Corridor rating (IBC 2018)

[mtlogcabin]

What I am trying to avoid is rating that corridor.

You are only required to be 1/2 hour and twenty minute doors
1/2" gypsum board and 2 X 4 wood studs @ 16" OC gives you 35 minutes using 722.6.2
Pretty much standard commercial construction

708.3 Fire-resistance rating.
Fire partitions shall have a fire-resistance rating of not less than 1 hour.

Exceptions:

1. Corridor walls permitted to have a 1/2-hour fire-resistance rating by Table 1020.1.

 

[redeyedfly]

You are only required to be 1/2 hour and twenty minute doors
1/2" gypsum board and 2 X 4 wood studs @ 16" OC gives you 35 minutes using 722.6.2
Pretty much standard commercial construction

708.3 Fire-resistance rating.
Fire partitions shall have a fire-resistance rating of not less than 1 hour.

Exceptions:

1. Corridor walls permitted to have a 1/2-hour fire-resistance rating by Table 1020.1.

B Occ w/o sprinklers is 1hr unless there are local amendments. As Steveray pointed out there's still 20min doors w/ smoke seals and fireblocking or draftstopping to the deck above. And closers and penetration firestopping.

 

[Sifu]

In the drawing posted I would agree those are corridors. As for the rating requirement I a not sure the code as written supports dividing the occupant load between the exit points. If we take the requirement for panic hardware, the code says if a door serves a an A or E space with an occupant load > 50 then panic hardware is required. So regardless of how many doors are serving the space, if there are 50 occupants the doors must have panic hardware. (At least that's how I interpret it.) Using that same logic then it doesn't matter how many ways out of the corridors you have, if there are 42 occupants then the rating requirements are triggered. However, I am still having trouble applying this to a single tenant space, where the activities and hazards are known.

Now, for the sake of educating myself, open up some of those rooms in the center to say an open break room, a pass through records room, a couple of nurses stations etc. I don't think those rooms would be considered as lobbies or similar uses, so do we then lose the "enclosed" portion of the definition? Thereby eliminating 1020? Is there less reason to protect the corridor/aisle/pathway? How about one big open cube farm for medical billing cubes? There must be some point at which we don't have a "corridor" anymore. It sounds like other individual AHJ's have addressed this by adding more specific definitions. Maybe the IBC could benefit from some more critical thinking on this. Maybe they are already! See below from the 2024 code change proposals:

 

[mtlogcabin]

B Occ w/o sprinklers is 1hr unless there are local amendments

I disagree
1020.1 Construction.
Corridors shall be fire-resistance rated in accordance with Table 1020.1. The corridor walls required to be fire-resistance rated shall comply with Section 708 for fire partitions.

Table 1020.1 is based on the use and OL of the corridor to determine when Fire Resistance construction is required

The corridor walls required to be fire-resistance rated shall comply with Section 708 for fire partitions.
This tells you you need to comply with 708

708.3 Fire-resistance rating.
Fire partitions shall have a fire-resistance rating of not less than 1 hour.

Exceptions:

1. Corridor walls permitted to have a 1/2-hour fire-resistance rating by Table 1020.1.

2. Dwelling unit and sleeping unit separations in buildings of Types IIB, IIIB and VB construction shall have fire-resistance ratings of not less than 1/2 hour in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.

708.3 specifically requires Fire Partitions to have a minimum rating of not less than 1-hour with 2 exceptions. Corridor walls and Dwelling and sleeping unit separations are permitted to be reduced to 1/2 Hour protection.

 

[redeyedfly]

I disagree
1020.1 Construction.
Corridors shall be fire-resistance rated in accordance with Table 1020.1. The corridor walls required to be fire-resistance rated shall comply with Section 708 for fire partitions.

Table 1020.1 is based on the use and OL of the corridor to determine when Fire Resistance construction is required

The corridor walls required to be fire-resistance rated shall comply with Section 708 for fire partitions.
This tells you you need to comply with 708

708.3 Fire-resistance rating.
Fire partitions shall have a fire-resistance rating of not less than 1 hour.

Exceptions:

1. Corridor walls permitted to have a 1/2-hour fire-resistance rating by Table 1020.1.

2. Dwelling unit and sleeping unit separations in buildings of Types IIB, IIIB and VB construction shall have fire-resistance ratings of not less than 1/2 hour in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.

708.3 specifically requires Fire Partitions to have a minimum rating of not less than 1-hour with 2 exceptions. Corridor walls and Dwelling and sleeping unit separations are permitted to be reduced to 1/2 Hour protection.

I believe you're misreading Exception 1. It does not say "Corrididor walls are permitted to have..."
The exception only applies to corridor walls permitted to have a 1/2 hr FRR listed in Table 1020.1. Only R occupancies are allowed 1/2 hr. The exception does not apply to all corridors.

 

[mark handler]

If I add a 3rd exit door I basically have only 21 people using each of the remaining doors thus staying under the 30 occupants served by the corridor.

No the corridor still serves your occupant load of 42 people.
The exits would be divided by three, not the corridor.

