Circular stairs

masyva

Because we had to change the internal radius of the stairs after the outside wall was built, there is now 6-7 thread that are wider than the rest of the stair case. On plans, it looks like a bump on the external radius of the stair case and this makes the threads of different width (see attached). At the widest point, the thread is 215mm wider.

If one follows the wall on the external radius, he might experience different going length, in a similar way as if he was walking from the internal radius towards the external radius.

Does any one have a similar situation or can anyone provide a risk analysis of this situation showing how likely someone could get injured because of the difference in the going?

Can anyone recommend an engineer who could study the situation and provide a risk analysis?

Knowing that there is no railing on the external radius because of the wall, I'd assume in case of emergency one would take the shortest route and use the handrail on the internal radius; therefore he won't experience going differences. If this assumption could be backed up by facts or a study, my problem would be sorted...

I'm based near Galway.

Thanks,
Yvan

BryanF

on first glance id suggest plasterboard out the area shown dotted (maybe add a book shelf)and ensure all the stairs risers and going are equal. all other talk about risk assessments etc is irrelevant as its against the planning regs to have different goings in a flight. also you may want check the rest of the regs
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1651,en.pdf


coming soon, or maybe forgotten about?!?

http://www.environ.ie/en/Legislation/DevelopmentandHousing/BuildingStandards/FileDownLoad,26938,en.pdf

masyva

Hi BrianF, thanks for the quick reply but I'd like to try other options first as there is a window in the middle of that "bump".

Here is what the document says: "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"

The regulation is about safety and if it can be proven that my stairs are safe, I'm happy with it.

There is something I don't understand in the regulation and maybe you can enlighten me: under paragraph 1.1.6, it says "Public stairs should not contain tapered steps." Does that mean that it's against regulation to have circular stairs in public building?

BryanF

is this new building?
who is the certifying architect /engineer?

you might be happy with your interpretation of safety but my reading if regs is clear. i paraphrase: each step/ going/ rise should be the same

is this a public building if so you need to consider part M
are there tapered steps in you stairs?yes.
if its the only stairs and this is a public building and you really want it, i would request a letter of consent from your local building control officer.

masyva

Thanks for pointing out the local building control officer, that gives me somewhere to look!

No, this is not a public building. I was just curious of how one is supposed to interpret the regulation. What is your interpretation of that part regarding public stairs should not contain tapered steps?

masyva

Also, the regulations specifies "if the flight is 900 mm or wider, measured 270
mm from each side."

Where do we start the measurement? From the handrail or from the wall? How precise does the measurement have to be knowing there will be stone cladding on that wall (what's the tolerance)?

BryanF

don't have them, simple as that!

what tends to happen in reality is between fire, disabled and stair regs you put in a feature stairs that's got whatever tapers, glass, shape - essentially a focal point. but you also have the correct escape, disabled, equal riser/ going etc steps elsewhere in the building to comply.

your being selective in the questions your answering! - where is your architect? why is s/he not sorting this out? even if this is a hippie hobbit house, an architect is still required to ensure building regulations are complied with (huge presumption made here:o solely on the curved wall:D, but also your approach and lack of understanding of building regulation:()

BryanF

masyva wrote: »

How precise does the measurement have to be knowing there will be stone cladding on that wall (what's the tolerance)?

??

would you like me to recommend a good architect in your area? that would be happy to prepare a detailed drawing and discuss your requirements. i think it would be best;)

masyva

BryanF wrote: »

??

I have an architect and that's the problem!
Another problem is I gave the go ahead for those stairs
Another problem is I don't want to stud out the wall and make the window smaller
Another problem (and you pointed out correctly), I'm very selective
And last but not least, I'm stubborn and when I have an idea, I don't let go that easily! :rolleyes:

Seeing you know the stuff (free consulting, woo hoo!), would you consider my staircase as "helical stair" according to BS 5395-2? If so, BS 5395-2 says the following:

5.4 Going
[...]
The outer going, which is the maximum going,
should be measured at a point 270 mm horizontally
from the outer handrail or string, whichever is the
least radius

If I put a handrail on the wall and it follows the dotted lines, my "going" problem will then be solved, right? What's your interpretation on this?

