3. It’s All Noise Lee Hager, COHC 3M 517-290-1907 lhager@mmm.com Lee Hager, COHC 3M 517-290-1907 lhager@mmm.com © 3M 2013. All Rights Reserved.

4. Analysis Recordkeeping Education & Training Hearing Protection Audiometric Testing Admin. Controls Noise Controls Noise Monitoring Hearing Loss Prevention Hearing Loss Prevention— Simple, But Not Easy © 3M 2013. All Rights Reserved.

5. Risk Management Assess Risk Noise Exposure Assessment Mitigate Risk Noise Control Hearing Protection Assess Effect Hearing Testing Quality of program HERE drives … Integrity of program here. © 3M 2013. All Rights Reserved.

6. The Package  SL1.0 –Buy it Quiet  SL 2.0 –Assess Risk  SL 3.0 –Manage effect of noise  SL1.0 –Buy it Quiet  SL 2.0 –Assess Risk  SL 3.0 –Manage effect of noise © 3M 2013. All Rights Reserved.

7. Today’s Agenda  Better understanding of noise –Terminology –Physical Aspects –Decibels  Leads to better decisions about exposure  Better understanding of noise –Terminology –Physical Aspects –Decibels  Leads to better decisions about exposure © 3M 2013. All Rights Reserved.

8. Definitions: Sound or Noise  How about this?  Or this?  Trick question …  Bonus track  How about this?  Or this?  Trick question …  Bonus track 1.Keep ‘Em Coming, Alkaline Trio 2.Truck Song, Lyle Lovett 3.Donna Lee, Jaco Pastorius © 3M 2013. All Rights Reserved.

9. Describing Sound Physical Properties What We Hear Frequency in Hertz (Hz) Pitch Level in decibels (dB) Loudness Duration in hours Length © 3M 2013. All Rights Reserved.

10. Sound Frequency  Sound waves per second Hertz (Hz)  We hear a change in frequency as a change in pitch  Sound waves per second Hertz (Hz)  We hear a change in frequency as a change in pitch Low frequency— fewer waves per second High frequency— more waves per second © 3M 2013. All Rights Reserved.

11. Range of Human Hearing— Frequency  Greatest sensitivity to speech sounds ~250 Hz to 8000 Hz InfrasoundUltrasound Human hearing range 20 Hz20 kHz Hearing sensitivity Speech © 3M 2013. All Rights Reserved.

12. Frequency Response & Weighting “A” and “C” weighting curves © 3M 2013. All Rights Reserved.

13. Sound Level The sound pressure of painfully loud sounds is more than 10 million times greater than the sound pressure of the quietest sound we can hear! © 3M 2013. All Rights Reserved.

14. 20 µPa 200,000,000µPa Threshold of hearing Threshold of pain Human hearing range Sound Pressure 0 dB 140 dB dB Range of Human Hearing - Level © 3M 2013. All Rights Reserved.

15. Loudness and SPL  Intensity/loudness –Decibel 1/10 of a Bel – an Alexander Graham Bell to be precise –1 dB barely audible –3 dB clearly audible –Energy doubles @ 3 –Loudness doubles @ 10 –Risk doubles @ 3 or 4 or 5  Frequency –Measured in CPS –Expressed as hz –Middle C = 256 hz  Intensity/loudness –Decibel 1/10 of a Bel – an Alexander Graham Bell to be precise –1 dB barely audible –3 dB clearly audible –Energy doubles @ 3 –Loudness doubles @ 10 –Risk doubles @ 3 or 4 or 5  Frequency –Measured in CPS –Expressed as hz –Middle C = 256 hz © 3M 2013. All Rights Reserved.

16. Sound Energy  Sound energy decreases over: –Time –Distance – the Inverse Square Law  Sound energy decreases over: –Time –Distance – the Inverse Square Law 1 meter 110 dBA 2 meters 104 dBA 4 meters 98 dBA © 3M 2013. All Rights Reserved.

17. Critical Noise Terminology Regulatory Issues  Criterion - The level at which 8 hours exposure would yield maximum allowable exposure, equivalent to PEL. –US OSHA 90 dB TWA  Threshold - The level below which all measured values are assigned a value of zero energy or contribution to dose. –US OSHA 80 dB  Criterion - The level at which 8 hours exposure would yield maximum allowable exposure, equivalent to PEL. –US OSHA 90 dB TWA  Threshold - The level below which all measured values are assigned a value of zero energy or contribution to dose. –US OSHA 80 dB © 3M 2013. All Rights Reserved.

18. Exposure = Noise*People*Time Exposure Time in Hours Allowable TWA using OSHA 5 dB Exchange Allowable TWA using 3 db Exchange 1105 dB99 dB 2100 dB96 dB 495 dB93 dB 890 dB 1685 dB87 dB 3280 dB84 dB © 3M 2013. All Rights Reserved.

19. Decibels Are Logarithmic  Exchange Rate (doubling, trading) – Increase (or decrease) in decibel level that results in a doubling (or halving) of exposure accumulation. –US OSHA 5 –Rest of world 3  Meaning – increase of 5 dB is DOUBLE the energy –DOUBLE the risk of hearing loss  Meaning – simple math does not work  Exchange Rate (doubling, trading) – Increase (or decrease) in decibel level that results in a doubling (or halving) of exposure accumulation. –US OSHA 5 –Rest of world 3  Meaning – increase of 5 dB is DOUBLE the energy –DOUBLE the risk of hearing loss  Meaning – simple math does not work © 3M 2013. All Rights Reserved.

20. Decibel Manipulation Example: Add 88, 85, 77, and 88 dB © Associates in Acoustics, Inc. www.esion.com  Formula method: L Pt = 92.1 dB © 3M 2013. All Rights Reserved.

