Enclosed elevator in rated stair tower.

[Fast_Edd1e]

This is something I have seen before, but on a current project we are being told by another architect, we cant do.

Michigan Building Code 2015, See attached plan.

We have a masonry elevator between 2 floors. This elevator is in a rated masonry stair tower with the stairs going around the elevator shaft. This stair tower has direct exit to the exterior so we don't have "exit passageways" This would be considered an Interior Exit Stairway 1023.

They haven't said what section of the code denies this design. We haven't been caught on it before. And I'm my own search I'm not finding anything since they are all rated assembly. If anything i would consider it an "elevator lobby"

Any thoughts on it?

 

[RLGA]

The other architect is correct. Section 1023.1 limits exit stairways for the purpose of means of egress and circulation (not circulation via an elevator). More specifically, Section 1023.4 states, "Elevators shall not open into interior exit stairways and ramps."

 

[Fast_Edd1e]

I guess my rebuttal to this is that the elevator is not an opening, but encapsulated by the rated exit stairway. I can see if the elevator shaft was outside of the stairway with the door entering thru as an "opening" But that isnt the case.

 

[Yikes]

I guess my rebuttal to this is that the elevator is not an opening, but encapsulated by the rated exit stairway. I can see if the elevator shaft was outside of the stairway with the door entering thru as an "opening" But that isnt the case.

1023.4 gives even greater context. Interior exit stairways should only have doors required for "exit access to the enclosure from normally occupied spaces and for egress from the enclosure".

And 1023.4 doesn't say "elevator shafts shall not open into interior exit stairways"; it says "elevators [e.g. the cab] shall not open into interior exit stairways".

That doesn't mean your design is prohibited - - it just means it's not prescriptively allowed in the code for an interior exit stairway enclosure. You can always take the 104.11 route of "alternative materials, design". The burden of proof would upon you to demonstrate how it is as safe or safer than the prescriptive code.

Or maybe another approach is to treat the stairway exit enclosure more like an atrium instead? See 404 (especially 404.10), 707.3.6, and 907.2.13 to see if you could make it work in the larger context of your building design.

 

[BayPointArchitect]

I don't believe that it is technically correct, but we used to allow elevators and restrooms to be located within the fire-rated stair shaft. It made sense to me given that it is unlikely that the paper towels are going to catch fire and cause a big problem in the restroom. I still think it's acceptable but when two or three building officials disagree, then we settle on the most restrictive.

 

[Paul Sweet]

2018 IBC 3002.7 says "Elevators shall not be in a common shaft enclosure with a stairway."

Elevators have lots of motors (door operators as well as the machine) and other electrical stuff that could spark or smolder and fill the stairway with smoke.

 

[Lo_Res_Sam]

2018 IBC 3002.7 says "Elevators shall not be in a common shaft enclosure with a stairway."

Elevators have lots of motors (door operators as well as the machine) and other electrical stuff that could spark or smolder and fill the stairway with smoke.

I don't know if I'm correct (I'm probably not), but I'd like to read this as "elevators must be in their own shaft enclosure, not sharing a common shaft with a stair" and to me, that is what is in the OP's design.

The stair shaft is a donut shaped shaft.
The elevator is a donut-hole shaped shaft.
Both are enclosed by individually rated fire barriers and wholly separate from each other.

To me, the problem isn't IBC 3002.7, but actually 1023.4 which says "Elevators shall not open into interior exit stairways and ramps." That reads pretty black and white. Even if they're not sharing a common shaft enclosure (they're not, imo), the elevator can't open into the interior exit stairway.

I'm working on a project with a similar design and I want to find an appeal path, but I'm at a dead end. I think I'll approach it with the AHJ by offering automatic smoke control curtains on the elevator so that in the event of a smoke event, the elevators will not open into the interior exit stair... but as a matter of normal day-to-day use, they will.

Thoughts from the group?

 

[steveray]

I'm working on a project with a similar design and I want to find an appeal path, but I'm at a dead end. I think I'll approach it with the AHJ by offering automatic smoke control curtains on the elevator so that in the event of a smoke event, the elevators will not open into the interior exit stair... but as a matter of normal day-to-day use, they will.

Thoughts from the group?

No....It would need to be a fire barrier at a minimum if it were allowed...

 

[Yikes]

I don't know if I'm correct (I'm probably not), but I'd like to read this as "elevators must be in their own shaft enclosure, not sharing a common shaft with a stair" and to me, that is what is in the OP's design.

The stair shaft is a donut shaped shaft.
The elevator is a donut-hole shaped shaft.
Both are enclosed by individually rated fire barriers and wholly separate from each other.

To me, the problem isn't IBC 3002.7, but actually 1023.4 which says "Elevators shall not open into interior exit stairways and ramps." That reads pretty black and white. Even if they're not sharing a common shaft enclosure (they're not, imo), the elevator can't open into the interior exit stairway.

