Exit discharge problem

[BayPointArchitect]

Given:

2018 IBC

Section 1028

EXIT DISCHARGE​

1028.1 General.

Exits shall discharge directly to the exterior of the building. The exit discharge shall be at grade or shall provide a direct path of egress travel to grade. The exit discharge shall not reenter a building. The combined use of Exceptions 1 and 2 shall not exceed 50 percent of the number and minimum width or required capacity of the required exits.

Exceptions:

2. Not more than 50 percent of the number and minimum width or required capacity of the interior exit stairways and ramps is permitted to egress through a vestibule provided that all of the following conditions are met:

2.1. The entire area of the vestibule is separated from areas below by construction conforming to the fire-resistance rating of the interior exit stairway or ramp enclosure.

2.2. The depth from the exterior of the building is not greater than 10 feet and the length is not greater than 30 feet.

2.3. The area is separated from the remainder of the level of exit discharge by a fire partition constructed in accordance with Section 708.

2.4. The area is used only for means of egress and exits directly to the outside.

Questions:

1. How is the depth and length measured for this existing building?

See attached floor plan.

2. If all of the walls surrounding the yellow exit access area are noted as two-hour fire-rated, can this be solved as a horizontal exit?

As always, thanks in advance for your help. Meanwhile, I will see if I can find a code commentary that explains this.

ICC Certified Plan Reviewer
NFPA Certified Fire Plan Examiner

 

[Yankee Chronicler]

Q.1: Depth of a vestibule is measured perpendicular to the exterior wall(s). Length is measured parallel to the exterior wall. The main hallway in the plan shown is not a vestibule.

Q.2. The main hallway might be a horizontal exit. Among other requirements, a horizontal exit may need to be be provided with standpipes. IBC 905.4, #2:

905.4 Location of Class I standpipe hose connections.
Class I standpipe hose connections shall be provided in all of
the following locations:
...
2. On each side of the wall adjacent to the exit opening of
a horizontal exit.
Exception: Where floor areas adjacent to a horizontal
exit are reachable from an interior exit
stairway hose connection by a 30-foot (9144 mm)
hose stream from a nozzle attached to 100 feet (30
480 mm) of hose, a hose connection shall not be
required at the horizontal exit.

Where's the grade plane?

My questions:

1. What's the problem you're trying to solve? This appears to be the ground floor plan, so all exits discharge to grade. Exception number 2 applies to discharge from exit stairs. Where are the exit stairs? How many exit stairs are there, and how do the other exit stairs discharge?

2. What's the stair that comes down in the main hallway? How many stories above does it serve? Is it enclosed as an exit stair above?

3. What's the total occupant load served by the main hallway? You have two doors opening toward each other, restricting the passage width. Doors when open 90 degrees cannot reduce the clear passage width to less than half the required width.

 

[Yankee Chronicler]

I think it might help if you would state more clearly what the question is, rather than quoting large-ish selections from the code without explaining why you think there might be an issue.

 

[Yankee Chronicler]

New observation: Doors 101B and 105 are doors in series. It doesn't appear that the plan provides 48" beyond the swing of door 101B. That's in construction shown as a new wall, so you can't argue technical infeasibility.

2018 IBC:

1010.1.8 Door arrangement. Space between two doors in
a series shall be 48 inches (1219 mm) minimum plus the
width of a door swinging into the space. Doors in a series
shall swing either in the same direction or away from the
space between the doors.

 

[BayPointArchitect]

Plan review comment:
"Exit discharge is not complying with IBC Section 1028.1 item 2."

There was a second floor but that is being abandoned because plan reviewer required an exterior second stairway to be constructed from this historic military building. So theoretically, we could remove the stairs altogether. Total occupant load from the daycare is only 27 people and converges with the occupant load from a vacant office tenant. Distance between two opposing doors provides for egress capacity of 160 people.

Question:
How does this plan get fixed? How do I satisfy the plan reviewer?

Code Chronicle, the reason why I provided the large section of code is that whenever I ask a question, people provide large sections of code (which I have already made reference to) without providing any useful commentary on that code. Understand?

