Resumo

CASTILLO, Juan  e  OROZCO, Alejandro. Evaluation of a calculation method for estimating work load in workers exposed to thermal stress. Salud de los Trabajadores [online]. 2010, vol.18, n.1, pp.17-33. ISSN 1315-0138.

Accurate estimation of physical load represents a challenge when determining optimal working times and distribution of tasks in work system design. Tools that allow a rapid and objective evaluation, for the purpose of establishing adequate work-rest cycles, are needed in industrial environments. In this study, worker activity was measured through the use of action analytical actigrams, aided by Kronos data logging software. For estimation of physical work load we used a modified equation based on the average metabolic rate calculation described in the TLV booklet and on the safety guide "Exposition professionnelle à la chaleur". Calculation of the thermal comfort index was based on the thermal stress and thermal demands indices developed by Malchaire (1986). Results from this study establish that physical work load estimation requires the use of a model that calculates and integrates several variables (tasks and activities structure, effective time of exposure, and WBGT index). The analytical method used allows estimation of physical work load. However, it should be recognized that physical work load estimation requires the correct identification and understanding of the relationships between work conditions and the physiological demands of the job. Industrial application: the method developed in this study represents a reliable and valid tool for assessing physical work load under conditions of thermal stress.

Palavras-chave : Ergonomics; Work Load; Hot Temperature.