Anti heat stress clothing for construction workers in hot and humid weather
Abstract
Summer time in Hong Kong is hot and humid. Record from the Hong Kong Observatory (2010a) indicates that the outdoor temperature and relative humidity in summer time can be as high as 34.9˚C and 95% respectively. Construction workers have to undertake physical demanding activities in an outdoor environment which is hot and humid during summer time. Work in such an environment poses a significant challenge for the cardio-vascular system (Marszalek et al, 2005). Construction workers are vulnerable to heat stress in summer as heat stroke has already caused a number of deaths and injuries (Apple Daily, 2010a). Construction safety clothing is gear worn by construction workers to protect them from many potential hazards inherent on the job. Often workers dislike wearing safety clothing because it can be hot, cumbersome and slow down work progress (Donald, 2010). Heat and inappropriate clothing may make workers sweat a lot. Construction workers are at greater risk for heat-related illnesses such as heat rash which is a skin irritation caused by excessive sweating during hot and humid weather (MedicineNet.com, 2010). Proper clothing is essential to combat heat rash and other heat-related illnesses. Comfort in the hot season depends on the choice of fabrics. Clothing should make workers feel cool, dry and comfortable, and more importantly, able to protect them against the damaging UV rays from the sun. Construction work is a tough job which demands additional requirements on clothing. High quality industrial apparel is important for providing a layer of protection against cuts and abrasions, as well as the environment and weather. Clothing has to be durable with high thread count, reinforced seams, and heavy duty rivets that fit well enough to not present a hazard around moving parts, but still provide flexibility to react on the job site (Palmer, 2010). Obviously, clothing for construction workers during summer time warrants special attention.
The Construction Industry Council (CIC) addressed this important issue by setting up an Informal Task Force on Working in Hot Weather. The CIC has promulgated a set of basic guidelines on site safety measures in hot weather and provided some recommendations on clothing and protective equipment (Section 16 of the Guideline, Construction Industry Council, 2008). The Informal Task Force, however, advocated in the 5th Progress Report of Committee on Construction Site Safety to the CIC that further research on thermal stress measured by established parameters should be conducted to refine the initial guidelines.
The aim of this study is to address this pressing need of the industry by adopting a scientific approach to assess the effects of heat stress on construction workers and to design proper clothing for construction workers accordingly. A set of physiological and environmental parameters, namely oral temperature, skin temperature, ambient temperature, relative humidity, wind velocity, solar infrared radiation and UV radiation, heart rate variability, energy expenditure, minute ventilation, blood pressure and sweating responses will be measured and monitored to find out physiological limit values at different heat exposures. With these parameters in place, proper clothing will be designed and engineered for construction workers to cope with the hot and humid weather by systematic investigating the impact of key factors such as garment style, fit, structures of fibres, yarns and fabrics, and their functional performances/properties such as breathability, ventilation, thermal insulation, IR and UV blocking/transfer, sweat transfer and anti-microbial function.
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