The development of a rational heat stress index called thermal work limit (TWL) is presented. TWL is deŽ ned as the limiting (or maximum) sustainable metabolic rate that euhydrated, acclimatized individuals can maintain in a speciŽ c thermal environment, within a safe deep body core temperature (< 38.20±C) and sweat rate (< 1.2 kg/hr¡1). The index has been developed using published experimental studies of human heat transfer, and established heat and moisture transfer equations through clothing. Clothing parameters can be varied and the protocol can be extended to unacclimatized workers. The index is designed speciŽ cally for self-paced workers and does not rely on estimation of actual metabolic rates, a process that is difŽ cult and subject to considerable error. The index has been introduced into several large industrial operations located well inside the tropics, resulting in a substantial and sustained fall in the incidence of heat illness. Guidelines for TWL are proposed along with recommended interventions. TWL has application to professionals from both the human and engineering sciences, as it allows not only thermal strain to be evaluated, but also the productivity decrement due to heat (seen as a reduced sustainable metabolic rate) and the impact of various strategies such as improved local ventilation or refrigeration to be quantitatively assessed.
- Scarlet Tech Ltd.
- Limiting metabolic rate (thermal work limit) as an index of ...
Beat the Heat: Occupational Exposure to Heat and Hot Environments
With summer underway, now is the perfect time for organizations to examine their policies and procedures regarding employee heat exposure, especially in light of the recently published document from NIOSH titled, “Occupational Exposure to Heat and Hot Environments”, Publication Number 2016-106. What is the Issue? Heat-related injuries and illnesses in the workplace are more common than you would think. In 2010, for example, there were 4,190 injury or illness cases related to heat that resulted in...
Empirical validation of a new heat stress index
Thermal stress is a well-recognised health hazard in the workplace. In addition to the health deficits, working in the heat can impact significantly on the productivity of some industries which are located in harsh environments. A long-standing dilemma in OHS has been the specification of what constitutes a safe working environment. The current indices used to evaluate the environment are either flawed or are difficult to implement. A new heat stress index, the thermal work limit, has now been developed which...
Heat waves in Central Europe (1991–2006)
The extreme weather phenomenon of heat waves poses a serious threat to humans and has been shown to contribute to increased sickness rates and even deaths, mostly in large cities. The paper concerns the occurrence of heat waves in Central Europe. Data was collected from five regional weather stations in Budapest, Krakow, Lvov, Prague and Vienna and included records of the average, maximum and minimum daily air temperatures during the period 1991–2006. The authors defined a heat wave as an unbroken period of at...
New Measures to Protect Workers from Heat Stress in China
Work system to control heat exposure It is stipulated in the Measures that working time under high temperature shall be controlled by employers, unless exceptional cases of damaging life & property security and public interest exist. When the temperature reaches 40°C, outdoor work shall cease. When it stands at 37°C to 40°C, outdoor work shall not exceed more than 5 hours. Whereas at 35°C to 37°C, shifts shall be arranged so that continuous exposure to high temperature is avoided,...
Heat Stress In The Workplace
Heta stress monitoring, why you should monitor, effects of heat stress and how to combat it in the workplace. Why should you measure heat stress? If you or your employees work in hot environments you may be susceptible to heat stress. Heatstress us caused when the temperature of a surround area or the core body temperature is raisedresulting in dangerous high levels. High core body temperature can result in internal heat damage tovital organs. How can you tell? If you do work in hot environments there are...