Respiratory Protection
in Workplace
A. H. Mehrparvar, MD
Occupational Medicine department
Yazd University of Medical Sciences
Airborne contaminants

Particulate (aerosol)
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Dust
Mist
Smoke
Gas
 Vapor

Methods of controlling airborne
contaminants

Engineering controls (elimination of the
hazard)
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substitution
Isolation
vetilation
Administrative controls
 Personal protective devices

Respiratory personal protective devices
(respirators)
used to protect against inhaled agents or
to improve the quality of inhaled air
 An effective component of a worker
protection program
 Used for protection against chemical
agents (e.g., asbestos, lead), and biologic
agents

Use of Respirators
not the method of choice for controlling
exposures
 completely dependent on voluntary
compliance by the worker
 requires an ongoing multifaceted program
to ensure proper maintenance and
utilization

When respirators are needed?
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when the work is of a varied nature, preventing
the construction of adequate engineering controls
during maintenance and repair operations when
ventilation controls are disengaged or
nonoperative.
when relatively infrequent operations are
conducted (e.g., transfers of liquid raw
materials).
for emergency and unplanned events (e.g., as
part of the emergency response to a spill) or
when the agent is unknown.
when product substitutions or engineering
controls are not financially feasible.
Different kinds of respirators
(a) air-purifying respirators use ambient
air and filter or adsorb the contaminants
 (b) atmosphere-supplying
 Most respirators in use are air-purifying
respirators.
 Generally, atmosphere-supplying
respirators provide a higher level of
protection.

Air-purifying respirators

decrease contaminant levels by several
mechanisms:
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Filtration
Electrostatic characteristics
Sorbent respirators
Air- purifying respirators
Mechanical filter
 Chemical-cartridge respirator
 Gas mask
 Powered air-purifying respirator

Mechanical-filter respirator
For particulates
 3 kinds:
 N (Not resistant to oil)
 R (Resistant to oil)
 P (oil Proof)
 efficacy
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95
99
100
Chemical-cartridge respirator
For vapors and gases
 Cartridge contains chemical to absorb
gases and vapors
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Gas mask
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Designed for:
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Organic vapors and gases
Alkaline gases
Acid gases
Pesticides
Paint vapors
Radioactive particulates
Dusts
Fumes
Mists
Full face
Use a canister (sorbent: 2-10 times a cartridge)
Powered air-purifying respirator (PAPR)

Used for particulates, gases and vapors
Atmosphere -supplying
Self-contained breathing apparatus
(SCBA)
 Air line: air via a hose
 Combined air line with backup tank

SCBA
Airline
Combination
Atmosphere -supplying
Continuous flow
 Demand: air flow only during inspiration
 Pressure demand: attempts to maintain
mask pressure positive throughout
respiration

Mask type
Quarter mask
 Half mask
 Full-face mask
 Other (e.g., air hat)

Quarter Mask
Half Mask
Full Face
Fit type
Tight fitting
 Loose fitting

Tight-fitting
respirator

Loose fitting- PAPR helmet
Respirator efficacy
The overall efficacy of the respirator is
described by protection factor.
 Protection factor: the ratio of the
contaminant concentration outside the
mask to the concentration inside the
mask.
 Assigned protection factor (APF)
 Measured protection factor (MPF)
 Workplace protection factor (WPF)
 Usually MPF>APF>WPF

Fit Testing and Checking
Every time a user dons a respirator,
should perform a fit check
 Typically for the first time
 Qualitative and quantitative fit tests
 Qualitative: detection of a tracer material
by the subject.
 Quantitative: concentration of a marker
substance inside and outside the mask is
measured under laboratory conditions for
the specific user.

