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Landing required every 12' in residential spiral stairs?

gnarkill283

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Have a project in Florida with a spiral stair that's 17' tall. The stair is not used for emergency egress. Do I still need to provide a landing at 12'?
 

tbz

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I don't believe you can go more than 151" between landings per FBC adopted IRC R311.7.3 even with the spiral stair.

Unless I am reading something wrong I don't see an exception from max between landings


The FBC IBC 1011.8 Vertical rise the exception from the max 144 in the IBC is for spirals, but only spirals used for Means of Egress from technical production areas


Thus not over 151 in the IRC and the IBC is specific only for MOE from a specfic type of area, forewhich you note your requirement is not for MOE, thus does not comply.

But I will let the Floridians have the last word.
 

tbz

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This is a single family 5th floor and roof penthouse suite of a multi use building
So this is not under the IRC, it's an R2,

Thus under the IBC, 144in max rise between landings per the FBC, I would check with the local AHJ and see if they do consider it an MOE and if they will let you apply for a variance, its a direction and shot, but as on the books, max 144 and needs a mid landing.
 

gnarkill283

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What about minimum tread depth? I see 7.5" required within the first foot of the narrowest edge in the FBC but again this stair isn't required for egress. In that case, does this requirement not matter?
 

tbz

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What about minimum tread depth? I see 7.5" required within the first foot of the narrowest edge in the FBC but again this stair isn't required for egress. In that case, does this requirement not matter?
its simple,

You are not required to install the spiral, but if you do it has to be per code.

The same goes for an electrical outlet, just because you add another outlet on the wall and the spacing is less than 72" x 72", does not mean the outlet in between doesn't have to comply with the electrical code.

Its a minimum building code, just because you add more than the code requires, does not mean you don't have to install all the extra stuff to code.
 

gnarkill283

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its simple,

You are not required to install the spiral, but if you do it has to be per code.

The same goes for an electrical outlet, just because you add another outlet on the wall and the spacing is less than 72" x 72", does not mean the outlet in between doesn't have to comply with the electrical code.

Its a minimum building code, just because you add more than the code requires, does not mean you don't have to install all the extra stuff to code.
I see the residential FBC has less stringent spiral stair requirements than the regular FBC: "Each tread shall have a depth of not less than 6-3/4 inches (171 mm) at the walkline" I'm allowed to use this code for this residential apt in a mixed use commercial building correct?
 

tbz

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I see the residential FBC has less stringent spiral stair requirements than the regular FBC: "Each tread shall have a depth of not less than 6-3/4 inches (171 mm) at the walkline" I'm allowed to use this code for this residential apt in a mixed use commercial building correct?
The IRC is for 1 and 2 family dwellings 3 stories or less in total height.

By being a mixed use building, I envision a private condo or rented apartment over a store front or other tenants below and more times than not in my area more than 3 stories.

So, from where I sit, I would say no you can't use the IRC code in a building governed by the IBC,

The FBC is an adoption of many codes and standards, however for the project you are working on, you are funneled in to a mix use to the IBC portion of the FBC as adopted with modifications.

Hence from my understanding of the FBC, no you can't use an IRC code in a IBC USE Group building unless specifically spelled out in the FBC-IBC adopted code.

Now with all that said, I am not a building official or inspector in the state of Florida, thus from my original post #3 above, "I will let the Floridians have the last word"
 

gnarkill283

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So this is not under the IRC, it's an R2,

Thus under the IBC, 144in max rise between landings per the FBC, I would check with the local AHJ and see if they do consider it an MOE and if they will let you apply for a variance, its a direction and shot, but as on the books, max 144 and needs a mid landing.
What are the requirements of a 12' landing for a long spiral stair? The width of the stair is 5' - does the outer edge of the landing have to be 5' then?
 

gnarkill283

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I also see a requirement that the stair to be considered a spiral stair can't be more than 24.5" wide from center point to walkline or else its considered a stair with max riser height of 7" instead of 9.5". This stair's walkline is 30" away (1.5' to 6.5" from center line for 5' stair). I don't see this in the FBC standard building code
 

tbz

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Messages
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I also see a requirement that the stair to be considered a spiral stair can't be more than 24.5" wide from center point to walkline or else its considered a stair with max riser height of 7" instead of 9.5". This stair's walkline is 30" away (1.5' to 6.5" from center line for 5' stair). I don't see this in the FBC standard building code
If this is in the individual space of an R2, and is a winder not a spiral, then the riser could be 7.75"

As to the landings min width, it has to be at least the same width on the stair flight it serves
 

bill1952

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Clayton NY
As the proponent for the change that resulted in the exception for technical production areas, and having a spiral stair in most of my projects, stages, I think landings in spirals was a mistake from a code reorganization. 30 to 40 ' not unusual rise. Landings just force steeper rises and lower head clearance. Not arguing code interp but it's a fundamental problem. I'd seek a variance especially if the building otherwise met means of egress requirements without the spiral.

Actually, if you include a spiral stair, it is a required means of egress for the person using the stair. It's their only way out from any place on the stair. A catch 22.
 
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