Monitoring Thermal Stress of Steel Re-Rolling Mill Workers

Monitoring heart rates using portable sport tester, this study investigated thermal stress as an important parameter of measuring physical effort of steel re-rolling mill workers. In all, 34 adult male subjects (age: 36 ± 4.1 years) volunteered for physiological tests that provided physiological reactions from the implication of their strenuous job-tasks and heat exposure. The subjective perceptions on the prevalence of heat stress, sweating, and heat exhaustion from extremely hot working environment was investigated using a questionnaire and ergonomic checklist. In findings, there were no significant differences of age, height, weight and rest pause except higher heart rates and sweat loss among most of the workers involved in strenuous job-tasks. The maximum working heart rate was measured as 140–190 beat per minute (bpm). The rise in oral temperature was found as 37.8°C (± 0.15°C) among the workers who worked in high heat and radiant environment. The results should however be compared with and confirmed for other stressful manual activities in high heat and radiant work environment. It would thus be appropriate to develop a local standard that can be useful to eliminate an eventual biasing effect of monitoring heart rates for measuring thermal stress for tropical countries. Further study is sought with the control subjects due to different socio-cultural, climatic and psychological factors of the sample used in the context of Bangladesh.