Visibility of airport markings is key for maintaining scheduled on time airport take-offs in day, night and adverse weather conditions. Delayed flights cost the industry billions, therefore using the right products is essential for airports to continue to run on time. Regulations in the airport industry provide a clear focus on safety and visibility. To ensure markings within airfields are clear, reflective glass beads can be combined with the paint to enhance visibility during darkness by up to 600%.
The principle of glass beads is that they provide a reflective material embedded within the paint, similar to those found in cat’s eyes on the road. There are various grades of glass beads for different applications. The beads themselves are tiny and have a similar appearance and texture to a clear white sand, as with sand there are various sizes and grades. The grades determine their suitability for purpose and although they may look similar to look at close up the glass beads provide different reflectivity, durability and compliance values.
When it comes to the question of glass beads, there is a selection of options available:
Type I highways grade glass beads: These beads offer 3-5 times more visibility and retro-reflectivity than normal non-reflective markings.
Type III airport grade glass beads: Offer 3-5 times more retro-reflectivity than Type I beads.
Type IV highways grade glass beads: Offer 2-3 times more retro-reflectivity than do Type I beads.
The higher the reflectivity rating from the glass beads the greater the visibility from a further distance. Airport grade beads are visible not just from ground level but also from the air. Leading lines and airport taxiway markings need to be bright and reflective to reduce runway incursions and avoid incidents on the airfield.
See the glass bead comparisons table below to see the differences in retro-reflectivity.
|TYPE I BEAD||TYPE III BEAD|
|“Highway Bead” Reclaimed Glass 1.5 IOR||“Airport Bead” Virgin Glass or Direct Melt 1.9 IOR|
|At installation, Type I Should yield 300-450 mcd/m2/lux on white markings and 175-250 mcd/m2/lux on yellow.||At installation, Type III Should yield 600-1300 mcd/m2/lux on white markings and 350-550 mcd/m2/lux on yellow.|
|Suitable for use on highways, and roads||Suitable for airport taxiways and leading lines.|
HOW DO GLASS BEADS WORK?
Standard highway specification glass beads reflect light directly back at the source. Beads that are specially formulated for airport applications, reflect the light in multiple directions, thus providing enough reflectivity for pilots to see the markings clearly (see illustration below).
Photo showing the vibrancy of type III compared with type I beads from 5.5m height and 15.25m distance, (how a pilot would see the airfield markings).
(Photo taken at dusk).
VISIBILITY & SAFETY:
As previously mentioned, visibility is key for maintaining scheduled on time airport take-offs. It is also a large factor for improved safety on the airfield. Type III airport grade beads can dramatically increase the retro-reflectivity and contrast of airfield markings, making them up to 600% more visible than unbeaded markings. (See below image of reflectivity differences between no glass beads, type I and type III)
Three photos sticthed together to show vibrancy differences between beads.
Illustration together to show vibrancy differences between beads.
Not only do glass beads greatly increase reflectivity, but they also increase the durability of the marking by up to 4 – 5 times longer than when beads are not applied. This is due to the fact that when a wheel, or likewise passes over the line it comes mainly in contact with the elevated embedded bead rather than the paint line.
It’s important to note that glass beads cannot just be applied to any type of paint, as the structure of chemicals within the paint needs to be sufficient to secure the bead and not encapsulate it. This is often referred to as the solids content of the paint, and to ensure your line marking remains compliant you will need a high-solids paint with a compatible bead fit for purpose.
HOW BEADS ARE APPLIED:
Application of the bead is as important as the type of bead that you choose, there would be little point in mixing beads in with the paint as the reflectivity would be severely diminished. Ideally the paint needs to be applied via an airless spray machine with the beads applied using a pressurised bead system designed to maximise bead retention, durability and consistent distribution.
To find out how airport beads can make a difference at your airport, Meon offer free site appraisals at your airfield. We offer training packages for your staff to ensure you remain compliant and your line markings are visible from the ground and air.