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RE: Area separation walls

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Tarno Coleman and I had an off line discussion about penetrations of fire
walls.  I thought that the thread might prove to be informative to the
entire list.  

Tarno pointed out the distinction between area separation walls and
occupancy separation walls.

Harold Sprague

	-----Original Message-----
	Sent:	Wednesday, February 23, 2000 1:31 PM
	To:	SpragueHO(--nospam--at)
	Subject:	Re: RE: Area separation walls.


	The code has many different requirements that specify fire resistive
	construction.  Different types of separations (occupancy; area;
	specific) may have the same hourly fire-resistant and can result in
	confusion.  All walls with a equal fire-resistance hourly rating are
	not necessarily the same for code purposes. An area separation wall
	a special critter.  Exit enclosures are an example of specific
	requirements for stairway protection.

	The following is from the 1997 UBC and the 1997 UBC Handbook:

	 1997 UBC Volume 1

	"504.6 Area Separation Walls.

	504.6.1 General. Each portion of a building separated by one or more
	area separation walls that comply with the provisions of this
	may be considered a separate building. The extent and location of
	area separation walls shall provide a complete separation.
	When an area separation wall also separates occupancies that are
	required to be separated by an occupancy separation, the most
	restrictive requirements of each separation shall apply."


	"504.6 Area Separation Walls. In Section 302 the code introduced the
	concept of the fire-resistive separation, designated the "occupancy
	separation," where the openings in the separation wall are protected
	by fire-protection assemblies. The Uniform Building Code has a
	type of fire-resistive separation, which is called the "area
	separation wall." The intent of the code is that the function of the
	wall is exactly as its name implies-a vertical wall that separates
	areas. This is to distinguish it from an occupancy separation that
	be horizontal. Structural members that penetrate area separation
	could limit the effectiveness and would not comply with the
	that states such walls "shall provide a complete separation." Any
	member that passes through an area separation wall could affect the
	integrity of the required fire-resistive construction. However, the
	code does not prohibit western platform framing to divide a two-hour
	area separation wall if solid blocking is provided within the floor
	roof cavity. See Footnote 2 for a reference to an article by Paul
	Sheedy which illustrates this concept."  (emphasis added)

	>>> "Sprague, Harold O." <SpragueHO(--nospam--at)> 02/23/00 08:38AM >>>

	I have often seen stairwells in buildings with rated enclosures that
	had to be sealed at the top to prevent smoke from entering the stair
	enclosure.  Or another one was a small office adjacent to a
	facility.  The roof structure went through uninterrupted.  They were
	referred to as area separation walls.  This is very common in the
	metal building industry.

	Is this a correct interpretation?

	Harold Sprague

	> -----Original Message-----
	> Sent: Wednesday, February 23, 2000 10:33 AM
	> To: SpragueHO(--nospam--at) 
	> Subject: Area separation walls.
	> Excuse the off-line reply, but our mail system does not permit
	> to the list.
	> Our interpretation of the UBC regarding area separation wall is
	> no structural members pass through it.  The logic being if the
	> fails on the fire side it may pull the wall apart.
	> As an alternate method on one job, we accepted 2-hour protection
	> beams and columns supporting the beam that passed though the area
	> separation wall. (sismic tie) This building was fully sprinklered.

	> ps: I appreciate your thoughtful and incisive responses to the
	> Tarno Coleman, PE
	> Plan Check Engineer
	> 503.566.3964
	> e-mail: tcoleman(--nospam--at) 
	> Marion County Building Inspection
> PO Box 14500, Salem, Oregon  97309