BryanF

masyva wrote: »

If I put a handrail on the wall and it follows the dotted lines, my "going" problem will then be solved, right? What's your interpretation on this?

yes, (caveat: this presumes that all risers /threads /goings inside of your handrail are equal, and presumes domestic construction)
draw it up and ask your architect will s/he certify it, if not comeback with their reasons.

is this entire area a window? surely there is a way of plaster boarding the area, leaving the window as is or creating some compromise, that will look good as well as practical - I'm intrigued to know your archs perspective?

masyva

See attached, that's the drawing she came up with. She's saying the exact same thing as you...

But as I said, I'm a bit stubborn and because I think those wide stairs look nice, I'm trying to find another way around it. I hope someone can come up with something that doesn't involve changing anything and us being able to have that part of the construction certified!

You can say I'm a dreamer... but I'm not the only one...!

BryanF

i prefer your architects approach, thats a decent drawing shes gone to the trouble of doing, maybe a compromise would be to splay the window side reveals a little.but keeping the handrail as shown.

on a side note, i hope there's a better window detail being prepared? also on the landing those Double doors sort of block the landing, thats grand if there just cupboards,

Mellor

masyva wrote:

No, this is not a public building. I was just curious of how one is supposed to interpret the regulation. What is your interpretation of that part regarding public stairs should not contain tapered steps?

Public building can't contain tapered steps. I'm not sure what there is to interpret here, its pretty straight forward.

masyva wrote: »

Seeing you know the stuff (free consulting, woo hoo!), would you consider my staircase as "helical stair" according to BS 5395-2? If so, BS 5395-2 says the following:
If I put a handrail on the wall and it follows the dotted lines, my "going" problem will then be solved, right? What's your interpretation on this?

A helix is a spiral. A handrail along the true circle line solves the issue. It also solves the problem of widening and narrowing of the stairs

The drawing provided solves the issue. I'm not a huge fan of the handrail turning into the wall mid flight and would actually prefer that there was no handrail that side. IMO no handrail is safer than one that suddenly stops. Also, i think an 80mm diameter handrail is too big.
Obviously you'd still keep the glass balustrade. I'd look at edge supporting it to prevent/reduce and step in the outer wall.

I would also have splayed reveals on the curved window opening, this prevents it narrowing and reducing light.


As an alternative solution. The stairs could be freestanding. Independent from the wall, in the shape of a smooth circle. Glazed both sides of course. The wall following the outer radius.

masyva

Thanks to both BrianF and Mellor.

Can anyone tell me if the attached stair case is built according to regulation and if yes, where I can find the information? (private house)

BryanF

I gave you the building regs above, why not have a read!

masyva

Not really helpful reply BrianF...

I've seen the attached stairs being built in a joinery company and if I understand the regulation correctly, they are not compliant.

Or did I miss something?

sydthebeat

why do you think its not compliant?

sydthebeat

ive read this whole thread and im not quite sure what the confusion is over.


as per your "current layout" link
the flight is not less than 900 wide therefore the taper is measured in the middle. That equates to a going of 350 which is loads.

Where the width exceeds 1000 you need two handrails. is that the query?

Is the stairs in the photo your actual stairs? It seems to form a point where the threads are widest, whereas the design shows a curve there.

masyva

sydthebeat wrote: »

why do you think its not compliant?

For a few reasons:

1. Nothing is mentioned regarding such enclosure.
2. Paragraph 1.1.4 says: (d) all tapered steps should have the same going.
3. Paragraph 1.1.6 says: For tapered treads, the going should conform with par. 1.1.4 when measured as follows: (b) if the flight is 900 mm or wider, measured 270 mm from each side.
4. Finally, if we measure the going 270mm on the square enclosure, it will be different than 270mm where there is no enclosure.

