1. Noise Control In Highway Construction Kwangseog Ahn, MS and Susan Moir, MS Department of Work Environment University of Massachusetts Lowell www.uml.edu/Dept/WE/COHP

2. Big Dig Highway construction in Boston Replacing old elevated highway Constructing tunnels

3. Study Objectives Evaluate noise Reduce exposures Recommend practical controls

4. Noise In Highway Construction Widespread & multiple sources Exposed at/close to sources Short-term peak exposures Vibration & chemical hazards Safety hazards

5. Noise Exposure Evaluation Methods Personal samples Octave band samples Walkthrough observation Area samples Conversations with safety officers and workers

6. Targeted Sources Drilling rig Portable air compressor Power tool for tying rebars Impact/impulsive noise

7. Drilling Rig engine exhaust

8. Air Compressor exhaust engine

9. Power Tool Tying Rebars

10. Short-term Noise Levels

11. Octave Band Spectra

12. Noise Control Ideal control hierarchy 1. Engineering 2. Administrative 3. Hearing protectors Practical control hierarchy 1. Hearing protectors 2. Administrative 3. Engineering

13. Hearing Protectors Widely used Workers often not wearing Not sufficient protection Supplemental to engineering and administrative controls

14. Noise Reduction Rating (NRR) Single-number rating Tested in laboratory Derated under real conditions (NIOSH criteria, 1998) –Earmuffs: subtract 25% –Formable earplugs: subtract 50% –Other earplugs: subtract 75%

15. Required NRR (dB) PPETarget Level (dBA) Sound Pressure Level (dBA) 8590 95 100105110 Earmuff 80162329364349 85 916 23 293643 903916232936 Formable Earplug 80243444546474 85142434445464 9041424344454 Other Earplug 8040577390107123 852340577390107 9072340577390

16. Assessment of Noise Levels: Existing methods Noise dosimetry Task-based dBA levels Published reference values Takes too much time Sources/technology not available

17. Administrative Controls Reduce exposure time –Adjust worker schedule “Noise perimeter zone” –Keep unnecessary workers out of high noise zone –Only designated workers within zone

18. Calculating a Noise Perimeter Zone 1. Measure sound pressure level at a distance from a noise source 2. Measure distance between the noise source and measurement point 3. Convert sound pressure to estimated sound power (Table #1) 4. Calculate a Noise Perimeter Zone (Table #2) 5. Estimate maximum exposure time within a Noise Perimeter Zone (Table #3)

19. Calculating a Noise Perimeter Zone 1. Measure sound pressure level at a distance from a noise source 2. Measure distance between the noise source and measurement point 3. Convert sound pressure to estimated sound power (Table #1) 4. Calculate a Noise Perimeter Zone (Table #2) 5. Estimate maximum exposure time within a Noise Perimeter Zone (Table #3)

20. Table #1. Converting Sound Pressure Measurement to Sound Power Level (dB) Measured Sound Pressure Level (dB) Measured Distance from Source (ft) 5 7 10152030 809598101104107110 8297100103106109112 8499102105108111114 86101104107110113116 88103106109112115118 90105108111114117120 92 107 110 113116119122 94109112115118121124 96111114117120123126 98113116119122125128 100115118121124127130

21. Sound Power Level 110 dB Sound Pressure LevelSound Power Level 80 dB74 dB X 2X Single Number IndexDepending on Distance

22. Calculating a Noise Perimeter Zone 1. Measure sound pressure level at a distance from a noise source 2. Measure distance between the noise source and measurement point 3. Convert sound pressure to estimated sound power (Table #1) 4. Calculate a Noise Perimeter Zone (Table #2) 5. Estimate maximum exposure time within a Noise Perimeter Zone (Table #3)

23. Table #2. Calculating Noise Perimeter Zone from Sound Power Measurement Sound Power Level (dB) Target Control Level (dB) 80 8590 321 95532 100953 1051695 110 29 169 115522916 120925229 1251649252 13029216492

24. Calculating a Noise Perimeter Zone 1. Measure sound pressure level at a distance from a noise source 2. Measure distance between the noise source and measurement point 3. Convert sound pressure to estimated sound power (Table #1) 4. Calculate a Noise Perimeter Zone (Table #2) 5. Estimate maximum exposure time within a Noise Perimeter Zone (Table #3)

25. Table #3. Maximum Exposure Time Within a Noise Perimeter Zone Sound Pressure Level (dBA) Maximum Exposure Time (Minutes) NIOSH (85dBA & 3dB) OSHA (90dBA & 5dB) 85480960 90151480 9548 240 10015120 105560 110130

26. Engineering Controls Internal combustion engines - acoustical enclosures and barriers Exhausts - mufflers/silencers Vibrating parts, pipes, etc. - isolation/sound absorbing material Good maintenance

27. Noise Control in Highway Construction Engineering and administrative + hearing protectors Full support of top management –Purchasing policy –Construction plan Hearing conservation program

28. References - Noise Exposures In Construction Workers Blute N et al, Appl Occup Environ Hyg 14(9):632-641 (1998) Legris M and Poulin P, AIHAJ 59:774-778 (1998) Neitzel R et al, AIHAJ 60:807-817 (1998) Sinclair JDN and Haflidson WO, Appl Occup Environ Hyg 10(5):457-460 (1995)