Subject: RE: Firewall:(was)CMU Wall Supported by Plyw
From: Scott Maxwell <smaxwell(--nospam--at)engin.umich.edu>
Date: Fri, 23 Feb 2001 18:05:02 -0500 (EST)
You can check out the NCMA Tek 5-8A called Details for Concrete Masonry
There might be another NCMA Tek note about firewalls, but I cannot find it
right now. So, I am not sure if I have the one listed above or if it is
another one (the one listed above was from a search on NCMA's web page).
Hope that helps,
On Fri, 23 Feb 2001, dcarroll wrote:
> WHAT IS THE MEANING OF "SNIP" ???? are you referring to
> some attachment(s) that you inadvertently omitted, since you only comment
> on one method after you say there are several ways to accomplish the reqd
> result ?
> I appreciate your comments and am currently developing a study on this
> very subject. Is there a good treatise on structural design/detailing for
> fire walls??? pls write back - and thx again
> PS: Our (Kentucky) SEAOK group is writing a White Paper on Firewalls - does
> ANYBODY out there have some neat, clean details for these animals? I would
> love for you to mail, fax, or email me
> Pls send to: David Carroll PE
> c/o BFM ENGINEERS, Inc 241 Regency Circle, Lexington, Ky. 40503
> Ph: 859_278-5050 ,, Fax 859_278-6060
> -----Original Message-----
> From: Roger Turk [mailto:73527.1356(--nospam--at)compuserve.com]
> Sent: Thursday, February 22, 2001 12:32 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Firewall:(was)CMU Wall Supported by Plyw
> Scott Maxwell wrote:
> . > Now about firewalls...
> . > The first thing is to realize that there is a difference between a
> . > firewall and a fire separation wall. A fire separation wall is a wall
> . > between two spaces that is meant to stop or slow the spread of fire. A
> . > fire wall is essentially a fire separation wall that MUST remain
> . > AFTER one side of the building has collapsed (or is one of the two
> . > buildings has collapsed).
> . > If you must have a firewall, then that wall between the two buildings
> . > be designed in a fashion that it would remain standing if either
> . > collapses. Thus, if the new building falls, then the fire wall MUST
> . > remain standing or if the existing building falls, then the fire wall
> . > remain standing.
> . > This can typically be done one of several ways. You can:
> . > 1) [snip]
> . > 2) Do a single wall that is tied to each structure that has "break away"
> . > connections so that one side can fall without causing the other to
> . > collapse or bringing down the wall. With a masonry wall with wood
> . > this has traditionally been done with a "fire cut".
> . > 3) [snip]
> It seems to me that a "fire wall" would be virtually impossible in seismic
> country as the code requires that the diaphragm be tied to masonry/concrete
> walls. "Fire cuts" would be ineffective as the joists are tied to the wall
> with "tension ties" or other anchors. A "fire cut" would only be effective
> for wood joists resting on or in walls without any other type of connection
> between the joist and the wall. For a fire cut to be effective with tension
> ties, the tension tie would have to be a fusable link and even then it is
> questionable whether that would work, e.g., a fire destroys the wood joist
> mid-span, but does not reach releasing temperature at the fusable link at
> A. Roger Turk, P.E.(Structural)
> Tucson, Arizona