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The thermal environment
Published in Sue Reed, Dino Pisaniello, Geza Benke, Kerrie Burton, Principles of Occupational Health & Hygiene, 2020
Wet bulb globe temperature (WBGT) uses air temperature (Ta), globe temperature (Tg) and a natural wet bulb temperature (Tnwb). These parameters are incorporated into one of two formulae for either indoor or outdoor measurements: Indoor:WBGT=0.7Tnwb+0.3TgOutdoor:WBGT=0.7Tnwb+0.2Tg+0.1Ta
The thermal environment
Published in Sue Reed, Dino Pisaniello, Geza Benke, Principles of Occupational Health & Hygiene, 2020
Ross Di Corleto, Jodie Britton
Wet bulb globe temperature (WBGT) uses air temperature (Ta), globe temperature (Tg) and a natural wet bulb temperature (Tnwb). These parameters are incorporated into one of two formulae for either indoor or outdoor measurements: Indoor:WBGT=0.7Tnwb+0.3TgOutdoor:WBGT=0.7Tnwb+0.2Tg+0.1Ta The basic effective temperature (BET) is used predominantly in the underground coal-mining industry, and combines dry bulb and aspirated wet bulb temperatures with air velocity. It should be noted that caution should be exercised when utilising BET in situations where values above 31°C may be encountered, since the index is less accurate above this value (Hanson et al., 2000).
Overview of the Most Significant Standards on Thermal Comfort
Published in Ivana Špelić, Alka Mihelić-Bogdanić, Anica Hursa Šajatović, Standard Methods for Thermal Comfort Assessment of Clothing, 2019
Ivana Špelić, Alka Mihelić-Bogdanić, Anica Hursa Šajatović
ISO 7243, ISO 7933 and ISO 9886 provide the current ISO system for the assessment of heat stress (Parsons, 1999, 2013). ISO 7243:2017 Ergonomics of the Thermal Environment – Assessment of Heat Stress Using the WBGT (Wet Bulb Globe Temperature) Index, also known as BS EN 27243:2017, provides a method for monitoring the thermal conditions to which workers are exposed (ISO 7243:2017). The WBGT index value is used to predict the heat stress and thermal strain when working in hot environments together with additional factors of activity and clothing. ISO 7243 was first published in 1982 presenting the WBGT index in order to avoid the complicated determination procedure for the effective temperature index. The index combined temperature, humidity, radiation and wind into a single value (Parsons, 2006).
Actual and simulated weather data to evaluate wet bulb globe temperature and heat index as alerts for occupational heat-related illness
Published in Journal of Occupational and Environmental Hygiene, 2019
Courtney E. Morris, Richard G. Gonzales, Michael J. Hodgson, Aaron W. Tustin
Wet bulb globe temperature (WBGT) was developed in the 1950s as part of a program to manage heat stress in U.S. Marine Corps trainees. WBGT is a weighted average of dry bulb (ambient) temperature, natural wet bulb temperature, and globe temperature. WBGT instruments respond to all four environmental heat determinants—air temperature, relative humidity, air movement, and radiant heat (e.g., sunlight)—to which humans are exposed. For this reason, in the early 1970s, ACGIH and NIOSH began advocating the use of WBGT as part of occupational heat stress control programs.[2,7] Since then, despite some limitations,[8] WBGT has remained the preferred environmental heat metric for HRI prevention at both civilian and military workplaces.[1,2,9]
The heat exposure risk to outdoor workers in Brazil
Published in Archives of Environmental & Occupational Health, 2020
Daniel Pires Bitencourt, Paulo Alves Maia, Rodrigo Cauduro Roscani
The meteorological data used to estimate the WBGT were: air temperature (T), in °C; relative humidity (RH), in %; and wind velocity (V), in m s−1. These data were collected at the weather station network of the National Meteorological Institute, which is composed of 265 conventional stations (Figure 1). The data are available at http://www.inmet.gov.br/projetos/rede/pesquisa for 18 Universal Time Coordinates (UTC) (15-Local Standard Time (LST)) and cover the period between January 1, 1961 and December 31, 2010. Based on the available data (00, 12, and 18 UTC), the 15 LST is the time closest to the time of the highest temperature of the day.
The association between wet-bulb globe temperature and other thermal indices (DI, MDI, PMV, PPD, PHS, PSI and PSIhr): a field study
Published in International Journal of Occupational Safety and Ergonomics, 2020
Sajad Zare, Naser Hasheminejad, Mokhles Bateni, Mohammad Reza Baneshi, Hossein Elahi Shirvan, Rasoul Hemmatjo
The WBGT, commonly used to assess heat stress, was developed by the US navy [33]. According to Standard No. ISO 7243:2017 [34,35], WBGTeff is calculated based on measurements of natural wet temperature, radiation temperature and dry temperature. If the environment is heterogeneous and the heat load varies in different heights, it is necessary to measure WBGTeff at three heights: ankle, abdomen and heart [35]. The amount of metabolism for each occupation is calculated according to Standard No. ISO 8996:2004 [32]. Then, the weighted average time for the amount of metabolism for all responsibilities of each occupation is calculated.