Respiratory Protection (29 CFR 1910.134)

Title 29: Labor
PART 1910—OCCUPATIONAL SAFETY AND HEALTH STANDARDS
Subpart I—Personal Protective Equipment
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§ 1910.134 Respiratory protection.
This section applies to General Industry (part 1910), Shipyards (part 1915), Marine Terminals (part 1917), Longshoring (part
1918), and Construction (part 1926).
(a) Permissible practice. (1) In the control of those occupational diseases caused by breathing air contaminated with harmful
dusts, fogs, fumes, mists, gases, smokes, sprays, or vapors, the primary objective shall be to prevent atmospheric contamination.
This shall be accomplished as far as feasible by accepted engineering control measures (for example, enclosure or confinement
of the operation, general and local ventilation, and substitution of less toxic materials). When effective engineering controls are not
feasible, or while they are being instituted, appropriate respirators shall be used pursuant to this section.
(2) A respirator shall be provided to each employee when such equipment is necessary to protect the health of such employee.
The employer shall provide the respirators which are applicable and suitable for the purpose intended. The employer shall be
responsible for the establishment and maintenance of a respiratory protection program, which shall include the requirements
outlined in paragraph (c) of this section. The program shall cover each employee required by this section to use a respirator.
(b) Definitions. The following definitions are important terms used in the respiratory protection standard in this section.
Air-purifying respirator means a respirator with an air-purifying filter, cartridge, or canister that removes specific air contaminants
by passing ambient air through the air-purifying element.
Assigned protection factor (APF) means the workplace level of respiratory protection that a respirator or class of respirators is
expected to provide to employees when the employer implements a continuing, effective respiratory protection program as
specified by this section.
Atmosphere-supplying respirator means a respirator that supplies the respirator user with breathing air from a source independent
of the ambient atmosphere, and includes supplied-air respirators (SARs) and self-contained breathing apparatus (SCBA) units.
Canister or cartridge means a container with a filter, sorbent, or catalyst, or combination of these items, which removes specific
contaminants from the air passed through the container.
Demand respirator means an atmosphere-supplying respirator that admits breathing air to the facepiece only when a negative
pressure is created inside the facepiece by inhalation.
Emergency situation means any occurrence such as, but not limited to, equipment failure, rupture of containers, or failure of
control equipment that may or does result in an uncontrolled significant release of an airborne contaminant.
Employee exposure means exposure to a concentration of an airborne contaminant that would occur if the employee were not
using respiratory protection.
End-of-service-life indicator (ESLI) means a system that warns the respirator user of the approach of the end of adequate
respiratory protection, for example, that the sorbent is approaching saturation or is no longer effective.
Escape-only respirator means a respirator intended to be used only for emergency exit.

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Filter or air purifying element means a component used in respirators to remove solid or liquid aerosols from the inspired air.
Filtering facepiece (dust mask) means a negative pressure particulate respirator with a filter as an integral part of the facepiece or
with the entire facepiece composed of the filtering medium.
Fit factor means a quantitative estimate of the fit of a particular respirator to a specific individual, and typically estimates the ratio
of the concentration of a substance in ambient air to its concentration inside the respirator when worn.
Fit test means the use of a protocol to qualitatively or quantitatively evaluate the fit of a respirator on an individual. (See also
Qualitative fit test QLFT and Quantitative fit test QNFT.)
Helmet means a rigid respiratory inlet covering that also provides head protection against impact and penetration.
High efficiency particulate air (HEPA) filter means a filter that is at least 99.97% efficient in removing monodisperse particles of
0.3 micrometers in diameter. The equivalent NIOSH 42 CFR 84 particulate filters are the N100, R100, and P100 filters.
Hood means a respiratory inlet covering that completely covers the head and neck and may also cover portions of the shoulders
and torso.
Immediately dangerous to life or health (IDLH) means an atmosphere that poses an immediate threat to life, would cause
irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere.
Interior structural firefighting means the physical activity of fire suppression, rescue or both, inside of buildings or enclosed
structures which are involved in a fire situation beyond the incipient stage. (See 29 CFR 1910.155)
Loose-fitting facepiece means a respiratory inlet covering that is designed to form a partial seal with the face.
Maximum use concentration (MUC) means the maximum atmospheric concentration of a hazardous substance from which an
employee can be expected to be protected when wearing a respirator, and is determined by the assigned protection factor of the
respirator or class of respirators and the exposure limit of the hazardous substance. The MUC can be determined mathematically
by multiplying the assigned protection factor specified for a respirator by the required OSHA permissible exposure limit, short-term
exposure limit, or ceiling limit. When no OSHA exposure limit is available for a hazardous substance, an employer must determine
an MUC on the basis of relevant available information and informed professional judgment.
Negative pressure respirator (tight fitting) means a respirator in which the air pressure inside the facepiece is negative during
inhalation with respect to the ambient air pressure outside the respirator.
Oxygen deficient atmosphere means an atmosphere with an oxygen content below 19.5% by volume.
Physician or other licensed health care professional (PLHCP) means an individual whose legally permitted scope of practice ( i.e.,
license, registration, or certification) allows him or her to independently provide, or be delegated the responsibility to provide,
some or all of the health care services required by paragraph (e) of this section.
Positive pressure respirator means a respirator in which the pressure inside the respiratory inlet covering exceeds the ambient air
pressure outside the respirator.
Powered air-purifying respirator (PAPR) means an air-purifying respirator that uses a blower to force the ambient air through airpurifying elements to the inlet covering.
Pressure demand respirator means a positive pressure atmosphere-supplying respirator that admits breathing air to the facepiece
when the positive pressure is reduced inside the facepiece by inhalation.
Qualitative fit test (QLFT) means a pass/fail fit test to assess the adequacy of respirator fit that relies on the individual's response
to the test agent.

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Quantitative fit test (QNFT) means an assessment of the adequacy of respirator fit by numerically measuring the amount of
leakage into the respirator.
Respiratory inlet covering means that portion of a respirator that forms the protective barrier between the user's respiratory tract
and an air-purifying device or breathing air source, or both. It may be a facepiece, helmet, hood, suit, or a mouthpiece respirator
with nose clamp.
Self-contained breathing apparatus (SCBA) means an atmosphere-supplying respirator for which the breathing air source is
designed to be carried by the user.
Service life means the period of time that a respirator, filter or sorbent, or other respiratory equipment provides adequate
protection to the wearer.
Supplied-air respirator (SAR) or airline respirator means an atmosphere-supplying respirator for which the source of breathing air
is not designed to be carried by the user.
This section means this respiratory protection standard.
Tight-fitting facepiece means a respiratory inlet covering that forms a complete seal with the face.
User seal check means an action conducted by the respirator user to determine if the respirator is properly seated to the face.
(c) Respiratory protection program. This paragraph requires the employer to develop and implement a written respiratory
protection program with required worksite-specific procedures and elements for required respirator use. The program must be
administered by a suitably trained program administrator. In addition, certain program elements may be required for voluntary use
to prevent potential hazards associated with the use of the respirator. The Small Entity Compliance Guide contains criteria for the
selection of a program administrator and a sample program that meets the requirements of this paragraph. Copies of the Small
Entity Compliance Guide will be available on or about April 8, 1998 from the Occupational Safety and Health Administration's
Office of Publications, Room N 3101, 200 Constitution Avenue, NW, Washington, DC, 20210 (202–219–4667).
(1) In any workplace where respirators are necessary to protect the health of the employee or whenever respirators are required
by the employer, the employer shall establish and implement a written respiratory protection program with worksite-specific
procedures. The program shall be updated as necessary to reflect those changes in workplace conditions that affect respirator
use. The employer shall include in the program the following provisions of this section, as applicable:
(i) Procedures for selecting respirators for use in the workplace;
(ii) Medical evaluations of employees required to use respirators;
(iii) Fit testing procedures for tight-fitting respirators;
(iv) Procedures for proper use of respirators in routine and reasonably foreseeable emergency situations;
(v) Procedures and schedules for cleaning, disinfecting, storing, inspecting, repairing, discarding, and otherwise maintaining
respirators;
(vi) Procedures to ensure adequate air quality, quantity, and flow of breathing air for atmosphere-supplying respirators;
(vii) Training of employees in the respiratory hazards to which they are potentially exposed during routine and emergency
situations;
(viii) Training of employees in the proper use of respirators, including putting on and removing them, any limitations on their use,
and their maintenance; and