Is my reasoning correct? Am I missing something that tells me that those stairs are compliant with regulation?

sydthebeat wrote: »

ive read this whole thread and im not quite sure what the confusion is over.

There is no confusion, I just want to either prove that my stairs are compliant with regulation (first post - "current layout") or that the regulation contradicts itself

sydthebeat wrote: »

as per your "current layout" link
the flight is not less than 900 wide therefore the taper is measured in the middle. That equates to a going of 350 which is loads.

I think you got it the wrong way around: if it's less than 900mm then it must be measured in the middle. My stairs are more than 900mm and therefore the going should be measured 270mm from each side.

sydthebeat wrote: »

Where the width exceeds 1000 you need two handrails. is that the query?

I've just realised that this could be another problem so I'll pretend I never read it - but you're right, it seems if the width exceeds 1000mm, there must be a handrail on both sides...

sydthebeat wrote: »

Is the stairs in the photo your actual stairs? It seems to form a point where the threads are widest, whereas the design shows a curve there.

No, these are not my stairs. It's just something I saw in a workshop and I'd like to know which regulation they are following to be compliant...

sydthebeat

well i cant see any way in which the 'going' can be an issue.

you have 240mm on the shortest side, this alone would comply.

in your design "current layout" all the tapers are the same, whether the stair width widens or not is irrelevant.

Its the handrail where i think you may have an issue, but you can always carry that through the window.. its not a big deal.

also ensure the window is toughened glazing.

masyva

sydthebeat wrote: »

well i cant see any way in which the 'going' can be an issue.

:):)

I'm thrilled! You're the first one to say what I want to hear!

sydthebeat wrote: »

in your design "current layout" all the tapers are the same, whether the stair width widens or not is irrelevant.

That's what I thought! Now I need to prove that to my architect so she will certify the stairs!

How can I do that? Is there some regulation, technical document or anything else where I can find what you just said?

Thanks!

sydthebeat

the minimum going for a private stairs is 220... your narrowest going is 240... absolute no issue.

At the end of the day it comes down to interpretation and opinion.
It would be my opinion that, once the handrail issue is sorted, that the stairs complies.

all the regulation that you need is contained within TGD K


what is your architects difficulty with the stairs?

masyva

sydthebeat wrote: »

what is your architects difficulty with the stairs?

Her problem is that the going is not the same as measured 270mm from the wall, see attached, one going is 407mm and the other going is 450mm...

Tell me that this is not a problem and explain to me where I can find "whether the stair width widens or not is irrelevant."

sydthebeat

the threads are the same when measured from the other side.. paragraph 1.1.6 (b) states as measured from each side.

Thats 19 out of the 26 'measured' threads that are consistent.

For the 1.1 radial width of the stairs all the threads are contant.


This is a situation which cant be covered in every aspect of the regs, so you need to understand the spirit behind them. Having unequal threads on tapered steps is an obvious tripping hazard. In your case your threads are well above minimum standards, are constant for the average width of the stair, and have a consistent radial turn. There is no increased risk to safety in my opinion.

To pull you up on this is pedantry in the extreme.

I see the hand rails as a much bigger issue actually.

at the end of the day, as i said before, it comes down to opinion.

masyva

sydthebeat wrote: »

at the end of the day, as i said before, it comes down to opinion.

If only she could see it this way...

Mellor

sydthebeat wrote: »

the threads are the same when measured from the other side.. paragraph 1.1.6 (b) states as measured from each side.

Thats 19 out of the 26 'measured' threads that are consistent.

For the 1.1 radial width of the stairs all the threads are contant.

A hazard or not is one thing and a matter of opinion. But the stairs doesn't comply with TGD K. So I can understand somebody not wishing to sign off on it.

