A digital anemometer is traditionally used to measure various atmospheric conditions and effects, such as wind/air speed, air temperature and air humidity. It can be used by hobbyists such as plane, skydiving or kite enthusiasts, but the extremely accurate readings produced by an anemometer are critical in many other applications, such as environmental monitoring for ventilation certification in premises, aviation, nautical studies, weather stations and ship navigation.
Apart from checking that ventilation systems are extracting the correct amount of air from buildings, another health & safety application for using an anemometer is to confirm wind conditions are not too dangerous for working at height.
What is a digital anemometer?
The traditional way to measure wind speed and velocity is to use a manual anemometer, which can be fitted with cups or vanes to physically catch the wind and provide a reading using a sensor which counts and converts the rotations. In truth, a digital anemometer works in much the same way, except the sensor provides digital readings which are converted much more accurately. A digital anemometer is a lightweight hand-held instrument with a large, backlit digital screen and which has a circular set of wind vanes or blades encased in the top section in a wheel shape. The instrument will usually be supplied with in a rubber moulding, which is used to protect the instrument from knocks and rain ingress.
A digital anemometer, such as the TIS 1309 supplied by Test Instrument Solutions, is powered by a battery and most instruments are capable of recording wind/air speed in a variety of units, such as litres per second, miles per second, kilometres per hour, feet per minute, knots, miles per hour and nautical miles per hour, along with displacement volumes and are accurate to within 3%.
How the digital anemometer works
In order to establish an accurate reading it is important that a digital anemometer is always within its calibration cycle, in other words it has been calibrated within a specified time period. If the instrument is out of calibration, ie. the specified time/date has passed, you cannot rely on the instrument’s readings and you shouldn’t use it.
Most digital anemometers can test for wind/air speed, wind/air temperature (either Celsius or Fahrenheit) and wind strength, using the Beaufort scale. So the first task is to turn the instrument on, ensure it has a battery fitted and then scroll through the modes to find and select the correct measurement test setting for the test you want. You can then scroll through the various units of measure and select the right one.
To carry out the test itself you should hold the instrument as high up in the air as possible. Align the instrument with the wind/air direction as closely as you can. The speed at which the vanes turn on the instrument is proportional to the wind/air speed, a sensor in the instrument then measures the speed of rotation in the vanes, processes the data collected and converts this to a wind/air speed reading. Other sensors in the instrument can measure the temperature and humidity.
Unless you are measuring a wind tunnel in controlled conditions, it is important to note that wind/air speed and strength changes all the time, and therefore so too will the reading on the LCD screen. However, the instrument should give you a minimum and maximum reading for the period you test for, and an average reading for the period you test for. These readings can be used to establish an accurate picture of the atmospheric conditions over this time period, particularly where you are measuring external atmospheric conditions.
Please note that this section is for information purposes only. Anyone using equipment referred to in this section must be suitably qualified and/or experienced within the respective field. If in doubt before use, please consult a qualified electrician or engineer & thoroughly read all instruction booklets.