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(ix) Procedures for regularly evaluating the effectiveness of the program.
(2) Where respirator use is not required:
(i) An employer may provide respirators at the request of employees or permit employees to use their own respirators, if the
employer determines that such respirator use will not in itself create a hazard. If the employer determines that any voluntary
respirator use is permissible, the employer shall provide the respirator users with the information contained in appendix D to this
section (“Information for Employees Using Respirators When Not Required Under the Standard”); and
(ii) In addition, the employer must establish and implement those elements of a written respiratory protection program necessary
to ensure that any employee using a respirator voluntarily is medically able to use that respirator, and that the respirator is
cleaned, stored, and maintained so that its use does not present a health hazard to the user. Exception: Employers are not
required to include in a written respiratory protection program those employees whose only use of respirators involves the
voluntary use of filtering facepieces (dust masks).
(3) The employer shall designate a program administrator who is qualified by appropriate training or experience that is
commensurate with the complexity of the program to administer or oversee the respiratory protection program and conduct the
required evaluations of program effectiveness.
(4) The employer shall provide respirators, training, and medical evaluations at no cost to the employee.
(d) Selection of respirators. This paragraph requires the employer to evaluate respiratory hazard(s) in the workplace, identify
relevant workplace and user factors, and base respirator selection on these factors. The paragraph also specifies appropriately
protective respirators for use in IDLH atmospheres, and limits the selection and use of air-purifying respirators.
(1) General requirements. (i) The employer shall select and provide an appropriate respirator based on the respiratory hazard(s)
to which the worker is exposed and workplace and user factors that affect respirator performance and reliability.
(ii) The employer shall select a NIOSH-certified respirator. The respirator shall be used in compliance with the conditions of its
certification.
(iii) The employer shall identify and evaluate the respiratory hazard(s) in the workplace; this evaluation shall include a reasonable
estimate of employee exposures to respiratory hazard(s) and an identification of the contaminant's chemical state and physical
form. Where the employer cannot identify or reasonably estimate the employee exposure, the employer shall consider the
atmosphere to be IDLH.
(iv) The employer shall select respirators from a sufficient number of respirator models and sizes so that the respirator is
acceptable to, and correctly fits, the user.
(2) Respirators for IDLH atmospheres. (i) The employer shall provide the following respirators for employee use in IDLH
atmospheres:
(A) A full facepiece pressure demand SCBA certified by NIOSH for a minimum service life of thirty minutes, or
(B) A combination full facepiece pressure demand supplied-air respirator (SAR) with auxiliary self-contained air supply.
(ii) Respirators provided only for escape from IDLH atmospheres shall be NIOSH-certified for escape from the atmosphere in
which they will be used.
(iii) All oxygen-deficient atmospheres shall be considered IDLH. Exception: If the employer demonstrates that, under all
foreseeable conditions, the oxygen concentration can be maintained within the ranges specified in Table II of this section (i.e., for
the altitudes set out in the table), then any atmosphere-supplying respirator may be used.
(3) Respirators for atmospheres that are not IDLH. (i) The employer shall provide a respirator that is adequate to protect the
health of the employee and ensure compliance with all other OSHA statutory and regulatory requirements, under routine and

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reasonably foreseeable emergency situations.
(A) Assigned Protection Factors (APFs). Employers must use the assigned protection factors listed in Table 1 to select a
respirator that meets or exceeds the required level of employee protection. When using a combination respirator (e.g., airline
respirators with an air-purifying filter), employers must ensure that the assigned protection factor is appropriate to the mode of
operation in which the respirator is being used.
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Table 1—Assigned Protection Factors

Type of respirator1,2

Quarter
mask

1. Air-Purifying Respirator

5

Half
Full
Loose-fitting
mask facepiece Helmet/hood facepiece
3

10

50

50

1,000

• Demand mode

10

50

• Continuous flow mode

50

1,000

• Pressure-demand or other positivepressure mode

50

1,000

10

50

50

10,000

10,000

2. Powered Air-Purifying Respirator (PAPR)

4

25/1,000

25

4

25/1,000

25

3. Supplied-Air Respirator (SAR) or Airline
Respirator

4. Self-Contained Breathing Apparatus
(SCBA)
• Demand mode
• Pressure-demand or other positivepressure mode (e.g., open/closed
circuit)
Notes:
1

Employers may select respirators assigned for use in higher workplace concentrations of a hazardous substance for use at lower
concentrations of that substance, or when required respirator use is independent of concentration.

2

The assigned protection factors in Table 1 are only effective when the employer implements a continuing, effective respirator
program as required by this section (29 CFR 1910.134), including training, fit testing, maintenance, and use requirements.

3

This APF category includes filtering facepieces, and half masks with elastomeric facepieces.

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The employer must have evidence provided by the respirator manufacturer that testing of these respirators demonstrates
performance at a level of protection of 1,000 or greater to receive an APF of 1,000. This level of performance can best be
demonstrated by performing a WPF or SWPF study or equivalent testing. Absent such testing, all other PAPRs and SARs with
helmets/hoods are to be treated as loose-fitting facepiece respirators, and receive an APF of 25.
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These APFs do not apply to respirators used solely for escape. For escape respirators used in association with specific
substances covered by 29 CFR 1910 subpart Z, employers must refer to the appropriate substance-specific standards in that
subpart. Escape respirators for other IDLH atmospheres are specified by 29 CFR 1910.134 (d)(2)(ii).

