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Fire rating of elevator shaft/enclosure in 2 story building B-occupancy (IBC 2006)

L

Leo

Member
Joined
Sep 6, 2011
Messages
7
Section 3002.1 requires elevator hoistways to be constructed in accordance with Section 707.

Section 707.2 requires openings through floor/ceiling and roof/ceiling to be protected by a shaft enclosure complying with this section.

Exception #7 states that in other than Goup I-2 and I-3 shaft enclosures are NOT required for a floor opening or an air transfer openings

that comply with:

7.1. Does not connect more than two stories.

7.2. Is not part of the required means of egress system, except as permitted in Section 1020.1.

7.3. Is not concealed within the building construction.

7.4. Is not open to a corridor in Group I and R occupancies.

7.5. Is not open to a corridor on nonsprinklered floors in any occupancy.

7.6. Is separated from floor openings and air transfer openings serving other floors by construction conforming to required shaft enclosures.

7.7. Is limited to the same smoke compartment.

In my instance I have an elevator in a two story building with B-occupancy.

The elevator is housed within for walls.

I consider that in this instance the elevator complies with exceptions 7.1 through to 7.7 and therefore the enclosure does not need to be fire rated.

Section 3006.4 requires that machine rooms require fire barriers having fire resistance rating not less than the required elevator hoistway rating.

I consider that the machine room is not required to be fire rated because the hoistway does is not required to be fire rated.

Section 707.12 requires the top of a shaft to be enclosed with a rated lid or terminate at the underside of the building roof deck.

If my elevator hoistway penetrates the main roof and extends above the main building roof, I believe both the above two requirements are not applicable.

Any expert comments are welcome.

(obviously the plan reviewer does not agree with this and requires a 1 hour rated shaft and machine room with a 1 hour rated lid)
 
Welcome to the board. My experience is that once you put solid walls around an elevator a rating becomes required. If you use glass walls or another open material, the exception to a fire resistive rated shaft would apply. The solid hoistway walls make the opening concealed within the building construction.
 
I agree with you Leo, the shaft is not required to be rated, nor is the equipment room since you are serving only two floors, provided you meet all of the exceptions as you have noted in your post.
 
Is it part of the required means of egress and are the stairs open?

Exception 7 addresses the issue of floor openings

and air transfer openings that are not a part of the required

means of egress. For example, convenience

stairs are often provided for building occupants. Such

stairways serve as a means of communication between

two adjacent floors and are not used as a required

means of egress component. To maintain the

integrity of the exit access corridor, such stairs may not

connect with an exit access corridor in Groups I and R

[see Figure 707.2(3)] because occupants can be

sleeping and the integrity of the corridor system is especially

important under such conditions.

Supplemental stairs are also not permitted to be

connected to any other floor opening that connects to

an additional floor level. Such stairs must be separated

from such floor openings by construction that

complies with this section for shaft enclosures. This requirement

limits the use of this provision so that an

opening between two stories does not openly communicate

with another opening to an additional story and,

therefore, interconnect three or more different levels.

Stairs must also comply with other requirements of

Chapter 10, such as headroom, handrails, guards and

tread and riser relationships.
 
The elevator is not a means of egress.

There are two stairways, unenclosed stairways because only serving a two story building.

7.3 is maybe doubtfull.....what am I concealing, the enclosure ? no the enclosure is visible at both floors.

Am I concealing the elevator? maybe yes...then again the code mentions the enclosure, not what is within the enclosure.
 
Leo said:
The elevator is not a means of egress.There are two stairways, unenclosed stairways because only serving a two story building.

7.3 is maybe doubtfull.....what am I concealing, the enclosure ? no the enclosure is visible at both floors.

Am I concealing the elevator? maybe yes...then again the code mentions the enclosure, not what is within the enclosure.
Click to expand...
No, you're concealing the hole. You're concealing it within the building construction. That construction is the walls.

The code mentions concealing the *opening* not concealing the enclosure.

And thanks for coming to the forum; welcome!
 
According to the IBC Commentary (2009 version), if you meet the provisions as Leo has noted, the shaft is not required to be rated. Read the commentary for section 708.14 on elevator, dumbwaiter and other hoistways.

"Section 708.2 lists exceptions for shaft enclosures around floor openings and is applicable to all hoistways. In addition, shaft enclosures are not required for elevators located in an atrium, since there is no penetration of floor assemblies."
 
The code does allow an open or glass enclosed elevator for a limited number of floors based upon atria or shaft provisions. However, once you coneal the "opening" behind solid construction, a rating is usually required by the AHJ's in my experience. The latest round I had on this issue was an open and glass enclosed elevator. The doors had a 90 minute UL listing and the elevator inspector tried to require a rated shaft since he felt that a rated door could not be installed in a non rated wall. Fortunatly, the elevator code was clarified to allow rated doors in non rated walls. Even if you can get a building official to accept an enclosed non rated elevator shaft, you better also check with the elevator jurisdiction, since they may not agree with the BO/FM interpretation. If the elevator inspectors won't approve it, then no elevator permit and no elevators in the building. Been down that path also.

I hope you find this board useful Leo!
 
