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The Fire Escape Stair

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Some time ago now, Misha in Canada emailed to ask why so many residential buildings in South-East Asia have only one fire stair. He asked why do building codes in East Asia allow one exit stair in tall buildings? This is not the case in the Anglo world or in codes inspired by them, but I think it’s true not only in China but at least also in S. Korea (and maybe Japan?), so it can’t be just a matter of prosperity. Isn’t having only two units per floor expensive, unless they’re very large?

Misha was probably referring to fire stairs such as this one in an 18-storey building I used to live in. The building wasn’t that new, as you can probably tell by what is essentially deck access with the route to the end apartments passing by the living rooms of the inner apartments. This is how it looks from the north side. It all look a bit basic but there are no flammable finishes anywhere. You’re probably going to get to the fire escape stair without becoming an incident.

It is true that many high-rise residential developments in mainland China have only two apartments per core, but they have as many as three or four cores. The left image below shows a residential development configured like the building above, with four units and centrally placed elevators and fire escape stair but the development on the right has one elevator and fire stair per two units, with that module repeated for the higher buildings at the rear. A couple of years ago I learned that a Chinese-built elevator costs about US8,000 per floor and reasoned that building two apartments per two elevators + stair is probably cheaper than to scrimp on elevators and be forced to build the additional volume of corridor to pass by those extra apartments which are probably still going to have bathroom and kitchen windows on the corridor side.

There’s not danger of intrusiveness or even of meeting your neighbors with an arrangement such as this next one. One way of reducing the intrusiveness of this is to have the corridor as a detached bridge like corridor as in the following example. All buildings bar #10 and #11 at the rear have paired units but the problem with this of course is what happens when the single elevator requires maintenance? The choice is between units serviced by a single elevator or a corridor passing behind two inner units, whether that corridor is detached or not. This isn’t a fire-safety problem.

One good compromise is to keep the inner units as dual aspect and to have a detached bridge to the rear linking two cores each having one elevator and one fire stair. This entails an additional fire-escape stair and this is basically the same as having one at each end of a corridor. It also means that each elevator serves two units but there is also the option of crossing the bridge to the other core should one of them be out of action or inconvenienced by people moving in, for example. Although the bridge is still passing in front of windows, there aren’t that many people who will be using it. It’s a neat solution. Although the rooms overlooking the bridge don’t receive as much light, I’m glad to be seeing this improved configuration more often.

The price of the additional fire stair must be less than providing two elevators per half core. Over in Dubai, high-rise residential or mixed use towers come in all shapes and sizes but there seems to be a preference for a fire escape stair at each end of the access corridor and this is of course a sensible thing to do.

The typical floor layout on the left below is an application of the minimum distance rule to “reach a point where there is a choice of two alternative escape routes” and is probably a legacy of British-based design firms operating there. It does seem entrenched though, Cayan Tower (on the right, SOM) has two fire escape stair accessed from opposite sides of a circular corridor even though it’s possible to argue that the one fire escape stair can still be the destination of two alternative escape routes.

It would have been possible to configure a scissor stair to have two fire escape stairs accessed from opposite sides of the circular corridor but this hasn’t been done. It may not even be permitted by the UAE Fire Code. On page 266 of 136 it does state that “a scissor or interlocking stair shall be considered as a single exit” even though this doesn’t preclude it being reached by more than one route. There are some informative diagrams though. The one on the left below shows preferred configurations for fire stairs, although “d” with its door opening outwards doesn’t seem like a good idea. The middle image shows some unacceptable configurations and most involve winders and short flights. The general rule – as it is most everywhere – is not to have any surprises just inside the door. The diagram on the right is a typical stair that meets the code although I don’t like the way the door swing enters the line of traffic as in fact it does in many of the “preferred” configurations.

Scissor stairs are of course allowed in Hong Kong and used to great advantage by the Hong Kong Housing Authority because of the additional door that minimizes travel distances. It’s basically putting two staircases into a single stairwell whether it services four units from a straight corridor or eight units from an H-shaped one.

There’s no downside to this, although fire escape stairs with single runs of 20 or more stairs aren’t allowed in many countries. Canada isn’t one of them, as this stairwell in MAD’s Absolute Towers in Mississauga just outside of Toronto shows.

I don’t know about the case for the US, although 432 Park Avenue is a paired U-shaped scissor stair and the only one I know of. It’s U-shaped to not so much to reduce the number of risers in a single run, but to reduce the overall length and thus the size of the core. Scissor stairs are good for saving space, but unless they’re switchback, they require a corridor at least the length of the stair to reach both exits. This is not necessarily a bad thing as in Hong Kong where the length of the stair is usually equal to the width of two or three elevators and works to increase the distance between units. The length of the fire escape stairs at 432 is designed to take as little space as possible and, for the same reason, its walls are also super thin.

