Wind Sock Fabric – ICAO & FAA Guidelines
A conical textile tube that resembles a giant sock is
known as a Windsock. It is identified with a tapered sleeve open at the both
ends. FAA provides detailed guidelines of
Specification for Wind Cone Assemblies No: 150/5345-27E
Major usage of a Windsock
• Basic guide for recognizing wind direction, strength and
speed at airports and helipads
• For wind speed and direction in chemical industries and Refineries.
How fabric plays a role in functioning of a Windsock?
To answer that, firstly it is important to be aware about
Basic functioning of a Windsock
Windsock is designed in such a way that a metal frame
holds the wider end open allowing the air flow in the wider end and exit in the
smaller end, with this the orientation of the windsock helps to identify the
direction of the wind and the shape of the tube gives an estimate of the wind
speed. Windsocks are lit at night with flood lights – either the one mounted on
the pole shining inside it or on top surrounding it at many airports.
Real Science behind Windsock functioning
Windsock is installed in the opposite direction of wind;
in short, wind direction is the opposite of the direction in which the windsock
is pointing, therefore a windsock pointing due north is actually indicating a
southerly wind. The Wind speed is indicated by the windsock's angle which is
relative to the mounting pole as per which in low winds, the windsock droops
and in high winds, it flies horizontally.
To help estimate the speed of wind, alternating stripes
of high visibility color are used where each stripe adds up to 3 knots to the
estimated wind speed and on the other hand, some circle frames mountings that
makes the windsocks to be held open at one end thereby indicating a velocity of
3 knots. The specialty of the windsock is that it is a standalone system which
works without power and displays wind speed directly to pilots and other users
whereas anemometers does not show wind speed directly and need a dissemination
system to provide the information.
Importance of Wind Sock Fabric as per ICAO and FAA
The standards listed by ICAO and FAA for fabric windsocks
explain the importance of fabric upfront with essential functioning facts. As per these reputed authorities,
• The wind cone assemblies must be designed to operate
under any ambient temperature between -67°F (-55°C) and 131°F (+55°C) and wind
speed up to 75 knots (140 km/hr or 86 mph).
• The fabric windsock must be designed in such a manner
that it takes the shape of a truncated cone when filled with air.
• The fabric windsock must be reinforced at all points
which are prone to abrasion due to flexing against the metal framework and thus
should be designed in such a manner that should allow removal and replacement
without the use of stitching.
• The fabric windsock must be constructed in such a way
that it should drain out the water.
• The minimum effective length and the throat end opening
diameter of the fabric windsock should be 8 feet & 12 feet in length with
18 inches & 36 inches throat diameter respectively.
• The fabric windsock must be designed in such a way that
it causes the windsock to fully extend when exposed to a wind of 15 knots or
• The fabric should be made of either synthetic material;
cotton or a blend of both with coating over it.
• The fabric should be water repellent.
• The fabric must have a minimum breaking strength
considering Warp - 150 pounds and Filling - 150 pounds
• Strong testing methods should be followed to determine
the minimum strength of the fabric.
How SGS Windsocks fulfill the ICAO and FAA guidelines?
Along with maintaining general listed standards of ICAO
color as SGS makes use of Hypalon fabric which is made waterproof with a high
quality UV coating that can stay unchanged for a very long life keeping
the windsock fabric water resistant easily in rainy season.
• The windsock fabrics of SGS Frangible do not offer any
electromagnetic interference and thus does not pose any danger to communication
and airline system at airports thereby ensuring safety and no deflection.
• The thickness of the windsock fabric is rightly
maintained at SGS along with all cabling and power circuits included in the
• The wind sock fabric of SGS Frangible has a shelf life
of up to 6 months to 1 year depending upon the installation area and thus
proves to be a complete value for money.
As Wind Sock specifications vary based on the type of
use, the SGS Frangible Towers has the ability of offer standardized
customization right from windsock framework to its fabric that’s why our
windsocks has been successfully tested for -
• Full impact crash test by 3rd party along with Salt
Spray+ test thereby proving its authentication.
• Temperature Resistance and Di-Electric Strength test
• Wind Load Deflection and Flammability test
• Flexural Strength; UV Resistance and Tensile Strength
• Flame Spread & Smoke develop Index
While evaluating the strength and life of windsock
fabric, it is important to consider the location for a wind sock. In addition to that, the evacuation lanes along with
their routes must be taken into consideration specifically in industrial and
agricultural areas, reason being an improper placement of the wind sock could
lead to an unsafe evacuation of personnel to a safe assembly area, so SGS
Frangible ensures perfect wind sock fabric along with perfect wind sock
classifications for all operating environments like airport, Helipads and
marine and intelligently provides frangible solutions by defining and simply
meeting the regulations for wind sock fabric, wind sock height and size and
lastly a satisfactory installation and maintenance which qualifies and proves
us as one of the most authentic and reliable provider of frangible structures;
accessories; products and quality composite solutions.