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(B) Maximum Use Concentration (MUC). ( 1 ) The employer must select a respirator for employee use that maintains the
employee's exposure to the hazardous substance, when measured outside the respirator, at or below the MUC.
( 2 ) Employers must not apply MUCs to conditions that are immediately dangerous to life or health (IDLH); instead, they must use
respirators listed for IDLH conditions in paragraph (d)(2) of this standard.
( 3 ) When the calculated MUC exceeds the IDLH level for a hazardous substance, or the performance limits of the cartridge or
canister, then employers must set the maximum MUC at that lower limit.
(ii) The respirator selected shall be appropriate for the chemical state and physical form of the contaminant.
(iii) For protection against gases and vapors, the employer shall provide:
(A) An atmosphere-supplying respirator, or
(B) An air-purifying respirator, provided that:
( 1 ) The respirator is equipped with an end-of-service-life indicator (ESLI) certified by NIOSH for the contaminant; or
( 2 ) If there is no ESLI appropriate for conditions in the employer's workplace, the employer implements a change schedule for
canisters and cartridges that is based on objective information or data that will ensure that canisters and cartridges are changed
before the end of their service life. The employer shall describe in the respirator program the information and data relied upon and
the basis for the canister and cartridge change schedule and the basis for reliance on the data.
(iv) For protection against particulates, the employer shall provide:
(A) An atmosphere-supplying respirator; or
(B) An air-purifying respirator equipped with a filter certified by NIOSH under 30 CFR part 11 as a high efficiency particulate air
(HEPA) filter, or an air-purifying respirator equipped with a filter certified for particulates by NIOSH under 42 CFR part 84; or
(C) For contaminants consisting primarily of particles with mass median aerodynamic diameters (MMAD) of at least 2
micrometers, an air-purifying respirator equipped with any filter certified for particulates by NIOSH.
Table I—Assigned Protection Factors
Table II

Altitude (ft.)
Less than
3,001

Oxygen deficient Atmospheres (% 02) for which the employer may rely on atmospheresupplying respirators
16.0–19.5

3,001–4,000 16.4–19.5
4,001–5,000 17.1–19.5
5,001–6,000 17.8–19.5
6,001–7,000 18.5–19.5
7,001–8,0001 19.3–19.5.

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1

Above 8,000 feet the exception does not apply. Oxygen-enriched breathing air must be supplied above 14,000 feet.

(e) Medical evaluation. Using a respirator may place a physiological burden on employees that varies with the type of respirator
worn, the job and workplace conditions in which the respirator is used, and the medical status of the employee. Accordingly, this
paragraph specifies the minimum requirements for medical evaluation that employers must implement to determine the
employee's ability to use a respirator.
(1) General. The employer shall provide a medical evaluation to determine the employee's ability to use a respirator, before the
employee is fit tested or required to use the respirator in the workplace. The employer may discontinue an employee's medical
evaluations when the employee is no longer required to use a respirator.
(2) Medical evaluation procedures. (i) The employer shall identify a physician or other licensed health care professional (PLHCP)
to perform medical evaluations using a medical questionnaire or an initial medical examination that obtains the same information
as the medical questionnaire.
(ii) The medical evaluation shall obtain the information requested by the questionnaire in Sections 1 and 2, part A of appendix C of
this section.
(3) Follow-up medical examination. (i) The employer shall ensure that a follow-up medical examination is provided for an
employee who gives a positive response to any question among questions 1 through 8 in Section 2, part A of appendix C or
whose initial medical examination demonstrates the need for a follow-up medical examination.
(ii) The follow-up medical examination shall include any medical tests, consultations, or diagnostic procedures that the PLHCP
deems necessary to make a final determination.
(4) Administration of the medical questionnaire and examinations. (i) The medical questionnaire and examinations shall be
administered confidentially during the employee's normal working hours or at a time and place convenient to the employee. The
medical questionnaire shall be administered in a manner that ensures that the employee understands its content.
(ii) The employer shall provide the employee with an opportunity to discuss the questionnaire and examination results with the
PLHCP.
(5) Supplemental information for the PLHCP. (i) The following information must be provided to the PLHCP before the PLHCP
makes a recommendation concerning an employee's ability to use a respirator:
(A) The type and weight of the respirator to be used by the employee;
(B) The duration and frequency of respirator use (including use for rescue and escape);
(C) The expected physical work effort;
(D) Additional protective clothing and equipment to be worn; and
(E) Temperature and humidity extremes that may be encountered.
(ii) Any supplemental information provided previously to the PLHCP regarding an employee need not be provided for a
subsequent medical evaluation if the information and the PLHCP remain the same.
(iii) The employer shall provide the PLHCP with a copy of the written respiratory protection program and a copy of this section.

Note to paragraph (e)(5)(iii): When the employer replaces a PLHCP, the employer must ensure that the new PLHCP
obtains this information, either by providing the documents directly to the PLHCP or having the documents
transferred from the former PLHCP to the new PLHCP. However, OSHA does not expect employers to have

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employees medically reevaluated solely because a new PLHCP has been selected.
(6) Medical determination. In determining the employee's ability to use a respirator, the employer shall:
(i) Obtain a written recommendation regarding the employee's ability to use the respirator from the PLHCP. The recommendation
shall provide only the following information:
(A) Any limitations on respirator use related to the medical condition of the employee, or relating to the workplace conditions in
which the respirator will be used, including whether or not the employee is medically able to use the respirator;
(B) The need, if any, for follow-up medical evaluations; and
(C) A statement that the PLHCP has provided the employee with a copy of the PLHCP's written recommendation.
(ii) If the respirator is a negative pressure respirator and the PLHCP finds a medical condition that may place the employee's
health at increased risk if the respirator is used, the employer shall provide a PAPR if the PLHCP's medical evaluation finds that
the employee can use such a respirator; if a subsequent medical evaluation finds that the employee is medically able to use a
negative pressure respirator, then the employer is no longer required to provide a PAPR.
(7) Additional medical evaluations. At a minimum, the employer shall provide additional medical evaluations that comply with the
requirements of this section if:
(i) An employee reports medical signs or symptoms that are related to ability to use a respirator;
(ii) A PLHCP, supervisor, or the respirator program administrator informs the employer that an employee needs to be reevaluated;
(iii) Information from the respiratory protection program, including observations made during fit testing and program evaluation,
indicates a need for employee reevaluation; or
(iv) A change occurs in workplace conditions (e.g., physical work effort, protective clothing, temperature) that may result in a
substantial increase in the physiological burden placed on an employee.
(f) Fit testing. This paragraph requires that, before an employee may be required to use any respirator with a negative or positive
pressure tight-fitting facepiece, the employee must be fit tested with the same make, model, style, and size of respirator that will
be used. This paragraph specifies the kinds of fit tests allowed, the procedures for conducting them, and how the results of the fit
tests must be used.
(1) The employer shall ensure that employees using a tight-fitting facepiece respirator pass an appropriate qualitative fit test
(QLFT) or quantitative fit test (QNFT) as stated in this paragraph.
(2) The employer shall ensure that an employee using a tight-fitting facepiece respirator is fit tested prior to initial use of the
respirator, whenever a different respirator facepiece (size, style, model or make) is used, and at least annually thereafter.
(3) The employer shall conduct an additional fit test whenever the employee reports, or the employer, PLHCP, supervisor, or
program administrator makes visual observations of, changes in the employee's physical condition that could affect respirator fit.
Such conditions include, but are not limited to, facial scarring, dental changes, cosmetic surgery, or an obvious change in body
weight.
(4) If after passing a QLFT or QNFT, the employee subsequently notifies the employer, program administrator, supervisor, or
PLHCP that the fit of the respirator is unacceptable, the employee shall be given a reasonable opportunity to select a different
respirator facepiece and to be retested.
(5) The fit test shall be administered using an OSHA-accepted QLFT or QNFT protocol. The OSHA-accepted QLFT and QNFT
protocols and procedures are contained in appendix A of this section.