Fire escape stairs are usually tucked away inside the core of high-rises but, in the Russian Federation, it’s a requirement to have one fire escape entered from from outside the building. It gives rise to typical floor layouts like this next one for Living Project on Rublevskoye HighwayMoscow, by Sergey Skuratov architects. This is a code requirement, not something done for aesthetic reasons or an active facade.

Then there’s this next fire escape stair we’re all familiar with. It’s been described as “sculptural” but, rather than being there to be sculptural, it’s an additional fire-safety requirement for the non-residential spaces. In order to maintain an alternative means of escape, the occupants of this floor must presumably be able to access at least one of the the residential fire-escape stairs. Plans of the market level are difficult to come by. [If anyone has one, I’m interested in seeing it.] This photo below does show the fire escape door leading to the external and allegedly sculptural fire escape stair. As ever, if you can’t solve a problem then make a feature out of it.

Fire-escape stairs that also function as a major external design feature are few and far between but maybe we’ve just been thinking about them the wrong way. There’s no reason why a fire-escape stair shouldn’t also be an external design feature. Since we have to have them anyway, it makes sense to extract a but more functionality or – dare I say it? – pleasure from them.

I’m inclined to dismiss the Hi-Tech fire-escape stairs as just more opportunities for shiny metal on the outside but they were important in making us see fire-escape stairs as something to be looked at. It became possible to see them as part of a design, such as with these three narrow buildings in Japan where putting the fire-escape stair on the front of the building is a sensible thing to do.

In more recent history we have Kazuyo Seijima’s 1996-98 Gifu Kitagata with its many staircases. Many things are happening in this building but these staircases are one of the more interesting. Having experimented with repeating and stacked staircases myself, there’s always a problem at the ends of the building where there’s no more staircases coming down. It’s no problem when staircases wraps around the corner (as on the left-side end in the image below) but it is when they don’t (as on the right-side end). Sprinklers? Still, this building brought fire-escape stairs back into the picture as a design element.

My second example is Takefumi Aida’s 2005 Numata Building. It’s pretty. The fire escape stair as well as every opening in the building have been considered for its decorative potential and the result is audaciously and consciously pretty. In its own way, it’s redefining architecture by pushing those boundaries that lie in the other direction.

My third example is again from Japan and I’m not going to think about what this might mean. It comes from Nikken Sekkei which is one of Japan’s huge design offices but also a creative force. The corner two elevations of their 2018 Arakawa Building have exposed fire-escape stairs as a major design element. Configuring an external fire-escape stair in this way is an enormous contrivance but most design elements, if not entire buildings, are. As well as the building having no two identical floors, it’s also an expensive undertaking in terms of design and documentation time. Architects in a small office might do something like this to make a name for themselves but Nikken Sekkei has no need for that. Somebody there had the idea and there were the resources there to work it through and I’m glad they did.

Riken Yamamoto’s biography on the Pritzker Prize website says that Yamamoto reconsidered boundaries between public and private realms as societal opportunities, committing to the belief that all spaces may enrich and serve the consideration of an entire community, and not just those who occupy them. All architects like to say their buildings help “build communities” but few systematically focus on how the building envelope can achieve and promote that. Seeing those boundaries as potential societal interfaces between inside and outside is the important part. If Yamamoto’s architecture makes much use of frame structures and windows, then it’s because these are an expedient way of telling us what goes on inside a building and, at the same time, let people inside know about the people on the other side. This is something the word “community” doesn’t convey because, all too often, it’s used to describe homogenous groups of persons separated from the world outside and this is the opposite of what Yamamoto tries to achieve. Bearing this in mind, we don’t know what happens inside this office building but, if those fire-escape stairs are used – and it looks like would be because they lead directly from offices to the street – then we can form an idea of the internal life of the building. The dusk photo above, hints at this internal life – as much as a professional photographic representation can. The following professional photographic representations do the same thing vis-à-vis the street but we get the idea. Perhaps all that people on the street will see are bento being delivered and groups of salarymen having a cigarette but this might be all this fire escape stair need do as a social interface. It doesn’t look like it should be that difficult to achieve.

The reason buildings have fire-escape stairs is to direct people to the outside in case of fire and, in the case of fire-fighting stairs, to direct firefighters inside to fight the fire and rescue people. The fire-escape stair is a necessary physical interface between inside and outside. Thinking of them as having a social interface dimension doesn’t require any huge leap of imagination and is perhaps a good idea whose time has come.

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Comments

  • I’m happy to hear my question lee to this post – a very interesting read!
    As an update on my original question, there has been a lot of discussion in North America recently about the problems created by the requirement for two exit stairs – both economically in making apartment buildings with small floor plates more viable, and in terms of providing higher quality units with dual aspect – and also making units with more bedrooms in smaller area possible.
    Washington State recently permitted municipalities to allow single exit buildings up to 6 storeys (Seattle is an exception, it is allowed there since 1977). British Columbia is now looking to allow it up to 8 storeys.
    There is more info about it here: https://secondegress.ca/

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