject shall be given a
description of the fit test and the test subject's responsibilities during
the test procedure. The description of the process shall include a
description of the test exercises that the subject will be performing. The
respirator to be tested shall be worn for at least 5 minutes before the
start of the fit test.
13. The fit test shall be performed while
the test subject is wearing any applicable safety equipment that may be
worn during actual respirator use which could interfere with respirator
fit.
14. Test Exercises. (a) The following test exercises are to
be performed for all fit testing methods prescribed in this appendix,
except for the CNP method. A separate fit testing exercise regimen is
contained in the CNP protocol. The test subject shall perform exercises,
in the test environment, in the following manner:
(1) Normal breathing. In a normal
standing position, without talking, the subject shall breathe normally.
(2) Deep breathing. In a normal standing position, the subject
shall breathe slowly and deeply, taking caution so as not to
hyperventilate.
(3) Turning head side to side. Standing in place,
the subject shall slowly turn his/her head from side to side between the
extreme positions on each side. The head shall be held at each extreme
momentarily so the subject can inhale at each side.
(4) Moving
head up and down. Standing in place, the subject shall slowly move his/her
head up and down. The subject shall be instructed to inhale in the up
position (i.e., when looking toward the ceiling).
(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.
Rainbow Passage
When
the sunlight strikes raindrops in the air, they act like a prism and form
a rainbow. The rainbow is a division of white light into many beautiful
colors. These take the shape of a long round arch, with its path high
above, and its two ends apparently beyond the horizon. There is, according
to legend, a boiling pot of gold at one end. People look, but no one ever
finds it. When a man looks for something beyond reach, his friends say he
is looking for the pot of gold at the end of the rainbow.
(6)
Grimace. The test subject shall grimace by smiling or frowning. (This
applies only to QNFT testing; it is not performed for QLFT)
(7)
Bending over. The test subject shall bend at the waist as if he/she were
to touch his/her toes. Jogging in place shall be substituted for this
exercise in those test environments such as shroud type QNFT or QLFT units
that do not permit bending over at the waist. (8) Normal breathing. Same
as exercise (1).
(b) Each test exercise shall be performed
for one minute except for the grimace exercise which shall be performed
for 15 seconds. 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.
The respirator shall not be adjusted once the fit test exercises begin.
Any adjustment voids the test, and the fit test must be
repeated.
B. Qualitative Fit Test (QLFT) Protocols
1. General
(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.
C. 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:
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 Dynatech Nevada 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 test subject shall be
trained to hold his or her breath for at least 20 seconds.
(6) The
test subject shall don the test respirator without any assistance from the
individual who conducts the CNP 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 shall have an
effective audio warning device when the test subject fails to hold his or
her breath during the test. The test shall be terminated whenever the test
subject failed to hold his or her breath. The test subject 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.
Part II. New Fit Test Protocols
A. Any person may submit to OSHA an application for approval of a
new fit test protocol. If the application meets the following criteria,
OSHA will initiate a rulemaking proceeding under section 6(b)(7) of the
OSH Act to determine whether to list the new protocol as an approved
protocol in this Appendix A.
B. The application must include a
detailed description of the proposed new fit test protocol. This
application must be supported by either:
1. A test report prepared
by an independent government research laboratory (e.g., Lawrence Livermore
National Laboratory, Los Alamos National Laboratory, the National
Institute for Standards and Technology) stating that the laboratory has
tested the protocol and had found it to be accurate and reliable; or
2. An article that has been published in a peer-reviewed
industrial hygiene journal describing the protocol and explaining how test
data support the protocol's accuracy and reliability.
C. If OSHA
determines that additional information is required before the Agency
commences a rulemaking proceeding under this section, OSHA will so notify
the applicant and afford the applicant the opportunity to submit the
supplemental information. Initiation of a rulemaking proceeding will be
deferred until OSHA has received and evaluated the supplemental
information.
[63 FR 20098, April 23, 1998] |
|