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Q: Egress rate from a resturaunt ( Answered 5 out of 5 stars,   3 Comments )
Question  
Subject: Egress rate from a resturaunt
Category: Miscellaneous
Asked by: smallbusinessjim-ga
List Price: $10.00
Posted: 24 Mar 2006 13:24 PST
Expires: 23 Apr 2006 14:24 PDT
Question ID: 711575
I need to know the rate of egress for people in a resturaunt
environment through a standard door.  For example: "100 people are sitting in
a dining room, the fire alarm goes off, there are 2 doors, how long
till everyone is outside?"

What I really need is a time per person, then I can apply the math to
the occupancy of our resturaunt.  I will also need a source for the information to
backup my findings.
Answer  
Subject: Re: Egress rate from a resturaunt
Answered By: cynthia-ga on 24 Mar 2006 16:15 PST
Rated:5 out of 5 stars
 
Hi smallbusinessjim,

Egress is measured in "people per minute." The short answer to your
question, with an impeccable source --is this:

26 people per foot (width) of door, per minute.

Calculate rate of egress: 

Stairway rate 18 people/foot/minute.
For a 4 foot wide stair the rate is 4 feet x 18 people/foot/minute
= 72 people/minute

Doorway rate 26 people/foot/minute.
For a 3 foot wide door the rate is 3 feet x 26 people/foot/minute
= 78 people/minute

YOUR SOURCE IS:

INTERNATIONAL BUILDING CODE ? MEANS OF EGRESS (top right of page 1)
http://www.iccsafe.org/cs/codes/2003-04cycle/faa/FAA-IBC-MOE.pdf

Density figures and calculations from:

SFPE Handbook of Fire Protection Engineering
http://www.nfpa.org/catalog/product.asp?pid=HFPE01&target_pid=HFPE01&src_pid=FPH1903&link_type=up_sell


Technically, this is the end of your Answer, however I'm passing along
all the other resources I found along the way. Note at Evacunet (not
as good a source), they measure "headway" :


EVACNET4 USER'S GUIDE ? DOORS
http://www.ise.ufl.edu/kisko/files/evacnet/EVAC4UG.HTM
..."Headway is an important idea relevant to modeling the flow
capacity of doors; headway is the average time between two successive
users of a door. If the headway is too small, then successive users of
a door would interfere with one another.

As an example of headway, if the headway of a door is 1 second, then
the average time between successive users is second. Dividing 60
seconds per minute by the headway of a door gives the average flow
capacity of the door in people per minute. A door with a headway of 1
second has a flow capacity of 60 people per minute.

Fruin [3] points out that "Entrances are, in effect, walkway sections
in which pedestrians have been channeled into equal, door-width
traffic lanes." This remark suggests that, if carefully used, flow
volume for walkways may be applicable for doors.

Fruin [3] gives data for several entrance doors. For free-swinging
entrance doors, he has observed that average headway is 1.0 and 1.5
seconds, giving 40 to 60 people per minute being able to use the
doors. In the case of a door revolving in one direction, he has
observed that average headway is between 1.7 and 2.4 seconds, giving
25 to 35 people per minute being able to use the doors..."


Means of Egress
http://www.ci.seattle.wa.us/dpd/static/1egress_LatestReleased_DPD_001932.pdf


NFPA 101B, Code for Means of Egress for Buildings and Structures, 2002 edition
http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=101B  
$41.00


ADA Accessibility Guidelines for Buildings and Facilities (ADAAG)
http://www.access-board.gov/adaag/html/adaag.htm


Hope this helps! If you need clarification, please don't hesitate to ask.


~~Cynthia


Search strategy used at Google:
"building codes" 
evacuation
"people per minute" 
egress
smallbusinessjim-ga rated this answer:5 out of 5 stars and gave an additional tip of: $2.00
Thank you.  Exactly what I was looking for, we researched codes but
never made it to the NFPA Books.

Comments  
Subject: Re: Egress rate from a resturaunt
From: ansel001-ga on 24 Mar 2006 13:41 PST
 
That will depend on a lot of things.  I assume you are thinking of how
long it will take to evacuate the restaurant in case of a fire?  You
need to look at the layout of the room and where the tables are.

How long before an alarm is sounded to evacuate?
How good or poor is the visibility?  There could be smoke or the power
and lighting could go out.
Are there other traffic bottlenecks besides the doors?
How long before the first people start to exit?
How many people can exit the doors before a backup at the doors starts?
Will equal numbers of people go to each door or will most go to the
main entrance rather than the second door?
What about stragglers?  This could include people in the bathrooms,
the disabled, etc.
Subject: Re: Egress rate from a resturaunt
From: smallbusinessjim-ga on 24 Mar 2006 14:44 PST
 
True, there are a lot of components to the study, but all I'm asking
is for the rate of travel through a door.  Assume a big room, well
lit, no smoke, no bottlenecks and a line of people at the door. 
Moving in an orderly fashion, what is their rate of exit?
Subject: Re: Egress rate from a resturaunt
From: frde-ga on 25 Mar 2006 02:47 PST
 
As others have said, there are so many imponderables.

For example with airlines they always make sure that fit and capable
people sit beside the emergency exits.

Reputedly they also do their tests with students wearing trainers.

Personally in that situation I would head for the window and put a
chair through it - people panic - and crowds get out of control very
easily.

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