Theoretical help needed

[Tom W]

Gentleman lend me your ears of wisdom 

I am trying to (for my studies) work out an average time for being let back in an average building.

So lets say for arguments sake this building is 4 floors (ground +3) roughly 180 staff on site.

The FIRE ALARM GOES OFF, its connected to a monitoring station so the signal is sent immediately.

Am I right in thinking the quoted target time will be respond within 8 minutes?

So 8 mins down the line the boys in red are on site, they are informed marshalls have swept the site and all is ok.

What would be their next step and how long would that take?

I want to know on average from the fire alarm going off (on a false alarm) to staff being allowed back in.

I know this could be how long is a piece of string but if we take the idea that its 8 mins for the response how much do i add on for the building to be deemed safe?

So we could say

Small office + 10 mins?

Med office +15 mins?

Large site + 25 mins?

Please help me stabb a guess at this!

[kurnal]

Dear Piglet
It depends whether there is a fire or not.
The trend towards the management of unwanted fire signals places greater onus on responsible persons sweep searching the building to check for signs of fire before or parallel with the activity of calling the fire brigade.

The brigade may be called or may not. They may challenge the call and ask the responsible person to go and check- especially if it is not a sleeping risk. There are no standard attendancetimes any longer- you will have to check with the brigades IRMP (integrated Risk Management Plan).

It is quite in order for the responsible person, having completed the sweep search and either finding the cause of the alarm, or finding nothing, to authorise re-occupation of the building. If this occurs the whole process can be completed within minutes, the alarm silenced - and reset if the fire brigade have not been called. The RP can then authorise re-occupation of the building- fire brigade or not.

So you can say within 5 minutes for small premises and up to 15 minutes for large complexes such as shopping centres- though usually in the latter case a system of staff alarms will ensure the premises are only evacuated if they really need to be.

The Responsible Person should take charge and make the decisions- unless there is a fire in which case the fire  service will take as long as they need to control the fire, ventilate the building and make it safe.

[Nearlybaldandgrey]

Very well put Kurnal, I was going to raise the same points, so thanks for saving me some work! 

On another point, it is important that companies have proper emergency procedures in place and not just evacuation. Obviously this will depend on the premises, so a hotel will ned to be evacuated and the Fire and Rescue Service called, although this can vary dependant on times of day, but in an office environment, there should be no reason why the cause of alarm is not investigated by the staff.

There are issues of business continuity to think about too .... how much business is lost while the staff are standing outside and of course, the disruption.

I always challenge the occupiers to ascertain if they have investigated, and if not, ask why, as this may indicate they have insufficient procedures in place.