How Did Benson & Forsyth Do This?

How Did Benson & Forsyth Do This?

Postby mulp » Tue Jul 07, 2009 1:21 pm

I would appreciate some informed opinions on this issue:

Benson & Forsyth's National Gallery Extension contains two public staircases that do not meet the guidance set out in TGD Part k: Length of Flights: 1.1.11 There should not be more than sixteen risers in any one flight.

The flight at the rear of the main hall has 20 risers and the uppermost flight at the rear of the extension has 19 risers. They are straight flights without any half landings.

I don't consider these stairs to be in any way unsafe, but the TGD evidently does.
Compliance with the TGD demonstrates compliance with the Regulation, but the designer is free to demonstrate other methods of compliance.
I am designing an extension to a protected structure in which I want to have a straight fllght with 18 risers. A lift is to be located adjacent to the stair. I don't consider a stair with 18 risers to be any more unsafe than one with 16 and believe that the elderly or infirm would opt for the lift. My main concern is public liability.

Can anyone suggest how B&F would have demonstrated compliance with Part K in the Gallery?
Would you, as a designer, be prepared to certify a similar stair as compliant?

(Note: I can't see any way that the 'protected' status of the main gallery is relevant in relation to a relaxation, as the works are entirely within the new extension).

Thanks.
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Re: How Did Benson & Forsyth Do This?

Postby Paul Clerkin » Tue Jul 07, 2009 1:52 pm

There is a central handrail since this photo was taken - was added very soon after opening.

at least I think there is.... fuzzy today
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Re: How Did Benson & Forsyth Do This?

Postby parka » Tue Jul 07, 2009 1:57 pm

Central handrail has been added with some pot plants, I find the 'gaps' in the walkway even more worrying
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Re: How Did Benson & Forsyth Do This?

Postby missarchi » Tue Jul 07, 2009 3:13 pm

in the south pole you can do 18 steps! if you want more here you get a dispensation for a performance based provision... you might have to pay a consultant! normally the regulation is vague (the short bit at the front) and the rest is should... All from the same old British regs but remixed. I'm so over trying to interpret standards and pay consultants everyone reads them differently... And nobody does any inspections in Ireland. The fire regulations are OTT normally sprinklers can make the impossible possible... not in Ireland where the water is free...

I guess its a bit like a train platform with more than a metre drop... you should have a handrail and balustrade or some steps so you don't fall on the tracks while your waiting...

I admire the Irish reg's for being so simple and un-bible like (forgot about part b)

http://www.flickr.com/photos/44535691@N00/389436674/sizes/l/

why don't you just go to the source and call them? and let us know

everyone so worried about not getting sued these days there is not much room for architecture...
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Re: How Did Benson & Forsyth Do This?

Postby henno » Tue Jul 07, 2009 3:38 pm

compliance on building regulations is a matter of opinion.

Whose opinion matters?

A building control officers opinion is no more valid than a street buskers opinion. At the end of the day the only opinion that matters is the judges opinion in a case where someone falls and gets injured, and an action is taken.
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Re: How Did Benson & Forsyth Do This?

Postby Copo » Tue Jul 07, 2009 4:02 pm

The latest British Standard (BS8300-2009_Design of buildings and their approaches to meet the needs of disabled people: Section 5.9.3 Rise of a flight) proposes 'no flight on an external stepped access route should contain more than 20 risers and, as far as possible, the numbers of risers in successive flights should be uniform'. This also applies to internal stairs.
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Re: How Did Benson & Forsyth Do This?

Postby henno » Tue Jul 07, 2009 4:30 pm

most fire officers will tak ethe view that the TGDs supercedes any BS...
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Re: How Did Benson & Forsyth Do This?

Postby Copo » Tue Jul 07, 2009 5:00 pm

henno wrote:most fire officers will tak ethe view that the TGDs supercedes any BS...


My understanding would be that fire officers refer primarily to TGD Part B which does not govern the maximum no. of risers.
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Re: How Did Benson & Forsyth Do This?

Postby henno » Tue Jul 07, 2009 5:38 pm

Copo wrote:My understanding would be that fire officers refer primarily to TGD Part B which does not govern the maximum no. of risers.


primarily Part B yes, but not exclusively...

they will refer to part k for stairs etc... ..
part j for heat producing appliances....
part m for disabled access...

etc
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Re: How Did Benson & Forsyth Do This?

