Alleviation of Heat Strain by Cooling Different Body Areas during Red Pepper Harvest Work at WBGT 33

Department of Clothing & Textiles, College of Human Ecology, Seoul National University, Korea.
Industrial Health (Impact Factor: 1.12). 01/2009; 46(6):620-8. DOI: 10.2486/indhealth.46.620
Source: PubMed


The purpose of the present study was to examine the effects of different types of personal cooling equipments (PCE) on the alleviation of heat strain during red pepper harvest simulated in a climatic chamber. The experiment consisted of eight conditions: 1) Control, 2) Neck cooling scarf A with a cooling area of 68 cm2, 3) Neck cooling scarf B (cooling area 154 cm2), 4) Brimmed hat with a frozen gel pack, 5) Cooling vest (cooling area 606 cm2), 6) Hat+Neck Scarf B, 7) Hat+Vest, and 8) Hat+Neck Scarf B+Vest. Twelve subjects worked a red pepper harvest simulated in a climatic chamber of WBGT 33 degrees C. The result showed that rectal temperature (T(re)) was effectively maintained under 38 degrees C by wearing PCE. Mean skin temperature (T(sk)) and heart rate (HR) became more stable through wearing PCE. When wearing the 'Hat+Scarf B+Vest', particularly, T(sk) and HR quickly decreased to the comfort level during the mid-rest stage. We confirmed that the vest with a cooling area of only 3.3% body surface area (BSA) was effective in alleviating heat strain in a simulated harvest work. Furthermore, the heat strain of farm workers can be considerably eliminated by the combination of the cooling vest, a scarf, and a brimmed hat, with the total cooling area of 4.2% BSA.