 

[mtlogcabin]

I believe you're misreading Exception 1. It does not say "Corrididor walls are permitted to have..."
The exception only applies to corridor walls permitted to have a 1/2 hr FRR listed in Table 1020.1. Only R occupancies are allowed 1/2 hr. The exception does not apply to all corridors.

After looking over what I posted and a few more code sections. I believe you are correct and I am wrong. The R occupancies are the only group that is permitted a 1/2 hour rating for corridors.
Thanks for getting me back on track

I failed to follow what I give to all my inspectors and plans examiners

“It doesn’t say what you think it says, nor what you remember it to have said, nor what you where told that it says, and certainly not what you want it to say, and if by chance you are the author, it doesn’t say what you intended it to say. Then what does it say? It says what it says. So if you want to know what it says, stop trying to remember what it says, and don’t ask anyone else. Go back and read it, and pay attention as though you are reading it for the first time”

Charles E. Beck P.E. Seattle WA.

 

[Genduct]

I am assuming corridors. What I am trying to avoid is rating that corridor. If my occupant load is 42 people for the entire space/building that "seems" to ppoint to I have to rate the corridor based on Table 1020.1 which says OCCUPANT LOAD SERVED BY CORRIODR is greater than 30 people = 1-hour rating. BUT if I add just one additional exit door I am distributing or lessening the number of occupants during exiting in the Corridors. With 3 exits I have 14 occupants in general exiting each of the 3 exit doors., if there is a fire blocking one of the doors, then the distribution is 21 people per the remaining two doors.
ALSO, There is commentary language in the 2015 IBC...Where the corridor serves a limited number of people (second column in Table 1020.1), the fire-resistance rating is eliminated because of the limited size of the facility and the likelihood that the occupants would become aware of a fire buildup in sufficient time to exit the structure safely.

 

[WolfmanofDelRio]

Bumping this topic. I have a similar situation that comes up somewhat frequently.

I renovate existing single tenant small clinics in rural towns who use various 3rd party reviewers. Invariably these clinics are un-sprinkled and have no rated walls of any kind. Typically these are Level 2 renovations (IEBC) where we may move some walls, but generally leave the overall plan intact. Example below (more intensive version than most) . So I have always interpreted that if I am within the exit access distance to the nearest exit, have a clear discernible path to egress, and don't intervene spaces that are not accessory to each other, then I should not have to call these spaces Corridors. I am currently in negotiation with a reviewer over this exact distinction. My opinion is that this is an aisle, but they argue that this is technically an exit access corridor, not an aisle.

So if the reviewer is correct, I would have to go back in, extend all walls to deck and rate all the doors 20 min. I guess alternately we could provide a 2 hour wall through the middle of it, but that feels like it misses the point of the code to me. I see sawhorses change proposal language and generally think it applies here. In a totally new build, I would sprinkle, just to avoid the debate, but obviously that's onerous in a renovation project (occupied building).

Am I way off base?

 

[mtlogcabin]

So if the reviewer is correct,

I do not believe he is and you are not off base with what you are designing

2018 IEBC
805.1 Scope.
The requirements of this section shall be limited to work areas that include exits or corridors shared by more than one tenant within the work area in which Level 2 alterations are being performed,

803.2.2 Groups A, B, E, F-1, H, I, M, R-1, R-2, R-4, S-1 and S-2.
In buildings with occupancies in Groups A, B, E, F-1, H, I, M, R-1, R-2, R-4, S-1 and S-2, work areas that have exits or corridors shared by more than one tenant or that have exits or corridors serving an occupant load greater than 30 shall be provided with automatic sprinkler protection where both of the following conditions occur:

1. The work area is required to be provided with automatic sprinkler protection in accordance with the International Building Code as applicable to new construction.

2. The work area exceeds 50 percent of the floor area.

#1 is not applicable
Unless it is ambulatory care with more than 4 procedure rooms a "B" occupancy does not require sprinklers.

801.2 Alteration Level 1 compliance.
In addition to the requirements of this chapter, all work shall comply with the requirements of Chapter 7.

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

703.1 General.
Alterations shall be done in a manner that maintains the level of fire protection provided.

704.1 General.
Alterations shall be done in a manner that maintains the level of protection provided for the means of egress.

 

[Yankee Chronicler]

Bumping this topic. I have a similar situation that comes up somewhat frequently.

I renovate existing single tenant small clinics in rural towns who use various 3rd party reviewers. Invariably these clinics are un-sprinkled and have no rated walls of any kind. Typically these are Level 2 renovations (IEBC) where we may move some walls, but generally leave the overall plan intact. Example below (more intensive version than most) . So I have always interpreted that if I am within the exit access distance to the nearest exit, have a clear discernible path to egress, and don't intervene spaces that are not accessory to each other, then I should not have to call these spaces Corridors. I am currently in negotiation with a reviewer over this exact distinction. My opinion is that this is an aisle, but they argue that this is technically an exit access corridor, not an aisle.

