You have probably heard of the term ‘heat index’ used when a temperature ‘feels’ different than what your weather app is showing you. Heat index simply takes into account humidity to the temperature in shaded areas. This means that if you work in direct sunlight you can not be sure that you are safe.

In order to determine the true real feel of the weather, a technology known as Wet Globe Bulb Thermometers provide precise readings on when being exposed to the heat is too dangerous. Heat stress trackers can be used in a vast range of industries such as agriculture, construction, military and facility management.

The Kestrel 5400 not only provides heat index readings, but uses Wet Globe Bulb Thermometer (WBGT) to provide an indication on heat stress in direct sunlight and therefore provides a fantastic solution to occupational heat tracking needs. WBGT is based on an equation that uses a combination of environmental elements to calculate the reading including humidity, wind, sun angle and cloud cover.

Industries such as sport, military, construction and agriculture are prime examples of professions that require WBGT technology, as much of their work is done outside in direct sunlight. The Kestrel 5400 is sold at RPR beginning at £408.29 (ex. VAT) for the non-LiNK version and is the leading choice in heat stress management.

The Kestrel 5400 displays a Thermal Work Limit (TWL) which measures real human heat stress. TWL is measured in terms of the heat energy a person can dissipate from their surface area in Watts per square meter (w/m2) and provides solutions already to US organisations such as National Athletic Trainers Association (NATA), National Collegiate Athletic Association (NCAA) and the Women’s Tennis Association (WTA).

For further accuracy, the Kestrel 5400 allows you to change 4 settings to get the most out of your meter. These settings include position of the body, surface area of the body, intrinsic clothing insulation factor, and vapor permeation factor (AKA how much of your body is allowed to breathe).

Made in the USA, the Kestrel 5000 series provides data on a full suite of weather paaramaters including dew point, density altitude, wind chill, air, water, and snow temperature and wind speed. The Kestrel 5400 is waterproof, has an easy-to-read backlit display and can be linked to a data logger or the LiNK bluetooth app to provide easy-to-read graphical data that can be stored and customised.

A fresh batch of Kestrel 5400’s have just hit our store. If you are interested in how heat stress trackers can be used in your workplace, give us a call at +44 (0) 1590 641223 or email the sales team at