Hi Tom, I too work in a multi occupancy building, this time only three floors, we carry out planned exercises twice each year, there is obviously a requirement to conduct training in the fire safety order and evacuation exercises are seen as part of this training requirement. The requirement to carry out fire drills is also identified in the numerous department of communities and local government guidance documents BS9999 Code of practice for fire safety in the design, management and use of buildings states, "Implementation of procedures should be tested at least once, but preferably twice, in each twelve month period and there should be a test evacuation of the entire building at least once per year. Staff employed in particular zones of a complex should take part in a test evacuation exercise at least twice per year. Any observed deficiencies in the fire safety management should be remedied, and any improvements found necessary to the management of evacuation should be reflected in formal amendments to the written instructions." Hope this helps Ade

I always treat an evacuation due to a false alarm as a drill (provided it is carried through and not halted before everyone is accounted for) - I write up a report on it and subtract it from the number of drills still required. You have an opportunity to learn slightly different things than when everyone knows it is a drill (and unfortunately, if anyone knows then generally everyone does).

and you need as many to cover all employees e.g. nightshifts etc Lilian