Effect of ventilated workwear and working schedule on physiological and psychological responses of construction workers, no. 2: Actual investigation at an active construction site

Abstract

Although the use of cooling garments to prevent heat disorders has been increasing, the effectiveness of such garments at construction sites (CSs) remains underexplored. We investigated the relationship between the thermal environment at a CS and the physiological and psychological responses of workers wearing/not wearing ventilated work wear (VWW). The study participants were rebar placers and form workers employed at an outdoor CS. The thermal environmental conditions and the physiological and psychological responses of the workers were measured. The overall, chest, and forearm skin temperatures of the workers not wearing VWW were significantly higher than those of workers wearing VWW. To clarify the effects of VWW and working schedules on body weight loss (BWL), the BWL rate was simulated based on the evaporation rate according to a regression formula of measured data in an artificial chamber. The BWL during the late shift was higher than that in the early shift, causing dehydration in the afternoon. To prevent this condition, more water intake is required during the late shift.

Analysis of sweating efficiency and its effects on the heat strain alleviation of clothed subjects

“…The accurate evaluation of the SE can be a cornerstone for the prediction of the heat strain of a human subject, which can lead to a new heat‐strain index expected to replace it with the empirical WBGT. Besides, in recent years, an increasing number of workers have been wearing jackets with fans to reduce the heat strain in a hot environment, where the trunk areas of the body are exposed to an airflow of higher air velocity (Kuwabara et al, 2020); the new approach of this paper could open the way to identify the characteristics of this garments rationally and to improve them with the predicted heat strain of MST. Further studies on the SR and CE for other conditions are desired for the identification of the SE.…”

“…1. Two-part-pattern: The SR arranged for the typical regions of the body is shown in Figure 1 (Kuno, 1934;Weiner, 1945), where the data (= S i in W•m −2 ) are shown in the ratio of S i over that of the mean value S w , S i /S w . As it is apparent at first glance, the body surface appears to be divided into two parts as a stepwise: the high (head and trunk) and low (limbs) SR parts.…”

“…These eight sections are used to calculate the surplus of the ineffective dripping sweat rate and organize the data of SR in corresponding sections. The typical 8-step-pattern of SR for exercising subjects is F I G U R E 1 Normalized regional sweat rate S i /S w (SR) at typical sections of the body given by Kuno (1934) and Weiner (1945) (Data modified by the authors).…”

“…shown in Figure 2 based on the existing data (Kuno, 1934;Smith & Havenith, 2011;Weiner, 1945), which were used in the present work for the analysis.…”

“…In the present study, we first analyze the SE based on the relationship between the regional SR and regional CE focusing on exercising subjects. Many studies were performed on SR (Kuno, 1934;Smith & Havenith, 2011;Weiner, 1945) and CE (Nishi & Gagge, 1970;Oliveira et al, 2014), where the CE is evaluated based on the convective heat transfer coefficients. However, to our knowledge, no attempt has been made to consider the SE quantitatively in relation to the regional SR and CE.…”