There’s nothing more welcoming than a door opening for you. ¹______ the need to be touched to open or close, automatic doors are essential in ²______ disabled access to buildings and helping provide general ³______ to commercial buildings.

Self-sliding doors began to emerge as a commercial product in 1960 after being invented six years ⁴______ by Americans Dee Horton and Lew Hewitt. They ⁵______ as a novelty feature, but as their use has grown, their ⁶______ have extended within our technologically advanced world. Particularly ⁷______ in busy locations or during times of emergency, the doors ⁸______ crowd management by reducing the obstacles put in people’s way.

⁹______ making access both in and out of buildings easier for people, the difference in the way many of these doors open helps reduce the total area ¹⁰______ by them. Automatic doors often open to the side, with the panels sliding across one another. Replacing swing doors, these ¹¹______ smaller buildings to maximise the usable space inside without having to ¹²______ the way for a large, sticking-out door. There are many different types of automatic door, with each ¹³______ specific signals to tell them when to open. ¹⁴______ these methods differ, the main ¹⁵______ remain the same.

Each automatic door system ¹⁶______ the light, sound, weight or movement in their vicinity as a signal to open. Sensor types are chosen to ¹⁷______ the different environments they are needed in. ¹⁸______, a busy street might not ¹⁹______ a motion-sensored door, as it would constantly be opening for passers-by. A pressure-sensitive mat would be more ²⁰______ to limit the surveyed area.