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Stair egress capacity problem in existing high rise building

T

Tim Mailloux

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Feb 12, 2018
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769
Location
Hartford CT
I am working on a renovation in an existing high rise, type 2A construction, for a local universities downtown campus. The existing floor plan consists of 5 large classrooms and a couple of small offices and a conference room. We are going to be demolishing one of the classroom and the existing offices and making a new office suite with a mix a new offices and conference rooms to support the remaining (4) classrooms. While our project area is only about half the existing floor plate I have calculated the occupant loads of the entire floor (renovated & non-renovated areas) and the total occupant load is 60 people larger than the existing stairs egress capacity as calculated by current Connecticut Building code. I have also calculated the occupant load of the existing floor plan with the (5) classrooms and the occupant load calculates out to be 80 people larger than the existing stairs egress capacity as calculated by current Connecticut Building code.


Is there any leeway in the Existing Building code to make the argument that while the proposed occupant load exceeds the existing stair egress capacity, the new occupant load is lower than the existing occupant load thus making a bad situation better, but still not up to code?
 
Well

No code section, but the city/ university accepted the exiting as is.

Only thing the occupant load calc originally may have been different than what you calc
 
That's a tough one. I face this type of thing very often. We have a lot of buildings that don't meet the codes under which they were originally constructed. Mostly, we make them upgrade.......but there are limits to what we make them do. It really stinks to tell an owner that the building they were told was acceptable really wasn't. These buildings are the most frustrating set of problems I face on a day to day basis. I don't know for sure it will help but you might look at the compliance alternatives. I have only ever had one applicant go that route, and it did give alternatives in his case.
 
Tim Mailloux said:
I am working on a renovation in an existing high rise, type 2A construction, for a local universities downtown campus. The existing floor plan consists of 5 large classrooms and a couple of small offices and a conference room. We are going to be demolishing one of the classroom and the existing offices and making a new office suite with a mix a new offices and conference rooms to support the remaining (4) classrooms. While our project area is only about half the existing floor plate I have calculated the occupant loads of the entire floor (renovated & non-renovated areas) and the total occupant load is 60 people larger than the existing stairs egress capacity as calculated by current Connecticut Building code. I have also calculated the occupant load of the existing floor plan with the (5) classrooms and the occupant load calculates out to be 80 people larger than the existing stairs egress capacity as calculated by current Connecticut Building code.


Is there any leeway in the Existing Building code to make the argument that while the proposed occupant load exceeds the existing stair egress capacity, the new occupant load is lower than the existing occupant load thus making a bad situation better, but still not up to code?
Click to expand...


If the stairs get brought up, you can always ask for a smaller assigned occupant load.
 
A constant issue I run into here in CT are existing stairs. The model IBC allows for stair egress capacity of .3 inches per person in non sprinklered buildings and a stair egress capacity of .2 inches per person in sprinklered buildings. The state of CT has a code amendment making the stair egress factor .3 inches per person regardless of sprinklers. If I could use the .2 factor from the model IBC I would rarely have this type of issue.
 
cda said:
If the stairs get brought up, you can always ask for a smaller assigned occupant load.
Click to expand...
The CT State Building code doesn't allow for an occupant load lower than calculated by table by table 1004.1.2 to be posted. The occupant load per 1004.1.2 is the minimum occupant load of the room / space. Your occupant load can be higher, but never lower.
 
Sifu said:
but you might look at the compliance alternatives. I have only ever had one applicant go that route, and it did give alternatives in his case.
Click to expand...

I will look into the compliance alternatives. Its been a very long time since I went that route on a project.
 
Just asking;
1) the conference rooms are reserved for office and classrooms; thus the occupant will not increase but moves from space to another similarly with school cafet?
2) similarly with schools this is a single tenant space? The provision for Level two (2) means of egress "shall be limited to work areas that include exits or corridors shared by more than one tenant within the work area"

The following (2012) sections can be avoided when the work area is 50% or less:
803.2.2
803.2.3
803.4.1
804.2.1.1
804.4.2
805.4.2.1
805.4.3.1
805.4.4.1
805.5.3.1
805.7.2
805.8.2

There may be other exceptions depending on the work area (see definition limited to the permit).
 