The plan reviewer refuses to discuss the issue with me. She says that I should be able to read the code and understand right away what the issue is. I've already talked to her about other issues related to this project and she is now done talking to me. Fair enough.

If I have a "exit discharge vestibule", then my size is 8'-4" deep x 36'-9" long. Which is 6'-9" too long because the maximum size is 10' x 30'. This lady will not budge from the strictest interpretation.

Question:
What is the easiest way to fix the exit discharge problem?

 

[Yankee Chronicler]

Your math is faulty. Total occupant load from the daycare is only 27 people and converges with the occupant load from a vacant office tenant.

I count 68, not 27. And you can't ignore the adjacent business occupancy just because it's currently vacant.

2028.1, Item 2, which you quoted in the opening post, specifically addresses interior exit stair and ramps. The stair down to the basement is one problem, and I don't have an easy solution to that. The stair down from the second floor into the central hallway (which is not a vestibule) seems to be the more serious issue. The walls on each side are 1-hour rated. I assume the doors are proper 1-hour fire doors. What is the configuration on the second floor? If those same two 1-hour rated walls continue through the upper story and access into it also has proper fire doors on the second floor, then the entire central hallway is, in fact, an exit stair enclose that discharges directly to the exterior.

Your screen profile says you are in Lincoln. Is that Lincoln, Nebraska? If so, Nebraska uses the Existing Building Code. The IEBC offers three paths ("methods") for achieving compliance: the prescriptive method (which is essentially doing everything to the IBC); the work area method (which is where you differentiate between Level 1, Level 2, and Level 3 alterations; and the performance method. Plus Chapter 10 for changes of occupancy. Which compliance method have you chosen to follow? If you haven't chosen the performance method -- have you considered it?

I would start by asking the plan reviewer for a better explanation of why/how the plan doesn't comply. I'm not seeing a problem on the first floor but, if the second floor only has one means of egress, that would certainly raise red flags.

 

[BayPointArchitect]

Very helpful comments Code Chronicle.
So I changed the numbers on the plan to include a calculated 17 occupants from the unoccupied office tenant. So long as I don’t exceed a total of 160 people trying to make their way into the center area of convergence, we are still okay.

Yes, all doors adjacent to the stairway from the second floor are labeled fire doors = either 60 or 90 minute. But we are abandoning the second floor after the fire marshal kept asking for the detailed code pathway that allows for a single stairway exception from the second floor. There were four exceptions that ALMOST work. But a few of the variables (multiple tenant building, second floor occupant load greater than ten, etcetera), it simply does not work.

I would normally ask the plan reviewer for a better explanation. But she refuses to discuss this project with me because we have already talked about this project. Classic example of one commercial plan reviewer for a large metropolis (not Lincoln) with too much work to do.

Thanks for mentioning the possibility of performance calculations in accordance with the International Existing Building Code. I have used that successfully a few other times with this same plan reviewer. Now that i think about it, every time I am dealing with an existing building. It just seems a little ridiculous to me - not to mention four hours of calculations followed by another denial, justifying my numbers, followed by final approval.

I will get started with the very tedious process of putting together those performance calculations.

 

[TheCommish]

Unacceptable answer from the plan reviewer. Appropriate answer is how does this design comply with sections XXX

 

[Yankee Chronicler]

Thanks for mentioning the possibility of performance calculations in accordance with the International Existing Building Code. I have used that successfully a few other times with this same plan reviewer. Now that i think about it, every time I am dealing with an existing building. It just seems a little ridiculous to me - not to mention four hours of calculations followed by another denial, justifying my numbers, followed by final approval.

I will get started with the very tedious process of putting together those performance calculations.

There's no assurance that the performance method will work. Everything depends on the criteria of the specific project. As for justifying your numbers, IMHO that shouldn't follow another denial. If I were doing a project using the performance method, I would prepare a written explnanatory narrative while doing the calculations and submit that along with the actual tabulation. Otherwise, the plan reviewer has to expend more time trying to get inside your head to understand why/how you came up with your numbers. I'm not saying you have to go that route and I'm not saying it will work. However, if you run the numbers -- honestly -- and they add up to a passing score, the plan reviewer has to accept it. But the plan reviewer is allowed to question each and every one of your numbers, so you certainly should be prepared to explain how you arrived at your numbers. If the plan reviewer doesn't question your numbers, he/she isn't doing his/her job.

