What do you call this?

[bldginsp]

I want to get the discussion going and then I'll give you the ICC interpretation. Sorry I'm computer stupid and don't know how to draw this and attach it so I'll describe and maybe someone will attach what I'm describing.

You have a office building that is square with offices along the exterior wall. You also have offices located in a square in the middle of the building. You have "hallways" attaching all of the offices together and have three exit discharges; one on the upper left, one on the upper right, and one in the middle on the bottom.

1. What are these spaces called that lead to the exit discharges?

2. How do you determine if they are rated and the occupant load?

 

[rshuey]

1. Exit Access

2. Takes a few sections, dont forget about access doorways(if any) or exit travel distance.

 

[Coug Dad]

1. Corridors?

2. sprinklered? Occupant load?

 

[Mule]

Sounds like a two story.

1. Agree with rshuey

2. May not need any rating at all. Too many scenarios.

Occupant load? Square footage divided by 100

 

[bldginsp]

1. Corridors?2. sprinklered? Occupant load?

A single cooridor? Not sprinklered. Lets say for grins the back offices on the back "cooridor" has 31.

 

[bldginsp]

Sounds like a two story.1. Agree with rshuey

2. May not need any rating at all. Too many scenarios.

Occupant load? Square footage divided by 100

Only a single story, total occupancy is 31 for grins.

 

[jpranch]

Can you scan the drawing and save it as a pdf? Then you could attache it here. I think the big question is sprinkler system? If sprinklered the corridors do not have to be rated. Business use = 100 gross per person. But you also have to account for other occupant loads such as 15 net for conference rooms, etc... With 3 exits I would assume that the occupant load is over 30?

 

[bldginsp]

1. Exit Access2. Takes a few sections, dont forget about access doorways(if any) or exit travel distance.

Common path of travel is 25 feet to the exit access. Hint, I was looking more for cooridor.

 

[bldginsp]

Can you scan the drawing and save it as a pdf? Then you could attache it here. I think the big question is sprinkler system? If sprinklered the corridors do not have to be rated. Business use = 100 gross per person. But you also have to account for other occupant loads such as 15 net for conference rooms, etc... With 3 exits I would assume that the occupant load is over 30?

I'll make this simple, I have many exit discharges because of the total travel distance, no sprinkler. Is this a cooridor and with the load I gave does it need rated? Tell me how you all determine the occupant load of the cooridor, not the building.

 

[bldginsp]

You're going to love the answer I got from ICC. We just need some discussion here.

 

[Mule]

The occupant load does not require it but the travel distance may require one.

Edit...you say ol 31? Table 1017.1 requires a rated corridor for B occupancy with an occupant load over 30.

 

[jpranch]

Beg to differ on the occupant load trigger. 2006 IBC Table 1017.1.

 

[Mule]

BUT if you have 3 exits because of travel distance then you may not have an occupand load of 31 because you are only splitting the occupant load to different exits and then it would just be a hallway. Only one exit is with under 49 ol.

 

[Mule]

jp, I edited while you begged to differ1 We actually said the same thing!

 

[jpranch]

Sure. I have seen many buildings / spaces with an occupant load of 49 with a single exit. Legal but always makes me a little nervious.

 

[Mule]

BUT if you have 3 exits because of travel distance then you may not have an occupand load of 31 because you are only splitting the occupant load to different exits and then it would just be a hallway. Only one exit is with under 49 ol.

What I am saying is that if the exits are layed out so that any of the hallways would not have more than 30 OL then you could have 3 hallways exiting 31 occupants. Then rating would not be required.

 

[jpranch]

But the occupant load is for the whole space, building, or combined spaces?? >30 rated regurdless of the corridor capacity.

 

[cda]

bldginsp::::

existing???

new???

remodel????

 

[bldginsp]

What I am saying is that if the exits are layed out so that any of the hallways would not have more than 30 OL then you could have 3 hallways exiting 31 occupants. Then rating would not be required.

But the occupant load is for the whole space, building, or combined spaces?? >30 rated regurdless of the corridor capacity.

Now were getting into the meat of the discussion I was looking for. How many cooridors do we have?

jpranch, are you asking a question or making a statement?

cda, a new building.

 

[jpranch]

statement.

2006 IBC Handbook Fire & Life Safety Provisions:

In buildings not equipped with an automatic sprinkler system throughout, corridors are

required to be fire-resistance-rated in all occupancies, based upon the occupant load served.

When a corridor serves an occupant load greater than 10 in a Group R occupancy or more

than 30 in a Group A, B, E, F, M, S or U occupancy, 1-hour fire-resistance-rated corridor

walls are required. Where the occupant load reaches the levels specified, it is appropriate to

afford those persons in the exit corridor some additional protection from potential fire

occurring in the enclosed spaces bordering the corridor. Therefore, a minimum separation

​

for the corridor of 1-hour fire resistance is deemed necessary.

 

[bldginsp]

statement.2006 IBC Handbook Fire & Life Safety Provisions:

In buildings not equipped with an automatic sprinkler system throughout, corridors are

required to be fire-resistance-rated in all occupancies, based upon the occupant load served.

When a corridor serves an occupant load greater than 10 in a Group R occupancy or more

than 30 in a Group A, B, E, F, M, S or U occupancy, 1-hour fire-resistance-rated corridor

walls are required. Where the occupant load reaches the levels specified, it is appropriate to

afford those persons in the exit corridor some additional protection from potential fire

occurring in the enclosed spaces bordering the corridor. Therefore, a minimum separation

​

for the corridor of 1-hour fire resistance is deemed necessary.

As stated above, "when a corridor serves an occupant load", how do you calculate the load of the corridor? I have got to figure out how to scan the plan and paste.

 

[jpranch]

You don't. With corridors you calculate capacity only to ensure it can handle the occupant load. To get the occupant load of a building or space within a building see IBC Section 1004 and Table 1004.1.1. Or you could just hire me a $120.00 an hour? LOL!

 

[Mule]

In buildings not equipped with an automatic sprinkler system throughout, corridors are required to be fire-resistance-rated in all occupancies,

BUT what if it's not a corridor? What if it's a hallway? If it's a hallway then no protection is required.

The original post said "You have "hallways" attaching all of the offices together and have three exit discharges;"

Notice the quotes around hallways. So the design professional has designed the office so that you have three different areas each with it's own hallway to exit into. If there wasn't three different exits then a rated corridor would be required.

Quote jp "With corridors you calculate capacity only to ensure it can handle the occupant load."

But you don't have a corridor. You have 3 groups of offices that each have an OL of less than 30 so there is a "hallway" for each group of offices. Now if each group of offices didn't have an independent hallway THEN a rated corridor would be required.

At home...and I don't have a codebook... I'll sleep on it and I will throw some more irons in the fire in the AM.

 

[jpranch]

Mule, with all do respect please fine me a definition of a "hallway" in the code? Perhaps only found in the legacy codes? Corridors have never been well defined in the I codes. It's a decision made by the AHJ. Hallway? Does not exist.