landings/spiral stairs

[rktect 1]

So I am reviewing a spiral staircase for an office building tenant finish out, not in the required means of egress. They want to add this staircase between three existing floors, 6th, 7th and 8th floor. But the floor level between is 13'-6". According to the code section 1009.6 vert. rise they can not exceed 12 feet between floors or landings. They have shown no landing. And my question is, can they even put in a landing on a spiral staircase? The overall width of the stairs is about 12 feet. Center core is 2 feet leaving about slightly less than 5 foot wide treads. I still don't see how a landing works out when it is required to be a min of the stair width by 44 inches in travel distance.

I'm not trying to design it, just trying to understand it and find out if it is possible to build within code.

 

[TimNY]

I picture it like this:

|__   |

Up one 6' high rise to a platform then continue on. I believe the landing ould be the width of the tread or greater, not the width of the stair. I don't see any exception for the length of the landing in the direction of travel where it pertains to spiral stairs (unlike tread depth, which has some flexibility when applied to spiral stairs)

 

[rktect 1]

How do you measure the width of travel distance, required 44 inches? Inside sprial, outside spiral or center of spiral or even at 12" inside of spiral where you measure the min. for 7.5" tread depth? Could even impact head height requirement, maybe.

 

[TimNY]

If I am understanding correctly, I believe the length of the landing in the direction of travel would be such that at any point measured from the last tread, you would have 44" of landing perpendicular to such point on the tread.

My interpretation would be that the landing must be the full width of the tread and must provide that full width perpendicular to the tread for the required distance in the direction of travel. If that makes any sense. YMMV.

 

[rktect 1]

Sorry, I corrected my first post, It is a spiral staircase connecting three floors of 20,000 sq. ft. per floor.

 

[TimNY]

If it is not in the means of egress, I believe your only limiting factor for the stairs would be the 12' height per flight (putting any other considerations ie fire barriers aside). This may be a good candidate for a variance.

 

[globe trekker]

rktekt 1,

Joining the discussion late...

Time for a dumb question. How are the spiral stairs not required to be enclosed,

per Section 1020.1 , Exception # 1, #4 & # 8? Possibly others... , or are

these spiral stairs enclosed?

.

 

[MarkRandall]

Globe,

There's no dumb questions here, but I do fail to see why the enclosure as any bearing on the question. For what it's worth, it sounds to me like it would meet exemption #4

 

[High Desert]

It would meet exception #4 as long as it also met 707.2 as referenced in that exception.

 

[globe trekker]

Mark ( and others ),

My question is not directly related to the OP, Sorry!

I hijacked the posting to inquire about other aspects of the spiral staircase

connecting 3 floors.

What exception in Section 707.2 exempts the stairs from being enclosed?

Just asking and trying to work thru this application in my "minds eye".

I apologize for hijacking the thread, but this curious, OCD mind has

got to know.

.

 

[rktect 1]

rktekt 1,Joining the discussion late...

Time for a dumb question. How are the spiral stairs not required to be enclosed,

per Section 1020.1 , Exception # 1, #4 & # 8? Possibly others... , or are

these spiral stairs enclosed?

.

The stairs are actually enclosed on the lowest floor by glass walls and a glass door opening into the staircase. The other two floors they are completly open. The building is completely sprinklered. No new layout yet. The fire department does require a set so I usually wait on them. I am a bit worried about section 1020.1 Exception #4 when I go and look at section 707.2 exception #2.1 They do not have a draft curtain on the two top floors and like I said they do not have a sprinkler plan in. I would have thought they would at least reference the requirements.

 

[globe trekker]

rktekt 1,

Thanks for your input! Please let us know what the final design is.

.

 

[TimNY]

The stairs are actually enclosed on the lowest floor by glass walls and a glass door opening into the staircase. The other two floors they are completly open. The building is completely sprinklered. No new layout yet. The fire department does require a set so I usually wait on them. I am a bit worried about section 1020.1 Exception #4 when I go and look at section 707.2 exception #2.1 They do not have a draft curtain on the two top floors and like I said they do not have a sprinkler plan in. I would have thought they would at least reference the requirements.

I believe they are going to have to provide both the draft curtain and "closely spaced sprinklers" at the curtain. Perhaps the FPE will pick up on the draft curtain.

Back on topic, what are you thinking regarding the landing?

 

[rktect 1]

The landing?

Right now all I know is I am going to tell them they are required to have one and see what they come up with. Once I see what they come up with I will have to make another decision as to if they meet the minimum foreward direction. But I suppose I would ok it if down the center pathway (direction of travel) they show a dimension of 44 inches.

 

[globe trekker]

rktekt 1,

Trying to get on the same page with ya'll...

I would not be too concerned with the 12' maximum "vertical rise" dimension,

as much as I would with the stairway width, ...depth of tread, ...riser heights,

...compliant handrailing and Section 1020.1.

One other thought is, on some of these type of spiral stairways; and Lord

only knows why, but they want to actually install a slippery type material

as the finished product ( i.e. - like marble, granite, decorative stone, etc. ).

It's tough enough as it is to navigate these type of stairs anyway, but

to add a slippery surface to boot. Hmmmmmm.... :???:

.