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(6) QLFT may only be used to fit test negative pressure air-purifying respirators that must achieve a fit factor of 100 or less.
(7) If the fit factor, as determined through an OSHA-accepted QNFT protocol, is equal to or greater than 100 for tight-fitting half
facepieces, or equal to or greater than 500 for tight-fitting full facepieces, the QNFT has been passed with that respirator.
(8) Fit testing of tight-fitting atmosphere-supplying respirators and tight-fitting powered air-purifying respirators shall be
accomplished by performing quantitative or qualitative fit testing in the negative pressure mode, regardless of the mode of
operation (negative or positive pressure) that is used for respiratory protection.
(i) Qualitative fit testing of these respirators shall be accomplished by temporarily converting the respirator user's actual facepiece
into a negative pressure respirator with appropriate filters, or by using an identical negative pressure air-purifying respirator
facepiece with the same sealing surfaces as a surrogate for the atmosphere-supplying or powered air-purifying respirator
facepiece.
(ii) Quantitative fit testing of these respirators shall be accomplished by modifying the facepiece to allow sampling inside the
facepiece in the breathing zone of the user, midway between the nose and mouth. This requirement shall be accomplished by
installing a permanent sampling probe onto a surrogate facepiece, or by using a sampling adapter designed to temporarily provide
a means of sampling air from inside the facepiece.
(iii) Any modifications to the respirator facepiece for fit testing shall be completely removed, and the facepiece restored to NIOSHapproved configuration, before that facepiece can be used in the workplace.
(g) Use of respirators. This paragraph requires employers to establish and implement procedures for the proper use of respirators.
These requirements include prohibiting conditions that may result in facepiece seal leakage, preventing employees from removing
respirators in hazardous environments, taking actions to ensure continued effective respirator operation throughout the work shift,
and establishing procedures for the use of respirators in IDLH atmospheres or in interior structural firefighting situations.
(1) Facepiece seal protection. (i) The employer shall not permit respirators with tight-fitting facepieces to be worn by employees
who have:
(A) Facial hair that comes between the sealing surface of the facepiece and the face or that interferes with valve function; or
(B) Any condition that interferes with the face-to-facepiece seal or valve function.
(ii) If an employee wears corrective glasses or goggles or other personal protective equipment, the employer shall ensure that
such equipment is worn in a manner that does not interfere with the seal of the facepiece to the face of the user.
(iii) For all tight-fitting respirators, the employer shall ensure that employees perform a user seal check each time they put on the
respirator using the procedures in appendix B–1 or procedures recommended by the respirator manufacturer that the employer
demonstrates are as effective as those in appendix B–1 of this section.
(2) Continuing respirator effectiveness. (i) Appropriate surveillance shall be maintained of work area conditions and degree of
employee exposure or stress. When there is a change in work area conditions or degree of employee exposure or stress that may
affect respirator effectiveness, the employer shall reevaluate the continued effectiveness of the respirator.
(ii) The employer shall ensure that employees leave the respirator use area:
(A) To wash their faces and respirator facepieces as necessary to prevent eye or skin irritation associated with respirator use; or
(B) If they detect vapor or gas breakthrough, changes in breathing resistance, or leakage of the facepiece; or
(C) To replace the respirator or the filter, cartridge, or canister elements.
(iii) If the employee detects vapor or gas breakthrough, changes in breathing resistance, or leakage of the facepiece, the

9

employer must replace or repair the respirator before allowing the employee to return to the work area.
(3) Procedures for IDLH atmospheres. For all IDLH atmospheres, the employer shall ensure that:
(i) One employee or, when needed, more than one employee is located outside the IDLH atmosphere;
(ii) Visual, voice, or signal line communication is maintained between the employee(s) in the IDLH atmosphere and the
employee(s) located outside the IDLH atmosphere;
(iii) The employee(s) located outside the IDLH atmosphere are trained and equipped to provide effective emergency rescue;
(iv) The employer or designee is notified before the employee(s) located outside the IDLH atmosphere enter the IDLH atmosphere
to provide emergency rescue;
(v) The employer or designee authorized to do so by the employer, once notified, provides necessary assistance appropriate to
the situation;
(vi) Employee(s) located outside the IDLH atmospheres are equipped with:
(A) Pressure demand or other positive pressure SCBAs, or a pressure demand or other positive pressure supplied-air respirator
with auxiliary SCBA; and either
(B) Appropriate retrieval equipment for removing the employee(s) who enter(s) these hazardous atmospheres where retrieval
equipment would contribute to the rescue of the employee(s) and would not increase the overall risk resulting from entry; or
(C) Equivalent means for rescue where retrieval equipment is not required under paragraph (g)(3)(vi)(B).
(4) Procedures for interior structural firefighting. In addition to the requirements set forth under paragraph (g)(3), in interior
structural fires, the employer shall ensure that:
(i) At least two employees enter the IDLH atmosphere and remain in visual or voice contact with one another at all times;
(ii) At least two employees are located outside the IDLH atmosphere; and
(iii) All employees engaged in interior structural firefighting use SCBAs.

Note 1 to paragraph (g): One of the two individuals located outside the IDLH atmosphere may be assigned to an
additional role, such as incident commander in charge of the emergency or safety officer, so long as this individual is
able to perform assistance or rescue activities without jeopardizing the safety or health of any firefighter working at
the incident.
Note 2 to paragraph (g): Nothing in this section is meant to preclude firefighters from performing emergency rescue
activities before an entire team has assembled.
(h) Maintenance and care of respirators. This paragraph requires the employer to provide for the cleaning and disinfecting,
storage, inspection, and repair of respirators used by employees.
(1) Cleaning and disinfecting. The employer shall provide each respirator user with a respirator that is clean, sanitary, and in good
working order. The employer shall ensure that respirators are cleaned and disinfected using the procedures in appendix B–2 of
this section, or procedures recommended by the respirator manufacturer, provided that such procedures are of equivalent
effectiveness. The respirators shall be cleaned and disinfected at the following intervals:
(i) Respirators issued for the exclusive use of an employee shall be cleaned and disinfected as often as necessary to be

