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The Kestrel 4400 is a portable handheld device that provides waterless WBGT measurements and displays an on-screen warning signal when environmental conditions enter a danger zone. Not only does it have all the features of the Kestrel 4000; a comprehensive weather instrument offering an accurate measurement of wind speed, temperature, humidity and barometric pressure, but it also provides Wet Bulb Globe Temperature, thermal work limits, globe temperature and naturally aspirated wet bulb temperature, which determine the heat strain on human performance.
The Kestrel 4400 comes in a handy transportable miniature briefcase with the Kestrel vane mount which allows the unit to be mounted on a tripod for longer-term monitoring and logging of heat stress conditions.
At the touch of a button environmental conditions are clearly shown in digital or graphical form. Individual functions can be displayed in a choice of three different formats either as a current reading or a minimum/maximum/average reading or a chart display. There are also three user screens, which can be customised to simultaneously display the three most appropriate functions for the application.
The Kestrel 4400 can be set up to log data manually or automatically at programmable intervals in order to display a history of weather information. Graphs display up to 2400 data points and the value, time, date of capture point can be shown.
The stored data can also be uploaded to a PC, for analysis/storage with the optional Kestrel Interface and Communicator software. With the Bluetooth® model, data may be streamed live via Bluetooth wireless technology.
High precision Zytel® bearings and a lightweight impeller provide accurate air flow measurements and the ability to operate at speeds as low as 0.6m/s. The impeller is user-replaceable in case of damage, also ensuring high accuracy levels are maintained for life. An integral flip-open hard cover protects the impeller when not in use which is particularly helpful when using other functions.
A precision external thermistor sensor provides fast response temperature readings and accuracy of +/- 1°C. The 0.1 degree resolution of the display aids in determining when a consistent reading has been reached. A special housing protects the relative humidity sensor from contamination providing an accuracy of +/-3%.
A monolithic silicon based pressure sensor enables barometric pressure and altitude to be calculated with a resolution of 0.1mb and 1m respectively.
The Kestrel 4400 also has a 1" black globe with a thermometer in the centre. This thermometer reads the temperature of the black globe which indicates the radiant heat exposure of one in sunlight. Also built into the Kestrel 4400 are advanced algorithms to calculate the wet bulb globe temperature (WBGT).
All text on the Kestrel can be displayed in a choice of five different languages, with a choice of English, French, Italian, Spanish or German.
The Kestrel 4400 is powered by two easily replaceable AAA batteries which enjoy prolonged battery life averaging around 400 hours, due to two power saving modes integral within the Kestrel settings.
And finally, the Kestrel 4400 comes with a 5 year limited manufacturers warranty from date of purchase.
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 air flow. The most common composite measurement used to determine appropriate exposure to heat stress conditions is Wet Bulb Globe Temperature or WBGT.
Until now, most accurate WBGT measurement tools were large, cumbersome to use (requiring the transport of distilled water along with the measurement unit) and/or expensive. NK have added a compact black globe thermometer to the already proven sensor suite of the Kestrel 4000 Pocket Weather Tracker, then built in advanced algorithms to calculate WBGT values within 2.2 deg C of the values obtained from a full-sized WBGT setup.
The Kestrel 4400 Heat Stress Tracker uses a 1" Black Globe which is calibrated to achieve the same measurements as a 6" globe.
The Kestrel 4400 Pocket Heat Stress Tracker fits in a pocket or small Kestrel Belt Carry Case and provides accurate waterless WBGT measurements within minutes of exposure to the air.
The Kestrel 4400 also displays thermal work limit (TWL), another recognised composite heat stress prediction tool. For both WBGT and TWL, the Kestrel 4400 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 customised, making the Kestrel 4400 particularly useful in activities requiring heavy protective gear which worsens heat stress. The Kestrel 4400 also displays natural wet bulb temperature, black globe temperature, and mean radiant temperature (MRT).
The Bluetooth® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any use of such marks by Richard Paul Russell Ltd is under license. Kestrel, Kestrel Tracker, Pocket Wind, Pocket Weather and the Kestrel logos are trademarks owned by Neilsen Kellerman. Other trademarks and trade names are those of their respective owners.