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Respirators From the preamble to the revision of 1910.134: “In principle, respirators frequently may be capable of providing adequate protection. However, problems associated with selection, fit, and use often render them ineffective in actual application, preventing the assurance of consistent and reliable protection, regardless of the theoretical capabilities of the respirator.”
A little respirator history. . . . • In Roman mines they used loose-fitting animal bladders to try to filter out lead • 1814: development of a particulate removing filter in a rigid container • 1854: discovery that activated charcoal could be used to capture some vapors • WWI: improvements in full face gas masks • 1930: the development of resin impregnated dust filters permitted cheaper, improved units • 1940s: SCBA developed from SCUBA concept
Types of Respirators Air-Purifying: cleans air* can’t add oxygen *maybe
Air- Purifying Respirators • removes particulate, or • removes vapor & gas, or • combination of the above
Air- Purifying Respirators • particulates: filters • gases or vapors: chemical cartridges or chemical canisters
Types of Respirators Air-Supplying: supply a clean* source of air *maybe
Air- Purifying Respirators • Negative pressure • user draws in air through a filter or cartridge • creates a negative pressure • Powered air-purifying (PAPR) • battery powered pump draws in air through a filter • provides positive pressure to user
Air-Supplying Respirators • Airline air is supplied to facepiece via air line from either a compressor, a large cylinder or cascade system • SCBA air is supplied via short air line from a user-worn cylinder (thus, “self- contained”) • Airline with escape bottle combo unit • SCBA escape only units
Operation modes: See tab3-3 • Demand mode • Positive pressure mode • Pressure-demand mode
Operation modes: • Demand mode: air enters facepiece only when wearer creates negative pressure • Positive pressure mode • Pressure-demand mode
Operation modes: • Demand mode • Positive pressure mode: facepiece is constantly positively pressurized (compared to air outside the facepiece) by a constant flow • Pressure-demand mode
Operation modes: • Demand mode • Positive pressure mode • Pressure-demand mode: facepiece is always positively pressurized but flow changes according to demand from user
Types of Facepieces • Tight-fitting: requires seal on face (thus no facial hair); air-purifying or air-supplying • Loose-fitting: no seal on face; airline only (but not airline with escape bottle)
Tight-fitting facepieces • Full face: hairline to below chin (covers nose, mouth & eyes) • Half face: nose & mouth, & seals under chin • Quarter face: nose & mouth, but seals between mouth & chin
Loose-fitting facepieces • Hood: device covering head & neck • Helmet: gives impact & penetration protection • variations; above with: Blouses (coversshoulders) or Full suits
TC approval schedules: • TC-13F-XXXX SCBA • TC-14G-XXXX gas masks • TC-19C-XXXX air supply • TC-21C-XXXX DFM (term out-dated) • TC-23C-XXXX chemical cartridge • TC-84A-XXXX non-powered APR (under 84)