Codegeek said:
According to the IBC Commentary (2009 version), if you meet the provisions as Leo has noted, the shaft is not required to be rated. Read the commentary for section 708.14 on elevator, dumbwaiter and other hoistways. "Section 708.2 lists exceptions for shaft enclosures around floor openings and is applicable to all hoistways. In addition, shaft enclosures are not required for elevators located in an atrium, since there is no penetration of floor assemblies."
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I agree. If you meet the provisions of the exceptions, a shaft is not required. One of those provisions is that the opening cannot be concealed within the building's construction. In this case it doesn't meet that exception.

Whether or not this is a worthy requirement is up for debate, but in my opinion, in strict code terms, it is not permitted.
 
LIke I stated, "provided you meet all of the exceptions as you have noted in your post". Thanks texasbo! :)
 
It does not sound like the building was designed as an atrium building, but that is an interesting concept from the commentary. Defining it to be an atrium space would require avoiding considering the elevator as "enclosed."

If you are able to consider the elevator opening as creating a 2-story atrium, then perhaps no shaft rating would be required, although there would be other implications from Section 404 to address.

There must be greater challenges than providing a rating for the shaft enclosure - perhaps it's a Type V-B building, and there are concerns with maintaining the rating of the enclosure in the presence of joists, beams or bracing extending from the elevator shaft construction.
 
AegisFPE said:
It does not sound like the building was designed as an atrium building, but that is an interesting concept from the commentary. Defining it to be an atrium space would require avoiding considering the elevator as "enclosed."If you are able to consider the elevator opening as creating a 2-story atrium, then perhaps no shaft rating would be required, although there would be other implications from Section 404 to address.

There must be greater challenges than providing a rating for the shaft enclosure - perhaps it's a Type V-B building, and there are concerns with maintaining the rating of the enclosure in the presence of joists, beams or bracing extending from the elevator shaft construction.
Click to expand...
I don't understand this post at all. By the very definition of atrium, it can't be an enclosed elevator. If it's not an enclosed elevator, it doesn't need to be called an atrium to avoid a rated shaft.

And elevators that are open to atria have been exempt from separation requirements for many code cycles.
 
Actually it is a very simple type V-B construction and the rating of the shaft didn't concern me all that mauch as I had it designed as a CMU enclosure anyway.

The problem arose where the code requires the machine room to have the same rating as the shaft. In this case it is a Kone Econo Space elevator which has the machine in the elevator shaft (at the top) with a "control closet" located on the second floor. The closet is 40 inches wide x 20 inches deep. This now is considered a "machine room". The problem is rating the floor of this closet. Either I isolate this small portion of floor and with a 1 hour fire rating, or I have to rate a fairly large portion of the surrounding timber framed floor together with supporting beams and columns. That is why I was exploring the non rated enclosure possibility. So another question arises, is this a "machine room" (it does not house any machinery) as it only houses the controls......
 
If the machine room is within the shaft, and the control closet is a separate enclosure outside of the shaft, I have trouble with the interpretation that it is a "machine room", or "machinery space", neither of which are defined in the code, by the way. Surely Kone can offer some help?
 
2009 Edition Section 708.2 Exception 7 (7.3) now states, "Is not concealed within the construction of a wall or a floor/ceiling assembly."

Does anyone think that the situation changes with this new wording?

It seems somewhat unnecessary to give an elevator shaft a rating when the stairways are open on each end of the building creating one big smoke compartment for the entire building.
 
JustReid said:
2009 Edition Section 708.2 Exception 7 (7.3) now states, "Is not concealed within the construction of a wall or a floor/ceiling assembly."Does anyone think that the situation changes with this new wording?

It seems somewhat unnecessary to give an elevator shaft a rating when the stairways are open on each end of the building creating one big smoke compartment for the entire building.
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My answer would be exactly the same if the stair was enclosed. An open stair or open elevator meets the exception. Isn't there an expectation that an unconcealed opening would allow early warning if there was a problem?

Maybe I'm out there. It would be nice to get input from more members.
 
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This one makes you think and I don't believe an elevator shaft is "concealed within the building construction" anymore than non rated stairwell which is allowed as long as it is not part of the required means of egress.

The "control closet" is not a machine room the machine room is located at the top of the shaft.
 
mtlogcabin said:
This one makes you think and I don't believe an elevator shaft is "concealed within the building construction" anymore than non rated stairwell which is allowed as long as it is not part of the required means of egress.The "control closet" is not a machine room the machine room is located at the top of the shaft.
Click to expand...
But do you consider the opening between floors to be concealed within the building construction?
 
texasbo said:
But do you consider the opening between floors to be concealed within the building construction?
Click to expand...
a straight hole in the floor no because the floor joist space should be sealed where the hole penetrates the floor ceiling assembly

Now a hole in the ceiling at point "A" that penetrates the floor at point "B" not directly above would be concealed within the building construction (of a wall or floor ceiling assembly) and would have to be protected. An example would be a plenum space
 
Ok! First it has been stated that this is a B-OCC. What is the type of construction being employed?

Next, If you enclose the elevator with walls have you not created a shaft?
 
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