Kestrel Meter 5400 Heat Stress WBGT Meters 

*Please Note: Tripods are not included with any 5400 Models.

Find Tripods in Accessories.

IMPORTANT: All Kestrel 5400 units are backed by a 5-year warranty. To ensure your warranty remains active, it is essential to keep your meter in a reasonable working condition.

To avoid voiding your warranty, only use lithium batteries with all Kestrel meter models. Alkaline Batteries will void you warranty This is clearly stated in the box of all Kestrel Meters and User Manual

Additionally, consider purchasing a 1060 Pelican case along with the required foam insert to protect your Kestrel 5400 and keep it within warranty requirements. See the links below for Pelican case products designed specifically for the Kestrel 5400.

Pelican 1060 Clear Micro Case

Pelican Case 1060 Pick 'N' Pluck Foam Insert

Models & SKUs:

• K5400 Heat Stress (Orange): 0854ORA
• K5400 Heat Stress (Tan): 0854TAN
• K5400 Heat Stress + Vane Mount (Orange): 0854VORA
• K5400 Heat Stress + Vane Mount (Tan): 0854VTAN
• K5400 Heat Stress Pro with Compass and LiNK + Vane Mount (Orange): 0854LVCORA
• K5400 Heat Stress Pro with Compass and LiNK + Vane Mount (TAN): 0854LVCTAN

What's new with the Kestrel 5400 over the Kestrel 4400/4600 it replaced in late 2015: 

As for weather reading features, they will be the same.  You won't get a 'better' temperature reading, wind reading, etc, or even more readings than available on the 4400/4600... Still, the same quality USA-made meter backed by a 5-year warranty.  That being said there are some pretty outstanding updates.

• Flag warnings via loud buzzer & LED beacon!
• Bluetooth LINK works with PC/Mac via Dongle
• Bluetooth LINK to Smartphones / Mobiel / Android / IOS
• Takes 1 AA battery (instead of 2 AAA)
• Battery door is in the back, sealed away from the motherboard, should your battery leak as was common with all the 4000 series.  All 5000 battery doors are the same and interchangeable.
• Slightly larger and improved higher contrast/resolution screen for any lighting (even sunlight) and easy on your eyes.
• Intuitive user-interface screen navigation
• Multiple Languages (English, French, German, Spanish)
• Scratch and breakage-resistant window
• All meters include both options of Red (NV - Night Vision) & White backlights.
• Slightly bigger, and more robust, though not really a noticeable difference.
• Roughly 10,000 data points.  4000 series all had under 5000 data points.

The Kestrel 5400 is revolutionary in size, cost, and capability for those in need of measuring Heat Stress.  Available with or without LiNK (Bluetooth) and/or a compass.

Along with having a Wet Bulb Global Temperature reading, the Kestrel 5400 displays thermal work limit (“TWL”), another recognized composite heat stress prediction tool. For both WBGT and TWL, the Kestrel 5400 provides on-screen alarms when conditions enter the caution and danger zones, providing clear and immediate guidance that heat illness prevention steps must be taken.  Clothing levels can also be customized, making the Kestrel 5400 particularly useful in activities requiring heavy protective gear which worsens heat stress.  The Kestrel 5400 also displays natural wet bulb temperature and black globe temperature.

Accurate and localized measurement of heat stress conditions is a key component of a heat illness prevention plan.  The Kestrel 5400 Heat Stress Tracker, new from NK, answers this need. 

Human heat stress results from a combination of many environmental factors – air temperature and humidity along with radiant heat from the sun and surfaces, balanced by the cooling effect of breezes or airflow. Anyone who has stood under welcome shade adjacent to a sizzling parking lot understands that these conditions must be evaluated exactly where peoples’ activities are taking place.  The most common composite measurement used to determine appropriate exposure to heat stress conditions is Wet Bulb Globe Temperature or “WBGT.”

Roberts WO. Medical management and administration manual for long distance road racing.

In: Brown CH, Gudjonsson B, eds. IAAF Medical Manual for Athletics and Road Racing Competitions:

A Practical Guide. Monaco: International Amateur Athletic Federation Publications; 1998: 39-75.

For comparative adjustments to Calor and Scarlet units please email us at [email protected]

How Does the Kestrel 5400 Work?

The Kestrel 5400 uses a 1-inch black globe to gather information about the environment, which isn't possible with current Kestrels. As is true with the original Wet Bulb Globe Temperature apparatus, a temperature sensor is installed inside the globe that will measure the temperature inside. The temperature inside the globe is a function of the ambient air temperature, solar insolation, and wind speed.

As one can imagine, a sunny day will make the globe hotter because it's painted black, and colder ambient temperatures will have a tendency to cool off the globe. Lastly, the wind will cause the globe to get closer to the ambient air temperature because it will carry heat away from the globe when the air is cooler, or increase heat transfer to the globe if the air is warmer than the globe.

The Kestrel must sit out for a period of time to allow the globe to adjust to true atmospheric conditions; we recommend a minimum of 7-10 minutes. The globe temperature is then taken into account along with other measurements, such as ambient temperature, humidity, and pressure, to calculate more meaningful measurements, such as Wet Bulb Globe Temperature and Thermal Work Limit.

