Which Environmental Indicator Is Better Able to Predict the Effects of Heat Stress on Construction Workers?

Abstract

Extremely hot and humid environments are common in numerous occupational settings. Construction work is tough and physically demanding, and the difficulty is exacerbated by the hot and humid weather of tropical and subtropical regions. Having established heat stress models through different environmental indicators, this study aims to ascertain which environmental indicator would be better able to predict the effects of heat stress on construction workers. Field studies were conducted during summer in Hong Kong from July 2011 to August 2011. Physiological, work-related, environmental, and personal parameters were measured to validate the established heat stress models on the basis of 411 sets of synchronized meteorological and physiological data collected from construction workers in two different construction sites. The mean absolute percentage error (MAPE) and Theil's U inequality coefficient were used to assess these models in terms of predictive accuracy. Wet bulb globe temperature (WBGT) was found to have the This is the Pre-Published Version.A c c e p t e d M a n u s c r i p t N o t C o p y e d i t e d2 highest validity (MAPE = 6.5%, Theil's U inequality coefficient = 0.05) and practicality in predicting the effects of heat stress on construction workers. Specific heat stress guidelines can be formulated based on WBGT, which can protect well the health and safety of site personnel working in hot and humid weather conditions.

Effects of Heat Stress on Construction Labor Productivity in Hong Kong: A Case Study of Rebar Workers

“…The WBGT guideline was used to modify basic training during extreme conditions. Although WBGT was recognized as the most widely used index to manage heat stress, and was revealed to have the highest validity in predicting the effects of heat stress on construction workers [ 27 ], there is no reference to national standards (e.g., ACGIH) or the International Standard for WBGT and the recommendations of construction work input. Thus, further WBGT guidelines for construction work should be developed by taking into account the intensity of construction work, site environment (e.g., in shade, outdoor, with or without cooling facilities), and the characteristics of construction workers.…”

“…The WBGT has been recognized by several agencies (e.g., the American Conference of Governmental Industrial Hygienists, National Institute for Occupational Safety and Health, International Organization for Standardization) as a safety index to set limits in industrial workplaces [ 11 ]. Furthermore, Yi and Chan revealed that WBGT has the highest validity in forecasting the impacts of occupational heat exposure in the construction industry [ 27 ]. In this study, we used an instrument (QuesTemp 36, Quest Technologies, Onoconomac, WI, USA) to measure and monitor the WBGT ( Figure 1 ).…”

“…The participants were asked to stop when their HR reached 95% of the age-predicted HR max , or when they self-reported reaching exhaustion (whichever came first). Rest periods of 15 and 30 min were arranged between bouts of work in the morning work session and afternoon work session (i.e., 10:00–10:15 in the morning and 15:00–15:30 in the afternoon) [ 27 ]. Thus, six test bouts were included, i.e., 1st morning work (MW 1 ), morning rest (MR), 2nd morning work (MW 2 ), 1st afternoon work (AW 1 ), afternoon rest (AR), and 2nd afternoon work (AW 2 ) in each day’s wear-trial test.…”

Health Profile of Construction Workers in Hong Kong

“…Although a great amount of effort has been made to improve safety and health [1,2,3,4], construction remains as one of the most hazardous sectors owing to its association with a high incidence of fatalities and injuries. Global estimates by the International Labor Organization (ILO) reported that more than 60,000 fatalities annually have occurred in the construction sector [5].…”

Optimal Work Pattern for Construction Workers in Hot Weather: A Case Study in Hong Kong

“…Based upon 281 sets of synchronized meteorological and physiological data collected from construction workers in four different construction sites between July and September 2010, physiological, work-related, environmental and personal parameters were measured to construct a HTT model (Chan et al 2012a). Having been verified and validated against virgin data, the HTT model was found to be statistical acceptable (Chan et al 2012a;Yi and Chan 2013b). HTT is defined as the duration that a construction worker can work continuously without endangering their health (voluntary exhaustion).…”