Tractor Age Effects on Occupational Noise Level Exposures Inside Agricultural Tractor Cabs

Abstract. The occupational noise level inside an acoustically insulated agriculture tractor cab typically measures less than 85 decibels (dBA) when the original equipment sound measurement is taken as part of the tractor performance test report. Tractor operators typically do not wear hearing protection inside an acoustically insulated tractor cab because they believe the tractor is at a safe noise level and hearing protection is not necessary. The Organization for Economic Co-operation and Development (OECD) Standard Code 5 Method was used to test tractors in use at University of Florida farms to see if the noise changed from the original equipment tractor test measurement. The final data set included nineteen tractors. The objective of this research aimed to evaluate if the noise level inside a tractor cab at the driver‘s position increased with use for tractors with well-maintained cabs. The original equipment range of sound measurements at the drivers‘ ear ranged from 68-81.4 dBA. The used tractor sound levels ranged from 68-82 dBA and were -1.0 dBA to +4.5 dBA from their respective new tractor measurements. The tractors with the least amount of hours generally had less change from the new tractor measurement than the tractors with more hours. The data showed a positive correlation of 0.308 between tractor age (hours of use) and increase in noise level on regularly maintained tractors in good condition. Further tests are needed to increase the reliability of the conclusions and to determine how damaged acoustic materials and seals affect the noise exposure on used tractors. In addition, there is still controversy over the sound level at which permanent hearing loss occurs with some believing the critical level may be closer to 80 dBA than the currently used 85 dBA. The effects of many tractor operators working more than eight hours per day also needs to be understood.