Occupational Respiratory Protection
Program
Assessment of whether respirators are
needed
 Exposure assessment
 Respirator selection
 Medical assessment of users
 Training
 Cleaning and maintenance
 Program audit

Respirator Selection

Two factors inform respirator selection:
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exposure situation per se
worker medical condition
Worker preferences
Sequence of activities
Should respirators be used at all?
 What are the exposures of concern?
 What degree of contaminant reduction is
necessary?
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permissible exposure level (PEL).
The ratio of the actual workplace exposure
level to the permissible exposure defines the
degree of reduction that the respirator must
afford.
the 8-hour time-weighted average (TWA)
short-term exposure limits (STEL)
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What safety factor is necessary?
A safety factor of tenfold is added
Greater safety factors are needed with highly
toxic agents on unpredictable exposures.
single-use disposable respirators have a
maximum assigned protection factor of 10 ppm
The fit test may misestimate the actual workplace
protection by a factor of ten.
Meaningful fit testing for single-use respirators
may not feasible since their protection factor is
only ten at most.
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Is there an immediately dangerous to life and health (IDLH)
situation ?
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Does the agent have good warning properties ?
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an atmosphere-supplying rather than an air-purifying
respirator is generally required.
In particularly hazardous situations, dual protection is
necessary to ensure safety
a full-face mask with positive pressure mode operation is
employed to avoid inward movement of contaminants during
inspiration.
End-of-service-life indicators (if available) are necessary if airpurifying respirators are employed with agents with poor
warning properties.
What respirator types are compatible with the work
situation ?
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Air-line respirators cannot be used where considerable mobility
is necessary.
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Can the individual worker safely and effectively
use the respirator?
Will the worker actually use the device when
needed?
What can be afforded?
How do respirators integrate with other
protective measures (e.g., protective suits)?
Respirator programs must be periodically
evaluated and adjusted to be effective in real-life
situations.
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ratio of workplace air concentration to the occupational
exposure level (e.g., PEL) defines the minimum degree of
protection to be afforded, and greater respiratory protection
may be needed occasionally.
physical state of an inhaled agent
Particle size
greater degree of respiratory protection for small-size
particles (e.g., fumes)
For fibers, the dimensions and charge affect uptake and
clearance
Greater degrees of respiratory protection for longer
duration of exposure
The level of exertion
Personal susceptibility
Medical evaluation for respirator use
Prior to respirator use
 Periodically during use
 Upon change in health status
 When respirator use problems are
suspected

A questionnaire about respiratory and
other health conditions, prior to use of
respirators
 Medical examination
 In some circumstances, a limited exercise
test
 In marginal cases, observation of the
worker using the respirator in the
workplace or during work simulation may
be needed.

Periodic evaluation of users is also
advisable.
 For special examinations of selected
individuals who have expressed difficulty
with respirator use, more intensive
assessment of the user is warranted.

