Jeong-Wha Choi

Clothing insulation and temperature, layer and mass of clothing under comfortable environmental conditions.

This study was designed to investigate the relationship between the microclimate temperature and clothing insulation (Icl) under comfortable environmental conditions. In total, 20 subjects (13 women, 7 men) took part in this study. Four environmental temperatures were chosen: 14°C (to represent March/April), 25°C (May/June), 29°C (July/August), and 23°C (September/October). Wind speed (0.14ms-1) and humidity (45%) were held constant. Clothing microclimate temperatures were measured at the chest (Tchest) and on the interscapular region (Tscapular). Clothing temperature of the innermost layer (Tinnermost) was measured on this layer 30 mm above the centre of the left breast. Subjects were free to choose the clothing that offered them thermal comfort under each environmental condition. We found the following results. 1) All clothing factors except the number of lower clothing layers (Llower), showed differences between the different environmental conditions (P<0.05). The ranges of Tchest were 31.6 to 33.5°C and 32.2 to 33.4°C in Tscapular. The range of Tinnermost was 28.6 to 32.0°C. The range of the upper clothing layers (Lupper) and total clothing mass (Mtotal) was 1.1 to 3.2 layers and 473 to 1659 g respectively. The range of Icl was 0.78 to 2.10 clo. 2) Post hoc analyses showed that analysis of Tinnermost produced the same results as for that of Icl. Likewise, the analysis of Lupper produced the same result as the analysis of the number of total layers (Ltotal) within an outfit. 3) Air temperature (ta) had positive relationships with Tchest and Tscapular and with Tinnermost but had inverse correlations with Icl, Mtotal, Lupper and Ltotal. Tchest, Tscapular, and Tinnermost increased as ta rose. 4) Icl had inverse relationships with Tchest and Tinnermost, but positive relationships with Mtotal, Lupper and Ltotal. Icl could be estimated by Mtotal, Lupper, and Tscapular using a multivariate linear regression model. 5) Lupper had positive relationships with Icl and Mtotal, but Llower did not. Subjects hardly changed Llower under environmental comfort conditions between March and October. This indicates that each of the Tchest, Mtotal, and Lupper was a factor in predicting Icl. Tinnermost might also be a more influential factor than the clothing microclimate temperature.

Validation of clothing insulation estimated by global and serial methods

Purpose – The purpose of this paper is to examine differences between thermal insulation calculated by a global and a serial method using a thermal manikin, in comparison with human trials.Design/methodology/approach – A total of 150 single garments and 38 clothing ensembles were assessed using the manikin; 26 seasonal clothing ensembles were selected for human trials.Findings – The results showed that total insulation of single garments was 16 percent higher in the serial method than in the global method. The difference was higher in garments with smaller covering area per unit garment mass (e.g. winter garments). For seasonal clothing ensembles, the serial values were 39.2 percent (0.18 clo) for spring/fall wear, 62.6 percent (0.15 clo) for summer wear and for winter wear 64.8 percent (0.69 clo) greater than the global values. The clothing insulation by the global method was systemically lower in all 26 seasonal ensembles than values by human trials, which suggests that the values by the global calculat...

Bed climate of Korean using ondol heating system

Abstract 1. 1. To examine the influence of different bed conditions (ondol sleep, bed sleep on ondol with same bedding) of the Korean ondol traditional heating system on human response during sleep, bed climates and physiological responses such as skin and rectal temperatures, weight loss, body movement and subjective sensation were measured with 4 grown-up females as subjects while they were sleeping for 7 h. 2. 2. Bed climate: Temperatures under the mattress and inside the quilt were higher on ondol while temperatures on the mattress and humidity inside the quilt were higher on the bed. 3. 3. Rectal temperature was significantly higher on ondol; skin temperature showed no major differences in relation to bed conditions. The frequency of body movements had the highest correlation with bed climate of the parameters measured. 4. 4. Mattress weight decreased on ondol and increased on the bed. 5. 5. The frequency of body movements was significantly higher in ondol sleep. 6. 6. The subjects sensation showed difference on cushion sensation between the two types of bed condition. 7. 7. To obtain the same level of comfort on both ondol and bed sleeping conditions less thermal insulating value is needed for ondol sleep.

Effects of Local Cooling on Heat Strain in the Hot Environment

This study was to determine the effect of cooling part of the trunk without harm for the health. The results provide basic data for the development of clothing which could increase work efficiency and reduce body strain in hot environment. Eight males took part in the study. The experiment was conducted in a climate-chamber controlled with 37±1℃, 50±5%R.H. The trunk was divided into six areas to be cooled: head, neck, chest, abdomen, the upper back, the lower back. According to preceding studies, permissible safety cooling limits of skin temperature, of each part of the trunk for four hours cooling were 25℃ on the head, 20℃ on the neck, 27℃ on the chest, 25℃ on the abdomen, 20℃ on the upper back, 20℃ on the lower back. So cooling temperatures of each region set up temperatures above mentioned. In conclusion, the head, the neck and the upper back cooling could reduce sweating amount, rectal temperature and heart rates and reduce the heat stress of workers exposing in the hot environment by decreased subjective sensations of heat and comfort. Thus, it was concluded that effectiveness of cooling among the trunk was best on the head and the neck.

