Every automatic door is the same three things working together: something that notices you, something that moves the door, and something that makes sure the door never hurts anyone. Understanding those three layers makes it much easier to specify, buy or troubleshoot an automatic entrance.
Key checks
- 01Activation sensors decide when to open; safety sensors decide when it is safe to move.
- 02The operator — motor, drive and controller — does the moving and holds the settings.
- 03BS EN 16005 governs the safety package; battery back-up keeps behaviour predictable in a power cut.
The sensors: how the door knows you are there
Most commercial doors use microwave radar mounted over the doorway to detect approaching movement, sometimes combined with infrared presence detection that watches for people standing still. Push pads, keypads, fobs and access-control systems do the same job where entry needs to be controlled rather than open to everyone.
Activation is only half the sensing story. Separate safety sensors — threshold beams across the opening, side-screen detection where sliding leaves park, and on-door laser scanning on swing doors — watch the space the door moves through, so the leaf slows or stops if someone is in the way.
The operator: the machine above the door
The operator is the drive unit, usually hidden in a header box above the opening. On a sliding door it moves the leaves along a track with a toothed belt; on a swing door an arm or spindle powers the leaf through its arc. A controller stores the opening speed, hold-open time, closing force and operating mode — automatic, exit-only, hold-open or locked — selected from a program switch that staff can use without an engineer.
Good installations add an EBU battery back-up module, so a power cut does not leave the entrance stuck open or trap it shut: the door completes a controlled, predictable action instead. Operators are also commonly wired to the fire-alarm panel so the entrance responds correctly — typically opening — when the alarm sounds.
The safety standard that ties it together
In the UK, BS EN 16005 is the safety-in-use standard for powered pedestrian doors. It sets out where sensing is required, how much force a moving leaf may exert, the safety distances around the opening and the testing an installer must complete at handover. A compliant installation is documented, and periodic servicing keeps the safety functions demonstrably working.
That is why an automatic door is best treated as working safety equipment rather than a convenience: the sensors, forces and emergency behaviour are all part of a tested system, and changes to any one part affect the whole entrance.