Negative pressure respirators
Half-face cartridge respirator
Full-face cartridge respirator
N95 Particulate respirator
Filters and cartridges
What are the ten parts of a
respirator program?
1. Administrator of the Program
 2. Medical Evaluation
 3. Selection of Respiratory Protection
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Choose the right respirator to protect from
contaminant-consult with EH&S.
Respirators must be NIOSH approved.
Evaluate workplace exposure, assume IDLH if
contaminant is not known.
Air purifying respirators cannot be used in
IDLH atmospheres.
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4. Training
Initial training required with periodic refresher
training every year. The training shall encompass
the following:
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Why the respirator is necessary and how improper fit,
usage, or maintenance can compromise the protective
effect of the respirator;
What the limitations are
Use of respirator effectively in emergencies, including
situations in which the respirator malfunctions;
How to inspect, put on and remove, use, check the seals
of the respirator
Maintenance and storage procedures
How to recognize medical signs and symptoms that may
limit or prevent the effective use of respirators
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5. Fit testing
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for all tight fitting respirators annually, or if
changes occur to facial features, weight
gain/loss, eyewear changes, fitcheck fails
6. Inspection & care
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inspect before each use
replace defective parts immediately
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7. Cleaning
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after each use, disassemble and thoroughly
clean and disinfect respirator
8. Use
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inspect before using, proper storage,
positive/negative fit check before each use,
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9. Review
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Periodic audits of the UR Respiratory Protection
Program
10. Record Keeping
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Medical certifications
Training records
Fit test records
Air monitoring records
Types of Fit Tests
• Qualitative:
•
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Test agent directed around the head of the
respirator wearer
If user can detect agent, test is failed
• Quantitative:
•
•
Test atmosphere
Quantifies respirator fit using instrumentation
to determine the amount of leakage into the
respirator facepiece
Qualitative Fit Test
•
•
•
•
Banana oil
Irritant smoke
Saccharin challenge
Bitrex solution
Quantitative Fit Test
•
•
Expensive machinery
Fit Factors
Outside to inside concentration
Standard prohibits facial hair which interferes
with face - to - facepiece seal or valve function
ASSIGNED PROTECTION FACTOR TABLE
Air-Purifying Respirators
Quarter Mask
APF=5
Filtering Facepiece
APF=10
Elastomeric Half Mask
APF=10
Full-Face Respirator APF=50
ASSIGNED PROTECTION FACTOR TABLE
Powered Air-Purifying Respirators
Half Mask
APF=50
Full-Face
APF=1,000
Hood/Helmet
APF=25/1,0004
4Must
Loose-fitting Facepiece
APF=25
be proven to
provide APF of
1,000 or be treated
as Loose-fitting
Facepiece PAPR
with APF=25.
ASSIGNED PROTECTION FACTOR TABLE
Demand Supplied-Air Respirators
Half Mask
APF=10
Full Face
APF=50
ASSIGNED PROTECTION FACTOR TABLE
Pressure Demand Supplied-Air Respirators
Half Mask
APF=50
Full Face
APF=1,000
ASSIGNED PROTECTION FACTOR TABLE
Continuous Flow Supplied-Air Respirators
Half Mask
APF=50
Full Face
APF=1,000
Hood/Helmet
APF=25/1,0004
4Must
Loose-fitting Facepiece APF=25
be proven to
provide APF of
1,000 or be treated
as Loose-fitting
Facepiece SAR
with APF=25.
ASSIGNED PROTECTION FACTOR TABLE
Demand Self Contained Breathing Apparatus
Half Mask APF=10
Full Face APF=50
Helmet/Hood
APF=50
ASSIGNED PROTECTION FACTOR TABLE
Hooded Demand Self Contained Breathing Apparatus
The demand unit is Draeger’s Air Boss
Guardian, which consists of a hood with
an inner nose cup with 30 minute air
supply. Neck seal forms gas-tight seal.
Per NIOSH, fit testing
requirements apply.
Fit Test adapter, P/n 4056314 for fit
testing with PortacountTM Plus
ASSIGNED PROTECTION FACTOR TABLE
Pressure Demand Self Contained Breathing Apparatus
Full Face APF=10,000
Includes closed circuit SCBA
Helmet/Hood
APF=10,000
Not NFPA compliant
ASSIGNED PROTECTION FACTOR TABLE
Pressure Demand Self Contained Breathing Apparatus
NIOSH certified the tight-fitting
hooded Survivair Puma respirator as a
pressure-demand SCBA with 30, 45, or
60 min air supply. Has a nosecup.
Inappropriate Marketing
NIOSH warns that facial hair cannot
interfere with neck or nosecup seal.
Fit test adapter for qualitatively
fit testing Puma
Combination Respirators
Not in APF
Table
Preamble states: “…the
combination pressuredemand full facepiece SAR
with auxiliary SCBA
respirator is equivalent to an
SCBA, and, therefore, the
APF for an SCBA applies.
When using a combination
respirator ensure that the APF is
appropriate to the mode of operation
in which the respirator is being used
[paragraph (d)(3)(i)(A)].
Full Face PD Airline APF = 1,000
Full Face Air-purifying APF = 50