Relationship between Thermal Insulation and the Combinations of Korean Women's Clothing by Season - Using a Thermal Manikin -

The purpose of this study was to examine the correlation between the combination of women`s clothing by season and thermal insulation using a thermal manikin. A total of 34 kinds of clothing ensembles were selected based on previous studies(8 types for spring/fall, 7 types for summer, and 19 types for winter). The results were as follows: The thermal insulation of clothing ensembles() ranged from for spring/fall, for summer, and for winter. The correlation coefficient between the thermal insulation of clothing ensembles and thermal insulation accumulated by the individual garments composing of the clothing ensembles() was 0.982(p showed higher relationships to the and total clothing weight than to the total clothing layers or surface area covered by clothing.

Determination of the Garment Pressure Level Using the Elastic Bands by Human Body Parts

This study was to decided the proper garment pressure level on the human body parts. Six volunteers (female: 30-40years) put on the same types of bands, a brief, and a non-woven gown. Garment pressure was measured in regular order with the elastic band on the human body parts such as the upper arm, the waist, the thigh, and the calf. At the same time, physiological responses such as the skin blood flow rate on 2 fingers, 7 different skin temperatures, rectal temperature, heat rates, and subjective responses about the pressure sensation, thermal sensation, and humidity sensation were measured and inquired. The results were as follows; 1. The thicker subcutaneous fat thickness, the higher the mean garment pressure on pressurizing the upper arm(p for fat people, 20gf/ for others on the upper arms and 24gf/ on the calf.

Physiological Responses of Wearing Safety Helmet with Cooling Pack in Hot Environment

Safety helmets are used widely in various industries by workers since they are legally required to wear them. However, thermal discomfort is one of the major complaints from helmet users. To relieve this problem, frozen gelled packs can be considered for use inside the helmets. In this paper, tests were performed on humans to evaluate the physiological strains of wearing safety helmets and to investigate the effects of using frozen gelled packs inside the helmets. Experiments were conducted in a climatic chamber of WBGT under four differed experimental conditions: 1) not wearing a safety helmet(NH); 2) wearing a safety helmet with frozen gelled pack A(HA); 3) wearing a safety helmet with frozen gelled pack B(HB); and 4) wearing only a safety helmet(OH). The results were as follows. First, when comparing NH with OH, physiological responses such as , HR and sweat rate were significantly higher in OH and subjective sensations were reported as less hot and more comfortable than NH(p increase, heat storage(p

Relationships between Insensible Perspiration and Thermo Physiological Factors during Wearing Seasonal Clothing Ensembles in Comfort

The purpose of this study was to examine the relationships between thermo-physiological factors and the insensible loss of body weight(IL) of resting women wearing seasonal comfortable clothing. Air temperature was maintained at a mean of 22.5, 24.7, and 16.8 for spring/fall, summer and winter, respectively. We selected a total of 26 clothing ensembles(8 ensembles for spring/fall, 7 ensembles for summer, and 11 ensembles for winter). The results showed that 1) IL was for spring/fall environment, for summer, for winter(p for winter and for summer. This difference was significant(p, air humidity, energy metabolism, ventilation, mean skin temperature

Permissible Safety Limits in Local Cooling Focused on the Parts of Human Body

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Effect of Cold Acclimatization Training on Body Composition

The objects of this study were to investigate responses and peculiarity during local cooling by parts of the human body and to show permissible safety limits without injurious to his health because of excessive cooling when he works hot environments. It were measured rectal temperature, skin temperature, heart rate, total body weight loss, local sweat in back and thigh, clothing microclimate and subjective sensation on 8 subjects and cooling parts were head, neck, chest, abdomen, back, waist, hip, upper arm, forearm, hand, thigh, calf and foot. According to above-mentioned the first experiment, we chose permissible safety limits by parts of the human body for one hour. In the second experiment, it was showed permissible safety limits by parts which examined their safety about health through 4 hours cooling test on 3 subjects. The results are as follows: 1. As a result of the first experiment, we chose permissible safety limits by parts, as follows, head , neck , chest , abdomen , back , waist , upper arm , forearm , hand , thigh , calf and foot in , 50%R.H. environment for 1 hour. 2. As a result of the second experiment, cooling on these safety limits temperatures except chest didn`t have a bad effect on health. So it was proved that right permissible safety limits of chest was . From these results, it has been suggested that skin temperature didn`t fall below permissible safety limits when human body was to be cool by parts.