Postby millennium » Tue Jul 07, 2009 8:13 pm

In Ireland we rely on self certification by Design Professionals and Builders (when requested) on completion to give an "Opinion" on compliance with the Building Regulations.
A Fire Safety application and approval procedure is uniquely required prior to commencement, but only to approve the design.
In some other countries approval of the design, to validate compliance with all Building Regulations, is given before construction is allowed to commence. Furthermore, local authority inspections take place during the build period to monitor variances between the lodged documents and what is actually built, and to keep an eye on the build process.
The problem with this method is that it is costly to set up and operate, and is open to corruption.
The problem with the Irish method is that too many things, outside Part B, slip through unchecked.
Finally, 16,18 or 20 steps without a landing is a subjective view of what is safe but has the backing of Codes.
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Re: How Did Benson & Forsyth Do This?

Postby missarchi » Wed Jul 08, 2009 6:28 am

here's another one for you.. what hurts more assuming same going?

falling 3520mm down 16 stairs at 220mm
falling 3300mm down 20 stairs at 165mm
falling 3135mm down 19 stairs at 165mm

Henno is saying 16 stairs or 12 considering its an place of assembly?
I would take the 20 stairs anyday;)

1.1.12 In places of assembly to which large
numbers of people have resort, there should be no
more than two consecutive flights each having a
maximum of twelve risers, without a change in
direction of at least 30° between flights (see
Diagram 3).

Sub-section 1.1
Stairways and Ladders
1.1.1 Paragraphs 1.1.2 to 1.1.20 give some
guidance on good practice insofar as it relates to
non-complex buildings of normal design and
construction.

millennium what about 20stairs = 4400@220mm
or 26 stairs = 4290@165mm?

26 stairs ok?
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Re: How Did Benson & Forsyth Do This?

Postby mulp » Wed Jul 08, 2009 9:28 am

missarchi wrote:here's another one for you.. what hurts more assuming same going?

falling 3520mm down 16 stairs at 220mm
falling 3300mm down 20 stairs at 165mm
falling 3135mm down 19 stairs at 165mm

Henno is saying 16 stairs or 12 considering its an place of assembly?
I would take the 20 stairs anyday;)



I wondered what the intent of the limitation to 16 risers was.
Was it regard to the elderly or infirm, to allow them a resting point?
(If you have an adjacent lift is the requirement negated?)

To introduce a landing in longer stairs to break a fall?
(missarchi's point is a good one in that regard).

or, as I suspect,
Is it mainly to provide a landing as resting point when two or three persons are carrying a wheelchair user down during an evacuation (when the lift can/may not be used)?

An evacuation chair is conspicuously located at the top of the rear, 19-riser flight in the gallery. Would the provision of this equipment demonstrate an alternative means of compliance?

The revised BS8300-2009 (Design of buildings and their approaches to meet the needs of disabled people) would seem very strange if it has increased this limit up to 20 risers. That whole document gets a slating from this reviewer: "Sleepwalking into Problems ?"

http://www.cjwalsh.ie/2009/06/bs-99992008-bs-83002009-sleepwalking-into-problems/comment-page-1/#comment-315

Just read that BS 8300-2009 does indeed permit max of 20 risers, describing how landings themselves can create problems for users such as the visually impaired.
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Re: How Did Benson & Forsyth Do This?

Postby henno » Wed Jul 08, 2009 9:52 am

missarchi wrote:here's another one for you.. what hurts more assuming same going?

falling 3520mm down 16 stairs at 220mm
falling 3300mm down 20 stairs at 165mm
falling 3135mm down 19 stairs at 165mm

Henno is saying 16 stairs or 12 considering its an place of assembly?
I would take the 20 stairs anyday;)



i dont know what you mean... :confused:

there are clear regulations as to the goings and risers based on the use of the building, you cant just pick and choose based on the number of steps....
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Re: How Did Benson & Forsyth Do This?

Postby wearnicehats » Wed Jul 08, 2009 9:56 am

Copo wrote:The latest British Standard (BS8300-2009_Design of buildings and their approaches to meet the needs of disabled people: Section 5.9.3 Rise of a flight) proposes 'no flight on an external stepped access route should contain more than 20 risers and, as far as possible, the numbers of risers in successive flights should be uniform'. This also applies to internal stairs.


when I saw this I was convinced it was a typo as I couldn't believe a jump from 12 risers in BS8300-2001 to 20 now. I'll stick to the TGD Part K unless I'm in real trouble
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Re: How Did Benson & Forsyth Do This?

