Fire exit separation distance

[Question That]

In the past I've used the entire building footprint longest diagonal to establishe the distance to divide by 2 or 3 to determine what distance between exits is required. I've almost exclusively used the IBC.... But I've always kind of questioned this mindset in some situations more than others.

Recently I got handed a project that the AHJ requires using NFPA101 and I've gotten reasonalbly familiar with it. There is some verbiage in there that has me thinking.....

Section 7.5.1.3.2 says-
To be considered remote, the exits, exit accesses and exit discharges in new buildings must be located at a distance "from one another not less than one-half (one-third if the building is fully sprinklered) the length of the maximum overall diagonal dimension of the building or AREA to be served".

This particular project is a relatively simple one. A covered pavilion that has restrooms. It's all open at the pavilion side with 2 gang toilets and a family restroom behind a privacy screen.
After reading the "area to be served" part I drew the diagonal just from corner to corner of the pavilion part.

Thoughts?

 

[RLGA]

The NFPA 101 language is identical to that used in IBC Section 1007.1.1:

Where two exits, exit access doorways, exit access stairways or ramps, or any combination thereof, are required from any portion of the exit access, they shall be placed a distance apart equal to not less than one-half of the length of the maximum overall diagonal dimension of the building or area to be served measured in a straight line between them. Interlocking or scissor stairways shall be counted as one exit stairway.

 

[Question That]

You know this is one of those rare times that I took a shortcut and as usual it bit me. I've been using IBC for so long now guess I just never really paid attention and assumed it was different.... therefor saved me the 30 seconds of going and checking.... although it definitely occured to me.
Oh well. Thanks for calling me on it.
So, that being the case, is my newly revised opinion on how this part of the code is supposed to function correct in your opinion? Or, is it always going to be a longest overall building diagonal that is going to be "required" to be used?

 

[RLGA]

It depends on what is under consideration for exit or exit access separation. Use the overall diagonal building measurement to separate exits from a story. If an area of the building (e.g., a large tenant space within an office building) requires two or more means of egress, the exit access doors out of the tenant space must be separated by 1/2 or 1/3 (as appropriate) of the overall diagonal measurement of the tenant space (i.e., "area to be served").

 

[Question That]

It depends on what is under consideration for exit or exit access separation. Use the overall diagonal building measurement to separate exits from a story. If an area of the building (e.g., a large tenant space within an office building) requires two or more means of egress, the exit access doors out of the tenant space must be separated by 1/2 or 1/3 (as appropriate) of the overall diagonal measurement of the tenant space (i.e., "area to be served").

Understand on the tenant spaces but doesn’t apply here.
Seems to me it makes no sense to factor in subordinate areas of a building that don’t contribute to occupant load (thinking toilets in an assembly occupancy)…. Which brings up additional intent questions….
I mean why would toilets off to the side of a space that they ACCESS need to be included in the diagonal? You’re not trying to get everyone out of the toilets you’re trying to get everyone out of the assembly space that were in that area before they went to the toilet. Right?

 

[bill1952]

Unless the occupant load requires 2 means of egress, I'd agree. Travel distance and common path of travel will protect people in toilet rooms.

 

[Question That]

Unless the occupant load requires 2 means of egress, I'd agree. Travel distance and common path of travel will protect people in toilet rooms.

Why differentiate between 1 and 2+?
I mean I understand why it would be required to have x distance separation between the available exits just don't understand why in the case stated above (and similar) why that separation distance would need to be based on the entire building footprint diagaonal when all you're really trying to accomplish is separate the exits in the space that people are trying to get out of.

 

[bill1952]

I meant if restroom occupant load required 2, then those would have to be separated.

I would use the room or assembly space - the area to be served - for diagonal as I think you suggest, and exclude restrooms, etc.

Listen to RLGA.

 

[Question That]

I meant if restroom occupant load required 2, then those would have to be separated.

I would use the room or assembly space - the area to be served - for diagonal as I think you suggest, and exclude restrooms, etc.

Listen to RLGA.

Thanks for the clarification Bill. Good to hear yours and RLGAs insight. Thanks for helping me make sense of this.

 

[RLGA]

Here is an illustration of what "area to be served" means (Shaded areas are the areas served):

People occupy restrooms, storage rooms, etc., and although they may not contribute to the occupant load, they are served by the egress components from the spaces they egress through.

 

[Question That]

Well the above illustrations while clear don't gel nicely with my situation..... for my arguing purposes which is obviously no ones intent- including mine.
But....
"People occupy restrooms, storage rooms, etc., and although they may not contribute to the occupant load, they are served by the egress components from the spaces they egress through." I follow this and am not arguing your point. What I don't understand however is that the spaces that they are occupying are not a part of the space that they are leaving. They left the "restroom", got out, entered into the assembly space and need to leave that space. So, from 50,000 feet, I just don't understand why the diagonal on ALL of those illustrations can't be the same diagonal as in C. I mean, why can't/ isn't that assembly space in and of itself the "area being served"?

 

[Question That]

Thanks for the illustrations btw

 

[TheCommish]

I think the point is an assembly space over 50 needs to meet remoteness and the building floor that the assembly space is in also has to meet the remoteness standard.

In your case the rest rooms are part of the floor area that needs to be calculated in the diagnal of the space.

Can you post a plan?
Is the actual distance that close that it matters?

 

[steveray]

Rons post #10 pretty much nails it...shows accessory spaces egressing through and not egressing through...that is the differentiation....