Steel

A Memorable Revival

Rebuilding a historic church after a ruinous fire was a project not to be forgotten.

Fire Rating For Sloped Roof Truss Assemblies

Question: 

A question has come up concerning sloped roof trusses and fire assembly ratings. Some are reluctant to rely on test results from flat (parallel chord) trusses applied to sloped roof trusses. Do you have any information regarding the suitability of the fire rated ceiling assemblies for sloped roof trusses? Does the “minimum depth” requirement of the parallel chord assembly apply to the minimum depth of a sloped roof truss (i.e., heel height?)

Information On Truss Fire Issues

Question: 

I am trying to develop a guideline for my firefighters regarding initial fire attack in buildings with light-weight trusses. My concern is truss failure, especially when exposed to fire. Is there any information on failure time related to flame impingement? Any information about truss failure – especially in a fire condition would be helpful.

Fire Rating For Truss Assemblies Built With 2x3 Lumber

Question: 

Are there any published studies or guidelines on the fire rating of floor trusses built with 2x3 lumber?

Duct And Light Penetrations Of Fire Rated Assemblies

Question: 

In a small scale multi-family residential project, I'd like to use a wood truss floor-ceiling assembly to achieve a one hour separation between units. I'd like to directly attach the drywall to the underside of the trusses & use the truss space for ducts & lighting (the floor above will be lightweight concrete on plywood sub-floor). UL assemblies do not seem to address the duct/light penetrations in such an assembly. Can I achieve a one-hour rating in such an assembly and how are penetrations addressed? Can the ducts in the truss space serve both units above and below?

Heavy Timber Connectors

Question: 

I am currently undertaking a project dealing with techniques and methods of joining structural timber members. Do you have any available information on timber connections like split rings and design software?

Post Fire Retardant Treatment

Question: 

Is a Class A fire rating (provided by our liquid spray-on fire retardant) acceptable in certain situations?

Penetration Of Fire Walls

Question: 

Can a roof truss penetrate a one-hr. tenant separation wall without having a one-hr. rated ceiling? The building official insists that the 2x4 chords are combustible and nullify the integrity of the one-hr. rated partition that is constructed in an attic above an 8 in. C.M.U. bearing wall. The partition consists of gypsum board attached to 2 x 4 stud framing. The building official insists that a ledger must be attached through the gypsum board to support the trusses each side of the wall. This is almost saying that any rated assembly must have bearing only on other rated assemblies.

Trusses Exposed To The Elements

Question: 

We are having a house built and on a recent visit we brought along a friend who builds houses for a living. He noticed that the trusses were wet and a bit moldy. The wood seemed warped, brown, and had white splotches on it. We are worried that it would later make the roof uneven. How could we tell how long the trusses have been exposed to the elements? What options do we have from here? Do we request new trusses, or can these be repaired?

Charring Of Trusses

Question: 

Our home caught fire last month and burned partly through a tongue and groove ceiling to the trusses. Some are charred. Our contractor did a moisture meter test. An engineer for the insurance company said the trusses were only smoke damaged & the moisture meter test is invalid (it can be set to read anything). I found one article on charred trusses, but it’s pretty vague. We do not feel safe with the insurance engineer’s assessment because some of the trusses are obviously charred. We hired an engineer who agreed with us.