Tractor Noise Levels Impact on Operator Safety

Abstract

Acoustic noise is one of the most persistent pitfalls of the operators of construction, mining and agricultural machineries, predominantly hearing loss or weak hearing. Also noise include decreased productivity, increased heart rate, and increased blood pressure, startle reaction, and other cardiovascular and psychophysiological system changes (Mansoor, et al. 2011, 2012). The aim of this reaserch was to investigate the impact of noise levels emitted from the agricultural tractors under field operations on the operator safety. Three types of tractors used in this study were Nasr, Belarus and Universal/UTB (Romani). They are without cabin and represent about 76% of the total number of tractors used in Egypt (Economic affair sector, 2012). The noise emitted from them was monitored and evaluated under plowing and land leveling operations as a heavy duty operation field. The data was collected at different engine speed and gears as recommended by the operator for each operation. Measurements of noise levels were taken with the use of Cirrus CR 110A doseBadge and RC 110A reader unit. The noise level measurements were performed in accordance with the Egyptian environmental law (EEL) number 4/1994 modified issue in 2012. Results show that the sound pressure level (SPL) in operator ear and the noise dose % from all tractors under all cases were more than EEL allowable 90 dBA criterion level for 8 hour of operation. The obtained results indicated that the noise levels with “A” frequency weighting (LAeqdB) for all tractors loaded with chisel plow were the highest measured values. The noise levels emitted from the Nasr tractor were the highest and ranged from 102 to 107 dBA, for Belarus tractor were ranged from 99 to 105 dBA and for UTB tractor were ranged from 96 to 104 dBA. The daily noise exposure levels (Lex(8)dB) from Nasr, Belarus and UTB  tractors were 105, 102 and 100 dBA and the corresponding noise dose % as function of equivalent-continuous sound pressure level were 800%, 560% and 400% respectively. The results showed that there was highly significant difference in the systolic blood pressure (SBP) before and after work shift. Similar results were found for the diastolic blood pressure (DBP). For the classification of blood pressure among the operators before and after work shift, majority of the operators was under stage one hypertension (64.5 %), followed by pre-hypertension (28.4 %) and stage two hypertension (7.1%). This study showed that there was association between noise exposure and blood pressure among the operators. It is recommended that; the tractors operators must use one of hear protecting tool to increase working hours, arrange work schedules to let operators exchange work activities so that no one person is exposed to the noise for more than permissible hours in one day and proved tractors with a cabin for the tractors types under this study.