1.1.6 The varying tread width of a tapered step
can cause people to misjudge distances and can lead
to falls. For this reason, the use of tapered steps
should be avoided. If it is necessary to use them,
they should preferably be situated at the bottom of
the stairs.
Public stairs should not contain tapered steps.
Where consecutive treads are used, a uniform going
should be maintained. For tapered treads, the going
should conform with par. 1.1.4 when measured as
follows
(a) if the flight is narrower than 900 mm,
measured in the middle, and
(b) if the flight is 900 mm or wider, measured 270
mm from each side.
In addition, the going at the narrow end should be a
minimum of 75 mm.

The bolded parts are where is doesn't comply.
The inner string is fine and more than comfortable. The outer string doesn't comply as doesn't have a uniform going. Because the stairs is wide, its natural for people to walk up along the handrail and the changing width inside the handrail could be considered a hazard. This is also why stairs over 900mm can't taper down to 75mm. the 270mm comes from where a foot falls inside the handrail.

The fact that each step has the same angular taper is irrelevant really.
I just realised that there is a solution in that fact. You can adjust the taper of the wider steps so that the width measured 270mm inside the handrail is equal. That way each step is the same step stretch to be slightly wider and not a step that increases to a bigger dimension. That way going is uniform on both sides and in the centre on every step. That would comply with TGD K and the architect should be happy with it.

This is a situation which cant be covered in every aspect of the regs, so you need to understand the spirit behind them. Having unequal threads on tapered steps is an obvious tripping hazard. In your case your threads are well above minimum standards, are constant for the average width of the stair, and have a consistent radial turn. There is no increased risk to safety in my opinion.

To pull you up on this is pedantry in the extreme.

I see the hand rails as a much bigger issue actually.

at the end of the day, as i said before, it comes down to opinion.

Radial turn is irrelevant. Physically, it makes no difference. Eg there is no issue going from a tapered to a straight step.
There is a potential risk to an elderly person walking up along the outer handrail where the steps increase significantly in width in that area.

i agree that the handrail is more important also.

masyva

Mellor wrote: »

I just realised that there is a solution in that fact. You can adjust the taper of the wider steps so that the width measured 270mm inside the handrail is equal. That way each step is the same step stretch to be slightly wider and not a step that increases to a bigger dimension. That way going is uniform on both sides and in the centre on every step. That would comply with TGD K and the architect should be happy with it.

Thanks Mellor, I like when people bring solutions but I'm not quite sure I understand what you mean by "adjust the taper of the wider steps". If you do that, won't the adjusted steps have a smaller going in the middle? If so, that would be a hazard, no?

masyva

Mellor wrote: »

Public building can't contain tapered steps. I'm not sure what there is to interpret here, its pretty straight forward.

See planning application for "circular stairs" at a shopping centre in Galway:
http://gis.galwaycity.ie/ePlan/InternetEnquiry/rpt_ViewApplicDetails.asp?validFileNum=1&app_num_file=FS2811

If public building couldn't contain tapered steps, the Eyre Square Shopping Centre would be illegal, right?

BryanF

See post 7
Why you're interested in a commercial stair, I don't know - a convolution is all!

Mellor

masyva wrote: »

Thanks Mellor, I like when people bring solutions but I'm not quite sure I understand what you mean by "adjust the taper of the wider steps". If you do that, won't the adjusted steps have a smaller going in the middle? If so, that would be a hazard, no?

The middle going will be the same for all steps if it's set out like I describe. Thats when it's measured at the middle if each thread/directly between handrails. As it stands, the exact middle if each thread actually different on the wider steps.

Think of it like this, if a triangle has a base 500mm wide, the width at the middle is 250mm. No matter what the height. The same idea applies to you steps. Let me know if what I'm describing isn't clear.

With the widths matched for all steps I believe the stairs will be more comfortable, and importantly will satisfy part K.

masyva

BryanF wrote: »

Why you're interested in a commercial stair, I don't know - a convolution is all!

BryanF, thank you for your reply.

