Steel

A Memorable Revival

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

Fire Damaged Trusses

Question: 

I have been hired by an insurance company to determine the extent of damage to roof trusses exposed to fire. How much fire damage compromises the structural integrity of the truss?

One Hour Fire Rated Assemblies

Question: 

The Gypsum Association “Fire Resistance Design Manual” (GA-600-12) lists file RC2601 with two layers of 5/8 in. gypsum wallboard (GWB) on wood joists.

Uplift Values On Truss Design Drawings

Question: 

I am a building inspector and I have a question on information provided on truss design drawings. What does the uplift reaction number represent? Some manufacturers are very specific and state “to provide for mechanical connection of the truss to the top plate with a connector capable of withstanding a specific load.” Others simply list the uplift reaction with no further information. These are the ones that have caused a debate as to what the number actually represents.

Metal Connector Plates In Fires

Question: 

I am thinking of using wood trusses for the roofing/ceiling structural systems on some houses I shall build. I remember, though, an engineer/volunteer fireman commenting back in 1989 that the connector plates are prone to expand and pop off, early on in a fire, causing catastrophic structural failure. Was this the case, and if so, has this problem been corrected?

Wood Three Hour Fire Assembly

Question: 

Is it possible to construct an assembly for ceiling between first and second floors using 2x with few layers of gypsum to obtain a 3-hour fire rating?

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?