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