Postby missarchi » Wed Jul 08, 2009 11:05 am

henno wrote:i dont know what you mean... :confused:

there are clear regulations as to the goings and risers based on the use of the building, you cant just pick and choose based on the number of steps....


I don't think they are regulations...
I assume the main issue the the judge will look at is "the regulation":


Stairways, ladders and ramps. K1 Stairways, ladders and ramps shall be such as to afford safe passage for the users of a building.

Protection from falling. K2 In a building, the sides of every floor and balcony and every part of a roof to which people normally have access shall be guarded to
protect users from the risk of falling therefrom.

Vehicle ramps, floors and roofs. K3 In a building, the sides of every vehicle ramp and every floor and roof to which vehicles have access shall be guarded against the risk
of vehicles falling therefrom.

Application of this Part. K4 The requirements of this Part apply to stairways, ladders and
ramps which form part of the structure of a building.

then

The Guidance
The materials, methods of construction, standards and
other specifications (including technical specifications)
which are referred to in this document are those which
are likely to be suitable for the purposes of the
Regulations. Where works are carried out in accordance
with the guidance in this document, this will, prima facie,
indicate compliance with Part K of the Second Schedule to
the Building Regulations. However, the adoption of an
approach other than that outlined in the guidance is not
precluded provided that the relevant requirements of the
Regulations are complied with. Those involved in the
design and construction of a building may be required by
the relevant building control authority to provide such
evidence as is necessary to establish that the requirements
of the Building Regulations are being complied with.

I would always follow the guidance where possible...

I mean just think of all those tube trains with disabled fire exits
how many people die from alcohol a year? car crashes? You can do all you want to comply with part B only for someone to disconnect a smoke alarm...
or fire bomb a house or make an insurance claim. Next thing they will recommend you wear a jet pack before you enter a building... and have skylights that you can launch out of
flying fox's with wheel chair harness's and escape slides...

reading this

People with disabilities have a right, recognized in international law after 3rd May 2008, to equal opportunity and non-discrimination in matters of building fire safety, protection and evacuation. A minimum response to Article 11 (Situations of Risk) in the 2006 United Nations Convention on the Rights of Persons with Disabilities is required, therefore, from fire regulators and code writers. Such a response is absent in British Standard BS 9999:2008.

we may as well have world war three and start fresh.
if your really worried about fire go and live in NORAD


There are also disabled architectural styles that have a right to be recognized...;)

henno you saying they should not of built this or let millions of people use it each year?
There is another one in D8
http://www.flickr.com/photos/birispaul/3604129900/
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Re: How Did Benson & Forsyth Do This?

Postby henno » Wed Jul 08, 2009 11:23 am

missarchi...

the point i was making, in response to your post, was that your comparison of a 20 riser stair at 165mm and a 16 riser stair at 220mm is moot because there are regulations which will dictate the rise measurement.

it is disingenuous to compare both of these because a 220mm rise should not exist in a public build... so the question should have been "would i prefer to to fall 16 steps in 165 or 20 steps in 165"... kinda speaks for itself really....

there are regulations... table 1 part k... max rise for a public stair 180mm ... optimum 150mm
If you choose not to implement the suggested compliance method in the TGDs, you'd need to be able to argue strongly as to why you did not comply...

as to whether the should have not built it.... i would say that it shows a lack of design skills not to be able to design a park K compliant stairwell into the building....
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Re: How Did Benson & Forsyth Do This?

Postby mulp » Wed Jul 08, 2009 11:52 am

henno wrote:missarchi...

If you choose not to implement the suggested compliance method in the TGDs, you'd need to be able to argue strongly as to why you did not comply...

as to whether the should have not built it.... i would say that it shows a lack of design skills not to be able to design a park K compliant stairwell into the building....



So, to get things back on track, in the example of B&F in the NATIONAL GALLERY, was there a 'Lack of Design Skills' or did they make a conscious design decision not to make two of their most prominent staircases non Part K compliant?
Does anyone have an opinion of what the strong argument as to why they did not need to comply with the TGD might have been?

P.S. The Sagrada Familia did predate TGD Part K, didn't it?
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Re: How Did Benson & Forsyth Do This?

Postby missarchi » Wed Jul 08, 2009 11:53 am

henno wrote:missarchi...


agreed I was talking about private but what about public...

