Positive Attachment for a Masonry Firewall

[SteelPE]

I am at the beginning stages of looking at a project that requires an internal firewall. The building is to be designed in accordance with IBC 2015. All I know about the building at this point is that it’s a warehouse that requires a firewall.

I have already tried to convince the architect to use two separate walls. He said no. I then tried to convince him to us a metal stud wall (as marino and Clark Dietrich both make “break away clips”). He said no.

His idea was to have steel rest against the firewall on each side (not attached to the firewall). That way if one building collapses then it will not take the wall down with it. I thought that was great no counting the fact that not having the wall attached to the other standing structure can cause some major issues.

I know this has been a problem for years. Has anyone actually come up with a good way to solve the issue?

I noticed the Heckmann makes some “Break-Away Firewall Anchors”. I was thinking of directing the architect in this direction.

http://www.heckmannbuildingprods.com/firewall_anchors.html

The thought process would be to have these anchors on both sides of the wall (see attached detail). I know the anchors do no have large capacities, but at least it would provide positive anchorage of the wall to the standing structure and keep the wall from falling on the rescue crew.

 

[BAretired]

There is no question that the double firewall is the best. Unfortunately, nobody wants to use it because of cost. The idea of using a firewall unattached to the building on both sides has been suggested by the architect. Unless it has been designed as a cantilever, the firewall can collapse before or after the fire has been extinguished.

The use of Break-Away Firewall Anchors is an approved way of attaching a firewall to the structure on each side. It relies on development of high temperature which melts or weakens the anchors on one side of the wall (the fire side).

My preferred way of dealing with the issue is to tie both sides of the firewall to the structure and to design each side to resist the horizontal forces which develop when fire exists on the opposite side.

BA

 

[DaveAtkins]

The 2018 IBC has finally given a design load for this type of wall. It is 5 psf (service load, unfactored), which is the load I have typically used.

So if you decide to design each wall as a cantilever, you can use 5 psf--you need not design for wind load.

DaveAtkins

 

[SteelPE]

Dave,

I thought the IBC had always given the 5psf load. Am I mistaken?

I have the 5psf going all the way back to IBC 2006 (1607.13) and probably before that.

 

[JAE]

I think DaveAtkins is talking about this section from IBC 2018:

 

[DaveAtkins]

JAE is correct, that is what I was referring to. There are past threads where we discussed what lateral load to use on a fire wall, and we did not all agree. Recently, the IBC included 5 psf for fire walls, not just for interior partitions.

DaveAtkins

 

[SteelPE]

Sorry Dave, I don't have a copy of IBC 18 and didn't realize this is what you were referring to. I was planning on defaulting to the 5 psf anyway. Pretty interesting that they use the word minimum in their definition.... but then again, so does table 1607.1

I wonder if someone who writes the code reads these forums. Maybe that is why it was changed.