10

maintained in a sanitary condition;
(ii) Respirators issued to more than one employee shall be cleaned and disinfected before being worn by different individuals;
(iii) Respirators maintained for emergency use shall be cleaned and disinfected after each use; and
(iv) Respirators used in fit testing and training shall be cleaned and disinfected after each use.
(2) Storage. The employer shall ensure that respirators are stored as follows:
(i) All respirators shall be stored to protect them from damage, contamination, dust, sunlight, extreme temperatures, excessive
moisture, and damaging chemicals, and they shall be packed or stored to prevent deformation of the facepiece and exhalation
valve.
(ii) In addition to the requirements of paragraph (h)(2)(i) of this section, emergency respirators shall be:
(A) Kept accessible to the work area;
(B) Stored in compartments or in covers that are clearly marked as containing emergency respirators; and
(C) Stored in accordance with any applicable manufacturer instructions.
(3) Inspection. (i) The employer shall ensure that respirators are inspected as follows:
(A) All respirators used in routine situations shall be inspected before each use and during cleaning;
(B) All respirators maintained for use in emergency situations shall be inspected at least monthly and in accordance with the
manufacturer's recommendations, and shall be checked for proper function before and after each use; and
(C) Emergency escape-only respirators shall be inspected before being carried into the workplace for use.
(ii) The employer shall ensure that respirator inspections include the following:
(A) A check of respirator function, tightness of connections, and the condition of the various parts including, but not limited to, the
facepiece, head straps, valves, connecting tube, and cartridges, canisters or filters; and
(B) A check of elastomeric parts for pliability and signs of deterioration.
(iii) In addition to the requirements of paragraphs (h)(3)(i) and (ii) of this section, self-contained breathing apparatus shall be
inspected monthly. Air and oxygen cylinders shall be maintained in a fully charged state and shall be recharged when the
pressure falls to 90% of the manufacturer's recommended pressure level. The employer shall determine that the regulator and
warning devices function properly.
(iv) For respirators maintained for emergency use, the employer shall:
(A) Certify the respirator by documenting the date the inspection was performed, the name (or signature) of the person who made
the inspection, the findings, required remedial action, and a serial number or other means of identifying the inspected respirator;
and
(B) Provide this information on a tag or label that is attached to the storage compartment for the respirator, is kept with the
respirator, or is included in inspection reports stored as paper or electronic files. This information shall be maintained until
replaced following a subsequent certification.
(4) Repairs. The employer shall ensure that respirators that fail an inspection or are otherwise found to be defective are removed

11

from service, and are discarded or repaired or adjusted in accordance with the following procedures:
(i) Repairs or adjustments to respirators are to be made only by persons appropriately trained to perform such operations and
shall use only the respirator manufacturer's NIOSH-approved parts designed for the respirator;
(ii) Repairs shall be made according to the manufacturer's recommendations and specifications for the type and extent of repairs
to be performed; and
(iii) Reducing and admission valves, regulators, and alarms shall be adjusted or repaired only by the manufacturer or a technician
trained by the manufacturer.
(i) Breathing air quality and use. This paragraph requires the employer to provide employees using atmosphere-supplying
respirators (supplied-air and SCBA) with breathing gases of high purity.
(1) The employer shall ensure that compressed air, compressed oxygen, liquid air, and liquid oxygen used for respiration accords
with the following specifications:
(i) Compressed and liquid oxygen shall meet the United States Pharmacopoeia requirements for medical or breathing oxygen;
and
(ii) Compressed breathing air shall meet at least the requirements for Grade D breathing air described in ANSI/Compressed Gas
Association Commodity Specification for Air, G–7.1–1989, to include:
(A) Oxygen content (v/v) of 19.5–23.5%;
(B) Hydrocarbon (condensed) content of 5 milligrams per cubic meter of air or less;
(C) Carbon monoxide (CO) content of 10 ppm or less;
(D) Carbon dioxide content of 1,000 ppm or less; and
(E) Lack of noticeable odor.
(2) The employer shall ensure that compressed oxygen is not used in atmosphere-supplying respirators that have previously used
compressed air.
(3) The employer shall ensure that oxygen concentrations greater than 23.5% are used only in equipment designed for oxygen
service or distribution.
(4) The employer shall ensure that cylinders used to supply breathing air to respirators meet the following requirements:
(i) Cylinders are tested and maintained as prescribed in the Shipping Container Specification Regulations of the Department of
Transportation (49 CFR part 180);
(ii) Cylinders of purchased breathing air have a certificate of analysis from the supplier that the breathing air meets the
requirements for Grade D breathing air; and
(iii) The moisture content in the cylinder does not exceed a dew point of −50 °F (−45.6 °C) at 1 atmosphere pressure.
(5) The employer shall ensure that compressors used to supply breathing air to respirators are constructed and situated so as to:
(i) Prevent entry of contaminated air into the air-supply system;
(ii) Minimize moisture content so that the dew point at 1 atmosphere pressure is 10 degrees F (5.56 °C) below the ambient

12

temperature;
(iii) Have suitable in-line air-purifying sorbent beds and filters to further ensure breathing air quality. Sorbent beds and filters shall
be maintained and replaced or refurbished periodically following the manufacturer's instructions.
(iv) Have a tag containing the most recent change date and the signature of the person authorized by the employer to perform the
change. The tag shall be maintained at the compressor.
(6) For compressors that are not oil-lubricated, the employer shall ensure that carbon monoxide levels in the breathing air do not
exceed 10 ppm.
(7) For oil-lubricated compressors, the employer shall use a high-temperature or carbon monoxide alarm, or both, to monitor
carbon monoxide levels. If only high-temperature alarms are used, the air supply shall be monitored at intervals sufficient to
prevent carbon monoxide in the breathing air from exceeding 10 ppm.
(8) The employer shall ensure that breathing air couplings are incompatible with outlets for nonrespirable worksite air or other gas
systems. No asphyxiating substance shall be introduced into breathing air lines.
(9) The employer shall use only the respirator manufacturer's NIOSH-approved breathing-gas containers, marked and maintained
in accordance with the Quality Assurance provisions of the NIOSH approval for the SCBA as issued in accordance with the
NIOSH respirator-certification standard at 42 CFR part 84.
(j) Identification of filters, cartridges, and canisters. The employer shall ensure that all filters, cartridges and canisters used in the
workplace are labeled and color coded with the NIOSH approval label and that the label is not removed and remains legible.
(k) Training and information. This paragraph requires the employer to provide effective training to employees who are required to
use respirators. The training must be comprehensive, understandable, and recur annually, and more often if necessary. This
paragraph also requires the employer to provide the basic information on respirators in appendix D of this section to employees
who wear respirators when not required by this section or by the employer to do so.
(1) The employer shall ensure that each employee can demonstrate knowledge of at least the following:
(i) Why the respirator is necessary and how improper fit, usage, or maintenance can compromise the protective effect of the
respirator;
(ii) What the limitations and capabilities of the respirator are;
(iii) How to use the respirator effectively in emergency situations, including situations in which the respirator malfunctions;
(iv) How to inspect, put on and remove, use, and check the seals of the respirator;
(v) What the procedures are for maintenance and storage of the respirator;
(vi) How to recognize medical signs and symptoms that may limit or prevent the effective use of respirators; and
(vii) The general requirements of this section.
(2) The training shall be conducted in a manner that is understandable to the employee.
(3) The employer shall provide the training prior to requiring the employee to use a respirator in the workplace.
(4) An employer who is able to demonstrate that a new employee has received training within the last 12 months that addresses
the elements specified in paragraph (k)(1)(i) through (vii) is not required to repeat such training provided that, as required by
paragraph (k)(1), the employee can demonstrate knowledge of those element(s). Previous training not repeated initially by the

