TYPE-I TAXIWAY GUIDANCE SIGNS
Type - I airfield guidance sign was originally manufactured by a Norwegian company call ‘Smiths Airfield Equipment (SAFE)’
The body of the sign is manufactured from anticorrosive aluminum extrusion which is powder coated with ‘aviation yellow’ paint. The extrusions interlocks creating a solid sign box structure which is water resistant to IP55. The fascia framework is also manufactured from an aluminum extrusion but is powder coated in black
When the type-I sign was first manufactured it utilised tungsten halogen lamps to illuminate the front polycarbonate fascia, but over time, technology has progressed. The concept of using fluorescent tubes was then adopted and specialized electronics were developed to control the brilliancy and operation of the unit. The third generation saw the implementation of LED’s in a grid format for the illumination. Throughout the different generations the power consumption of the unit reduced helping to minimize the rating of the constant current regulator (CCR) that is used to power the circuits.
Although different light sources have been used internally, the ICAO candela requirements of 150cd’s for yellow taxiway information signs, 300cd’s for white used on a mandatory sign, and 30cd’s for red colors, again on mandatory signs, have always been achieved.
Not only is the brilliancy of the sign important, but the chromaticity is essential ensuring that the information is displayed clearly to pilots and vehicles using the taxiway system. This is always tested during manufacture to ensure compliance of each sign against the necessary standards with a multispectral camera which also confirms light output.
There are different modes of operation the sign is designed to withstand, all of which are identified in the ICAO airport design manuals. These need to be considered when installing the sign as different couplings, may need to be used. Discussion with atg airports customer support team should be able to assist in this matter.
Type-I LED Conversion retrofit kit
Many type-I signs are installed at airports all over the world, and some have been in operation for more than 20 years, before the LED was even considered for airfield lighting applications. However, to enable clients to benefit from the energy saving of LED usage, a conversion kit for the ‘Smith (SAFE)’ sign and also the type-I is available, thus extending the life of the sign. The kit is installed into the sign and the old tungsten halogen, fluorescent or cold cathode technology can be removed. Once converted, the sign will achieve the same efficiency benefits of the type-I LED sign.