3. Respirator types

4. Respirators “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.” 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.”

5. A little respirator history.... n In Roman mines they used loose-fitting animal bladders to try to filter out lead n 1814: development of a particulate removing filter in a rigid container n 1854: discovery that activated charcoal could be used to capture some vapors n WWI: improvements in full face gas masks n 1930: the development of resin impregnated dust filters permitted cheaper, improved units n 1940s: SCBA developed from SCUBA concept

6. Types of Respirators

7. Air-Purifying: cleans air* can’t add oxygen *maybe

8. Air- Purifying Respirators n removes particulate, or n removes vapor & gas, or n combination of the above

9. Air- Purifying Respirators n particulates: filters n gases or vapors: chemical cartridges or chemical canisters

10. Types of Respirators Air-Supplying: supply a clean* source of air *maybe

11. Air- Purifying Respirators n Negative pressure user draws in air through a filter or cartridgeuser draws in air through a filter or cartridge creates a negative pressurecreates a negative pressure n Powered air-purifying (PAPR) battery powered pump draws in air through a filterbattery powered pump draws in air through a filter provides positive pressure to userprovides positive pressure to user

12. notes: n explain negative pressure: neg atmospheric pressure; lower pressure inside mask/facepiece, and so air moves into space n requires some work, and can have implications for lung function compromised persons n employees given option to choose PAPRs (arsenic, Pb, coke oven emission & cotton dust standards)

13. Air-Supplying Respirators n Airline air is supplied to facepiece via air line from either a compressor, a large cylinder or cascade system n SCBA air is supplied via short air line from a user-worn cylinder (thus, “self-contained”) n Airline with escape bottle combo unit n SCBA escape only units

14. Operation modes: See tab3-3 n Demand mode n Positive pressure mode n Pressure-demand mode

15. Operation modes: n Demand mode: air enters facepiece only when wearer creates negative pressure n Positive pressure mode n Pressure-demand mode

16. Operation modes: n Demand mode n Positive pressure mode: facepiece is constantly positively pressurized (compared to air outside the facepiece) by a constant flow n Pressure-demand mode

17. Operation modes: n Demand mode n Positive pressure mode n Pressure-demand mode: facepiece is always positively pressurized but flow changes according to demand from user

18. Types of Facepieces n Tight-fitting: requires seal on face (thus no facial hair); air-purifying or air-supplying n Loose-fitting: no seal on face; airline only (but not airline with escape bottle)

19. Tight-fitting facepieces n Full face: hairline to below chin (covers nose, mouth & eyes) n Half face: nose & mouth, & seals under chin n Quarter face: nose & mouth, but seals between mouth & chin

20. Loose-fitting facepieces n Hood: device covering head & neck n Helmet: gives impact & penetration protection n variations; above with: Blouses (covers shoulders) or Full suits

21. TC approval schedules: n TC-13F-XXXXSCBA n TC-14G-XXXXgas masks n TC-19C-XXXXair supply n TC-21C-XXXXDFM (term out-dated) n TC-23C-XXXXchemical cartridge n TC-84A-XXXXnon-powered APR (under 84)