A major occupational hazard for the workers in rice mills is the noise during the operation of various machines. A noise survey was conducted in the workrooms of eight renowned rice mills of the north-eastern region of India established during the period between 1980 and 1985. The rice mills were selected on the basis of the outcome of a walk-through noise survey involving several rice mills of the region. A noise survey map of each rice mill was drawn to identify the predominant noise sources and the causes of high noise in the workrooms of the rice mill. The sound-pressure level (SPL) in the workrooms of the rice mill varied from 78 to 92 dBA. The paddy cleaner, rubber roll sheller, compartment separator, rice cleaner, auxiliary sieve shaker and an electric motor without enclosure were found to be the predominant noise sources in the workrooms of the mill. The causes of high noise in the rice mills may be attributed to the use of a long flat belt drive, crank-and-pitman mechanism, absence of an electric motor enclosure, poor machine maintenance and inadequate acoustic design of the workroom of the rice mill. About 26% of the total labourers were found to be exposed to higher levels of noise than 85 dBA. Subjective response indicated that about 26% of the total labourers felt noise interferes in their work and about 49% labourers were of opinion that noise interferes with their conversation. Context: Noise from machines in the rice mills was found to be the major occupational hazard for the rice mill workers.
The predominant noise sources need to be identified and the causes of high noise need to be studied to undertake the appropriate measures to reduce the noise level. Aims: To identify the predominant noise sources and their distributions in rice mills, to study the causes of high levels of noise in rice mills and to examine the response of the workers towards noise. Settings and Design: A noise survey was conducted in eight renowned rice mills of the north-eastern region of India. The mills were selected based on a walk-through survey conducted for the identification of rice mills with high noise. A noise survey map of each rice mill was collected by following the guidelines of Canadian Centre for Occupational Health and Safety (CCOHS).
The basic concept of "rubber roller husker"is the process of peel bran (husk) using frictional forces that occur between rice and rubber roll. When un-hulled rice through the gap between the rubber roll, on the one hand will be restrained due to friction with the auxiliary roll and on the other hand will be pushed due to friction with the main roll. Because the distance between the two rollers arranged around 0.5-0.8 mm or smaller than the thickness of the un-hulled rice grain, then the friction that occurs will be stronger than the resilience husk itself. The condition causes the husk to be separated from brown rice.