First of all the law does not stipulate you must have evacuation chairs. However, there are requirements for responsible persons, as determined by legislation, to ensure suitable and sufficient procedures are in place to ensure the safe evacuation of all users of their building in the event of an emergency without the dependence on the emergency services.
Whilst the Fire Service will rescue people, they are not there to implement building emergency procedures. No-one can be left in a building in the event of a fire or other emergency and the culture of depending on the emergency services must change. Our simple reminder is, if you allow people in you must be able to get them out.