Unprotected staircase as a means of escape

[Guest Happycol]

Hi - I have a quick query and hope for a little advice, any help would be much appreciated.

We have a building that has an accommodation staircase between ground and the first floor. The first floor is to be used as an event space and we would like to have up to 200 people on the first floor. However due to the width of the 2 protected staircases provided the limit for people on the upper floors is 186.

We are investigating the feasibility of including the accommodation staircase as part of our calculations for occupancy, and understand that we can do this subject to a suitable risk assessment.  As part of the fire risk assessment we will include.

• Travel distance of route using staircase
• Level of management control in place
• Detection
• fire load/ignition sources in unprotected area 
• Number of fire marshals

Is this a reasonable approach and can you think of any other factors we should consider?

 

Many thanks

[Tom Sutton]

I cannot give a definitive response and would need a lot more information but I can give some observations that may be useful.

The use of accommodation staircases for means of escape is acceptable in small premises providing the bottom of the staircase is within 3 m of a final exit, also travel distances are limited. Because there is no compartmentation between the floors, both floors would have evacuated simultaneously and treated as one compartment.

As you are considering risk assessment to justify accepting the number of occupants above the occupancy limit you would need to reduce the times in ASET to accommodate the extra numbers.

Using automatic detectors and reducing fire load/ignition sources in unprotected area, you could reduce the ignition and detection of a fire.

Level of management control in place plus the use of fire marshals could reduce the recognition and response time.

The travel distance will be fixed so it is unlikely to be helpful in reducing ASET.

The tenable limit would be helped by responsible management control in place and early detection.

I think you have covered all the points and may be able to create a good argument but if it will convince the FRS is another matter.