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Avoiding use of Sprinklers - level of exit discharge + fire areas

L

lacoope

Member
Joined
Apr 20, 2014
Messages
3
Location
Seattle
I am designing a youth activity center on a large rural lot. The building is 3000sf total with an assembly room and storage/catering prep area in back. Above the back area is a storage mezzanine that meets the area requirements of IBC 505.2.1 so that the building can be considered a 1-story building.

I am classifying the building as:

Type VB Construction which has ZERO fire rating requirements

Mixed Occupancy: A3 (Assembly space) + S2 (Storage/Catering + Mezzanine)

My client would like to explore alternatives to installing sprinklers to save costs. I am proposing two approaches and have questions about both of them:

1. Add an exterior exit stair to serve as a second exit from the Mezzanine.

*QUESTION: Does the exterior exit stair count as part of the "Exit Discharge" so that the Mezzanine would now be located on a level of exit discharge? The site is completely flat and the exterior stair would descend about 9ft to reach grade. My hope is that this would meet the requirements of IBC 903.2.1.3 for A3 occupancies which do NOT require sprinklers if the fire area is located on the level of exit discharge. Even though the mezzanine is for storage, it is considered part of the A3 occ. fire area because they are not separated.

2. Divide building into two fire areas by constructing a 2HR wall from slab to roof to separate A3 from S2 occupancy. Per Section 903.2, this would mean A3 fire area is located on ground floor. The S2 fire area is allowed to include up to 3 levels above exit discharge level without triggering sprinkler requirement.

*QUESTION: Can my building still be considered a 1-story building and qualify as Type VB construction even though the mezzanine is closed off from room below? This would allow the 2hr separation wall to be the ONLY fire rated wall in the building. The rest of the structure would remain unrated per VB construction. IBC 502.3.1 states that Mezz can be closed off from room below if occupancy is less than 10. The Mezzanine meets that requirement.
 
Answer: Number #1:No level of eit discharge would be the other side of the exterior door from the mezzinine - a.k.a. landing.

Answer #2: Not sure that I fully agree with the S-2 provision for the catering/prep area..... as most catering prep areas usually stockpile quanities of dry goods - paper, plates, napkins, as such along with occasional sterno cans for keeping the food warm.......
 
Question 1: I agree with Bob

Question 2: I would be classifying Storage/Catering as S-1 and would accept a 3-hour fire barrier to create 2 fire areas to avoid sprinklers. Building still 1-story and VB.

3-hour per 2006 IBC Table 706.3.9.
 
3. The fire area is located on a floor other than a level of exit discharge serving such occupancies.

EXIT DISCHARGE, LEVEL OF. The story at the point at which an exit terminates and an exit discharge begins.

MEZZANINE. An intermediate level or levels between the floor and ceiling of any story and in accordance with Section 505.

Poor code language

The mezzanine is within the same story and fire area as the level of exit discharge.

No sprinklers required
 
The code you are on really matters because here is the definition per 2003 IBC:

EXIT DISCHARGE, LEVEL OF. The horizontal plane located at the point at which an exit terminates and an exit discharge begins.

And plane is waaaaaay different from story! Don't think I am a fan of this change...
 
2006 IBC:

EXIT. That portion of a means of egress system which is separated from other interior spaces of a building or structure by fire-resistance-rated construction and opening protectives as required to provide a protected path of egress travel between the exit access and the exit discharge. Exits include exterior exit doors at ground level, exit enclosures, exit passageways, exterior exit stairs, exterior exit ramps and horizontal exits.

EXIT DISCHARGE. That portion of a means of egress system between the termination of an exit and a public way.

EXIT DISCHARGE, LEVEL OF. The horizontal plane located at the point at which an exit terminates and an exit discharge begins.

Using the above definitions, the exit includes the exterior exit stair. You are not at the level of exit discharge until the base of the stair (grade level).

The mezzanine is not a story as described and as described, would also comply with the 2 highlighted exceptions below:

505.4 Openness.

A mezzanine shall be open and unobstructed to the room in which such mezzanine is located except for walls not more than 42 inches (1067 mm) high, columns and posts.

Exceptions:

1. Mezzanines or portions thereof are not required to be open to the room in which the mezzanines are located, provided that the occupant load of the aggregate area of the enclosed space does not exceed 10.

2. A mezzanine having two or more means of egress is not required to be open to the room in which the mezzanine is located if at least one of the means of egress provides direct access to an exit from the mezzanine level.

3. Mezzanines or portions thereof are not required to be open to the room in which the mezzanines are located, provided that the aggregate floor area of the enclosed space does not exceed 10 percent of the mezzanine area.

4. In industrial facilities, mezzanines used for control equipment are permitted to be glazed on all sides.

5. In other than Groups H and I occupancies no more than two stories in height above grade plane and equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, a mezzanine having two or more means of egress shall not be required to be open to the room in which the mezzanine is located.
 
Since IBC 505.2.1 is not in previous code editions I was using the 2012 for definitions.

505.1 General.

A mezzanine or mezzanines in compliance with Section 505 shall be considered a portion of the story in which it is contained. Such mezzanines shall not contribute to either the building area or number of stories as regulated by Section 503.1. The area of the mezzanine shall be included in determining the fire area defined in Section 902

The mezzanine is within the same fire area where the level of exit discharge is located. I believe both stairs would have to be located within the building envelope to be within the same fire area

Can you have one exit per2012 IBC 505.3 which sends you to 1014.3 common path of travel?
 
Thanks so much for all your replies. The code language is really confusing! I'm still not really sure I understand it. I had a pre-submittal appointment with the code official. His interpretation is.

1. Adding exterior exit stair to mezzanine does NOT qualify as a level of exit discharge. He says sprinklers are still required. I'm still confused by the code language, but willing to accept his interpretation.

2. He also says that the storage areas need to be classified as S1 not S2. That means a 3hr fire barrier! Oh my!

This comes to a new question. I'm thinking of classifying the mezzanine and catering/storage area as a B-occupancy to reduce fire barrier from 3hr to 2hr. Reality is that mezzanine will be used as a combination office, meeting room, storage room, hang-out room... not entirely sure.

HOWEVER... this brings up an accessibility question. S1/S2 storage mezzanine qualified for accessibility exceptions but B-occupancy is problematic. There is a discrepancy between Section 206.2.3 of ADA and Section 1104.4 of IBC. Question.... WHAT DO YOU DO WHEN THERE IS A DISCREPANCY BETWEEN ADA AND IBC????? Exception 2/4 of ADA/IBC works for S-occupancy. BUT for B-occupancy I would need to rely on Exception 1. In ADA, this exception only applies to Private buildings. In IBC, it doesn't specify public or private. For Land-use code reasons, our building is being classified as public/quasi-public.... hence the dilemma.

I'm not sure how to proceed? IBC says it is okay to have inaccessible mezzanine, but ADA does not.

Any thoughts?
 
Highly suggest hire a fire protection engineer or code consultant to help you through the project.

Hard sometimes to give an answer without seeing the entire project
 
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