Hi,

Im currently studying a Degree for Building Surveying and I’m beginning to have doubts about my tutors ability. Im doing an assignment on ‘Means of escape’ contained in Approved Document B, Buildings other than dwellings.

Calculating exit capacity 2.21 

Where multiple storey exits are available, fire might prevent one from being used. Remaining exits need to be wide enough for all occupants, so when using Table 2.3, the largest exit should be discounted.

I’ve asked my tutor about this part as I believe it applies to both multiple storey and single storey buildings, the latter being which my assignment is based upon.

My tutor says it only applies to multiple storey buildings however if that were the case I feel it would read as ‘Multiple exits from multiple storeys’ if he is correct.

A storey exit is defined further down in Approved Document B as ‘exits to stairways, external escape routes and final exits’ the latter always being on the ground floor.

Any guidance on this would be much appreciated.

Many Thanks

Christian.

 

I've never heard that one before! It's part of the initial planning for horizontal evacuation and has nothing to do with the stairs - windows aren't part of escape route planning so a fire can still block an exit overloading those remaining even at ground level.

As you will see from these two different guides discounting applies in all cases:

https://www.twfire.gov.uk/wp-content/uploads/2018/11/Occupancy-Figures-Calculation-Guidance.pdf

 

https://www.bedsfire.gov.uk/Business-safety/Premises-fire-safety/Calculating-Occupancy-Capacities-for-buildings-used-for-Assembly.pdf