So if the reviewer is correct, I would have to go back in, extend all walls to deck and rate all the doors 20 min. I guess alternately we could provide a 2 hour wall through the middle of it, but that feels like it misses the point of the code to me. I see sawhorses change proposal language and generally think it applies here. In a totally new build, I would sprinkle, just to avoid the debate, but obviously that's onerous in a renovation project (occupied building).

Am I way off base?



View attachment 14106

This looks to me like a level 3 alteration, not level 2.

 

[Genduct]

I am imagining your plan, and I am having trouble seeing it as a corridor. Most of these types of spaces are open to other areas, not "an enclosed exit access component". Are you sure you don't have an "aisle"? My understanding is that when you have a corridor, by definition enclosed, there is more risk because people on the other sides of the enclosure are not familiar with or not aware of what is going on in the spaces they are not in. So if you enclose it, it has a higher level of protection. But an aisle, which is unenclosed, does not carry that elevated risk because it is open and the occupants are generally familiar with the surroundings and activities. At a glance I would say if this is a single occupant, with individual offices, exam rooms, nurse stations, etc., you do not have corridors. Think about how many big office buildings we have been in with more than 50 of people on a floor in cubicle. They don't use corridors to get out, they use aisles.

Or I have no idea what I am talking about.

I didn't initially quote this very insightful thought you shared:

"But an aisle, which is unenclosed, does not carry that elevated risk because it is open and the occupants are generally familiar with the surroundings and activities"

It is in using a fundamental understanding of the INTENT of the ode, do we really do the Job

Well Said and Done
.

 

[steveray]

Bumping this topic. I have a similar situation that comes up somewhat frequently.

I renovate existing single tenant small clinics in rural towns who use various 3rd party reviewers. Invariably these clinics are un-sprinkled and have no rated walls of any kind. Typically these are Level 2 renovations (IEBC) where we may move some walls, but generally leave the overall plan intact. Example below (more intensive version than most) . So I have always interpreted that if I am within the exit access distance to the nearest exit, have a clear discernible path to egress, and don't intervene spaces that are not accessory to each other, then I should not have to call these spaces Corridors. I am currently in negotiation with a reviewer over this exact distinction. My opinion is that this is an aisle, but they argue that this is technically an exit access corridor, not an aisle.

So if the reviewer is correct, I would have to go back in, extend all walls to deck and rate all the doors 20 min. I guess alternately we could provide a 2 hour wall through the middle of it, but that feels like it misses the point of the code to me. I see sawhorses change proposal language and generally think it applies here. In a totally new build, I would sprinkle, just to avoid the debate, but obviously that's onerous in a renovation project (occupied building).

Am I way off base?



View attachment 14106

You are not way off base, you just don't have a good code arguement...MT gave some great code sections and my wrinkle would be this. "New" corridor walls and openings get built to new standards which is typically sprinklered or 1 hour:
702.7 Materials and Methods
New work shall comply with the materials and methods requirements in the International Building Code, International Energy Conservation Code, International Mechanical Code and International Plumbing Code, as applicable, that specify material standards, detail of installation and connection, joints, penetrations and continuity of any element, component or system in the building.

You don't get to call it not a corridor because it is inconvenient to you or the tenant.....

 

[mtlogcabin]

I would have to go back in, extend all walls to deck and rate all the doors 20 min.

Do the walls extend to the ceiling or are they not full height walls? What is the occupant load of the building?

[BE] CORRIDOR. An enclosed exit access component that defines and provides a path of egress travel.

 

[WolfmanofDelRio]

47 Occupants. Not ambulatory healthcare - just a boring B occ clinic.

Hard to sketch out in bluebeam, but with the exception of the offwhite rectangles in the middle, and the wall between the waiting room / back of house areas, the yellow areas are all "open". Wall generally go to the ceiling and stop.

I'm arguing the level 1 / level 2 alteration stance, but I still think the more accurate definition of space for this is an aisle due to its overall openness and providing many paths to various exits that also allow users the sensory perception noted in the commentary above. I guess I'll follow up when I hear back from the reviewer (and / or the city - my gut tells me I could have a reasonable conversation with the fire marshall and get approved).

 

[steveray]

If the walls go up to the ceiling and are capped by the ceiling....It is an enclosed exit access component.....And therefore............A witch.....

[BE] CORRIDOR. An enclosed exit access component that defines and provides a path of egress travel.

 

[Yankee Chronicler]

Hard to sketch out in bluebeam, but with the exception of the offwhite rectangles in the middle, and the wall between the waiting room / back of house areas, the yellow areas are all "open". Wall generally go to the ceiling and stop.

I'm arguing the level 1 / level 2 alteration stance, but I still think the more accurate definition of space for this is an aisle due to its overall openness and providing many paths to various exits that also allow users the sensory perception noted in the commentary above. I guess I'll follow up when I hear back from the reviewer (and / or the city - my gut tells me I could have a reasonable conversation with the fire marshall and get approved).


View attachment 14108

Corridor. You don't get to ignore those rooms in the center because they make it inconvenient for you.