I once reviewed a set of plans for an alteration and change of occupancy in a total firetrap of an old building. The architect gave me a "Chapter 34" score sheet (from when it was in Chapter 34 of the IBC) that showed the design passing by a wide margin. When I looked at it, virtually none of the scores he had claimed could be justified. I knew the architect -- in fact, I had once worked with him in the same architectural office -- so I called him and asked him how he got the numbers. He admitted that he had no idea how to do one of those evaluations but someone had told him he needed to pass the minimum mandatory score, so he just picked numbers that added up to a passing score.

Nope, that's not how it works.

You still haven't said what method you are using under the IEBC. It's apparent that you're not using the performance method, so that leaves the prescriptive method and the work area method. Since you're not touching the second floor and you're not touching the office area, under the work area method it looks like you would be in a Level 2 alteration (plus change of use?). Using that method, you go through chapters 8, 7, 3, and 10. If something isn't required by one of those chapters -- it isn't required.

Which method did you follow?

Remember -- as the designer, YOU choose which method you wish to follow, and the plan reviewer must review according to the method you chose. And you are required to state on the construction documents which compliance method you used. For a while, when I received plans for an existing building that didn't declare the method I would review to the IBC and tell applicants I was using the prescriptive method as a default. As I read the IEBC again, I realized that's not correct or appropriate. The designer/applicant has to choose a method and tell me what method they are using. These days, if I get a set of plans for an alteration that doesn't state the method -- I reject it and use that as the reason. IMHO, for me as a code official to make a decision that is supposed to be made by the applicant creates a potential liability for the municipality that employs me.

The underlying premise of the IEBC is "Don't make it any less safe." The IEBC came into existence because the code enforcement community and politicians realized that trying to apply a code written around new construction to buildings that have been in use for decades, if not hundreds of years, was resulting in taking a lot of potentially viable buildings out of use, off the tax rolls, and making them into fire traps or vacant eyesores. The entire premise of the IEBC is to require enough fire and life safety provisions in a building to make it "safe enough," without necessarily bringing it into full compliance as for a new building.

By the way -- you continue to use the term "convergence," but IMHO that's confusing. I know what you mean, but in the ICC codes egress "convergence" is when occupants from from a story above the level of exit discharge and occupants from a story below the level of exit discharge meet at the level of exit discharge. What you refer to as "convergence" is simply two doors allowing people from the same story to enter the exit. In IBC terms, that's not "convergence" any more than having three offices opening into the same exit access corridor would be convergence.

 

[Yankee Chronicler]

I'm coming back to this because every time I think about it, it bothers me.

Back to basics: The three components of a path of egress are the exit access, the exit, and the exit discharge. For a one-story building, unless it's VERY large and you need an exit passageway to meets the maximum exit access travel distance, typically there are NO exit enclosures. In most one-story buildings, the "exit" is to door itself -- what's inside is exit access, and what's outside is exit discharge.

We get to exit enclosures when we have multiple stories, and the upper story(ies) don't qualify for having an open stair used as exit access. In such buildings, the "exit" is the enclosed stair, and the exit discharge is the path from the door at the bottom of the stair to the street or public way. Are you with me so far?

The default of the code is that "exits" (meaning exit enclosures -- enclosed stairs and ramps, and exit passageways) shall discharge directly to the exterior. As it often does, the code them immediately offers exceptions for when an "exit" does not have to discharge directly to the exterior. That's what the exceptions to IBC 1028.1 discuss. The plan reviewer has homed in on Exception #2, stairs discharging through a vestibule.

But the stair that comes down into the main hallway doesn't HAVE a door at its bottom. It's open the the hallway. Therefore, the route from the bottom of the stair to the exterior door is NOT exit discharge. If the stair is an open stair qualifying as an exit access stair, then the path from the bottom of the stair to the exterior door is still exit access, and the exterior door itself is the exit. The exit discharge is everything outside the exterior doors, which is not shown.

