NFPA 221 has material on how cantilever, tied fire walls and double fire
walls are to be constructed. It also has requirements for exits through
fire walls. Your local fire department probably has copies of all the
NFPA's. It is also available from NFPA for $20.25 at 1-800-344-3555.
SDS Architects, Inc
205 N. Dewey Street
Eau Claire, WI 54703
From: David Handy [mailto:dhandy(--nospam--at)trg.ca]
Sent: Wednesday, June 28, 2000 8:02 PM
Subject: RE: Firewall construction
I would agree with Harold S. about the suitability of two walls in this
instance. The only time I use a single wall is with wood construction where
the tied weak link firewall can be used. I am sure that some of the other
types of tied fire walls have their uses but not in strange situations such
as the one you describe. Only in the very symmetrical situations do the
others seem to work. I have only used the cantilever walls in relatively
short one story buildings.
A question for those who use double firewalls....... If you are using two
8" block walls and they are bearing walls...what do you do at the doorways
through the walls. According to the rules the wall should maintain its
integrity for 2 hours. If one side collapses before this then the doorway
can't be attached to it. What if the other side falls down? I have come up
with my own solution but it can't be the only answer. I built a separate
structure around the doorway with concrete columns and beams and did not
rigidly attach the floor to it. It cantilevered from the foundations two
storeys. This way either wall could fall down and not affect the doorway.
Any other thoughts on ways to achieve this.
David Handy, P.Eng. dhandy(--nospam--at)trg.ca The Thompson Rosemount Group, Cornwall,
Ont. Canada Opinions expressed are personal only.