Designing a stacked levels public plaza.

[Tom Sutton]

We are designing a public plaza, with several stacked levels, all of which are open (without walls or enclosed staircases). The stacked plaza is hard to describe, but essentially it’s like an open sided multi-storey car park (16 Stories), but each level is double height, and all the stair cases are not enclosed (open) throughout and at ground.
 
Our query is if it is acceptable to have open escape stairs, especially if throughout the structure non-combustible materials are used? Also is there a minimum distance the fire exits on ground level will need to be set apart?

I have looked through the building regs Part B, but could not find information on open sided structures without enclosed escape routes. Are there any other guides you could refer us too?

Is there any guidance or advice you can offer us on this scenario.

I received the above query and I have never come across such a structure before any ideas?

[Midland Retty]

Thats an intresting one Tom. Seems a very ambitious design. My best advice would be to encourage the designer to have initial basic discussions with planners, building control and /or an approved inspector to get a handle on how the design will be received and the feasibility of the project. Seems very very high for that type of structure. We would certainly need much more info before we could comment.

[kurnal]

The question wasn't asked on April 1st was it?

Or may be it is a school/ college project.

My advice would be to appoint a reputable fire engineering contractor as advisor to review the feasibility of the proposal and consider whether a fire engineered solution can be achieved in accordance with BS7974. Inevitably protected staircases and fire fighting shafts will be required.

[lancsfirepro]

Tom, have a word with Mike Ward from Coopers Fire in Hampshire.  They specialise in fire/smoke curtains and have done some interesting things with the very scenario you have described.

[Fishy]

I agree - If I were the Fire Engineer on this Project I'd never embark upon a design for something so off-the-wall without using the BS 7974 FE process, including a QDR.

BTW - "....throughout the structure non-combustible materials are used...".  Are they sure???  No timber, plastics, coatings, floorcoverings, adhesives etc?  Everything to be A1 to the Euroclasses? Can't imagine what such a structure might be used for...

[kurnal]

 They specialise in fire/smoke curtains and have done some interesting things with the very scenario you have described.

Call me a dinosaur (I am) but I have walked away from two jobs where the architect and the Approved Inspector were adamant that drop down curtains were to be used to create a fire fighting shaft and lobby. Its my opinion that the integrity of fire fighting shafts must never be compromised in the interests of aesthetics.

[wee brian]

 They specialise in fire/smoke curtains and have done some interesting things with the very scenario you have described.

Call me a dinosaur (I am) but I have walked away from two jobs where the architect and the Approved Inspector were adamant that drop down curtains were to be used to create a fire fighting shaft and lobby. Its my opinion that the integrity of fire fighting shafts must never be compromised in the interests of aesthetics.

couldn't agree more. people use these things in ways that are clearly inapropriate. This would be one of them.

[nearlythere]

It's always a case of designers pushing the boundaries and the guidance trying to keep up. That's why we don't live in caves any more.

[Tom Sutton]

After the war most of the blocks of flats, up to seven storeys, had open staircases and open balcony’s and the architects worked on the principal of smoke dispersal, the fire service disagreed, they believed in smoke containment, but who was right? Is this not this similar, it would depend on how the structure is going to be used, which would decide on the fire loading and how a fire would spread. I know research was done on multi-storey car parks and fires were contained to the car of origin and in most cases, one car each side, would it not work with this design.

I have tried to get more information from the architect but no joy, he has receded into the shadows and not having direct contact it is difficult to contact him.

[kurnal]

There is some doubt on the suitability of car park design as cars have changed, with the increase in plastics and the increase in fire loading. And LPG fuelled vehicles. But most car parks have protected staircases and most larger ones have dry risers/ fire fighting shafts.
The big problem with fire engineered solutions is that generally the fire modelling that is carried out using FDS etc usually just  covers the evacuation phase and rarely does it cover access and fire fighting. Indeed this is even more unlikely since the repeal of the local enactments!

If I recall the longest scenario I have ever seen modelled is up to 15 minutes, which is probably OK if the fire is sprinkler controlled but if the fire is still growing does nothing for the safety of firefighters and for those the firefighters may be trying to help.

Pleased to hear that the architect has receded to the shadows. Long may he stay there.

[Fishy]

These drop-down curtains have their place, but not (in my opinion) as means of protecting fire-fighting access. 

I can't accept that they are as robust (in fire risk mitigation terms) as fixed walls & conventional doors (it's spooky how attractive the descent zones seem to be to users looking for convenient places to put display stands, chairs, bins & even fire extinguishers)! How many are properly maintained?  I'm aware that they might give you up to 4 hours fire resistance, but that's only the Integrity rating - few give any appreciable insulation performance & all the guidance that I know of is quite explicit in requiring insulation too (REI under the Euroclasses).

[Midland Retty]

Hi Tom

Without seeing the design then its really difficult to make comment other than to say that for a whole host of reasons (not just fire safety related) I can't see how such a building would ever be permitted even with lots and lots of fire engineered solutions thrown at it.

There is nothing wrong with a bit of creativity and flare, but in this instance the architect may have more chance of building a ladder to the moon or of getting Kelly Brook to be his lawful wedded wife than building his mega plaza.

[nearlythere]

Hi Tom

Without seeing the design then its really difficult to make comment other than to say that for a whole host of reasons (not just fire safety related) I can't see how such a building would ever be permitted even with lots and lots of fire engineered solutions thrown at it.

There is nothing wrong with a bit of creativity and flare, but in this instance the architect may have more chance of building a ladder to the moon or of getting Kelly Brook to be his lawful wedded wife than building his mega plaza.

Here. Leave my girlfriend out of this.