13

employer must be provided no later than 12 months from the date of the previous training.
(5) Retraining shall be administered annually, and when the following situations occur:
(i) Changes in the workplace or the type of respirator render previous training obsolete;
(ii) Inadequacies in the employee's knowledge or use of the respirator indicate that the employee has not retained the requisite
understanding or skill; or
(iii) Any other situation arises in which retraining appears necessary to ensure safe respirator use.
(6) The basic advisory information on respirators, as presented in appendix D of this section, shall be provided by the employer in
any written or oral format, to employees who wear respirators when such use is not required by this section or by the employer.
(l) Program evaluation. This section requires the employer to conduct evaluations of the workplace to ensure that the written
respiratory protection program is being properly implemented, and to consult employees to ensure that they are using the
respirators properly.
(1) The employer shall conduct evaluations of the workplace as necessary to ensure that the provisions of the current written
program are being effectively implemented and that it continues to be effective.
(2) The employer shall regularly consult employees required to use respirators to assess the employees' views on program
effectiveness and to identify any problems. Any problems that are identified during this assessment shall be corrected. Factors to
be assessed include, but are not limited to:
(i) Respirator fit (including the ability to use the respirator without interfering with effective workplace performance);
(ii) Appropriate respirator selection for the hazards to which the employee is exposed;
(iii) Proper respirator use under the workplace conditions the employee encounters; and
(iv) Proper respirator maintenance.
(m) Recordkeeping. This section requires the employer to establish and retain written information regarding medical evaluations,
fit testing, and the respirator program. This information will facilitate employee involvement in the respirator program, assist the
employer in auditing the adequacy of the program, and provide a record for compliance determinations by OSHA.
(1) Medical evaluation. Records of medical evaluations required by this section must be retained and made available in
accordance with 29 CFR 1910.1020.
(2) Fit testing. (i) The employer shall establish a record of the qualitative and quantitative fit tests administered to an employee
including:
(A) The name or identification of the employee tested;
(B) Type of fit test performed;
(C) Specific make, model, style, and size of respirator tested;
(D) Date of test; and
(E) The pass/fail results for QLFTs or the fit factor and strip chart recording or other recording of the test results for QNFTs.

14

(ii) Fit test records shall be retained for respirator users until the next fit test is administered.
(3) A written copy of the current respirator program shall be retained by the employer.
(4) Written materials required to be retained under this paragraph shall be made available upon request to affected employees
and to the Assistant Secretary or designee for examination and copying.
(n) Effective date. Paragraphs (d)(3)(i)(A) and (d)(3)(i)(B) of this section become effective November 22, 2006.
(o) Appendices. Compliance with Appendix A, Appendix B–1, Appendix B–2, Appendix C, and Appendix D to this section are
mandatory.

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

15

(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) Employers must perform the following test exercises for all fit testing methods prescribed in
this appendix, except for the CNP quantitative fit testing protocol and the CNP REDON quantitative fit testing
protocol. For these two protocols, employers must ensure that the test subjects ( i.e. , employees) perform the
exercise procedure specified in part I.C.4(b) of this appendix for the CNP quantitative fit testing protocol, or the
exercise procedure described in part I.C.5(b) of this appendix for the CNP REDON quantitative fit-testing protocol.
For the remaining fit testing methods, employers must ensure that employees perform the test exercises in the
appropriate test environment in the following manner:

16

(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.

17

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 °C (77 °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

18

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

19

assembly, parts # FT 14 and # FT 15 combined, is adequate.
(2) The test enclosure shall have a3/4-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.

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(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.
TM

4. Bitrex

(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

21

enclosure substantially similar to the 3M hood assembly, parts # FT 14 and # FT 15 combined, is adequate.
(2) The test enclosure shall have a3/4inch (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.

22

(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

23

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

24

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.

25

(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

26

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 (PortacountTM ) 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.

27

(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.

28

(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.

29

(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

Exercises1

Exercise procedure

Measurement procedure

Facing
Forward

Stand and breathe normally, without talking, for 30
seconds

Bending
Over

Bend at the waist, as if going to touch his or her toes, Face parallel to the floor, while
for 30 seconds
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.

30

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:

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.
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.
Appendix B–1 to §1910.134: User Seal Check Procedures (Mandatory)
The individual who uses a tight-fitting respirator is to perform a user seal check to ensure that an adequate seal is
achieved each time the respirator is put on. Either the positive and negative pressure checks listed in this appendix,
or the respirator manufacturer's recommended user seal check method shall be used. User seal checks are not

31

substitutes for qualitative or quantitative fit tests.
I. Facepiece Positive and/or Negative Pressure Checks
A. Positive pressure check. Close off the exhalation valve and exhale gently into the facepiece. The face fit is
considered satisfactory if a slight positive pressure can be built up inside the facepiece without any evidence of
outward leakage of air at the seal. For most respirators this method of leak testing requires the wearer to first remove
the exhalation valve cover before closing off the exhalation valve and then carefully replacing it after the test.
B. Negative pressure check. Close off the inlet opening of the canister or cartridge(s) by covering with the palm of the
hand(s) or by replacing the filter seal(s), inhale gently so that the facepiece collapses slightly, and hold the breath for
ten seconds. The design of the inlet opening of some cartridges cannot be effectively covered with the palm of the
hand. The test can be performed by covering the inlet opening of the cartridge with a thin latex or nitrile glove. If the
facepiece remains in its slightly collapsed condition and no inward leakage of air is detected, the tightness of the
respirator is considered satisfactory.
II. Manufacturer's Recommended User Seal Check Procedures
The respirator manufacturer's recommended procedures for performing a user seal check may be used instead of
the positive and/or negative pressure check procedures provided that the employer demonstrates that the
manufacturer's procedures are equally effective.
Appendix B–2 to §1910.134: Respirator Cleaning Procedures (Mandatory)
These procedures are provided for employer use when cleaning respirators. They are general in nature, and the
employer as an alternative may use the cleaning recommendations provided by the manufacturer of the respirators
used by their employees, provided such procedures are as effective as those listed here in appendix B–2. Equivalent
effectiveness simply means that the procedures used must accomplish the objectives set forth in appendix B–2, i.e.,
must ensure that the respirator is properly cleaned and disinfected in a manner that prevents damage to the
respirator and does not cause harm to the user.
I. Procedures for Cleaning Respirators
A. Remove filters, cartridges, or canisters. Disassemble facepieces by removing speaking diaphragms, demand and
pressure-demand valve assemblies, hoses, or any components recommended by the manufacturer. Discard or
repair any defective parts.
B. Wash components in warm (43 °C [110 °F] maximum) water with a mild detergent or with a cleaner recommended
by the manufacturer. A stiff bristle (not wire) brush may be used to facilitate the removal of dirt.
C. Rinse components thoroughly in clean, warm (43 °C [110 °F] maximum), preferably running water. Drain.
D. When the cleaner used does not contain a disinfecting agent, respirator components should be immersed for two
minutes in one of the following:
1. Hypochlorite solution (50 ppm of chlorine) made by adding approximately one milliliter of laundry bleach to one
liter of water at 43 °C (110 °F); or,
2. Aqueous solution of iodine (50 ppm iodine) made by adding approximately 0.8 milliliters of tincture of iodine (6–8
grams ammonium and/or potassium iodide/100 cc of 45% alcohol) to one liter of water at 43 °C (110 °F); or,
3. Other commercially available cleansers of equivalent disinfectant quality when used as directed, if their use is