As you can see from this thread, not everyone understands the regulation the same way.
In post #13, Mellor says "its pretty straight forward - Public building can't contain tapered steps".
I'm just trying to understand his point of view: if public stairs can't contain tapered steps, why, does he think, the planning mentioned in #28 has been approved.
Depending on the reason he gives, the same can apply to my stairs...

Similarly, I asked you a question in #15 but never answered. If the stairs in #16 are built according to regulation, I'd like to know which paragraph mentions it so maybe the same can apply to my stairs...

masyva

Mellor wrote: »

The middle going will be the same for all steps if it's set out like I describe. Thats when it's measured at the middle if each thread/directly between handrails. As it stands, the exact middle if each thread actually different on the wider steps.

Think of it like this, if a triangle has a base 500mm wide, the width at the middle is 250mm. No matter what the height. The same idea applies to you steps. Let me know if what I'm describing isn't clear.

With the widths matched for all steps I believe the stairs will be more comfortable, and importantly will satisfy part K.

It took me a while, but I think I understand your idea, thank you. My problem is the concrete stairs are already poured (see attached)...

Mellor

masyva wrote: »

I'm just trying to understand his point of view: if public stairs can't contain tapered steps, why, does he think, the planning mentioned in #28 has been approved.
Depending on the reason he gives, the same can apply to my stairs...

The eyre square stairs means nothing in relation to your stairs.

But, i'll answer your question anyway.
Firstly, planning is nothing to do with building regs. A building still has to comply with regs, even if it received planning for something that doesn't meet regs.
The TGDs are a guide for how to meet the regs. Generally, in domestic situations they cover all angles. Sometimes in larger buildings, that isn't possible and compliance can be achieved with specific solutions. Such as a engineer fire cert. In this case, maybe the provisions for ambulant disabled are adequate so that tapered steps were acceptable. Or maybe the taper is so subtle that it was not an issue. I don't know the situation, so that just speculation really.

Regarding public stairs and tapered steps. Its clearly general guidance. There is room for exceptions.
However, if your situation, it gives specific citeria and instructions.
As i said above, the galway stairs isn't related to your situation.


If you set it out like I suggested, and add a handrail. You'll comply with the regs, and get the large window from the original sketch. asfar as I cansee it solves the issues, and imo improves the stairs from a comfort point of view.

Mellor

masyva wrote: »

It took me a while, but I think I understand your idea, thank you. My problem is the concrete stairs are already poured (see attached)...

Oh. That's unfortunate. In that case, just add the handrail and proceed on the basis that the steps are generally uniform. Your architect should of resolved the issue before getting to this point.

masyva

Thank you Mellor, your explanations are clear and I understand your view now.

Let's say now that I install one of those fitted fire escape ladder (i.e.: http://www.safelincs.ie/Fixed-Fire-Escape-Ladders/) in one of the bedroom upstairs.

Would that make a difference? I.e. do my stairs still have to comply with TGD K?

BryanF

masyva wrote: »

Thank you Mellor, your explanations are clear and I understand your view now.

Let's say now that I install one of those fitted fire escape ladder (i.e.: http://www.safelincs.ie/Fixed-Fire-Escape-Ladders/) in one of the bedroom upstairs.

Would that make a difference? I.e. do my stairs still have to comply with TGD K?

NOooo stop squirming!

muffler

Everyone please be advised that as per the forum charter we are not a design service and I think this thread is on the verge of being locked. Pardon the pun, but tread carefully here people.

Mellor

masyva wrote: »

Thank you Mellor, your explanations are clear and I understand your view now.

Let's say now that I install one of those fitted fire escape ladder (i.e.: http://www.safelincs.ie/Fixed-Fire-Escape-Ladders/) in one of the bedroom upstairs.

Would that make a difference? I.e. do my stairs still have to comply with TGD K?

It's not a fire issue.
Talk to your architect, ultimately it's her opinion that matters not mine.