An Evaluation of the NIOSH Lifting Equation: A Psychophysical and Biomechanical Investigation
Using the results of psychophysical and biomechanical experiments, NIOSH (National Institute for Occupational Safety and Health) Recommended Weight Limit (RWL), the Lifting Index (LI), the form of the asymmetry multiplier, and the criterion for compression force were investigated. Analysis of the results indicated a significant difference between the NIOSH RWL and the reported Maximum Acceptable Weight of Lift (MAWL). Contrary to the NIOSH lifting equation, the form of the asymmetry multiplier was found to be non-linear. The overall average of peak compression force on the L5/S1 was 3685 N. Fifty-eight percent of all compression forces reported in the biomechanical experiment were found to exceed the suggested 3400 N set by NIOSH guidelines. These results support previous research findings on the validity of NIOSH guidelines.
Relationships between the NIOSH (1991) Lifting Index, Compressive and Shear Forces on the Lumbosacral Joint, and Low Back Injury Incidence Rate Based on Industrial Field Study
The main objective of this study was to investigate relationships between the values of NIOSH (1991) Lifting Index calculated for as set of industrial manual handling tasks, the corresponding (estimated) compressive and shear forces on the lumbosacral joint (L5/S1), and the back injury incidence rates based on analysis of the epidemiological field data. A strong positive correlation was observed between the estimated compressive forces on L5/S1 and the lifting index (LI) values, and between the incidence rates (IR) of low back injury and the LI index. Two sets of regression models describing the relationships between the lifting index (LI) and the compressive forces on the L5/S1 were developed. It was shown that the LI=1.0 corresponds to about 1.8 kN and 2.4 N of compression on the L5/S1, for the destination and origin of the lift, respectively. For the lumbar compressive strength values (with safety factor of one standard deviation) of 4.1 kN for males (40 years of age), proposed by Jager and Luttman (1992), the corresponding values of the lifting index are as follows: LI=4.1 (for the lift destination) and 6.4 (for the lift origin). Implications of results for prevention of back injury due to manual lifting were discussed.
Suitability and water quality criteria of an open drainage municipal sewage water at Coimbatore, used for irrigation.
Sanganur canal is the major open drainage system which has intricate linkage with storm water supply, domestic sewage and industrial effluent disposal. Water samples from various stations were collected and analysed for physicochemical parameters to assess the water quality of the Sanganur canal system. The study revealed that physicochemical parameters like pH, EC, TDS, DO, BOD, COD exceeded the permissible limit, clearly indicating the need of proper treatment of waste water before discharge into the Noyyal river.