21. Table Method Numerical difference between levels L P1 and L P2 (dB) L P3 : Amount to be added to the higher of L P1 or L P2 (dB) 03.0 12.5 22.1 31.8 41.5 51.2 61.0 70.8 80.6 90.5 100.4 >100.0 for all practical purposes Simpler gross estimate 1.Calculate difference in levels 2.Add to higher value © Associates in Acoustics, Inc. www.esion.com © 3M 2013. All Rights Reserved.

22. Example Add 88, 85, 77, and 88 dB L P1 = 88 dB L P2 = 88 dB L P3 = 85 dB L P4 = 77 dB Step 1 – List each level from highest to lowest: © Associates in Acoustics, Inc. www.esion.com © 3M 2013. All Rights Reserved.

23. Table Method Example: Add 88, 85, 77, and 88 dB Numerical difference between levels L P1 and L P2 (dB) L P3 : Amount to be added to the higher of L P1 or L P2 (dB) 03.0 12.5 22.1 31.8 41.5 51.2 61.0 70.8 80.6 90.5 100.4 >10 0.0 for all practical purposes L P1 = 88 dB L P2 = 88 dB L P3 = 85 dB L P4 = 77 dB Step 2 – Look up value to add to the higher number from table: Diff 0, add 3.0 = 91.0 Diff 6, add 1.0 = 92.0 Diff >10, add 0.0 = 92.0 dB = 92.0 dB From long form calc L Pt = 92.1 dB © Associates in Acoustics, Inc. www.esion.com © 3M 2013. All Rights Reserved.

24. Critical Noise Terminology Averages  Average Level (LAVG) - The level that if present continuously, would generate the same amount of energy as the varying levels that are present in the environment.  Equivalent Level (Leq) – As above, assuming 3 dB exchange rate and no threshold  Time Weighted Average (TWA) - A level average with an assumed fixed sample period of eight hours.  Action Level – Exposure at which hearing conservation program activity begins. –US OSHA 85 dB TWA or 50% dose.  Average Level (LAVG) - The level that if present continuously, would generate the same amount of energy as the varying levels that are present in the environment.  Equivalent Level (Leq) – As above, assuming 3 dB exchange rate and no threshold  Time Weighted Average (TWA) - A level average with an assumed fixed sample period of eight hours.  Action Level – Exposure at which hearing conservation program activity begins. –US OSHA 85 dB TWA or 50% dose. © 3M 2013. All Rights Reserved.

25. Dose  Dose - The daily exposure presented as a percentage of maximum allowable (100%). Dose is a function of sound level, time, criterion level, and exchange rate. As read from instrument, also function of measurement time.  Projected Dose – A “what if” dose calculation that assumes exposure conditions will continue as they were.  8 hours @ 90 dB = 100% dose (noise PEL)  With 5 dB exchange –8 hours @ 85 dB = 50% –16 hours @ 85 dB = –8 hours @ 95 dB = –12 hours @ 90 dB =  Dose - The daily exposure presented as a percentage of maximum allowable (100%). Dose is a function of sound level, time, criterion level, and exchange rate. As read from instrument, also function of measurement time.  Projected Dose – A “what if” dose calculation that assumes exposure conditions will continue as they were.  8 hours @ 90 dB = 100% dose (noise PEL)  With 5 dB exchange –8 hours @ 85 dB = 50% –16 hours @ 85 dB = –8 hours @ 95 dB = –12 hours @ 90 dB = © 3M 2013. All Rights Reserved.

26. Critical Noise Terminology Single Event  Maximum Level (Lmax) – The highest weighted slow level measured during sample period. –Pertains to ceiling level –US OSHA 115 dBA  Minimum Level (Lmin) – The lowest weighted slow level measured during sample period.  Peak Level (Lpk) The highest unweighted, fast response sound level measured during sample period. –US OSHA 140 dB  Response Time (fast or slow) – Indicates how the meter responds to changes in sound level. US OSHA uses slow –Equal amount of energy, distributed differently over time  Maximum Level (Lmax) – The highest weighted slow level measured during sample period. –Pertains to ceiling level –US OSHA 115 dBA  Minimum Level (Lmin) – The lowest weighted slow level measured during sample period.  Peak Level (Lpk) The highest unweighted, fast response sound level measured during sample period. –US OSHA 140 dB  Response Time (fast or slow) – Indicates how the meter responds to changes in sound level. US OSHA uses slow –Equal amount of energy, distributed differently over time © 3M 2013. All Rights Reserved.

27. Noise Happens Over Time Sound Level Time Fast response curve Slow response curve © 3M 2013. All Rights Reserved.

28. Exposure vs SL 1.0  SL 1.0 –No threshold –Msmt locations 1.5 m from floor1.5 m from floor 1 m from machine1 m from machine Include operator stationInclude operator station –Lavg not to exceed 80 dB at any location  SL 1.0 –No threshold –Msmt locations 1.5 m from floor1.5 m from floor 1 m from machine1 m from machine Include operator stationInclude operator station –Lavg not to exceed 80 dB at any location  SL 2.0 –80 dB threshold –Msmt locations Hearing zone of workerHearing zone of worker Task analysisTask analysis –TWA >= 85 HCPHCP HPD availableHPD available –TWA>= 90 HPD requiredHPD required EngineeringEngineering © 3M 2013. All Rights Reserved.

29. Thanks for Being Here…  It’s all noise  Better understanding makes for better decisions  Good luck!  It’s all noise  Better understanding makes for better decisions  Good luck! © 3M 2013. All Rights Reserved.