Noise in Road Construction

What this presentation covers Hearing loss rates and claims facts Noise levels of construction equipment Control methods to reduce harmful noise exposures Resources

Hearing loss is expensive! Hearing loss is 1/3 of all costs of permanent impairments. Hearing loss is the most expensive occupational disease for road construction workers. Incidence rate is 10 times higher for “Road Construction” risk class than for all other risk classes. Hearing loss claims rate is highest of all construction risk classes. In Washington State, The result is higher industrial insurance premiums paid by road construction contractors.

Noise and hearing loss Noise level (dBA) Noise is measured in units called decibels (dB). For more information on noise and hearing, see WISHA: Noise Exposure – Hearing LossWISHA: Noise Exposure – Hearing Loss (If two people 3 feet apart must shout to be heard, the background noise is too loud - above 85 dBA.) Scientific studies have shown that hearing loss can occur when 8-hour average noise exposure exceeds 85 decibels. Threshold of pain Freeway noise City traffic Normal conversation (3’) Urban residence Threshold of hearing Construction noise levels are often above 85 dBA (“A-weighting” is a standard of sound measurement used to evaluate continuous noise levels; designated as “dBA”) Bulldozer Jackhammer Chipping hammer Soft whisper (5’) Jet take-off (200’)

Some Common Noise Levels in Construction Source: Center to Protect Worker’s Rights Decibels (dBA) Jackhammer Concrete joint cutter Skilsaw Bulldozer Earth Tamper Crane Hammer Gradeall Front end loader Backhoe Pneumatic chipping hammer

Source: OSHA case files Sample Noise Level Measurements Saw Operator 95 dBA (7-hour sample)

Sample Noise Level Measurements Jackhammering 102 dBA (7.5-hour sample) Source: OSHA case files

Sample Noise Level Measurements Breaking pavement 112 dBA (7-hour sample) Source: OSHA case files

Sample Noise Level Measurements 97 dBA (6.5-hour sample) 104 dBA (7-hour sample) Lateral drilling Source: OSHA case files

Sample Noise Level Measurements Source: OSHA case files Sandblasting 125 dBA (4-hour sample) 109 dBA (inside hood)

Sample Noise Level Measurements Source: OSHA case files Dumping concrete 96 dBA (4-hour sample)

Noise Sources in Road Work Type and condition of equipment being operated Other equipment running at the same time Enclosed or partially enclosed spaces (e.g., underpass) Traffic around work site Several factors influence the noise levels to which workers are exposed: Underpass Underpass work

When is hearing protection required? At noise exposures of 85 dBA TWA 8 * and higher, you must use a hearing protection device. Wherever the noise exposure is 90 dBA TWA 8 and higher, feasible controls must be used to reduce your exposure. *Time-weighted average during an 8-hour period High Noise Exposures “Rules of Thumb” You need protection: If you have to shout at someone 3 feet away to be heard When using electric, gasoline, or air powered tools When sitting in an open cab of dozers, rollers, some cranes, earth moving or road building equipment

What are some methods to control noise exposures? Substitute quieter process or equipment Eliminate or minimize at the source Isolate/enclose the process or operator Increase distance from the source Change work practices Implement a hearing conservation program The most desirable methods of controlling a noise problem are to use quieter process/equipment, eliminate the noise at the source, or to block the noise from reaching you. Using hearing protection devices (ear plugs, muffs) isn't considered a control of the noise hazard. There are many drawbacks and using them will not always be effective.

What are some methods to control noise exposures? Substitute quieter process or equipment: Replacing a large jackhammer with a middle range one reduced the noise level by 10 dBA. New quieter generators have sound- proofing and produce only 75 dBA at 1 meter and 65 dBA at 7 meters under load.

What are some methods to control noise exposures? –Install silencers/mufflers –Retrofit old equipment –Operate equipment as designed per manufacturer’s instructions –Damp noisy equipment and parts  install sound-absorbing material or vibration isolation systems –Maintain equipment properly  replace worn, loose, or unbalanced machine parts that cause vibration  keep machine parts well lubricated to reduce friction  adjust belts and valves, tighten bolts Eliminate/minimize at the source: Acoustically treated operator cabins on earth- moving equipment have noise levels of 75 dBA or below.

What are some methods to control noise exposures? –Noise enclosures –Noise barriers  higher and wider than noise source  may be simple walls or curtains of acoustic materials  ½-inch plywood can provide a 10dB noise reduction  place close to noise source or to you –Include acoustic panels or baffles to walls/ceilings –Minimize leaks  e.g., cover joints with 1/8-inch thick neoprene strip or duct tape Isolate/enclose the process or operator: A portable screen set up around a power pack reduced the noise level from 98 to 90 dBA at 1 meter.

What are some methods to control noise exposures? Isolate/enclose the process or operator: (continued) Note: if the source of noise is equipment operated by you, a barrier placed close can increase your noise exposure by reflecting the noise back toward you. Be sure to line the barrier with sound absorbing material to reduce the reflected noise. Reflected Noise Noise from source BARRIER Transmitted Noise

What are some methods to control noise exposures? –Keep noisy equipment away from walls or other surfaces that will reflect noise toward you. –Combine distancing and barriers to further reduce noise exposure. Using both methods results in greater noise reduction than would be achieved from either method alone. Increase the distance between the noise source and you: –Every doubling of the distance between you and the noise source results in as much as a 6 dB decrease in noise level – that’s a four-fold reduction! (This is true if there is no reflected noise. The reduction will be less if there are walls or partitions between you and the noise source.)

What are some methods to control noise exposures? Change work practices: –limit time exposed: job rotation, rescheduling work –limit use of noisy equipment –rest breaks –turn off equipment not in use Hearing Conservation Program: Chapter WAC Chapter WAC –baseline and annual audiometric testing –monitoring of noise exposure levels –hearing protection devices (HPDs) –training and education –maintenance of employee exposure and hearing loss records

Summary Substitute quieter process or equipment Eliminate or minimize at the source Isolate/enclose the process or operator Increase distance from the source Change work practices Implement Hearing Conservation Program Hearing loss is expensive! Many construction noise levels are high and require controls to reduce workers’ exposures. Control methods:

WISHA Consultation Services Safety & Health program review and worksite evaluation By employer invitation only Free Confidential No citations or penalties Letter explains findings Follow-up all serious hazards For additional assistance, you can call one of our consultants. Click below for local L & I office locations:

Web Resources WISHA: Noise Exposure – Hearing Loss NIOSH: Noise and Hearing Loss Prevention OSHA: Construction - Noise and Hearing ConservationOSHA: Construction - Noise and Hearing Conservation National Hearing Conservation Association MSHA Noise Control Manual: Surface Mining EquipmentMSHA Noise Control Manual: Surface Mining Equipment Institute of Noise Control Engineering of the USAInstitute of Noise Control Engineering of the USA

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