converging occupant loads

[Nicole Brooks]

This is a secure scif space. The area to the left of vestibule 214 on the top half is not secure and has an occupant load of 24 and a common path of travel of less than 100' requiring a single exit access door. All other parts of the plan are secure. The portion of the suite on the lower half has an occupant load of 66. The two secure area on the top half has a combined occupant load of 44. My question is: the lower secure area requires two exits, assuming half goes out vestibule 200 and the other out vestibule 222, the cumulative occupant load for the upper secure space is now over 50 and would also require 2 exit access doors. However, if I take them back through vestibule 214, that would also increase my cumulative occupant load to more than 50, no longer allowing a single exit access door from the non secure space, but they are not allowed to exit through the scif area. Am I thinking this out correctly?

 

[Yankee Chronicler]

You have two vestibules numbered 200, and from your description I have no idea if rooms 215, 216, and 217 are in a secured area or an unsecured area.

 

[steveray]

Everything on the "south" side is numbered 200....And 200 and 222 both go into the same corridor...no bueno...

 

[Yankee Chronicler]

Looking at the exit chart at lower right:

The door is listed as 34.5 inches. That's unlikely. It's probably a standard 36-inch door. The clear exit width is measured from the face of the stop on the latch side to the face of the door when the door is open 90 degrees. The actual clear egress width is probably closer to 33.5 inches. According to UpCodes, Baltimore doesn't change the standard ocupant width factors from the IBC, so door require 0.2" per person. A 33.5" door has a maximum capacity of 167 people, not 230.

Stairs use a factor of 0.3 inches per person, so a 44-inch wide star has a maximum capacity of 146 people, not 220.

I don't understand what purpose any of the three vestibules serves. The one numbered 200 to the right of the stair doesn't connect to a corridor, it connects to another space, which then leads through vestibule 220 before getting to the corridor. It doesn't make any sense.

 

[Jay Smith]

Could we analyze this a little different way? The occupant loads that require access to two exits are not assumed to be split in half and then cumulative as you go along the exit path. This is a suite with an occupant load of 134 and access to presumably two exits, one of which does not appear on this plan. The spaces with occupant loads of 66 and 44 are connected and combined.

1. Space west of secure vestibule 214 can access corridor through one door because it complies with 1006.2.1.
2. Space north of 214 complies with 1006.2.1. Its common path ends in 214.
3. Space east of 214 can access corridor through one door at vestibule 222 if it complies with 1006.2.1.
4. South space must have two doors because it does not comply with 1006.2.1.
5. South space is connected to east space, so all of that must have two points of access to corridor that comply with 1007.1.1.
6. All of these occupants enter corridor, combine with the remainder of the floor and all must have access to at least two exits that comply with 1007.1.1.

I’m asking the experts rather than answering, though.

 

[Yankee Chronicler]

1. Space north of 214 complies with 1006.2.1. Its common path ends in 214.

Does this common path end at 214, or does it end in the shared corridor?

Devil's advocate: The common path of travel is:

That portion of exit access travel distance measured from the most remote point of each room, area or space to that point where the occupants have separate and distinct access to two exits or exit access doorways.

The Commentary for this definition further explains:

The common path of egress travel is a concept used to
refine travel distance criteria. A common path of travel
is the route an occupant will travel where the one way
in is also the one way out, similar to a dead-end corridor
or single-exit suite. Once occupants reach a point
where two different routes are available, and the two
different routes continue to two separate exits, then
common path of travel is finished. The length of a common
path of egress travel is limited so that the means
of egress path of travel provides a choice before the
occupant has traveled an excessive distance (see
Section 1006). This reduces the possibility that,
although the exits are remote from one another, a single
fire condition will render both paths unavailable.
The common path of egress travel is part of the overall
exit access travel distance. To be compliant, the path
of egress must meet criteria for both common path of
egress travel and exit access travel distance.

So the underlying principle is that the common path ends at whatever point you have separate access to at least two remote exits, with the intent that if one exit is blocked, you can go toward the other.

From Vestibule 214, whether you go left or right (east or west), both routes dump you into the same shared corridor, within a few feet of the exit door into Stair #3. Unless the two points at which occupants enter the shared corridor satisfy the remoteness criteria, I'm not (yet) prepared to agree that the common path of travel ends at Vestibule 214. Suppose the fire is in the shared corridor, right outside the exit door into Stair #3. If I go north from 214 I then loop around 212 and 213, and into Vestibule 222. If I open the door from 222 to the shared corridor, the fire is right there, blocking my access to Stair #3. My only escape, then, is to retrace my steps all the way to Vestibule 214, and then proceed west along Corridor 205, through Reception 201, and then into the shared corridor at a point that I hope is far enough away from the fire to allow me access to another exit somewhere off the current view to the left/west.

Once I'm in 222, if I can't exit that to the corridor, does the security locking allow me to re-enter the space to retrace my steps -- without the use of keys?

 

[Yankee Chronicler]

Can you provide a marked-up version of the plan that clearly shows which areas are secured, and which doors are secured? I assume that each secured area is not allowed access to or through any of the other secured areas -- is that correct? And the secured doors do NOT unlock in the event of a fire alarm or sprinkler activation?

 

[Yankee Chronicler]

A "SCIF" is a "Sensitive Compartmented Information Facility." The rules comprise 125 pages of typical governmental gobbledegook. The part about doors starts on page 15: https://www.dni.gov/files/NCSC/docu...artmented_Information_Facilities_v151_PDF.pdf

The way I read it, no sensitive compartment can egress through another sensitive compartment. Period.

We need to know the limits of each sensitive compartment, and the types of locks on each door.

 

[Jay Smith]

Does this common path end at 214, or does it end in the shared corridor?

Devil's advocate: The common path of travel is:



The Commentary for this definition further explains:



So the underlying principle is that the common path ends at whatever point you have separate access to at least two remote exits, with the intent that if one exit is blocked, you can go toward the other.

From Vestibule 214, whether you go left or right (east or west), both routes dump you into the same shared corridor, within a few feet of the exit door into Stair #3. Unless the two points at which occupants enter the shared corridor satisfy the remoteness criteria, I'm not (yet) prepared to agree that the common path of travel ends at Vestibule 214. Suppose the fire is in the shared corridor, right outside the exit door into Stair #3. If I go north from 214 I then loop around 212 and 213, and into Vestibule 222. If I open the door from 222 to the shared corridor, the fire is right there, blocking my access to Stair #3. My only escape, then, is to retrace my steps all the way to Vestibule 214, and then proceed west along Corridor 205, through Reception 201, and then into the shared corridor at a point that I hope is far enough away from the fire to allow me access to another exit somewhere off the current view to the left/west.

Once I'm in 222, if I can't exit that to the corridor, does the security locking allow me to re-enter the space to retrace my steps -- without the use of keys?

What you have said here does cause me some doubt about common path ending in 214, given that there is apparently no opportunity to backtrack when the occupant leaves that space in either direction.

 

[steveray]

"Please provide plans that comply with IBC 107.2.3 showing complete MOE details including OL in all rooms and spaces."