Pranab Kumar Nag

Work accidents among shiftworkers in industry

Abstract The study examined the risk potentials and accident patterns amongst the monthly rotating shiftworkers and permanent nightworkers in textile industries. The retrospective- cum-prospective study covered 3470 fatal and non-fatal accidents that had been taken place in 11 textile departments, spinning, weaving, engineering, etc. A detailed questionnaire survey indicates that frequent occurrence of accidents in the industries was a culmination of multiple factors, such as man-machine interfaces, methods of work, working conditions and environmental stresses. Man-days lost due to accidents were highest in spinning departments (i.e., 3.25 days per accident). Physical injuries in textile workers were moderate to serious in severity, and the fingers of the upper extremity accounted for highest number of accidents. Higher rate of accidents were noted during June to August, and January and February had lower rate of accidents. Analysis of log-linear model of contingency tables suggests that the time variations (e.g., first and second half of each shift) have some association with the occurrence of accidents in different activities. About 60% accidents of the morning shift were in the first half of the shift; in night work, the second half of the shift constituted 57% of the accidents. In general, there are two main risk factors: (i) the start up of the working period (e.g., first half of the morning shift) and (ii) the accumulated fatigue (e.g., a rise in percentage of accidents reaching peak at fifth or sixth hour in the night shift). Relevance to industry Industrial accidents result in considerable human suffering and economic losses at different levels in society. The paper describes the occurrence of accidents and types of traumatic injuries in textile industries, and relates to critical temporal factors as associated risks to work. Organizational commitment to safety promotion and joint optimization of work-time scheduling may add to strategic accident prevention.

Efficacy of a water-cooled garment for auxiliary body cooling in heat

The efficacy of a water-cooled jacket for auxiliary body cooling was examined under a simulated hot environment. The personal garment comprised of a water re-circulating three-layered vest of cotton fabric lined with 2 mm diameter latex tubing and inter-spaced coating of rubberized solution. Four subjects wearing the water-cooled jacket were tested in the environment chamber (30, 35 and 40 degrees C DB, 50-60% RH, air velocity 0.3, 0.6 and 0.9 m/s, with corresponding average effective temperature of 26 +/- 2.3, 33 +/- 1.1 and 36 +/- 1.5 degrees C). The inlet water temperature was maintained at 10-12 degrees C, with flow rates of 2.6 +/- 0.3, 4.3 +/- 0.3 and 5.1 +/- 0.3 l/h). At 30 degrees C DB, variation in water flow had marginal effect on microclimate, while at higher temperatures (35 and 40 degrees C DB), the re-circulating cooled water had noticeable effects in lowering microclimate, trunk and other skin temperatures, and maintaining the body core within 36.7 +/- 0.2 to 37.5 +/- 0.2 degrees C, over 2 h exposure at 35 and 40 degrees C DB. The observation indicates that the water-cooled jacket provided auxiliary cooling to maintain comfortable microclimate, skin and body core temperatures. This enabled subjects to sustain comfortable heat balance over 2 h heat exposure without any noticeable heat strain.

Ergonomics in sickle operation

Sickle operation in harvesting has been analysed with reference to design features of nine different types of sickles, and field and laboratory based investigations on biomechanical stresses and physiological valuation on six farmers. It has been indicated that the blade geometry contributes significantly to human performance and there is ample scope for further design optimisation. The suggested modifications are: (i) sickle weight - 200 g; (ii) total length of sickle - 33 cm; (iii) handle length - 11 cm; (iv) handle diameter - 3 c cm; (v) radius of blade curvature - 15 cm; (vi) blade concavity - 5 cm; (vii) serrated sickle: tooth pitch - 0.20 cm and tooth angle - 60 degrees; (viii) ratio of the length of cutting surface to chord length - 1.20.

Influence of arm and wrist support on forearm and back muscle activity in computer keyboard operation

The effects of forearm and wrist supports on the upper extremity postures in computer keying tasks and associated EMG activity of arm and back muscles were examined (N = 8). Four positions were forearms unsupported (floating) and supported, wrists supported by bead packed (WR1) and gel-filled (WR2) wrist rest. The right and left elbow extensions were 65 degrees and 68 degrees , respectively, in unsupported forearms. Bilateral elbow extension increased with the forearm/wrist supports and mostly, the elbow was maintained at around 90 degrees or greater. The wrist extension decreased with forearm/wrist supports over the unsupported condition. The forearm support significantly reduced the activity of forearm extensor digitorum, i.e., right (F((1, 47)) = 12.19, p < 0.01) and left (F((1, 47)) = 5.38, p < 0.05) and upper trapezius muscles over the floating posture. Wrist rests, however, increased load on the upper trapezius; the activities of flexor digitorum superficialis and erector spinae were close to the resting EMG activity for both forearm and/or wrist support. The type of wrist rests was a concern and this study indicated that the gel filled wrist rest was advantageous in reducing the forearm muscle load, in comparison to the bead packed cushions.

Endurance limits in different modes of load holding

This study examines the influence of different modes of load holding on the isometric strength exertion and endurance capacity. Six healthy males underwent longitudinal testing with the trunk, knee and elbow in 10 different (straight and bent) postures. The load heights (LH) of 320, 440, 850 and 1250 mm from the floor level with subject-load-distance (S-L-D) of 120 and 320 mm were used. It was noted that the level and duration of force exertion were higher when the load was placed closer to the body. The endurance times were consistently high with the increase in LH, highest being recorded in Position 9 - i e, with the load placed at the shoulder level and S-L-D of 120 mm. As evident from MVC and endurance times, the back straight/knee bent postures may not be preferred to back bent postures.

