Long Span Truss Roofs

[LeeJunkins]

I am working on a class on Long Span Truss Roofs, I would like to hear some of your comments,experiences, and expertise on the subject. The good, the bad, and the ugly,and how you dealt with them.

[firefiftyfive]

DON'T GO ON THEM!!! thats all I got!

[MemphisE34a]

DON'T GO ON THEM!!! thats all I got!

Well its not quite that easy, but the right generalization. Plenty of other factors to consider. The above statement is actually more accurate if you add, "large, unsupported spans utilizing prefabricated truss roof construction."

[LeeJunkins]

Well its not quite that easy, but the right generalization. Plenty of other factors to consider. The above statement is actually more accurate if you add, "large, unsupported spans utilizing prefabricated truss roof construction."

Well let's add them then, because they are a big part of the class.

[MrYuk]

There is a post floating around somewhere about this. There was a link to a good article explaining the structural integrety of a truss and how they are not as dangerous as everyone has been led to beleive. If I find the post, I will put it on here.

[MrYuk]

Here is the article:

http://www.firetimes.com/story.asp?FragID=12278

Also here is the forum. There is a little conversation about it:

http://forums.firehouse.com/showthre...ighlight=truss

[MemphisE34a]

Well let's add them then, because they are a big part of the class.

Many people seem to forget, or not realize that lightweight, prefabed construction is the norm in residential buildings as well as commercial. You never hear people exclaiming that they will NOT go into house fires because they have lightweight, wood truss roof construction. In most of these situations, the roof will burn away before it fails.

Again, it is only a problem when lightweight, prefabricated truss assemblies cover a large unsupported span. We use a general rule of 20'-25' of attic space with no interior walls before we worry about it.

[LeeJunkins]

Here is the article:

http://www.firetimes.com/story.asp?FragID=12278

Also here is the forum. There is a little conversation about it:

http://forums.firehouse.com/showthre...ighlight=truss

Thanks I was reading this article at the same time you were posting this.

I would like to find a copy of the testing he was telling about that Huston FD done.
I do agree with them about the way the plates come off, I have studyed on these quite extendsively. We have heard for years that the plates would warp from the heat and the warpping would cause them to pull out of the wood. Not so, in fact the plates transfer the heat by conduction to the teeth and the teeth then burn the wood around them and the plates fall off.
I have a good clear picture, in my slide show, of a lot of the plates that fell off the trusses in a church fire, that my own department lost three men in, and every one of them looks to be perfectly straight, no warpping, no teeth bent.

[MrYuk]

I would like to find a copy of the testing he was telling about that Huston FD done.

I can ask a few guys I know at the academy and see if they know anything about the testing. If I find anything out, I will be glad to let you know.

[LeeJunkins]

I can ask a few guys I know at the academy and see if they know anything about the testing. If I find anything out, I will be glad to let you know.

Thanks that would be great