32

recommended or approved by the respirator manufacturer.
E. Rinse components thoroughly in clean, warm (43 °C [110 °F] maximum), preferably running water. Drain. The
importance of thorough rinsing cannot be overemphasized. Detergents or disinfectants that dry on facepieces may
result in dermatitis. In addition, some disinfectants may cause deterioration of rubber or corrosion of metal parts if not
completely removed.
F. Components should be hand-dried with a clean lint-free cloth or air-dried.
G. Reassemble facepiece, replacing filters, cartridges, and canisters where necessary.
H. Test the respirator to ensure that all components work properly.
Appendix C to §1910.134: OSHA Respirator Medical Evaluation Questionnaire (Mandatory)
To the employer: Answers to questions in Section 1, and to question 9 in Section 2 of part A, do not require a
medical examination.
To the employee:
Can you read (circle one): Yes/No
Your employer must allow you to answer this questionnaire during normal working hours, or at a time and place that
is convenient to you. To maintain your confidentiality, your employer or supervisor must not look at or review your
answers, and your employer must tell you how to deliver or send this questionnaire to the health care professional
who will review it.
Part A. Section 1. (Mandatory) The following information must be provided by every employee who has been
selected to use any type of respirator (please print).
1. Today's date:____________________
2. Your name:____________________
3. Your age (to nearest year):____________________
4. Sex (circle one): Male/Female
5. Your height: __ft. __in.
6. Your weight: __ lbs.
7. Your job title:____________________
8. A phone number where you can be reached by the health care professional who reviews this questionnaire
(include the Area Code): ___
9. The best time to phone you at this number: __
10. Has your employer told you how to contact the health care professional who will review this questionnaire (circle
one): Yes/No

33

11. Check the type of respirator you will use (you can check more than one category):
a. __ N, R, or P disposable respirator (filter-mask, non-cartridge type only).
b. __ Other type (for example, half- or full-facepiece type, powered-air purifying, supplied-air, self-contained
breathing apparatus).
12. Have you worn a respirator (circle one): Yes/No
7 If “yes,” what type(s):____________________
____________________
Part A. Section 2. (Mandatory) Questions 1 through 9 below must be answered by every employee who has been
selected to use any type of respirator (please circle “yes” or “no”).
1. Do you currently smoke tobacco, or have you smoked tobacco in the last month: Yes/No
2. Have you ever had any of the following conditions?
a. Seizures: Yes/No
b. Diabetes (sugar disease): Yes/No
c. Allergic reactions that interfere with your breathing: Yes/No
d. Claustrophobia (fear of closed-in places): Yes/No
e. Trouble smelling odors: Yes/No
3. Have you ever had any of the following pulmonary or lung problems?
a. Asbestosis: Yes/No
b. Asthma: Yes/No
c. Chronic bronchitis: Yes/No
d. Emphysema: Yes/No
e. Pneumonia: Yes/No
f. Tuberculosis: Yes/No
g. Silicosis: Yes/No
h. Pneumothorax (collapsed lung): Yes/No
i. Lung cancer: Yes/No

34

j. Broken ribs: Yes/No
k. Any chest injuries or surgeries: Yes/No
l. Any other lung problem that you've been told about: Yes/No
4. Do you currently have any of the following symptoms of pulmonary or lung illness?
a. Shortness of breath: Yes/No
b. Shortness of breath when walking fast on level ground or walking up a slight hill or incline: Yes/No
c. Shortness of breath when walking with other people at an ordinary pace on level ground: Yes/No
d. Have to stop for breath when walking at your own pace on level ground: Yes/No
e. Shortness of breath when washing or dressing yourself: Yes/No
f. Shortness of breath that interferes with your job: Yes/No
g. Coughing that produces phlegm (thick sputum): Yes/No
h. Coughing that wakes you early in the morning: Yes/No
i. Coughing that occurs mostly when you are lying down: Yes/No
j. Coughing up blood in the last month: Yes/No
k. Wheezing: Yes/No
l. Wheezing that interferes with your job: Yes/No
m. Chest pain when you breathe deeply: Yes/No
n. Any other symptoms that you think may be related to lung problems: Yes/No
5. Have you ever had any of the following cardiovascular or heart problems?
a. Heart attack: Yes/No
b. Stroke: Yes/No
c. Angina: Yes/No
d. Heart failure: Yes/No
e. Swelling in your legs or feet (not caused by walking): Yes/No

35

f. Heart arrhythmia (heart beating irregularly): Yes/No
g. High blood pressure: Yes/No
h. Any other heart problem that you've been told about: Yes/No
6. Have you ever had any of the following cardiovascular or heart symptoms?
a. Frequent pain or tightness in your chest: Yes/No
b. Pain or tightness in your chest during physical activity: Yes/No
c. Pain or tightness in your chest that interferes with your job: Yes/No
d. In the past two years, have you noticed your heart skipping or missing a beat: Yes/No
e. Heartburn or indigestion that is not related to eating: Yes/No
f. Any other symptoms that you think may be related to heart or circulation problems: Yes/No
7. Do you currently take medication for any of the following problems?
a. Breathing or lung problems: Yes/No
b. Heart trouble: Yes/No
c. Blood pressure: Yes/No
d. Seizures (fits): Yes/No
8. If you've used a respirator, have you ever had any of the following problems? (If you've never used a respirator,
check the following space and go to question 9:)
a. Eye irritation: Yes/No
b. Skin allergies or rashes: Yes/No
c. Anxiety: Yes/No
d. General weakness or fatigue: Yes/No
e. Any other problem that interferes with your use of a respirator: Yes/No
9. Would you like to talk to the health care professional who will review this questionnaire about your answers to this
questionnaire: Yes/No
Questions 10 to 15 below must be answered by every employee who has been selected to use either a full-facepiece
respirator or a self-contained breathing apparatus (SCBA). For employees who have been selected to use other
types of respirators, answering these questions is voluntary.