On the other hand, if the main hallway is a 1-hour rated enclosure that is mirrored upstairs, creating a rated stair enclosure, there's nothing in the code that says a rated stair enclosure can't be larger than the footprint of the stairway itself. If the entire main hallway is the exit enclosure, then the exterior door is still the exit discharge, and the path from the foot of the stair to the exterior exit door is simply travel within the exit enclosure. Which is not in any way regulated as to length.

I don't think the plan reviewers problem is at all related to egress from the ground floor spaces. I think she's concerned with that stair, and doesn't understand that the first door coming off the stair is the exterior door, so THAT's the point where exit discharge begins. That stair does not "discharge" through the main hallway.

 

[Yankee Chronicler]

Post #5:

There was a second floor but that is being abandoned because plan reviewer required an exterior second stairway to be constructed from this historic military building.

Is the structure on the federal or state register of historic buildings? If so, have you looked at Chapter 12 of the IEBC? Remember, the underlying premise of the IEBC is "Don't make it less safe." If the second floor only has one means of egress and the occupancy of the second floor isn't changing to a more hazardous occupancy classification, then IMHO the code official cannot demand that a second exit stair be added.

The plan appears to show the first floor being used as a day care center. Is this a change of use/occupancy?

 

[BayPointArchitect]

Yes, the cover sheet states IEBC Level 2 compliance method. Change in occupancy to daycare.

I am well aware that I need to account for the number of people exiting into the central exit access area - both from the daycare and from the other business office tenant. Both tenants depend on this area where they CONVERGE. 17 people from the other tenant space = not a big deal.

Building sprinklers were recently added - making this 100 year old building safer. Registered historic buildings do not seem to impress the fire marshal. Usually they give some grace after adding a fire sprinkler system but no grace here.

 

[Yankee Chronicler]

Yes, the cover sheet states IEBC Level 2 compliance method. Change in occupancy to daycare.

I am well aware that I need to account for the number of people exiting into the central exit access area - both from the daycare and from the other business office tenant. Both tenants depend on this area where they CONVERGE. 17 people from the other tenant space = not a big deal.

Building sprinklers were recently added - making this 100 year old building safer. Registered historic buildings do not seem to impress the fire marshal. Usually they give some grace after adding a fire sprinkler system but no grace here.

My point was that in the ICC codes, "converging" egress has a specific meaning -- and it isn't occupants from two corridors on the same story entering the same exit enclosure.

As to the historic building, the chapter on historic structures calls for a report, and establishes some specific requirements and criteria. Have you prepared the report and submitted it with the construction documents?

2018 IEBC:

1201.2 Report. A historic building undergoing alteration
or change of occupancy shall be investigated and evaluated.
If it is intended that the building meet the requirements
of this chapter, a written report shall be prepared and filed
with the code official by a registered design professional
where such a report is necessary in the opinion of the code
official. Such report shall be in accordance with Chapter 1
and shall identify each required safety feature that is in compliance
with this chapter and where compliance with other
chapters of these provisions would be damaging to the contributing
historic features. For buildings assigned to Seismic
Design Category D, E or F, a structural evaluation describing,
at a minimum, the vertical and horizontal elements of the lateral
force-resisting system and any strengths or weaknesses
therein shall be prepared. Additionally, the report shall
describe each feature that is not in compliance with these provisions
and shall demonstrate how the intent of these provisions
is complied with in providing an equivalent level of
safety.

Commentary:

This section provides for a report that acts as a technical
backup for the code official’s judgment. The
intent is to be able to retain a record of the decisions
and the basis for those decisions for future reference.
The definition of “Historic building” refers to listing/
eligibility for national register, state designation, inclusion
in a survey or contributing to a national or state
historic district. Contributing features may be limited
to those features in nominations, historic structure
reports or other such documents. This represents a
systematized approach for evaluating proposals of
equivalent performance (see the definition of “Historic
building” in Section 202).

There is still the possibility that the central hallway is not an exit access corridor but is actually an exit enclosure. If that's the case, the entire central corridor IS the "exit," and the discharge is the doors to the exterior. I respecfully suggest that you need to determine exactly what the central hallway is.