Indoor Use

Reading the WBGT is important even in indoor settings where heat stress is a concern.  The Kestrel has an 'indoor' setting on the WBGT setting which basically turns off the function of taking into account the direct solar radiation from the sun.  It's important to place the Kestrel in a representative area of the conditions that the workers face.  Remember, wind plays a factor in WBGT, so a vane mount can be used indoors as well.  In the case of a ceiling fan, if the Kestrel doesn’t pick up the ceiling fan, then you are essentially getting the “worst case” WBGT readings which is not actually a bad thing.  If the airflow is pretty strong from the fan and you want to have that factored in, you could mount the Kestrel sideways (vs vertical) so the impeller picks up the wind more realistically.  You can use the Clamp to achieve this.

Why Use WBGT as a Heat Stress Indicator vs. just using the Heat Index? 

Wet bulb globe temperature (WBGT) is based on an equation that uses a combination of environmental elements to calculate the reading. The calculation is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle, and cloud cover (solar radiation).

Heat index takes into consideration temperature and humidity, and is calculated for shady areas.

There is a difference.

Monitoring the WBGT of the environment is quickly becoming the accepted and preferred method of measuring heat stress. Several sports organizations use WBGT to assess the potential risk of environmental stress on athletes. These organizations include the National Athletic Trainers Association (NATA), National Collegiate Athletic Association (NCAA), and the Women’s Tennis Association (WTA).

Thermal Work Limit (TWL) The unit will also display a measure of human heat stress known as “Thermal Work Limit” which, is measured in terms of the heat energy a person can dissipate from their surface area in Watts per square meter (w/m2). The measurement is based on Globe Temperature, Relative Humidity, Ambient Temperature, Barometric Pressure, Wind Speed, and four parameters specific to an individual and their clothing. 4 Settings with preset constants are pre-installed in the meter.

Please click here to read more about the Kestrel 5400 TWL algorithms and presets.

The Kestrel Meter 5400 Heat Stress Meter measures/features

• Wet Bulb Globe Temperature ("WBGT")
• Thermal Work Limit ("TWL")
• Waterless! Natural Wet Bulb Temperature accurately calculated from on-board digital sensors with no tedious setup or maintenance.
• Large, hi-res, hi-contrast, graphic display is perfectly readable in the brightest sunlight and is backlit for use in low-light conditions.
• Globe Temperature
• Naturally Aspirated Wet Bulb Temperature
• Wind Speed (Current, Average, & Maximum)
• Wind Direction – only possible when using together with a Vane Mount on a Tripod
• Crosswind – only possible when using together with a Vane Mount on a Tripod
• Head/Tail Wind – only possible when using together with a Vane Mount on a Tripod
• Altitude
• Pressure trend
• Barometric pressure
• Relative humidity in %
• Heat stress index 
• Dewpoint
• Wet bulb temperature
• Density altitude
• Wind chill
• Air, water, and snow temperature °F or °C
• Waterproof
• Time and date
• Easy- to-read backlit display
• Data Logger (automatic and manual)
• Customizable data storage - 2900 data points
• Humidity sensor can be calibrated in the field with our Relative Humidity Calibration Kit.
• Customize screens to display user-selected measurements
• Graph and recall trends
• User-replaceable impeller
• Data charting
• Upload to a computer (with optional interface)
• Meets MIL-STD-810F 516.5 Procedure IV Transit Shock test - 20 drops from 5 ft. IP-67 sealed to exclude dust and water at 3 ft. submersion
• Five languages (English, French, Spanish, German, and Italian)
• US Patent Nos. 5,783,753 and 5,939,645 and 6,257,074
• Made in the USA
• 5 Year Warranty

Works with Compatible Apps:

Kestrel LiNK for Windows & Mac

• Kestrel LiNK for Windows
• Kestrel LiNK for Mac(Coming Soon!)

Simple communication to Windows and Mac computers is provided through the optional LiNK. USB Dongle or USB Data Transfer Cable. Download your data to view, analyze and archive.  Enables firmware update of Kestrel 5 series meters.

Kestrel LiNK for iOS & Android

• Kestrel LiNK for iOS
• Kestrel LiNK for Android

Wirelessly connect with iOS and Android devices.  When in range, view real-time measurements, receive on-screen alerts and download your data.  Logged data can be viewed, analyzed, archived and shared via e-mail, Facebook and Twitter.  Enables firmware update of Kestrel 5 series meters. NOTE: Range up to 100’ line of sight – reduced by walls and obstructions.

Includes:

• Neck Lanyard
• AA Lithium Battery (Average Life 400 Hours)
• Protective Drawstring Pouch
• Instruction Manual 
• Five Year Warranty
• LiNK version also includes a sturdy zippered carry case

How to manage Heat Stress by monitoring your Hydration Levels:

Managing heat stress is crucial during hot weather. Healthdirect Australia, our national virtual public health information service, offers valuable guidance on how to monitor your hydration levels.

Their urine colour chart provides essential information to help individuals stay hydrated and cope with high temperatures effectively. By following the recommendations on the chart, people can better understand their hydration needs, identify signs of heat stress, and take necessary precautions.

With Healthdirect's support, staying informed and vigilant becomes easier, ensuring that everyone can enjoy a safer and healthier experience during heatwaves and hot climates.