No abstract

Global average temperature has increase 0.2°C in the past 10 years. Furthermore, several studies have predicted that the temperature will keep increasing due to lack of effort in restricting carbon emission. Therefore, the objective of this review is to examine the impact of heat stress towards construction workers productivities and health and also assess the risk of exposure. Literature review was done through scoping method on major journal database and Google Scholar. Major heat stress models are Heat Index, Wet bulb globe temperature and Thermal Work Limit. On the other hands, there are more complex heat stress model that incorporate complex data measurement, such as Predicted Heat Strain endorsed by ISO 7933:2004. Several studies have been conducted based on these heat stress model. Findings of these studies shown that hot and humid countries, such India, China, Hong Kong, Thailand, Japan, Iran, Saudi Arabia, Egypt, United Arab Emirates, and Australia WBGT level are at least 28°C, which is beyond safe level for medium and heavy construction work. Productivities were estimated to decline up to 2% for every 1°C increase in temperature above safe WBGT level. In extremely high temperature environment, productivities can decrease in the range of 48% - 94%. Heat stress negative side effect on health include minor heat related illness such as thirst, fatigue, headache, dehydration, vertigo, nausea and muscle pain.

The objective of this study is to determine the effect of ergonomic factors, such as temperature and illuminance level towards muscle activities through repetitive loading and unloading tasks. The study settings are in Ergonomic Laboratory Chamber and a rubber factory. Six male respondents that participated in this study wear Electromyography (EMG) device on both sides of their bodies to measure muscle fatigue. EMG output signal data were analysed to determine the correlation between muscle activities with illuminance level and temperature. At constant 500 lux illuminance level and 24˚C temperature, respondent’s body shows optimum correlation between left sides and right sides. On the contrary, findings show unbalanced correlation at 19˚C and 32˚C which indicate one side of the body is using too much energy for the task.