36

10. Have you ever lost vision in either eye (temporarily or permanently): Yes/No
11. Do you currently have any of the following vision problems?
a. Wear contact lenses: Yes/No
b. Wear glasses: Yes/No
c. Color blind: Yes/No
d. Any other eye or vision problem: Yes/No
12. Have you ever had an injury to your ears, including a broken ear drum: Yes/No
13. Do you currently have any of the following hearing problems?
a. Difficulty hearing: Yes/No
b. Wear a hearing aid: Yes/No
c. Any other hearing or ear problem: Yes/No
14. Have you ever had a back injury: Yes/No
15. Do you currently have any of the following musculoskeletal problems?
a. Weakness in any of your arms, hands, legs, or feet: Yes/No
b. Back pain: Yes/No
c. Difficulty fully moving your arms and legs: Yes/No
d. Pain or stiffness when you lean forward or backward at the waist: Yes/No
e. Difficulty fully moving your head up or down: Yes/No
f. Difficulty fully moving your head side to side: Yes/No
g. Difficulty bending at your knees: Yes/No
h. Difficulty squatting to the ground: Yes/No
i. Climbing a flight of stairs or a ladder carrying more than 25 lbs: Yes/No
j. Any other muscle or skeletal problem that interferes with using a respirator: Yes/No
Part B Any of the following questions, and other questions not listed, may be added to the questionnaire at the
discretion of the health care professional who will review the questionnaire.
1. In your present job, are you working at high altitudes (over 5,000 feet) or in a place that has lower than normal

37

amounts of oxygen: Yes/No
If “yes,” do you have feelings of dizziness, shortness of breath, pounding in your chest, or other symptoms when
you're working under these conditions: Yes/No
2. At work or at home, have you ever been exposed to hazardous solvents, hazardous airborne chemicals ( e.g.,
gases, fumes, or dust), or have you come into skin contact with hazardous chemicals: Yes/No
If “yes,” name the chemicals if you know them:____________________
3. Have you ever worked with any of the materials, or under any of the conditions, listed below:
a. Asbestos: Yes/No
b. Silica ( e.g., in sandblasting): Yes/No
c. Tungsten/cobalt ( e.g., grinding or welding this material): Yes/No
d. Beryllium: Yes/No
e. Aluminum: Yes/No
f. Coal (for example, mining): Yes/No
g. Iron: Yes/No
h. Tin: Yes/No
i. Dusty environments: Yes/No
j. Any other hazardous exposures: Yes/No
If “yes,” describe these exposures:____________________
____________________
4. List any second jobs or side businesses you have:____________________
____________________
5. List your previous occupations:____________________
____________________
6. List your current and previous hobbies:____________________
____________________
7. Have you been in the military services? Yes/No
If “yes,” were you exposed to biological or chemical agents (either in training or combat): Yes/No
8. Have you ever worked on a HAZMAT team? Yes/No
9. Other than medications for breathing and lung problems, heart trouble, blood pressure, and seizures mentioned
earlier in this questionnaire, are you taking any other medications for any reason (including over-the-counter
medications): Yes/No

38

If “yes,” name the medications if you know them:____________________
10. Will you be using any of the following items with your respirator(s)?
a. HEPA Filters: Yes/No
b. Canisters (for example, gas masks): Yes/No
c. Cartridges: Yes/No
11. How often are you expected to use the respirator(s) (circle “yes” or “no” for all answers that apply to you)?:
a. Escape only (no rescue): Yes/No
b. Emergency rescue only: Yes/No
c. Less than 5 hours per week: Yes/No
d. Less than 2 hours per day: Yes/No
e. 2 to 4 hours per day: Yes/No
f. Over 4 hours per day: Yes/No
12. During the period you are using the respirator(s), is your work effort:
a. Light (less than 200 kcal per hour): Yes/No
If “yes,” how long does this period last during the average shift:______hrs.______mins.
Examples of a light work effort are sitting while writing, typing, drafting, or performing light assembly work; or
standing while operating a drill press (1–3 lbs.) or controlling machines.
b. Moderate (200 to 350 kcal per hour): Yes/No
If “yes,” how long does this period last during the average shift:______hrs.______mins.
Examples of moderate work effort are sitting while nailing or filing; driving a truck or bus in urban traffic; standing
while drilling, nailing, performing assembly work, or transferring a moderate load (about 35 lbs.) at trunk level;
walking on a level surface about 2 mph or down a 5-degree grade about 3 mph; or pushing a wheelbarrow with a
heavy load (about 100 lbs.) on a level surface.
c. Heavy (above 350 kcal per hour): Yes/No
If “yes,” how long does this period last during the average shift:______hrs.______mins.
Examples of heavy work are lifting a heavy load (about 50 lbs.) from the floor to your waist or shoulder; working on a
loading dock; shoveling; standing while bricklaying or chipping castings; walking up an 8-degree grade about 2 mph;
climbing stairs with a heavy load (about 50 lbs.).

39

13. Will you be wearing protective clothing and/or equipment (other than the respirator) when you're using your
respirator: Yes/No
If “yes,” describe this protective clothing and/or equipment:____________________
____________________
14. Will you be working under hot conditions (temperature exceeding 77 °F): Yes/No
15. Will you be working under humid conditions: Yes/No
16. Describe the work you'll be doing while you're using your respirator(s):
____________________
____________________
17. Describe any special or hazardous conditions you might encounter when you're using your respirator(s) (for
example, confined spaces, life-threatening gases):
____________________
____________________
18. Provide the following information, if you know it, for each toxic substance that you'll be exposed to when you're
using your respirator(s):
Name of the first toxic substance:____________________
Estimated maximum exposure level per shift:____________________
Duration of exposure per shift____________________
Name of the second toxic substance:____________________
Estimated maximum exposure level per shift:____________________
Duration of exposure per shift:____________________
Name of the third toxic substance:____________________
Estimated maximum exposure level per shift:____________________
Duration of exposure per shift:____________________
The name of any other toxic substances that you'll be exposed to while using your respirator:
____________________
____________________
____________________
19. Describe any special responsibilities you'll have while using your respirator(s) that may affect the safety and wellbeing of others (for example, rescue, security):
____________________
Appendix D to §1910.134 (Mandatory) Information for Employees Using Respirators When Not Required Under the
Standard
Respirators are an effective method of protection against designated hazards when properly selected and worn.
Respirator use is encouraged, even when exposures are below the exposure limit, to provide an additional level of
comfort and protection for workers. However, if a respirator is used improperly or not kept clean, the respirator itself
can become a hazard to the worker. Sometimes, workers may wear respirators to avoid exposures to hazards, even

40

if the amount of hazardous substance does not exceed the limits set by OSHA standards. If your employer provides
respirators for your voluntary use, or if you provide your own respirator, you need to take certain precautions to be
sure that the respirator itself does not present a hazard.
You should do the following:
1. Read and heed all instructions provided by the manufacturer on use, maintenance, cleaning and care, and
warnings regarding the respirators limitations.
2. Choose respirators certified for use to protect against the contaminant of concern. NIOSH, the National Institute
for Occupational Safety and Health of the U.S. Department of Health and Human Services, certifies respirators. A
label or statement of certification should appear on the respirator or respirator packaging. It will tell you what the
respirator is designed for and how much it will protect you.
3. Do not wear your respirator into atmospheres containing contaminants for which your respirator is not designed to
protect against. For example, a respirator designed to filter dust particles will not protect you against gases, vapors,
or very small solid particles of fumes or smoke.
4. Keep track of your respirator so that you do not mistakenly use someone else's respirator.
[63 FR 1270, Jan. 8, 1998; 63 FR 20098, 20099, Apr. 23, 1998, as amended at 69 FR 46993, Aug. 4, 2004; 71 FR 16672, Apr. 3,
2006; 71 FR 50187, Aug. 24, 2006; 73 FR 75584, Dec. 12, 2008; 76 FR 33607, June 8, 2011]
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