Francis Vineyard said:
Just asking;
1) the conference rooms are reserved for office and classrooms; thus the occupant will not increase but moves from space to another similarly with school cafet?
2) similarly with schools this is a single tenant space? The provision for Level two (2) means of egress "shall be limited to work areas that include exits or corridors shared by more than one tenant within the work area"
.
Click to expand...

1) what you are referring to here is the concept of Non-simultaneous occupancy, which is not recognized by the IBC or the state of CT. In CT the state building official will only allow Non-simultaneous occupant load calculations to be used for plumbing fixture calculations in certain occupations, but never for life safety.

2. Regardless of the size of the work area I need to prove I can get all the occupants off the floor. Are you saying that as long as a renovation does not exceed 50% of the floor area I could add 200 people to the occupant floor occupant load and wouldn't matter?
 
So are you using 20 net for the classrooms or something else such as assembly?

Tim Mailloux said:
The CT State Building code doesn't allow for an occupant load lower than calculated by table by table 1004.1.2 to be posted. The occupant load per 1004.1.2 is the minimum occupant load of the room / space. Your occupant load can be higher, but never lower.
Click to expand...

For an existing building the posted OL should be the most restrictive along the egress path not what the room or floor will accommodate based on a supposed use. In your case it is .3 for the size of the existing stairs.
If you check the legacy code the building was built under it was more than likely .3 for stairs back in the day
 
Who owns the building, university or private? If university owned it may have some leeway to self determine.
 
Tim Mailloux said:
1) what you are referring to here is the concept of Non-simultaneous occupancy, which is not recognized by the IBC or the state of CT. In CT the state building official will only allow Non-simultaneous occupant load calculations to be used for plumbing fixture calculations in certain occupations, but never for life safety.

2. Regardless of the size of the work area I need to prove I can get all the occupants off the floor. Are you saying that as long as a renovation does not exceed 50% of the floor area I could add 200 people to the occupant floor occupant load and wouldn't matter?
Click to expand...
Appreciate learning new words to my nomenclature! How about the exception to 1004.1.2?

Wouldn't that amount of increase be a change of occupancy applicable with Chapter 10?
 
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Tim Mailloux said:
The 2016 CT State Building Code is based on the 2012 IBC with amendments. CT deleted the exception to 1004.5 that allows the AHJ to assign a lower occupant load than calculated by table 1004.1.2.
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I overlooked this explanation and references between different code editions.

My understanding for providing alteration thresholds before adoption of the IEBC with the prescriptive methods is code officials were inadvertently causing buildings to be limited to repairs or become vacant by requiring the complete structure to comply with the provisions of the current codes for new construction.
This was cost prohibitive and sometimes technically infeasible to allow alterations .
As mentioned it's often found the existing occupant loads exceed both the current code and the code when the occupancy was first permitted.
And as previously pointed out the current code is limited to the "work area" as applicable.
Depending on the code CT adopted typically should not have to retrofit until it meets a special provision for a change of occupancy.
 
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Francis Vineyard said:
I overlooked this explanation and references between different code editions.

My understanding for providing alteration thresholds before adoption of the IEBC with the prescriptive methods is code officials were inadvertently causing buildings to be limited to repairs or become vacant by requiring the complete structure to comply with the provisions of the current codes for new construction.
This was cost prohibitive and sometimes technically infeasible to allow alterations .
As mentioned it's often found the existing occupant loads exceed both the current code and the code when the occupancy was first permitted.
And as previously pointed out the current code is limited to the "work area" as applicable.
Depending on the code CT adopted typically should not have to retrofit until it meets a special provision for a change of occupancy.
Click to expand...


Francis, thanks for the explanation.

So what your saying is that as long as there is no change of occupancy to the work area, the new occupant loads are not a factor in egress?

Also, digging deeper into IEBC section 805 Means of egress, that section seems only to apply to multi-tenant floors. My project is a single tenant floor so section 805 does not apply, but section 704 Means of Egress does apply.

704.1 General: Alternations shall be done in a manner that maintains the level of protection for the means of egress (could the ICC be any more vague? This leaves a lot open for interpretation).

