exit access and common path of egress

Site Zoning Vignette and Multiple Choice

exit access and common path of egress

Postby lcohen » Thu Sep 20, 2012 12:22 pm

I understand that there are different definitions and requirements between these two conditions and that the common path of egress is part of the total exit access travel distance but I'm having trouble understanding how one is identified from the other.
Exit access travel distance - the distance between the most remote point of the exist access to the entrance or exit (typically 200' max)
Common path of Egress Travel - The portion of an exit access that reaches two separate paths of egress leading to two available exits (typically 75')

The fact is the exist access does eventually lead to two separate paths of egress so why seperate out a common path of egress? Is there always a common path of egreess travel? It's obviously confusing to me..!

any help is appreciated...
lcohen
 
Posts: 3
Joined: Thu Sep 20, 2012 12:15 pm

Re: exit access and common path of egress

Postby TMD_Architecture » Tue Oct 08, 2013 12:13 pm

The maximum distance you can travel (while only having one choice of an exit, from the most remote point) is the common path (max 75'). Once the common path leads you to a choice of (2) exits, the max distance increases because you have more than one option to exit the building in the case of a fire. Its difficult to describe in words.
Google: rlga travel distance
There is a great article on this
TMD_Architecture
 
Posts: 31
Joined: Tue Oct 08, 2013 11:48 am

Re: exit access and common path of egress

Postby hnQ_9999 » Wed Apr 12, 2017 4:13 pm

ScreenShot-013.jpg

ScreenShot-003.jpg

ScreenShot-007.jpg


I scratched my head on this many times. Notice the highlights and the wording "portion of exit access"
I believe the 75' is for A SPACE only (1 room or 1 space, not a whole floor) when only 1 exit is provided.
And the 200' (or 250') is for the longer length, from most remote location to the split (into 2 available exit).
(The associated occupancy for this 200' also makes sense: E, A, S, M...)
[[ My way to memorize it: " split 250 FARMERS down to 75 " ]]

Anyone ?
You do not have the required permissions to view the files attached to this post.
Last edited by hnQ_9999 on Thu Apr 13, 2017 11:59 am, edited 2 times in total.
hnQ_9999
 
Posts: 1029
Joined: Tue Nov 26, 2013 1:35 am

Re: exit access and common path of egress

Postby vrcat25 » Wed Apr 12, 2017 8:20 pm

hnQ_9999 wrote:
ScreenShot-003.jpg

ScreenShot-007.jpg

ScreenShot-013.jpg


I scratched my head on this many times. Notice the highlights and the wording "portion of exit access"
I believe the 75' is for A SPACE only (1 room or 1 space, not a whole floor) when only 1 exit is provided.
And the 200' (or 250') is for the longer length, from most remote location to the split (into 2 available exit).
(The associated occupancy for this 200' also makes sense: E, A, S...)
Anyone ?


I don't believe this is correct. It's not just for "1 room or 1 space" and DOES include the whole floor.

Take any floor plan as an example and find the room/space furthest from the main entry. To keep it simple, don't consider any other doors if there are any. For cad, you simply draw a poly line from the furthest point until you get to the "EXIT ACCESS". Keep in mind that an Exit Access is not the actual exit in many cases. A set of fire stairs could be the exit access. If the polyline is shorter than 75 you need another exit. If not, you are ok. It will be easier to wrap your mind around it once you do a real life example.

The first table you posted is for a building/space with multiple exits. The second is for "spaces with one exit". The 75' rule for unsprinklered buildings is just to determine if you need more than one exit. The number of exits also depends on the occupant load and occupancy type. We had to work out a real life example for this at work for a 2 story office building. It was a small office building with only 4 offices, break room and bathrooms on second floor so it was just under 75' to the "exit access" stairwell from the back of the most remote office so we ended up being ok with just one exit. Making any more sense yet? Thoughts anybody? Please correct me if i'm wrong, thanks.
vrcat25
 
Posts: 1017
Joined: Sun Dec 27, 2015 11:19 am

Re: exit access and common path of egress

Postby hnQ_9999 » Thu Apr 13, 2017 1:11 pm

So as you said, for example here,
the CPOE = blue+violet+purple+green ?
I think CPOE=blue+violet only.
ScreenShot-046.jpg
You do not have the required permissions to view the files attached to this post.
Last edited by hnQ_9999 on Mon Apr 17, 2017 9:50 am, edited 1 time in total.
hnQ_9999
 
Posts: 1029
Joined: Tue Nov 26, 2013 1:35 am

Re: exit access and common path of egress

Postby vrcat25 » Thu Apr 13, 2017 5:28 pm

No, I never said that. You are assuming 2 exits for your example, but I was only assuming 1. The CPOE would be blue and purple if your example portrays two exits and the CPOE WOULD be blue and purple. Let's say that top right exit is your only exit and you are trying to determine if you need a second exit. The blue, purple and pink would be your travel distance and this is not to exceed 75' for unsprinklered buildings. TMD_Architecture explained it perfectly. As he said, it's difficult to describe in words and you are better off looking at some illustrations. It helped me to understand it that way. Here's two good examples, one with one exit and the other with 2.
only-one-exit72.jpg
common-path-of-egress72-460x345.jpg


I'm also sending an example i did. This assumes two exits. The yellow path represents your travel distance for the exit on right. The blue path would be the longer travel distance to another exit. The colored paths are "exit access" and assuming those stairs are fire stairs that would be the "exit". The green path and black star represents the point where two separate and distinct paths of egress travel to two exits are available. Clear as mud? Again, anybody can correct me if i'm wrong. Here's the example i did based on a few modifications to your example. ->
ScreenShot-7.jpg
You do not have the required permissions to view the files attached to this post.
vrcat25
 
Posts: 1017
Joined: Sun Dec 27, 2015 11:19 am


Return to PPP - PROGRAMMING, PLANNING & PRACTICE

Who is online

Users browsing this forum: No registered users and 41 guests

cron