ACGIH ® TLVs ® for Physical Agents Committee Update

1. ACGIH® TLVs® for Physical Agents Committee Update Vice-Chair: Thomas Bernard University of South Florida College of Public Health

2. TLV®Physical Agents Committee Process for Hazardous Agent Selection and Decision Making

3. Mission To foster, solicit, collect and evaluate data on potential health hazards of exposures to physical agents. When appropriate, recommend ACGIH® Threshold Limit Values® for physical agents.

4. 2002 PAC Harry Mahar Maurice Bitran Thomas Bernard Gerald Coles Anthony Cullen Daniel Johnson John Leonowich William Murray Bhawani Pathak Robert Patterson Thomas Tenforde Carla Treadwell Consultants: Thomas Adams Thomas Armstrong Gregory Lotz Martin Mainster Gary Myers

5. Overview • Physical Agents • Process • Committee Activities • TLV® Development • Future • Format • Agents

6. Disclaimer The opinions expressed here are those of the author and not of his employer, the Physical Agents Committee or the ACGIH® Worldwide.

7. Physical Agents It’s the Movement of Energy

8. Risk of Health Effects • What is the nature of the energy? • How much energy? • What is the interaction with tissue?

9. Nature of Energy • Electric and Magnetic Fields • Photons • Kinetic Energy • Pressure • Vibration • Mechanical • Heat

10. Amount of Energy • Total Amount of Energy Absorbed • What does it take to raise water temperature? • Rate of Absorption (Power or Intensity) • How fast does the temperature rise? • Normalized to Surface Area (e.g., mJ/cm2, mW/cm2)

11. Interactions • Electric and Magnetic Fields • Induce Currents • Align Molecules • Vibrate Molecular Bonds • Photons • Vibrate Molecular Bonds • Disrupt Molecular Bonds

12. More Interactions • Mechanical Disruption of Tissue • Pressure • Vibration • Force Applications • Loss of Tissue Function • Thermal: Gain or Loss of Heat

13. Bernard Watt-O-Meter {Not Accepted, or Considered Acceptable, by Any Authority} Power Limits for Various Exposures [mW/cm2] Electric and Magnetic Fields 170,000 Radiofrequency/Microwave 1.0 Infrared Light 10 Blue Light 0.0001 Ultraviolet Light 0.0012 Ionizing Radiation 0.00000003 Noise 0.00003 Heat Stress 30

14. Exposure • Energy Distribution in the Immediate Environment • The distribution is usually described as Power or Intensity (directly or through a surrogate) versus Frequency or Wavelength in Bands

15. Exposure Threshold • Total Energy • Ability to Absorb Energy • Rate of Energy (Power or Intensity) • Ability to Dissipate Absorbed Energy In a Band Integrated Over All Bands

16. Process Committee Activities Development of TLVs®

17. Representation • Usually one or two members with an expertise for a particular agent (e.g., a small portion of the electromagnetic spectrum) • Small committee to maintain a working and collegial group. We meet as a whole. • Leverage with outside experts

18. Updating TLVs® • PAC meets with outside experts • Members bring recommendations to the PAC for discussion • Consideration of actions taken by national and international committees or agencies

19. New TLVs® • Quintessential Example: Hand Activity • Formed a cadre of consultants • Convened a conference • Developed recommendation and Documentation • Presented to PAC and discussed • PAC voted after internal deliberations

20. Future Format Agents

21. Format • TLV® Book • Use of Flow Charts • Evolving (see Heat Stress and RF/MW) • Training • Documentation • Expanded and Focused (see HAL and Lifting) • Health Effects and Exposure Indices • Guidance (see Heat Stress)

22. Form • Physical agents have their own history and character with respect to measurement and exposure assessment • There is an underlying similarity among the physical agents that may be introduced

23. Example Set • Radiofrequency / Microwave Radiation • Optical Radiation (IR, Visible and UV) • Vibration (Hand-Arm and Whole Body) • Noise

24. 1000 100 10 Energy 1 0.1 0.01 0.001 0.01 0.1 1 10 100 1000 Bands Energy Distribution

25. 1000000 100000 10000 Energy Limit 1000 100 10 1 0.001 0.01 0.1 1 10 100 1000 Bands Energy Limits Within Bands Emin

26. 1000000 100000 10000 1000 Energy 100 10 1 PD Exp Lmt 0.1 0.01 0.001 0.01 0.1 1 10 100 1000 Bands Limits by Band Is the limit exceeded within one or more bands?

27. 1000 100 Sensitivity 10 1 0.1 0.001 0.01 0.1 1 10 100 1000 Bands Sensitivity Curve Sensitivity = Energy Limit / Emin

28. 1 0.1 Filter Multiplier 0.01 0.001 0.001 0.01 0.1 1 10 100 1000 Bands Hazard Function Hazard Function = 1.0 / Sensitivity

29. 1000 100 10 1 Energy 0.1 0.01 ED E-eff 0.001 0.0001 0.00001 0.001 0.01 0.1 1 10 100 1000 Bands Effective Exposure Effective Exposure = Energy Distribution x Hazard Function

30. Total Energy Multiplying • Energy Limits by Band • Hazard Function by Band and Integrating (Summing) Yields a Constant Value: A Total Energy Limit

31. Limit by Total Energy Total Energy • In One Band • Under the Effective Energy Curve Compared to Total Energy Limit

32. In Summary • TLVs® • Limit Power (Ability to Dissipate) • Limit Total Energy (Ability to Absorb) • Limit by • Band • Total

33. Agents Under Review • Lasers • Vibration • Cold Stress • Altitude • Impulse Noise • ELF H-Fields • HAL • Lifting • WMSDs • Wide-Band RF

34. Scheduled Break Take a minute to stretch!