704.2 (CT Amendment) Minimum Standards: in addition to the requirements of this code, means of egress in existing buildings shall meet the requirements of the provisions of Part IV of the CT State Fire Safety code for the proposed occupancy.

Part IV of the CT State Fire Safety code is 2012 NFPA 101 (with CT amendments) and it only applies to buildings built prior to 2005, which is when CT switched from BOCA to the IBC based code. Any buildings built after 2005 (under the IBC based codes) fall under part III of the CT State Fire Safety code witch is the 2012 IFC with CT amendments. Looks like I need to dig into the this a little more.
 
IEBC
CHAPTER 14
PERFORMANCE COMPLIANCE METHODS

1401.2 Applicability.
Structures existing prior to [DATE TO BE INSERTED BY THE JURISDICTION. NOTE: IT IS RECOMMENDED THAT THIS DATE COINCIDE WITH THE EFFECTIVE DATE OF BUILDING CODES WITHIN THE JURISDICTION], in which there is work involving additions, alterations or changes of occupancy shall be made to conform to the requirements of this chapter or the provisions of Chapters 5 through 13. The provisions of Sections 1401.2.1 through 1401.2.5 shall apply to existing occupancies that will continue to be, or are proposed to be, in Groups A, B, E, F, M, R and S. These provisions shall not apply to buildings with occupancies in Group H or I.

We use the adoption date of the 2003 IBC. It works very well with older building and achieving compliance with the "intent" of the code.

 
701.2 Conformance. An existing building or portion thereof shall not be altered such that the building becomes less safe
than its existing condition.

To reiterate; 'alterations shall not make the existing building less safe than its existing condition"
Comparison is made to the "existing condition" - not something that some past code might have required or "as required under the code in which it was constructed"

Hope the above is helpful with the CT amendments.
 
When was it built (or last remodeled), and what code was it built (or remodeled) under? Were any code modifications granted when it was built or remodeled?
 
I reached out to a couple of code consulting experts here in CT to get their take on use of the International Existing Building Code (IEBC) in the state of CT and validate my findings. As we all know the model IEBC is very soft on egress and occupant loads in existing renovated buildings requiring little to no analysis and apparently this was not to The State of CT’s liking. The state of CT amended the IEBC adding section 704.2 Minimum Egress Standards which states that : In addition to the Means of Egress requirements of the IEBC, means of egress in existing buildings shall meet the requirements of the provisions of Part IV of the Connecticut State Fire Safety Code. The state fire code then requires that egress components to be analyzed and occupant loads assigned in the new work areas AND the existing un-renovated portion of the building per per the requirements of the State fire code (which is very similar to chapter 10 of the IBC). The existing building must then be analyzed to determine that the existing egress components can accommodate the loads of both the existing and new occupant loads to safely egress all occupants from the building.

In a nut shell renovations to existing buildings are much stricter in CT than in other states.
 
Additionally, in the opinion of one of the code consultants I spoke with, use of IEBC Chapter 14, Performance Compliance Methods, is almost useless here in CT, based on the retroactive requirements of the CT State Fire Safety Code.
 
My take on it:

It sounds like you are lowering the occupant load from what it is now based on your posts. I'm going to assume that installing another exit will be so costly that the university will abandon this project and not just a slight modification. Based on this, I would approve the change as an improvement to occupant safety.

Can you do a timed egress study to demonstrate that exiting, while not code compliant, will meet the performance of the code? We see these on occasion here in Canada with some older buildings. But then again, we also do occupant loading based on non-simultaneous occupancy.

Where are your industry lobbyists when they are passing these amendments?
 
ADAguy said:
Who owns the building, university or private? If university owned it may have some leeway to self determine.
Click to expand...

In this project the university is leasing space in a privately owned building. Additionally here in CT, the model code has been amended to define the AHJ as the State Building Official or State Fire Marshall. The State Building Official and State Fire Marshall are the only persons in the state with authority to interpret the code and grant code modifications. Local officials are limited to code enforcement even though many of them think they have the authority to interpret the code. That is of course until you ask them to put something in writing, which they will then refer you to the state guys.
 
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