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Available from: Joo Young Lee, Feb 05, 2014
    • "In contrast, PCSs equipped with portable ventilation fans (i.e. using air fans) are portable , lighter and applicable to a broader range (Xu and Gonzalez 2011), but their effectiveness greatly relies on the excellent air ventilation around the torso (Chan, Song, and Yang 2015). Hybrid PCSs combine two or more passive and/or active cooling methods (Choi, Kim, and Lee 2008) and are discovered to be more effective in reducing body heat stress (Chan, Song, and Yang 2015). Hybrid PCSs using both air and liquid are mostly assessed and discovered to have a limited effect in alleviating physiological and perceptual strain compared to individual air cooling or liquid cooling systems in earlier studies (Chan, Song, and Yang 2015). "
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    ABSTRACT: This study aimed to examine the effectiveness of a hybrid personal cooling system (PCS) in mitigating body heat stain while exercising in a hot environment. Eight subjects underwent two trials: PCS and CON (i.e., no cooling). All trials were conducted at an air temperature of 36±0.5 °C and RH=59±5%. The key findings demonstrated that the PCS could significantly reduce the core temperature, mean skin temperature, heart rate and physiological strain index during both exercise and recovery periods (p<0.05). Subjective perceptions were also significantly alleviated in PCS at the end of the exercise and during the recovery (p<0.05). Besides, the PCS could also bring remarkable benefits in lowering local skin temperatures and in improving perceptual sensations in both upper and lower body during both exercise and recovery periods (p<0.05). It was thus concluded that the hybrid PCS is effective in mitigating body heat strain while exercising in a hot environment.
    No preview · Article · Sep 2015 · Ergonomics
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    • "All rights reserved. Cadarette et al., 2006; Chou et al., 2008; House et al., 2013; Gao et al., 2011; Kenny et al., 2011), athletes performing sports activities or exercises (Purvis and Cable, 2000; Tate et al., 2008; Barwood et al., 2009a; Brade et al., 2010), and people doing office or other physical work (Choi et al., 2008; Gao et al., 2012; Nishihara et al., 2002). The cooling efficiency of PCM incorporated clothing has been widely studied by using thermal manikins, human trials and physiological models (ASTM F2371; Bogerd et al., 2010). "
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    ABSTRACT: Introduction: Heat stress has been considered as a common risk to impair work performance, which may lead to heat illnesses, work incidents, or even fatality. Over the past few decades, various types of personal cooling systems (PCSs) have been developed to mitigate heat strain, e.g., cooling vests with ice packs or phase change material (PCM) packs or frozen gel strips, garments with liquid cooling systems and garments with forced air ventilation. In this study, a novel personal cooling system (PCS) incorporated with both PCMs and ventilation fans was developed and its cooling efficiency was evaluated on a sweating manikin. Methods: A novel hybrid portable PCS incorporated with PCMs and ventilation fans was developed, which consisted of a long sleeve jacket and a pair of long pants. Four fans were embedded at the lower back and the lateral pelvis regions of the PCS. Twenty-four PCM packs (Gao et al., 2012) were also incorporated into the PCS. Six PCM packs were located at the chest region, 8 packs at the back region, 4 packs at the upper arm regions and 6 packs at the front thigh regions. A polyester T-shirt and briefs were worn under the PCS. A Newton type 34-zone sweating thermal manikin was used. A constant surface temperature of 34.0 °C was used to evaluate the cooling effect of PCS in the so-called isothermal condition (Tmanikin = Ta = Tr). The sweating rate was set at 1200 Four test scenarios were chosen: fans off with no PCMs (Fan-off, i.e., CONTROL), fans on with no PCMs (Fan-on), fans off with fully solidified PCMs (PCM+Fan-off ), and fans on with fully solidified PCMs (PCM+Fan-on). Two hot environments were selected: hot humid (HH) and hot dry (HD). The relative humidity (RH) of the HH and HD conditions was 75% and 28%, respectively, and the mean (SD) air velocity was 0.4 (0.1) m.s-1. Results and Discussion: Table 1 shows the heat loss and the cooling time of the PCS under different scenarios. In both conditions, the heat loss of Fan-on was higher than that of Fan-off. The PCMs led to a higher manikin heat loss at the initial testing stage and it gradually decreases to a steady state. There was no significant heat loss difference between PCM+Fan-on and Fan-on when the PCMs were fully melted. Similarly, no heat loss difference was found between PCM+Fan-off and Fan-off. The PCM+Fan-on and Fan-on exhibited a higher cooling power than PCM+Fan-off. The PCMs provided about 90~110 min and 20~30 min cooling duration in HH and HD conditions, respectively. Conclusion: The results demonstrated that the portable PCS developed could be able to provide effective heat removal from a sweating manikin in two hot environments with differing humidity levels, with fan cooling being much more effective with a lower rh, and more. The PCMs applied in the PCS provide effective cooling at the initial stage; as the manikin skin surface gradually gets wet, ventilation fans start to provide evaporative cooling .
    Full-text · Conference Paper · Jun 2015
    • "This explains why much more energy as latent heat is stored/released when a PCM changes its phase compared with the energy stored as sensible heat (Mondal, 2008 ). Phase-change materials may be incorporated into fabrics, or packed and sealed as frozen gel and salt packs as used in various cooling vests (Bennett et al. , 1995 ; Choi et al. , 2008 ; Chou et al. , 2008 ; Gao et al. , 2010a ; Reinertsen et al. , 2008 ; Webster et al. , 2005 ). Based on their chemical and physical properties, commonly used PCMs may be categorized into inorganic salt hydrates, organic hydrocarbons and fatty acids (Table 9.1 ). "
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    ABSTRACT: The various types of phase-change materials (PCMs), which absorb or release stored latent heat when they change phases causing cooling and warming effects, are described and the working principles are outlined. The various ways of incorporating PCMs into textiles for protective clothing are explored, and critical factors identified that determine the effectiveness of PCM cooling and warming effects. Examples of applications are given. Standards and testing, future trends and challenges are discussed.
    No preview · Chapter · Jan 2014
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