Respiratory Protection
in WorkplaceA. H. Mehrparvar, MD
Occupational Medicine departmentYazd University of Medical Sciences
Airborne contaminants Particulate (aerosol)
Dust Mist Smoke
Gas Vapor
Methods of controlling airborne contaminants Engineering controls (elimination of the
hazard) 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?
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: 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
95 99 100
Chemical-cartridge respirator For vapors and gases Cartridge contains chemical to absorb
gases and vapors
Gas mask Designed for:
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:
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? 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)
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.
Is there an immediately dangerous to life and health (IDLH) situation? 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.
Does the agent have good warning properties? End-of-service-life indicators (if available) are necessary if air-
purifying respirators are employed with agents with poor warning properties.
What respirator types are compatible with the work situation? Air-line respirators cannot be used where considerable mobility
is necessary.
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.
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-
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.
4. Training Initial training required with periodic refresher
training every year. The training shall encompass the following: 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
5. Fit testing for all tight fitting respirators annually, or if
changes occur to facial features, weight gain/loss, eyewear changes, fitcheck fails
6. Inspection & care inspect before each use replace defective parts immediately
7. Cleaning after each use, disassemble and thoroughly
clean and disinfect respirator 8. Use
inspect before using, proper storage, positive/negative fit check before each use,
9. Review Periodic audits of the UR Respiratory Protection
Program 10. Record Keeping
Medical certifications Training records Fit test records Air monitoring records
Types of Fit Tests• Qualitative:
• 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 TABLEAir-Purifying Respirators
Quarter Mask APF=5
Filtering FacepieceAPF=10
Elastomeric Half MaskAPF=10
Full-Face Respirator APF=50
ASSIGNED PROTECTION FACTOR TABLEPowered Air-Purifying Respirators
Half Mask APF=50
Loose-fitting FacepieceAPF=25
Hood/HelmetAPF=25/1,0004
Full-Face APF=1,000
4Must 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 FaceAPF=1,000
Hood/HelmetAPF=25/1,0004
Loose-fitting Facepiece APF=25
4Must be proven to provide APF of 1,000 or be treated as Loose-fitting Facepiece SAR with APF=25.
ASSIGNED PROTECTION FACTOR TABLEDemand Self Contained Breathing Apparatus
Half Mask APF=10
Full Face APF=50Helmet/Hood
APF=50
ASSIGNED PROTECTION FACTOR TABLEHooded 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.
Fit Test adapter, P/n 4056314 for fit testing with PortacountTM Plus
Per NIOSH, fit testing requirements apply.
ASSIGNED PROTECTION FACTOR TABLEPressure Demand Self Contained Breathing Apparatus
Full Face APF=10,000
Includes closed circuit SCBA
Helmet/HoodAPF=10,000
Not NFPA compliant
ASSIGNED PROTECTION FACTOR TABLEPressure Demand Self Contained Breathing Apparatus
Inappropriate MarketingNIOSH warns that facial hair cannot interfere with neck or nosecup seal.
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.
Fit test adapter for qualitatively fit testing Puma
Combination Respirators
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 = 1,000Full Face Air-purifying APF = 50
Preamble states: “…the combination pressure-demand full facepiece SAR with auxiliary SCBA respirator is equivalent to an SCBA, and, therefore, the APF for an SCBA applies.
Not in APF Table