Wet Bulb Globe Temperature (WBGT)

The Recommended Measurement for Preventing Heat Stress Injury & Illness

Exertional heat stress poses a serious risk to people expected to practice, perform, or work in hot and humid environments. Monitoring the Wet Bulb Globe Temperature (WBGT) is the first step in assessing the actual heat stress risk in a specific environment.

Research shows that monitoring the environment contributes to better outcomes when it comes to mitigating risk and improving safety.

Athletic Heat Safety & Performance

Athletic Heat Safety & Performance

A 2017 study published in the Journal of Athletic Training shared research findings detailing the disparity between National Weather Service predictive measurements vs the actual, observed onsite WBGT measurements of athletic surfaces.

WBGT measurements should be taken at regular intervals on each outdoor athletic playing surface to adequately capture the environmental conditions affecting physical performance and the risk of exertional heat illness."

Onsite WBGT measurements are recommended before physical activity to best approximate the true heat-exposure effects on athletes' health, safety, and performance."

Key Study Findings

Onsite WBGT measurement remains the best option for determining environmental conditions and the need for heat-safety physical-activity modifications or cancellations.

The National Weather Service WBGT underestimated the local athletic-surface heat stress, especially when the surface was black or red or made of synthetic material.

Using National Weather Service wet-bulb globe temperature (WBGT) forecasts resulted in heat-safety category misclassification across all athletic surfaces.

Source: "The Heat Strain of Various Athletic Surfaces: A Comparison Between Observed and Modeled Wet-Bulb Globe Temperatures" J. Luke Pryor, PhD, ATC, CSCS*†‡; Riana R. Pryor, PhD, ATC*†‡; Andrew Grundstein, PhD; Douglas J. Casa, PhD, ATC, FNATA, FACSM‡ Journal of Athletic Training; Volume 52, Number 11, November 2017


Military Heat Safety & Performance

Military Heat Safety & Performance

Heat stress safety is of paramount importance in the military. Military personnel often operate in extreme environments, from scorching deserts to humid jungles, where high temperatures and intense physical activity can lead to heat-related illnesses such as heat stroke or exhaustion. Such conditions not only compromise the individual's health but also hinder operational effectiveness. Therefore, it's crucial to monitor and manage heat stress.

Wet bulb globe temperature (WBGT) should be measured 'at the location of greatest heat risk', not 'that of most convenience'. A handheld WBGT tracker used at point-of-exertion could reduce this incidence."

Source: “Measuring wet bulb globe temperatures at point-of-exertion in worldwide UK military settings: a longitudinal observational study determining the accuracy of a portable WBGT monitor” Patricia Falconer Hall1, J Blackadder-Coward2 and H Pynn3 AMS Support Unit, Army Medical Services, Camberley GU15 4PQ, UK DOI: 10.1136/bmjmilitary-2020-001551


Occupational Heat Safety & Performance

Occupational Heat Safety & Performance

Monitoring the Wet Bulb Globe Temperature (WBGT) is an essential aspect of heat safety and prevention for workers. By monitoring the WBGT regularly, employers can take necessary measures to ensure the safety and health of their workers, such as implementing rest breaks, providing cool drinking water, and modifying work schedules or tasks. This proactive approach can significantly reduce the risk of heat exhaustion, heat stroke, and other heat-related illnesses, making the workplace safer and more productive.

Heat conditions can change rapidly and management commitment to adjusting heat stress controls is critical to prevent heat illness. An individual at the worksite should be responsible for monitoring conditions and implementing the employer's heat plan throughout the workday."

The individual who is responsible for the heat plan should be on-site, where the workers are. On-site monitoring allows accurate determination of heat stress."

Source: OSHA


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