scholarly journals Measurement of the black globe temperature to estimate the MRT and WBGT indices using a smaller diameter globe than a standardized one: Experimental analysis

2019 ◽  
Author(s):  
Carlos Vargas-Salgado ◽  
Cristian Chiñas-Palacios ◽  
Jesús Aguila-León ◽  
David Alfonso-Solar
Keyword(s):  
Heat Stress ◽  
Human Performance ◽  
Mean Radiant Temperature ◽  
Measuring Device ◽  
Wet Bulb Globe Temperature ◽  
Margin Of Error ◽  
Globe Temperature ◽  
Radiant Temperature ◽  
Performance Behavior ◽  
Black Globe Temperature

Heat stress can affect negatively human performance, behavior and even health, therefore, mean radiant temperature (MRT) and wet-bulb globe temperature (WBGT) measurement and monitoring should be obtained for any environment in which people are constantly exposed. The aim of this work is to compare the globe thermometer temperature (tg), used for calculating both MTR and   WBGT, using a smaller globe compared to a standardized diameter. For such purpose, a prototype has been designed. The device consists of an Arduino MEGA board, three temperature sensors, two black globes (Copper globe, matt black painted) and an anemometer. As an effort to use a device with a globe easier to handle in a real measuring device, a 9 cm diameter globe has been used which has a smaller diameter than a standardized one (15 cm); the third temperature sensor is used to measure the air temperature. MRT monitoring tests were carried out using the proposed prototype,  collected data were compared between the smaller and the standardized diameter globes measurements according to UNE EN ISO 7723 and NTP 322 recommendations. Results of this work show that it is possible to use a smaller diameter globe in a heat stress monitor, with an acceptable margin of error compared to a standardized size globe.

scholarly journals Mean Radiant Temperature Measurements through Small Black Globes under Forced Convection Conditions

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 621
Author(s):  
Francesca Romana d’Ambrosio Alfano ◽  
Giorgio Ficco ◽  
Andrea Frattolillo ◽  
Boris Igor Palella ◽  
Giuseppe Riccio
Keyword(s):  
Heat Stress ◽  
Forced Convection ◽  
Response Times ◽  
Table Tennis ◽  
Mean Radiant Temperature ◽  
Metrological Analysis ◽  
Experimental Apparatus ◽  
The Mean ◽  
Globe Temperature ◽  
Radiant Temperature

One of the most critical variables in the field of thermal comfort measurements is the mean radiant temperature which is typically measured with a standard 150 mm black globe thermometer. This is also the reference instrument required for the assessment of heat stress conditions by means of the well-known Wet Bulb Globe Temperature index (WBGT). However, one of the limitations of this method is represented by the relatively long response time. This is why in recent years there has been a more and more pressing need of smart sensors for controlling Heating Ventilation and Air Conditioning (HVAC) systems, and for pocket heat stress meters (e.g., WBGT meters provided with table tennis balls). Although it is widely agreed that there is a clear advantage of small probes in terms of response times, their accuracy is a still a debated matter and no systematic studies aimed at metrologically characterizing their performances are actually available, due to the difficulty of reproducing measuring conditions such as a black enclosure at uniform temperature. In this paper the results of a metrological analysis of two small globes (38 and 50 mm diameter) carried out by means of an experimental apparatus specifically designed to reproduce a black uniform enclosure are presented and discussed. Experimental results revealed a systematic underestimation of the mean radiant temperature predicted by small globes of more than 10 °C in forced convection and at high radiative loads.

scholarly journals Arduino-based prototype to estimate heat stress indices in urban environments

2019 ◽  
Author(s):  
Carlos Vargas-Salgado ◽  
Lina Montuori ◽  
Paula Bastida-Molina ◽  
David Alfoso-Solar
Keyword(s):  
Heat Stress ◽  
Atmospheric Pressure ◽  
Urban Environments ◽  
Tree Planting ◽  
Stress Index ◽  
Wet Bulb Globe Temperature ◽  
Globe Temperature ◽  
Heat Stress Index ◽  
Radiant Temperature ◽  
Comfort Indices

Thermal comfort indices are normally used for assessing and controlling heat stress conditions in both: insides and outsides environment. In this paper, the results of the design and test of an Arduino-base prototype for estimating heat stress index is presented.  This prototype allows the accurate detection of wind speed, air temperature, relative humidity, precipitation, atmospheric pressure, irradiation and globe temperature. By means of these parameters, it is possible to obtain indices such as mean radiant temperature (MRT) and wet bulb globe temperature (WBGT). As a result, the indices are estimated, storage in a database and analyzed. These values will be used in the future to measure the mitigation of heat stress in urban environments, by means of the construction of green facades and green roof or tree planting.

