Overview/summary for Manufacture
Heat stress issues in the manufacturing industry relates to a combination of environmental/climatic factors (with absolute air temperature and humidity as the predominant stressors for WBGT-indoor heat load), additional heat from the industrial production, the workers’ metabolic heat production and clothing that reduces heat dissipation. The manufacturing sector includes a great range of activities and production techniques, from small-scale enterprises using traditional production techniques to very large enterprises using robots and automated production systems. Temperatures at production/work-sites may be very heterogeneously distributed, but are often higher than the outdoor (shade) temperature, as industrial machinery adds heat to the outdoor heat load. The limited ability to get rid of industrial heat at specific production sites is a challenge that requires attention at the planning stage as well as implementation stage of manufacturing processes.
Occupational heat stress is highly dependent on individual work intensity (and hence endogenous heat production) and heat-dissipation possibilities (boundary effects provided by special clothing/helmets/safety shoes etc. worn for protective purposes). Hence, higher heat stress than prescribed/interpreted from climatic/environmental data is often observed among manufacturing workers. Preliminary research from the HEAT-SHIELD project, conducted on manufacturing workers, indicates that workers engaged in manual tasks and required to wear protective clothing are especially affected by heat during a large part of the year (from one-third to half of the year). Fatigue, thirst, and notably high head temperatures (for those wearing safety-helmets) were the most frequent issues/symptoms reported. Many workers appear to commence work in a hypo-hydrated state or fail to maintain hydration during the work-shift and dehydration will aggravate heat-issues such as dizziness, fatigue and concentration problems.
To minimize heat-health problems as well as avoid significant loss of productivity, the following actions and precautions should be considered (with timely relevant training of workers and supervisors) to increase awareness of preventive methods available:
Allow workers to have scheduled (brief) breaks with “active resting” e.g. planned hydration and cooling (e.g. by one of the below mentioned methods) – overall this will benefit productivity and prevent excessive fatigue or lost work time due to illness.
Ensure access to cold drinking water (during severe periods crushed ice to maximize cooling) and advise workers to drink on a regular basis – and drink before getting thirsty.
Make it possible to adjust airflow at individual workstations to facilitate heat dissipation.
When heat loads are very high, and especially for elderly workers, encourage spreading water on exposed skin to support evaporative cooling.
Consider optimization of clothing – although protective clothing is required in many manufacturing setting – it is possible to find (scenario-specific) solutions that allows for protection but with breathable material that allows for airflow and evaporation.