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Noise Control In Highway Construction

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

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Noise Control In Highway Construction

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  1. Noise ControlIn 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 ExposureEvaluation 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 exhaust engine exhaust engine

  8. Air Compressor exhaust engine

  9. Power Tool Tying Rebars

  10. Short-term Noise Levels

  11. Octave Band Spectra

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

  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. PPE Target Level (dBA) Sound Pressure Level (dBA) 85 90 95 100 105 110 Earmuff 80 16 23 29 36 43 49 85 9 16 23 29 36 43 90 3 9 16 23 29 36 FormableEarplug 80 24 34 44 54 64 74 85 14 24 34 44 54 64 90 4 14 24 34 44 54 OtherEarplug 80 40 57 73 90 107 123 85 23 40 57 73 90 107 90 7 23 40 57 73 90 Required NRR (dB)

  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. Calculatinga 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. Calculatinga 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. Measured Sound Pressure Level (dB) Measured Distance from Source (ft) 5 7 10 15 20 30 80 95 98 101 104 107 110 82 97 100 103 106 109 112 84 99 102 105 108 111 114 86 101 104 107 110 113 116 88 103 106 109 112 115 118 90 105 108 111 114 117 120 92 107 110 113 116 119 122 94 109 112 115 118 121 124 96 111 114 117 120 123 126 98 113 116 119 122 125 128 100 115 118 121 124 127 130 Table #1. Converting Sound Pressure Measurement to Sound Power Level (dB)

  21. Sound Power Level Sound Power Level Sound Pressure Level 2X X 110 dB 80 dB 74 dB Single Number Index Depending on Distance

  22. Calculatinga 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. Sound Power Level (dB) Target Control Level (dB) 80 85 90 90 3 2 1 95 5 3 2 100 9 5 3 105 16 9 5 110 29 16 9 115 52 29 16 120 92 52 29 125 164 92 52 130 292 164 92 Table #2. Calculating Noise Perimeter Zone from Sound Power Measurement

  24. Calculatinga 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. Sound Pressure Level (dBA) Maximum Exposure Time (Minutes) NIOSH(85dBA & 3dB) OSHA(90dBA & 5dB) 85 480 960 90 151 480 95 48 240 100 15 120 105 5 60 110 1 30 Table #3. Maximum Exposure Time Within a Noise Perimeter Zone

  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 Controlin Highway Construction • Engineering and administrative + hearing protectors • Full support of top management • Purchasing policy • Construction plan • Hearing conservation program

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