Solution Summary: Quieter Rollers
Quieter rollers are designed to limit noise exposure from loud equipment engines by enclosing the engine.
Description:
Quieter rollers use engineering controls to limit noise exposure. Rollers use gas and diesel engines to flatten and/or compact earth, asphalt, and other surfaces to be leveled. These quieter machines are designed to muffle noise from the engine to prevent it from reaching the operator. Through the use of quieter engines and specially designed enclosures for the engines, the sound level at the operator’s ear is reduced.
Through the use of specially designed engine enclosures, the noise produced by the roller engine is limited and exposures are reduced. However, sound pressure levels on the construction site may still be above the OSHA permissible exposure limit and workers should wear hearing protection for more than intermittent visits.
Wacker Neuson RD 12A-90 Roller
| Model | Engine (horsepower) | Fuel | Vehicle Weight (pounds) | Vehicle Height | Drum Width (inches) | Drum Diameter (inches) | Operator Sound Pressure Level (dBA) |
| RD 12A-90 | 20.3 | Gas | 2,171 – 2,689 | 7 feet, 7 inches | 35.4 | 22 | 85.6 |
| RD 27-120 | 32.7 | Diesel | 6,226 | 9 feet, 2 inches | 47.2 | 27.6 | 88.0 |
- Sound Pressure Level Prior to Re-design: 102-106 dBA
- OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA
- Noise Control Methods: re-designed engine enclosure
Dynapac Rollers
| Model | Engine (horsepower) | Vehicle Weight (pounds) | Vehicle Height | Drum Width (inches) | Drum Diameter (inches) |
| CC1100 | 35 | 5,070 | 8 feet, 8 inches | 42 | 27 |
| CC1200 | 35 | 5,400 | 8 feet, 8 inches | 47 | 27 |
| CC1300 | 45 | 8,270 | 9 feet | 51 | 32 |
- Fuel: diesel
- Sound Pressure Level Prior to Re-design: 104-105 dBA
- Operator Sound Pressure Level: 85±3 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
- Noise Control Methods: re-designed engine enclosure, water-cooled engine
Risks Addressed:
Over time, exposure to noise levels at or above 85 decibels will lead to permanent hearing loss. The NIOSH recommended exposure limit (REL) for occupational noise is 85 decibels on an A-weighted scale as an 8-hour time weighted average (U.S. Department of Health and Human Services, 1998). OSHA limits noise exposure to 90 decibels, also on an A-weighted scale and as an 8-hour time weighted average (U.S. Department of Labor, 2008). A-weighting is an adjustment that gives lower frequencies less weight or significance than higher frequencies. An A-weighted sound level more closely resembles the human ear’s response to noise.
The American Conference of Governmental Industrial Hygienists (ACGIH) assigned noise a Threshold Limit Value (TLV) of 85 dBA as an 8-hour time weighted average. Exposure to 88 dBA is limited to 4 hour, exposure to 91 dBA is limited to 2 hours, exposure to 94 dBA is limited to 1 hour and so on (ACGIH, 2011).
|
TLVs for Noise |
||
|
|
Duration per Day |
Sound Level (dBA) |
|
Hours |
24 |
80 |
|
16 |
82 |
|
|
8 |
85 |
|
|
4 |
88 |
|
|
2 |
91 |
|
|
1 |
94 |
|
|
Minutes |
30 |
97 |
|
15 |
100 |
|
|
7.50 |
103 |
|
|
3.75 |
106 |
|
|
1.88 |
109 |
|
|
0.94 |
112 |
|
Noise exposure has also been associated with temporary hearing loss, decreased perception of noisiness and masking, increased stress, fatigue, disturbance of sleep and decreased concentration and mental performance (Osada, 1988). Noise-induced hearing loss starts in the higher frequencies (3,000 to 6,000 Hz) and slowly develops from chronic exposure to excessive sound. Sound must exert a shearing force on the hair cells lining the inner ear in order to be perceived, and if the force is too strong, cell damage and cell death can occur (Berger et al., 2003).
In a 2004 report from the University of Washington, Seixas and Neitzel indicated an average noise level of 88.2 dBA for rollers used by operating engineers.
The American Industrial Hygiene Association conducted a study in 1988 to quantify noise exposure among heavy equipment operators. Ten different asphalt rollers were sampled during construction activities for several hours each. The range of noise measured between the machines was 85 to 103 dBA, with a mean noise level of 95 dBA (Legris, 1998).
In a study to determine construction noise from a jobsite, different machines were monitored during normal operation. Several rollers, mostly vibration rollers, were tested at a distance of 25 feet (7.5 meters) while constructing a roadway. The loudest roller produced between 89 and 93 dBA while the quietest, non-vibration roller produced 79 dBA (Minina, 2008).
How Risks are Reduced:
These rollers are powered by gas or diesel engines and are used to flatten and compact earth, asphalt, and other surfaces. These quieter machines are designed to muffle noise from the engine to prevent it from reaching the operator. Through the use of quieter engines and specially designed enclosures for the engines, the sound level at the operator’s ear is reduced.
While there are no published sampling data on these specific controls, safety and health experts believe exposure to noise can be significantly reduced through the use of noise control techniques. The extent of the reduction is dependent on the type of work being performed, the size of the engine, the amount of noise in the environment, the level of effort required by the machine, and the operator’s proximity to the engine.
Industrial hygienists use sound level meters or noise dosimeters to determine noise levels and recommend the use of quieter techniques to prevent hearing loss and reduce the risk of accidents. Proper maintenance and retrofitting existing equipment can decrease excess sound as well (Suter, 2002).
Wacker Neuson states that its roller reduces sound levels to 85.6 dBA.
Dynapac claims that “the machines are powered by water-cooled Kubota diesel engines, which are designed to run quietly and fuel efficiently.”
Effects on Productivity:
Lower noise levels are expected to reduce stress and fatigue, and increase the concentration and mental performance of workers. Improved worker health, comfort and concentration may lead to greater productivity. Reduced sound levels can also lower the risk of accidents as communication among workers is easier and more effective.
Additional Considerations:
The use of gas and diesel-powered equipment poses the risk of carbon monoxide exposure, especially in areas where airflow is reduced. Steps to control exposure are important because the gas is invisible, odorless and tasteless. Poisoning by carbon monoxide can occur quickly indoors, but working outdoors does not ensure operators won’t be overcome. Small, inexpensive personal monitors should be worn by the operator to warn of unacceptable exposures. Equipment should not be left idling to cut down on carbon monoxide and to conserve fuel.
As is the case with any construction equipment, users should follow manufacturer scheduled maintenance safety recommendations and comply with any applicable local, state or federal regulations.
Contributors:
Andrew Kingston, Michael R. Cooper and Bruce Lippy - The Lippy Group, LLC
Availability
NIOSH Workplace Solutions Sheet
The National Institute of Safety and Health (NIOSH) has published a series of “Workplace Solutions”, which are easy-to-understand recommendations from NIOSH research results. Related to this Construction Solution, please find more information on:
Preventing Injuries When Working With Ride-On Roller/Compactors
Dynapac CC1100 Rollers
To obtain information, visit http://www.dynapac.com/en-us
or contact 1-800-732-6762
Wacker Neuson RD 12A-90 & RD 27-120 Rollers
To obtain information, visit http://www.wackerneuson.us
or contact 1-800-770-0957