 

[Paul Sweet]

What did you want to put upstairs? Based on the 10'-6 1/2" dimension, it looks like the area to the inside face of the exterior walls is about 36' x 41', which is just under 1500 SF, or 10 occupants @ 1 per 150 SF for a B occupancy.

 

[princeofpen]

My 2 cents.... this isn't a vestibule nor does it need to be but is rather a corridor that will need to be based upon size of occupants using it. It doesn't meet the section as a vestibule as it can't as designed. As long as the occupants get from Access to Exit to Discharge in appropriate distances you are complaint. As noted prior that section deals with multi-story egress from stair enclosures. You are more complaint with #1 of the section than vestibules in #2

The comment earlier about horizontal exit..... HE's are only required if exit travel distances would be such that they are placed into building sections for compliance not just because you are passing through a fire barrier or fire wall

 

[steveray]

My 2 cents.... this isn't a vestibule nor does it need to be but is rather a corridor that will need to be based upon size of occupants using it. It doesn't meet the section as a vestibule as it can't as designed. As long as the occupants get from Access to Exit to Discharge in appropriate distances you are complaint. As noted prior that section deals with multi-story egress from stair enclosures. You are more complaint with #1 of the section than vestibules in #2

The comment earlier about horizontal exit..... HE's are only required if exit travel distances would be such that they are placed into building sections for compliance not just because you are passing through a fire barrier or fire wall

That is what I was thinking, but it still seems like the 50% is an issue as you have 2 stairs that both "reenter" the building.....IMO an HE "extension" would solve that...Remoteness seems sketchy too...

1028.2 Exit Discharge​

Exits shall discharge directly to the exterior of the building. The exit discharge shall be at grade or shall provide a direct path of egress travel to grade. The exit discharge shall not reenter a building. The combined use of Exceptions 1 and 2 shall not exceed 50 percent of the number and minimum width or required capacity of the required exits.
Exceptions:

1. Not more than 50 percent of the number and minimum width or required capacity of interior exit stairways and ramps is permitted to egress through areas, including atriums, on the level of discharge provided that all of the following conditions are met:
   1. Discharge of interior exit stairways and ramps shall be provided with a free and unobstructed path of travel to an exterior exit door and such exit is readily visible and identifiable from the point of termination of the enclosure.
   2. The entire area of the level of exit discharge is separated from areas below by construction conforming to the fire-resistance rating for the enclosure.
   3. The egress path from the interior exit stairway and ramp on the level of exit discharge is protected throughout by an approved automatic sprinkler system. Portions of the level of exit discharge with access to the egress path shall be either equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1 or 903.3.1.2, or separated from the egress path in accordance with the requirements for the enclosure of interior exit stairways or ramps.
   4. Where a required interior exit stairway or ramp and an exit access stairway or ramp serve the same floor level and terminate at the same level of exit discharge, the termination of the exit access stairway or ramp and the exit discharge door of the interior exit stairway or ramp shall be separated by a distance of not less than 30 feet (9144 mm) or not less than one-fourth the length of the maximum overall diagonal dimension of the building, whichever is less. The distance shall be measured in a straight line between the exit discharge door from the interior exit stairway or ramp and the last tread of the exit access stairway or termination of slope of the exit access ramp.

 

[Yankee Chronicler]

I couldn't log onto this site from work. I'm home now, with another wrench to toss into the gears:

We've been looking at section 1028.2 of the IBC. This is an existing building, and the project is being designed under the Work Area method for a Level 2 alteration. That means the starting point is the IEBC. BayPointArchitect (hereinafter BPA) thus needs to look first at IEBC chapter 3 (Compliance Provisions for all Compliance Methods), then at chapters 8 and 7 (Level 2 and Level 1, respectively), then at chapter 10 (Change of Occupancy), and finally at chapter 12 (Historic Buildings). You can't look at section 1028 of the IBC unless one of the applicable sections in the IEBC sends yo to section 1028 of the IBC.

I don't have time to do a deep dive through all that, but my vague impression is that there may not be anything in the IEBC as it applies to this project that sends you to IBC 1028.2. If not, then the plan reviewer was off base when she cited it.