HOW TO READ THE WIND WITH A WINDSOCK?
KNOW WIND DIRECTION AND STRENGTH
Placed outdoors and shaped like a cone, windsocks easily indicate wind direction. All you have to do is look at the tip of the sleeve, which is always pointing in the direction of the wind.
Windsocks can also be used to measure wind speed. The wind enters through the larger end and inflates each coloured ring one by one. It is estimated that each inflated ring is equivalent to 5 knots. When the sleeve is fully inflated, the wind is blowing at over 25 knots (45km/h). Conversely, if the sleeve is parallel to the mast and therefore fully deflated, the wind force is said to be "zero", i.e. less than 5 knots.
However, a windsock can only provide an estimate of wind speed, and will never be as accurate as an anemometer.
WHERE ARE WINDSOCKS INSTALLED?
To ensure perfect visibility, windsocks are installed in clear, unobstructed areas.
Windsocks can be installed in a multitude of locations. For example, they can be found on beaches, building sites, terraces, or paragliding landing and take-off sites. As a general rule, they are small and do not necessarily come in the standard colors (red and white). Their main purpose is to indicate wind direction.
Furthermore, in certain fields of activity or under certain conditions, ITS INSTALLATION MAY BE MANDATORY:
AIRPORTS AND AIRFIELDS
Windsocks at airports and aerodromes are essential for pilots to know the direction and strength of the wind on the ground. Installed at the edge of the runway, they must meet STNA standards and be approved by the International Civil Aviation Organization.
FREEWAYS AND VIADUCTS
The Highway Code provides for the installation of windsocks along freeways and viaducts in areas prone to frequent high winds. Called J7 beacons, they help motorists avoid being caught out by the wind. They are usually accompanied by an A24 crosswind warning sign.
HELIPORTS
Heliports, like airports and aerodromes, are required to install a "wind direction and intensity signal". These windsocks must be positioned so as to be perfectly visible to helicopters in flight, day and night. To this end, a LED lighting system is added to the windsock.
SEVESO SITES AND CONSTRUCTION SITES
European industrial sites classified as SEVESO are required by law to install windsocks to prevent the spread of toxic substances by the wind. (Instruction of 4/9/1970, circular of 24/7/72) Ministry of the Environment). On construction sites, windsocks help to prevent wind-related accidents, particularly with regard to crane stability.
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