What is a sign housing?
The enclosure around everything that makes a sign work. It holds the face, the LED module and the driver, keeps the weather out, and is built to break away if an aircraft strikes it.
An airfield sign stands beside a runway or taxiway, in wind, rain, snow and jet blast, close enough to aircraft to be struck. Its housing has to protect the electronics and the face, and at the same time not become a hazard to the aircraft it serves.
1Enclose and protect
A shell, commonly aluminium or glass-reinforced plastic, holds the face panel, the LED module, the driver and the wiring. A gasket seals the face to the shell, and the cable entry is sealed too, so rain, snow and dirt stay out. The shell and its fixings are built to withstand wind and jet blast.
2Low, light and frangible
Annex 14 asks for signs to be frangible and low enough to keep clearance for propellers and the engine pods of jet aircraft. So the housing is kept low and light, and the mounting is designed to break away if it is hit. The legs and the frangible point are covered in the entries that follow.
3Open, check and close
Isolate, lock out and prove the circuit dead before opening the sign. In many designs the face frame or a cover opens so the LED module and driver can be reached. When it is closed again the gasket must seat properly and the fixings must be tightened as the manufacturer instructs. Look for cracks, loose fixings, damaged seals and water inside, and keep the face clean.
| Part | Job |
|---|---|
| Shell | Encloses the parts and sets the sign’s size and depth |
| Face panel | Carries the legend and lets the light out |
| Gasket | Seals the face to the shell |
| LED module and driver | Make and control the light (see Entries 14 and 15) |
| Cable entry | Lets the supply lead in and stays sealed |
| Mounting legs | Hold the sign at the right height and clearance |
| Frangible point | Lets the mounting break away if struck |
| Standard | Annex 14: signs must be frangible and low |
Frequently Asked Questions
Q1What is the housing of an airfield sign?
The enclosure that holds the sign face, the LED module, the driver and the wiring. It protects them from weather and holds the face in position.
Q2Why must a sign housing be frangible?
Aircraft can strike a sign. Annex 14 asks for signs to be frangible and low enough to clear propellers and engine pods, so a sign breaks away on impact and does less harm to the aircraft.
Q3What is a sign housing made of?
Aluminium and glass-reinforced plastic are common choices. The material depends on the manufacturer and the standard the sign is built to, so check the datasheet.
Q4How does the housing stay watertight?
A gasket seals the face to the shell, and the cable entry is sealed too. Fasteners must be tightened as the manufacturer instructs, and any damaged seal should be replaced.
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