The study of work-related musculoskeletal disorders amongst workers in brick making factory in South Africa

Abstract: In brick manufacturing industries, studies have been conducted and there has
been a general indication that working with bricks may dispose towards upper
limb disorders This study investigated WMSDs in one brick-making factory,
concentrating on the sorting section. The primary objective was to identify
specific ergonomic risk factors for WMSDs among the brick sorters. The
Logical Framework Approach method has been used in the designing of this
project because of its simplicity and is objectives oriented, target group
oriented as well as participatory oriented.

Semi-structured interviews were conducted regarding subjective
pain/discomfort on different body regions and psychosocial situations, which
brick sorters perceived as contributing factors to those disorders.
Workplace analysis has been accomplished by observing the employees as they
were doing the task. The main demands of the tasks and the risk factors as
to, which may be present, were listed.
Physical exposure to risks for potential WMSDs has been assessed using ovako
working posture analysis method. Lifting indices (LI) based on the 1993
revised National Institute for Occupational Safety Health lifting (NIOSH)
equations were calculated.

Results of the interviews showed that all of the respondents reported having
experienced pain/discomfort arising from work, with the body parts most
commonly affected being the low back, followed by the wrists/hands,
shoulders, neck and upper back. The respondents consistently identified
factors such as frequent twisting and bending of the trunk as the leading
cause of the pain/discomfort. These results were supported by the posture
analysis results, which also recommend that the corrective measures for
improving the working postures are needed immediately. NIOSH results showed
the recommended weight limit ranging from (0.50-0.93 kg) substantially less
than the weight of even a single brick (2. 7 kg). The LI ranged from 2.90-
5.4, which exceeds 1.0 indicating the job to be stressful. As a result, the
study suggests that the job should be redesigned ergonomically to eliminate
the risk factors that may dispose towards upper limb disorders.

In conclusion, the results of this study point out a number of important
factors that must be addressed in order to reduce WMSDs among brick sorters.
These include the workplace design necessitating frequent bending and
twisting of the trunk, handling techniques, the way work is organized. Other
problems such as inadequate breaks and high speed of work also need to be
addressed.