EFFECTS OF INONIZING RADIATION CAUSED HEAT STRESS ON THE HUMAN BODY FOR STANDARD ISO 7243

2013 ◽  
pp. 47-57
Author(s):  
Van Trong Le ◽  
Thi Tuyet Mai Nguyen ◽  
Thi Xuan Duyen Nguyen ◽  
Ba Luan Nguyen ◽  
Tuyen Pham ◽  
...  
Keyword(s):  
Heat Stress ◽  
Risk Assessments ◽  
Management Systems ◽  
Temperature Index ◽  
Wet Bulb Globe Temperature ◽  
Simple Index ◽  
Simple Tool ◽  
Results Management ◽  
Globe Temperature ◽  
Hot Environments

Objectives: Presents heat stress Standard ISO 7243, which is based upon the wet bulb globe temperature index (WBGT), and considers its suitability for use worldwide. Materials and Methods: The WBGT index are considered and how it is used in ISO 7243 and across the world as a simple index for monitoring and assessing hot environments. Results: Management systems, involving risk assessments, that take account of context and culture, are required to ensure successful use of the standard and global applicability. For use outdoors, a WBGT equation that includes solar absorptivity is recommended. A ‘clothed WBGT’ is proposed to account for the effects of clothing. Conclusion: ISO 7243 is a simple tool to assess the heat stress and may be applicated worldwide.

scholarly journals Estimation of Mean Radiant Temperature in Urban Canyons Using Google Street View: A Case Study on Seoul

2022 ◽  
Vol 14 (2) ◽  
pp. 260
Author(s):  
Eun-Sub Kim ◽  
Seok-Hwan Yun ◽  
Chae-Yeon Park ◽  
Han-Kyul Heo ◽  
Dong-Kun Lee
Keyword(s):  
Heat Stress ◽  
Spatial Patterns ◽  
High Density ◽  
View Factor ◽  
Mean Radiant Temperature ◽  
Street Canyons ◽  
Google Street View ◽  
Street Level ◽  
Street View ◽  
Radiant Temperature

Extreme heat exposure has severe negative impacts on humans, and the issue is exacerbated by climate change. Estimating spatial heat stress such as mean radiant temperature (MRT) is currently difficult to apply at city scale. This study constructed a method for estimating the MRT of street canyons using Google Street View (GSV) images and investigated its large-scale spatial patterns at street level. We used image segmentation using deep learning to calculate the view factor (VF) and project panorama into fisheye images. We calculated sun paths to estimate MRT using panorama images from Google Street View. This paper shows that regression analysis can be used to validate between estimated short-wave, long-wave radiation and the measurement data at seven field measurements in the clear-sky (0.97 and 0.77, respectively). Additionally, we compared the calculated MRT and land surface temperature (LST) from Landsat 8 on a city scale. As a result of investigating spatial patterns of MRT in Seoul, South Korea, we found that a high MRT of street canyons (>59.4 °C) is mainly distributed in open space areas and compact low-rise density buildings where the sky view factor is 0.6–1.0 and the building view factor (BVF) is 0.35–0.5, or west-east oriented street canyons with an SVF of 0.3–0.55. However, high-density buildings (BVF: 0.4–0.6) or high-density tree areas (Tree View Factor, TVF: 0.6–0.99) showed low MRT (<47.6). The mapped MRT results had a similar spatial distribution to the LST; however, the MRT was lower than the LST in low tree density or low-rise high-density building areas. The method proposed in this study is suitable for a complex urban environment consisting of buildings, trees, and streets. This will help decision makers understand spatial patterns of heat stress at the street level.

