RESPIRATORY PROTECTION …examination of the appropriate role of personal protection against inhalation hazards

Some History first century: men wore animal bladders 1907: apparatus for breathing oxygen 1917: canister gas masks in military 1930s: effective dust respirators US Bureau of Mines: tested/certified NIOSH: research, testing, certification

Use of Respirators When engineering controls are not practical #1 priority: keep contaminant controlled For short, infrequent exposures special cleaning; maintenance operations In emergency situations

Types of Respirators Air-purifying Air-supplied self-contained breathing apparatus (SCBA) air-line

Mask integral feature of all respirators varying amount of protection types quarter half full hood, helmet, etc.

Air-Supplied Respirators Type A: full mask; body harness, tube up to 300 ft.; blower; OK in IDLH areas Type B: similar to Type A; no blower; not for use in IDLH areas Type C: air-line respirator; compressed air supply; need for air quality; not for use in IDLH areas Abrasive Blasting Respirators

Types of Flow Control constant flow demand pressure-demand

Self-Contained Breathing Apparatus Air supply is independent of surrounding OK in toxic & low-O 2 environments Basic types Non-recirculated (open circuit) Recirculated (closed circuit) rebreather

Air-Purifying Respirators extract contaminant from the air must be specific for contaminant cannot be used in oxygen deficient atmospheres types: aerosol removing respirators/mechanical filters gas/vapor removing respirators combination (aerosols and gases/vapors)

Mechanical Filter Respirators for dusts, fumes, mists, smokes half- or full-facepiece; replaceable filter one or more fibrous filters no good for gases, vapors or low O 2 make sure it is designed for the job problems: limited life; clogging; hot; uncomfortable

Gases & Vapors Respirators objective: remove contaminant from air design: via adsorption or absorption usually specific for a group or type of contaminant; should not be used for any other respirator contains granular chemicals either in a cartridge (small) or canister (large capacity)

Respirator Adsorbents work on surface attraction forces materials with high affinity for certain types of chemical some examples activated charcoal silica gel Hopcalite

Respirator Absorbents granular material with chemical to react with toxic contaminant most common application: soda lime for use against acid gases a few other chemicals with reaction-specific applications

Chemical Cartridge Units for use against toxic gas/vapor acceptable conditions for use construction: half-mask + cartridge(s) cartridge replacement regularly when indication of pass through often combined with filter

Gas Masks for use against toxic gas/vapor acceptable conditions for use construction: full face- piece, canister, harness identification of type on canister label color coded canister replacement

Universal Canister Type N contains several sorbents in layers provides protection against most contaminants; useful for emergencies protection against acid gases, organic vapors, ammonia, carbon monoxide and particulates

Respirator Selection identity and nature of contaminant amount of employee exposure atmosphere physical configuration of job site worker medical condition worker comfort capabilities of respirator protection factors

Protection Factors & Fit Testing Protection factor respirators efficiency in removing air contaminants Purpose of fit testing assuring that the respirator is the correct one and that it is working negative and positive pressure tests Qualitative fit testing irritant smoke odorous vapor taste Quantitative fit testing

Respirator Limitations poor means of worker protection leakage problems (poor fit) broken seals (facial hair, improper use) communication interference vision problems (fogging of lenses) discomfort difficult to enforce proper usage

Respiratory Protection Program selection of respirators medical surveillance/fit testing issuance and use training supervision storage & maintenance recordkeeping