Noise source identification and assessment of two noise controls on light towers.
Hemmelgarn-A; Zechmann-E; Hayden-C II
Inter-Noise 2012. The 41st International Congress and Exposition on Noise Control Engineering, August 19-22, 2012, New York, New York. Indianapolis, IN: Institute of Noise Control Engineering, 2012 August; 12:10469-10475
Light towers are used on many night-time and tunnel construction worksites and other environments where light is needed and power is not readily available. Noise emissions from a light tower's diesel engine/electric generator combination are typically above the National Institute for Occupational Safety and Health's Recommended Exposure Limit of 85 dBA 8-hour time-weighted average. Two methods of noise control were examined to determine their control effectiveness: redirecting the exhaust using a 25-foot length of flexible duct over existing exhaust pipe, and placing acoustic blankets over openings in the light tower trailer encasing the motor/generator. Noise level testing on 5 different model light towers was completed in a large unoccupied parking lot using 10 microphones over a reflecting plane as specified in ISO 3744. The light towers were tested with varying loads on the generator. Cooling air turbulent flow and diesel engine combustion vibro-induced noise through and around the trailer casing along with engine exhaust noise were major sources of noise. The exhaust and barrier controls tested provided less than 3-dB noise reduction. Future noise control research should concentrate on optimizing noise controls for the exhaust and cooling air system, reducing engine vibration, and exploring quiet-by-design formats.
Lighting; Lighting-systems; Diesel-engines; Noise; Noise-exposure; Noise-levels; Exposure-limits; Exposure-levels; Noise-control; Engineering-controls; Control-technology
Inter-Noise 2012. The 41st International Congress and Exposition on Noise Control Engineering, 19-22 August, 2012