I'm working on a project with a similar design and I want to find an appeal path, but I'm at a dead end. I think I'll approach it with the AHJ by offering automatic smoke control curtains on the elevator so that in the event of a smoke event, the elevators will not open into the interior exit stair... but as a matter of normal day-to-day use, they will.

Thoughts from the group?

In post #1, the attached floor plan .jpg clearly shows the elevator door opening onto the stair landing.

 

[Paul Sweet]

The elevator shaft within a stair shaft is still within the stair shaft. The doors between the stair and elevator connect the two shafts. Elevator doors are not smokeproof, so any smoke from the elevator would get into the stairs.

Some people just don't understand "NO!". Maybe the "Hell" confuses them.

 

[Yankee Chronicler]

I'm working on a project with a similar design and I want to find an appeal path, but I'm at a dead end. I think I'll approach it with the AHJ by offering automatic smoke control curtains on the elevator so that in the event of a smoke event, the elevators will not open into the interior exit stair... but as a matter of normal day-to-day use, they will.

Thoughts from the group?

If I were the AHJ, I wouldn't approve it. And I would forever after consider any design professional who came to me with such an idea to be someone whose work cannot be trusted and has to be checked extra carefully.

 

[Yikes]

The elevator shaft within a stair shaft is still within the stair shaft. The doors between the stair and elevator connect the two shafts. Elevator doors are not smokeproof, so any smoke from the elevator would get into the stairs.

Right. It’s the doors that connect the two shafts.
Perhaps the OP could redesign and analyze this more like an Atrium per IBC 404.10.
Or, engage a Fire Protection Engineer to provide a performance analysis; that’s what they did for the Stratosphere in Las Vegas, which went against the prescriptive requirements of the code.

 

[Yikes]

As a thought experiment:
What if, instead of this being an enclosed elevator, this doughnut-shaped stair had nothing in the middle, EXCEPT at the lowest flight of stairs they installed a wheelchair lift? The lift is essentially open on all sides, no enclosure of its own that would collect smoke. Would code allow that piece of equipment inside a stairwell enclosure?

 

[steveray]

You could theoretically have the elevator go through a "tunnel" and not enter the exit stair with no communication and have it work...but that seems difficult and not the design intent...

 

[Yikes]

You could theoretically have the elevator go through a "tunnel" and not enter the exit stair with no communication and have it work...but that seems difficult and not the design intent...

Agreed, but I think the OP is asking 100% the opposite: what if the elevator enclosure and all its openings is contained entirely within the stairwell enclosure, with no direct communication into any other part of the building?

The image below is likely a residential installation, I've seen these often in old European buildings. For sake of discussion, let's pretend its is a rated stairwell under the IBC, separated from the rest of the occupied floors, with the elevator contained entirely within the rated stairwell.
In this scenario, if a fire were to start at the ground floor in the stairwell, in your opinion does the presence or absence of the glass enclosure below make any physical difference in the spread of smoke within the upper portion of the stairwell?

 

[steveray]

Agreed, but I think the OP is asking 100% the opposite: what if the elevator enclosure and all its openings is contained entirely within the stairwell enclosure, with no direct communication into any other part of the building?

The image below is likely a residential installation, I've seen these often in old European buildings. For sake of discussion, let's pretend its is a rated stairwell under the IBC, separated from the rest of the occupied floors, with the elevator contained entirely within the rated stairwell.
In this scenario, if a fire were to start at the ground floor in the stairwell, in your opinion does the presence or absence of the glass enclosure below make any physical difference in the spread of smoke within the upper portion of the stairwell?
View attachment 15880

Not really...but also not allowed...

 

[Yikes]

@steveray: totally agree. Elevators are prescriptively not allowed in 1023.4. That’s why the burden of proof is on the OP if they are going to propose a modification to the code, to demonstrate how having an elevator in the stairwell is as safe or safer than not having it in the stairwell. Engaging a FPE to discern the underlying safety issue in 1023.4 would be a start.

In the thought experiment in post #15, I find it interesting that 1023.4 prohibits elevators in exit enclosures but does not expressly prohibit platform lifts, which are listed as a possible component in a “circulation path” in CBC 202. This leads me to wonder if the main concern might not be merely the presence of machinery in the stairwell but the concept of the elevator shaft communicating smoke into the stairwell enclosure. I’ve not researched this further, but if the OP wants to pursue it and propose an alternative, they may want to research the code proceedings when this was adopted, or hire an FPE.

 

[Paul Sweet]

". . . they may want to research the code proceedings when this was adopted, or hire an FPE."

This was adopted long ago. 1922 Building Code Recommended by the National Board of Fire Underwriters, Section 90, par. 11:
"A stairway and elevator shall not be permitted within the same enclosure."