Open staircase

[Davo]

Advice please....

Looking at final??  plans for new build  offices/scientific

103 metres by 26 metres approx, three floors, megabucks


Stairs are external spiral stairs 1000mm at either long end, centre rear open plan stair 1000mm and front enclosed stair with three toilets and a small (uncompartmented) store
Centre lift unlobbied.

Occupancy up to 570, I am aware of a handful of disabled persons with limited mobility

Compartmentation down the centre 1 hour, mainly open plan but with scientific rooms compartmented. Proposal for full water mist sprinkler.

Obviously the small stores need compying, question is

Am I right in
a) insisting the rear stair be enclosed or I discount it as MoE thus screwing occupancy up?

b) throwing a wobbly over external unprotected spiral if you please stairs?


davo


 

[nearlythere]

Advice please....

Looking at final??  plans for new build  offices/scientific

103 metres by 26 metres approx, three floors, megabucks


Stairs are external spiral stairs 1000mm at either long end, centre rear open plan stair 1000mm and front enclosed stair with three toilets and a small (uncompartmented) store
Centre lift unlobbied.

Occupancy up to 570, I am aware of a handful of disabled persons with limited mobility

Compartmentation down the centre 1 hour, mainly open plan but with scientific rooms compartmented. Proposal for full water mist sprinkler.

Obviously the small stores need compying, question is

Am I right in
a) insisting the rear stair be enclosed or I discount it as MoE thus screwing occupancy up?

b) throwing a wobbly over external unprotected spiral if you please stairs?


davo


 

Do all occupants have access to at least one protected stairways if one other was affected by fire without having to enter the open stairways area?
Have you a drawing available?

[nearlythere]

Nearlythere

The internal stairs are in seperate compys although nearly central.
So one side will only have the external stair and the unprotected stair (Doc B 4.23 says it should be protected I have since found)

davo

It is a difficult one to picture. Have you drawings?

[jokar]

Surely it does not meet travel distance recommendations in ADB.  Is the compartment wall there for PHE for the disabled evacuation strategy?  I was under the impression that spiral stairs are only for limited amounts of people, used to be 50, and in this instance they would have to take half the population if PHE is the strategy.

[kurnal]

Lots of questions Davo but first of all why is water mist being proposed? Is it a compensatory feature? If so for what and to what standard is it to be installed.

Water mist is fantastic in the right place and installed for the right reasons. But you need to know exactly what is being installed, for what reason and where is the evidence it will do the job being asked of it.

Is there any weather protection to these external spiral staircases?

The evacuation strategy for disabled people needs to be very carefully worked through.

You know if I was to make a guess I would say it sounds lke one of those government sponsored  exemplar designs that somehow allow imagination to run riot through sensible building regulations.

I know a chap who could evaluate the design for you if you wish.

[jokar]

As a by the by, has this been designed to DD or BS 9999?