spiral stairs

[Guest]

Can one of you clever people give me a hand on spiral stairs,If  I have an external spiral , from handrail to handrail it is 1100mm,then i go to B1 table 7  serving 2 floors I get 260 people ,,, is that the end of it or do I then ,or should I then look at bs5395 table 2 that says i come in from the centre 270  mm and i should have min 150going because if i do that there is now only 850 usable width even though the handrails are still 1100 apart,This obviously reduces means of escape numbers drastically.Also table 2 of bs 5395 states  1100mm width(between h.rails) can be used for "large numbers"what is a Large number I think it works easy for helical but seems strange for trad spirals where the inner 6"(150mm is unusable)  Point 3 how do you in your various job roles feel about new build spirals and disabled evacuation..

[pugh]

Spiral stairs have  always made me dizzy, but not as dizzy as your post though.  Yeesh!
 

[Guest]

My personal view is that spiral stairs are not recommended for used in evacuation where large numbers of people gathered. I've encountered an incident of injury by one lady evacuue slip and hurt her back! Definitely not suitable for disabled evacuation.

[Guest]

Dear Pugh in the sunny middle east (friendly place i hope)I am sitting in a run down inner city no sunshine,It took me ages to understand the question myself ,,and i wrote it ,but their is a valid question there somewher i need help with

[pugh]

It's a balmy 40 degrees and I'm just off home for a couple of cold ones.  Things are much simpler out here.  If you want a spiral stair as your prime m.o.e then you put one in.  As far as I can see nobody has the knowledge or the clout to stop you.  There are a number of places I don't go just because they are so inherently unsafe, vis-avis m.o.e.

Just reading all the various options in your post though leaves me breathless.  I can't remember how I used to cope with it all those years ago although I'm pretty certain if I had access to the doc's I could manage a reasonably sensible answer.

Good luck in your quest.  

I'll think of you when I'm on the beach.  (fat chance of that)
 

[Ken Taylor]

I hate spirals. They are specifically said to not be acceptable in schools for MoE. If you must have them I believe that only usable width should be considered. Helicals may be little better - depending upon core dimensions. Have you had any response from Building Control / Approved Inspector?

[Guest]

Yes  its the approved inspector whos discussing,,sorry telling me ,,they will be fitted to the size mentioned for 260 people and taking no accont of disabled or my thoughts,,He says they are 1100 between handrails and will take 260 people mmmmmmmm.

[Ken Taylor]

Mmmm! I wonder what the local Building Control interpretation would be?