Consistency Assessment of Heat Stress Monitoring of Outdoor Workers Using Sweat Rate Measurement and Wet Bulb Globe Temperature WBGT in Arid and Semi-Arid Climates

Health Scope ◽  
2018 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Hamidreza Heidari ◽  
Farideh Golbabaei ◽  
Aliakbar Shamsipour ◽  
Abbas Rahimi Forushani ◽  
Abbasali Gaeini
Keyword(s):  
Heat Stress ◽  
Sweat Rate ◽  
Rate Measurement ◽  
Stress Monitoring ◽  
Wet Bulb Globe Temperature ◽  
Outdoor Workers ◽  
Globe Temperature ◽  
Semi Arid

scholarly journals Trend Analysis and Temporal and Spatial Distribution of Wet Bulb Globe Temperature as a Heat Stress Index in Iran during the Summer Season over a 30-year Period

2021 ◽  
Author(s):  
Gholamabbas Fallah Ghalhari ◽  
Somayeh Farhang Dehghan ◽  
Elham Akhlaghi Pirposhteh ◽  
Mehdi Asghari
Keyword(s):  
Global Warming ◽  
Heat Stress ◽  
Stress Index ◽  
Upward Trend ◽  
Temporal And Spatial Distribution ◽  
Wet Bulb Globe Temperature ◽  
Globe Temperature ◽  
June July ◽  
Heat Stress Index ◽  
High Range

Introduction: Global warming is one of the most important environmental problems that have raised researchers’ attention. The present study aimed to analyze heat stress trends using the Wet Bulb Globe Temperature (WBGT) index in the country of Iran during the summer over a 30-year period. Materials and Methods: Daily summertime statistical data regarding mean temperature and mean relative humidity, taken from 40 synoptic meteorological stations across Iran during a 30-year period were obtained from the Iranian National Meteorological Department. The De Martonne climate classification system was used to categorize various climate regions of Iran. The WBGT index was calculated using the formula given by the Australian Bureau of Meteorology. The Mann-Kendall statistical test and the Sen's slope estimator were used to analyze the trends of the WBGT index. Results: The WBGT index had an upward trend during the three months of June, July, and August in 71.42%, 57.14%, and 66.66% of all stations and this trend was statistically significant in 53.32%, 50%, and 42.85% of those stations, respectively. Moreover, throughout the summer, 45% of the WBGT index measurements were in the medium range (18-23°C), 37.5% were in the high range (23-28°C), and 17.5% were in the very high range (> 28°C). Conclusion: The WBGT index followed an upward trend during the summer, especially in semi-arid regions of Iran. Considering the phenomenon of global warming, it is essential to monitor, plan ahead, and take necessary precaution measures for sensitive populations who are at high risk areas of the country.

scholarly journals Impacts of heat stress conditions on mortality from respiratory and cardiovascular diseases in Brazil

2020 ◽  
Vol 11 (3) ◽  
pp. 297-330
Author(s):  
Beatriz Fátima Alves de Oliveira ◽  
Ludmilla da Silva Viana Jacobson ◽  
Letícia Palazzi Perez ◽  
Ismael Henrique da Silveira ◽  
Washington Leite Junger ◽  
...  
Keyword(s):  
Heat Stress ◽  
Respiratory Diseases ◽  
Stress Conditions ◽  
Response Curves ◽  
Capital Cities ◽  
Wet Bulb Globe Temperature ◽  
Risk Of Exposure ◽  
Potential Impact ◽  
Globe Temperature ◽  
The Impact

This study assesses the risk of exposure to heat stress conditions and their potential impact on mortality from cardiovascular and respiratory diseases in Brazilian capital cities for warming levels of 1.5 °C, 2.0 °C and 4.0 °C in the RCP8.5 scenario. The risk of exposure and the impact of heat stress conditions on mortality were measured by the Wet Bulb Globe Temperature (WBGT) index. The impact on health was estimated by applying exposure-response curves between WBGT and health outcomes in the projections. The potential impact on mortality was measured by attributable fraction of mortality due to heat stress. The results showed an increase in heat stress conditions for Brazil, especially in the Northern and Center-Western regions. The estimated curves showed an association between the WBGT and mortality by cardiovascular and respiratory diseases in Brazil, with an upward impact trend, according to the levels of warming and heterogeneous results among the capitals.  

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