150mm x 16 rise =2400mm 19 is possible? = 2850
180mm x 16 rise =2880mm

so gaudi should should never have been allow to build the Sagrada familia?
You still have not answered the place of assembly question? 12 rises only?

mulp just call them!
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Re: How Did Benson & Forsyth Do This?

Postby wearnicehats » Wed Jul 08, 2009 12:13 pm

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Re: How Did Benson & Forsyth Do This?

Postby missarchi » Wed Jul 08, 2009 12:53 pm

"best practice in planning and development for the last 50 years"

carpark...
I'm surprised they don't have bigger fish to fry...
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Re: How Did Benson & Forsyth Do This?

Postby missarchi » Wed Jul 08, 2009 12:58 pm

Is norman foster best practice? about that handrail in the middle?

http://www.flickr.com/photos/dcdead/3287336343/sizes/o/
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Re: How Did Benson & Forsyth Do This?

Postby mulp » Wed Jul 08, 2009 1:03 pm



Thanks wearnicehats, should have looked properly for that.
Somehow I don't think B&F would be likely to have a chat about the issues raised if I were to call them.
Its interesting though:
"the Commissioners of Public Works requested a detailed report from the Gallery’s architects, Benson & Forsyth who advised that the stairs were in compliance with the relevant building regulations".

Simple really.
Just depends on your attitude to risk.

missarchi noted earlier: "everyone so worried about not getting sued these days there is not much room for architecture..."
I think on balance I would be prepared to take a risk and go with more than 16 risers if I felt there was a justifiable design reason and I had taken some form of compensatory measure(s).
However, shouldn't the question really be whether my client wants that risk of a resultant claim thrust upon him?
He may be supportive of my design intentions, but I am certain he will have no appetite for even having to defend against a single claim from that inevitable chancer.
As an architect it is my duty to not place him in that potential position.
Four little spills on the Gallery stair already. The big one will come one day after a few glasses of vino in the upper restaurant (when it reopens).
I doubt whether a presiding judge would accept B&F's reassurances.
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Re: How Did Benson & Forsyth Do This?

Postby mulp » Wed Jul 08, 2009 1:11 pm

Rock on Siza:

http://www.flickr.com/photos/jpmm/502049647/

...You can imagine what the stair up the bell tower is like!
I climbed it. Then crawled back down.
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Re: How Did Benson & Forsyth Do This?

Postby henno » Wed Jul 08, 2009 3:48 pm

missarchi wrote:so gaudi should should never have been allow to build the Sagrada familia?



mulp answered that one for me...

missarchi wrote:You still have not answered the place of assembly question? 12 rises only?



what question?
12 rises in a flight...

the B+F stair could have been split into two 10 step flights with an intermediate landing...
or any combination that wouldnt result in a flight with more than 12 risers.... i cant see where the confusion lies...

fair enough, B+F have made a conscious decision (i hope!) to design something that is outside of normal compliance, and they (should) feel strongly enough to be able to argue its merits should the need arise.........

i do not know the details of the construction that could make that argument valid... as mulp has alluded to earlier, perhaps they feel a nearby lift negates the need for an intermediate landing..... i dont know....
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Re: How Did Benson & Forsyth Do This?

Postby cajual » Wed Jul 08, 2009 7:16 pm

try this for a dubious stairs (artwork at Kroller Muller Museum in Arnhem).

Image

i started to go up but got too freaked out and had to come back after a few steps.

a visitor was seriously injured a few years ago- interesting comment on the nature of risk from the museums director here: http://www.kmm.nl/column-archive/3/Kijk-Uit-Attention-van-Krijn-Giezen?lang=en

The museum stood and continues to stand by the conviction that there is no danger whatsoever if the stairs are climbed and descended in a calm manner: the many tens of thousands of visitors who have safely climbed the stairs since they opened are proof of that. But the museum now knows that there is a risk. Although the museum does not consider itself liable for what happened on 24 May – because we believe that every visitor must take responsibility for themselves and others – it does feel responsible. On the basis of this responsibility we have decided to investigate which additional measures are desirable and possible.


Krijn Giezen and the museum’s staff were shocked by the accident. The artist sees the current closure of the work as a component of its functioning within time. One of the dilemmas we face is that fundamental structural changes will alter the work’s character and thus raise questions as to its legitimacy as a work of art in the sculpture garden.
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