Risk factors and musculoskeletal disorders among women workers performing fish processing

BACKGROUND The study examined the prevalence of musculoskeletal pain and discomfort (MSD) among workers engaged in fish processing activities and identified the occupational, environmental, and psychosocial factors contributing to the MSDs. METHODS An ergonomics checklist and questionnaire on general health and psycho-social issues were administered to women workers (N = 450). The relative risk for MSDs due to demographic factors, stress symptoms, and task variables were estimated. RESULTS Nearly 71% of the women (age 23.0 ± 6.4 years) reported MSDs, chiefly in upper back (54%), lower back (33%), knee (35%), and shoulders (27%). Workers engaged in mixed task (OR 13.8; CI 8.7-22.0), ring cutting (OR 18.3; CI 11.8-24.7), having job experience <3 years (OR1.9; CI1.3-2.9), being married (OR 1.5; CI 1.1-2.2), BMI18-25 (OR 1.7; CI 1.1-2.8) had increased risk of MSDs in the upper back. The severity of pain was high among the workers with elevated co-morbidity (pain in two or more regions). One third of the workers perceived the work environment to be cause of their MSDs. Multivariate analysis using binary logistic regression model indicated that highly specialized job (OR 13.0; CI 4.7-14.2), high physical activity (OR 11.7; CI 4.6-12.7), improperly designed tools (OR 8.1; CI 3.5-9.5), poor training (OR 7.0; CI 3.3-7.5), and poor job satisfaction (OR 1.5; CI 1.1-4.8) significantly increased the risk of MSDs. Almost all the psychosocial and work stress factors were associated with lower back MSD. CONCLUSION A cold and humid environment, awkward standing work posture for long hours, high physical activities, poor task clarity, and high mental overload are important risk factors for the development of MSDs.

Physiological Reactions of Female Workers in Indian Agricultural Work

The physiological reactions of eight female workers in agricultural tasks and in leisure time activities were determined with a view to standardizing occupational workload. Maximal oxygen uptake (V02 max ) was 1.892 L per minute. Their daily energy intake was 11.06 MJ, of which 85.4% was derived from carbohydrate. Pulmonary ventilation varied from 9.5 (pounding helper) to 26.4 (pounding alone) L/min. Maximum pulmonary ventilations in the tasks were only 27 to 31% of maximum breathing capacity. Average work pulse rate in many tasks was more than 130 beats per minute. Pounding alone or in pairs and digging dry soil are the heaviest jobs, while harvesting, transplanting, uprooting, and carrying loads are moderately heavy. Whole day energy expenditure was 10.61 MJ, of which 52% was expended for the working day, while physiological cost per unit time corresponds to 28% of V02 max The workloads of the females were within reasonable limits.

Occupational injury proneness in Indian women: A survey in fish processing industries

A cross sectional survey was initiated to understand the frequency of occupational injury occurrence and the associated factors in the fish processing industries of western India involving 185 randomly selected women subjects. All the subjects were interviewed with the help of an interviewer-administered questionnaire to collect information regarding their personal, occupational and work related morbidity details (including details of occupational injuries). Logistic regression method was used to analyze the data in order to obtain the contribution of individual factors on occupational injuries. This study has shown that work related morbidity like blanching of hand (OR; 2.30, 95%CI; 1.12–4.74) and nature of job like grading (OR; 3.99, 95%CI; 1.41–11.27) and packing (OR; 5.68, 95%CI; 1.65–19.57) had a significant impact on injury causation. This study eventually concludes that apart from nature of job of fish processing workers occupational hazards prevailing in the work environment contribute significantly to the occurrence of work related injuries and prevention of such occupational hazards may help in protecting workers from occupational injuries also.

HEAT STRESS OF WOMEN DOING MANIPULATIVE WORK

Six women were exposed to nine environmental conditions, ranging from 26.0 to 35.8 degrees C effective temperature (ET), in a climatic chamber. They were involved in manipulative work in a seated position for a duration of 3 hr. The O2 uptake, heart rate, deep body (Tc) and skin temperature (Tsk), sweat loss, and perception of thermal comfort were noted. The O2 uptake increased with the time of exposure at different heat levels. The work energy demand, which was 19% of VO2max at 26 degree C ET, increased to 35% of VO2max at 35.8 degrees C ET. However, the work output declined with the increase in ET. Thus, the elevated metabolic demands were the results of the thermal stimuli. The Tsk was greatly influenced by the environmental heat; the Tc changes were gradual. The highest mean Tsk attained was 37.3 degrees C at 33.8 degrees C ET when the gradient of Tc-Tsk was only 0.5 degrees C. The rate of change in mean Tsk for 31.6 to 33.8 degrees C ET was much faster compared to the range between 26.0 and 31.6 degrees C ET. From 32.1 degrees C ET onward the Tc and heart rates rose rapidly, while the sweating rate tended to fall, indicating some hindrance for evaporative cooling. Also, thermal sensations were noted as extremely hot for the conditions 32.1 to 35.8 degrees C ET with the increase in exposure duration.

Circulo-respiratory responses to different muscular exercises

SummarySix muscular exercises, i.e., pedalling sitting (PS), cranking sitting (CS), pedalling and cranking (PCC), cranking standing (CST), pedalling reclining (PR), and pedalling with back support (PBS) were compared to see the relationship between work patterns and bodily reactions. Five young males volunteered in the study. CST, CS, PR, PS, and PBS yielded 76, 72, 72, 87, and 97% of