Means of Egress - Maximum Overall Diagonal

[RANDOM]

CBC
Chapter 10 Means of Egress
1015.2.1 Exception 2
Exit door separation distance is 1/3 of the maximum overall diagonal.

The code is does not specify how this maximum overall diagonal (green), should be drawn. Does it go into the internal faces of walls?

or should be measured to the outside faces of the building walls?

 

[JBI]

Area is measured within the building walls and egress gets you out of the building.
I would measure inside face of corner to inside face of corner.

 

[ICE]

The inside face of the wall is where one can measure. Would a foot one way or the other matter?

 

[steveray]

I would go inside to inside....but where on the door do you measure?

 

[cda]

Half way as shown

Does it really matter

 

[RANDOM]

I would go inside to inside....but where on the door do you measure?

I would measure the mid point of the door. (both directions X,Y)

 

[cda]

Where's RGLA???

http://www.specsandcodes.com/articles/code_corner/The Code Corner No. 29 - Travel Distance.pdf

 

[RANDOM]

Half way as shown

Does it really matter

It does sometimes.

 

[cda]

So Random do you mind saying what you do for a paycheck or direct deposit ??

 

[steveray]

The door usually would matter more than the wall and you are walking through the door, not the exterior wall....

 

[RANDOM]

So Random do you mind saying what you do for a paycheck or direct deposit ??

My case:

I measured the building diagonal to the inside corner. My supervisor told me that it should be measured to the exterior corners of the building.

1)If I use my way I comply with code.

2)If we use his way we don't because the doors would be separated less than 1/3 of the overall diagonal. The difference is 1'-2". I know it's barely nothing, but still.

The structural engineer has already sent the concrete opening plans and my supervisor does not want them to do any changes to those plans.

I told him that it is not necessary because we do comply with code due to the fact explained before.

p.s. I work for an Architectural Firm.

 

[mtlogcabin]

Try this approach for your rational

2. Where a building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2, the separation distance of the exit doors or exit access doorways shall not be less than one-third of the length of the maximum overall diagonal dimension of the area served.

AREA, BUILDING. The area included within surrounding exterior walls (or exterior walls and fire walls) exclusive of vent shafts and courts. Areas of the building not provided with surrounding walls shall be included in the building area if such areas are included within the horizontal projection of the roof or floor above

 

[cda]

building or area to be served


If you go by supervisor, if you had an interior room, with no exterior walls, where would he measure from??

 

[cda]

building or area to be served

My case:



p.s. I work for an Architectural Firm.

It helps to answer some questions easier if we know how you butter your bread

 

[cda]

It does sometimes.

Must be some thick exterior walls

 

[RANDOM]

Must be some thick exterior walls

Yeah. Check the difference. The purple line is the internal corner. The green wall represents a concrete tilt up panel. There are almost 5 feet of difference.

 

[fatboy]

I believe you should take another run at your supervisor, now that you have other opinions supporting yours.

 

[north star]

@ * @

" I believe you should take another run at your supervisor, now that you have other opinions supporting yours "

Maybe, ...maybe not!.......Depends upon what kind of rapport **RANDOM**
has with his Supervisor......The Supervisor may not want to hear other
opinions, ...right or wrong !.......Tread lightly **RANDOM** !


@ * @

 

[fatboy]

@ * @

Maybe, ...maybe not!.......Depends upon what kind of rapport **RANDOM**
has with his Supervisor......The Supervisor may not want to hear other
opinions, ...right or wrong !.......Tread lightly **RANDOM** !


@ * @

That may be so.......but to knowingly support a bad interpretation, well...............

 

[north star]

@ ~ @

fatboy,

Unfortunately, I have the voice of experience speaking here.
Long, long ago, in a galaxy far, far away, ...I worked in an
environment where being right, or splitting hairs to be right
[ i.e. - code accurate ] could get one terminated, or
marginalized.

Just sayin'...


@ ~ @

 

[RANDOM]

@ * @

Maybe, ...maybe not!.......Depends upon what kind of rapport **RANDOM**
has with his Supervisor......The Supervisor may not want to hear other
opinions, ...right or wrong !.......Tread lightly **RANDOM** !


@ * @

I rather fly low for now. I am still new to the office and it would be wise if I did not antagonize anybody, specially in front of the principals.

But it's good to know that you guys thought likewise.

Thanks,

 

[Yikes]

Echoing what some other people said here:
1. The diagonal distance is to the area SERVED. The purpose of this "service" is to get people out of the building. People to not reside inside walls (unless you are in an ancient Assyrian palace and fell out of favor), so you only measure the diagonal within the occupiable space. Some people will excluded built-in cabinetry against a wall; or on sloped ceiling spaces, they will exclude areas with less than 5' headroom as being "served" by an exit because they are technically considered non-occupiable. I don't agree with the latter approach.

2. The length of the diagonal in question does not directly correlate to actual path-of-travel within the space. It is a straight line between two exit doors, regardless of what obstacles are in that line; in other words, it is not intended to prescribe a real-world exit path. It is simply a rule-of-thumb, a form-based concept that was found to be generally agreeable and was eventually adopted as a code standard to be likely to produce a safe space. Remember, it wasn't that long ago that the UBC required 1/2 diagonal, with NO 1/3 exception for sprinklered buildings. What happened since then that magically made a sprinklered building actually safer with 1/3 exit diagonal in 2012 than, say, 1994? Well, the main thing that happened was that we all agreed to it.

3. With that in mind, it is a "straight line" (1015.2.1), and it is measured "BETWEEN" exit doors. I believe it is acceptable to measure to the closest edges of the doorways to meet the definition of the word "between". If the code intended for it to be center of doorway, it would have said it by now.

Again, this is NOT about measuring maximum path-of-travel to exit; it IS about location of doorways.

BTW, for reference purposes, right now I happen to be looking at a 1994 UBC "Q and A" code applications manual. The ICBO staff responded:
"The code does not specify whether one measures the exit separation between the center lines of doors, between the nearest jambs, between door knob to door knob, or between any other points. However, we are of the opinion that regardless of which of the three methods outlined in your question are used, the difference is so slight as to be unimportant..."

 

[cda]

""""However, we are of the opinion that regardless of which of the three methods outlined in your question are used, the difference is so slight as to be unimportant...""""


As said what does it really matter

 

[Yikes]

^^^ CDA: true, but it is so rare to see someone in the code business actually say: "the difference is so slight as to be unimportant".
I end up doing a double-take!