I am employed on building services under contract to a major supermarket.
I can answer questions on auto doors, but as its for your Btec I will not supply large quantities of text that you might cut and paste unaltered!!!!!!!!!

Auto doors use detectors both sides.
A pressure strip on the edge will mean hitting the customer!!!!!! not good, think again.
Children and coffin dodgers??
What happens in the event of a fire?

Have you looked here:

http://www.irdoromatic.co.uk/index.php