Barny are there any such thing in place as fire breaks - e.g. roller shutter doors.

Maybe the previous tenant wrote a fire safety strategy into their FRA - If I'm correct the information in Approved Doc B for this size or premises is written guidance regarding 'life safety sprinkler systems' - given the fact it was a supermarket a fire strategy may have been written considering building design, construction and premises use before making a decision to install a life safety system - so basically if you have robust systems and processes to get people out in a timely manager (rapid evacuation) and the use of the binding may not be high risk they may have gotten around it. Its not that uncommon. In your FRA its very important you consider what's its to be used for - you may be able to do similar.

Invictus, I've now obtained the standard and I'll have a look through it. Can anyone answer me if the building was built before 2000 when the Approved Document B was introduced do they need to install a sprinkler system? Barney#1

Thank you for your helpful advice Bob!

Way of my area of knowledge so I might not be helping - but I do remember reading that large open building were built with considerable internal height as this allowed for safer fire management - i.e smoke gathered well above lighting etc and evacuation was OK. Is this how warehouse style shops etc meet requirements?