Steel Wall Studs and Rafters

[S. Cook]

Anyone have any experience with or knowledge of steel wall studs and/or rafters in residential construction?

[firecapt745]

There is a new residence in my fire district that is being built, and it has both steel wall studs and rafters, too. That is the only one that I know of at the present time. I am going to talk to the owner and try to get some info about it. If I come up with anything, I'll let you know.

[Truckie from Missouri]

There are several homes in my area that are built this way. A couple friends of mine just built one for their respective families, and they both have now been through a winter and have no complaints. Strong windstorms only ripped some shingles off of one. They seem to be pretty tuff.

I haven't been to any fires in them yet. I can only speculate here. I would presume that these houses would behave similar in a fire to any other Type 2 (or what ever a non-combustible structure is called today).

Tactically, I'd still go for life safety in these houses...get in, hit it hard while searching for life, remembering ventilation and all the rest of the tricks of our trade.

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Proud Member of IAFF Local 3133!

Stay safe.
Ken

[stone35]

When steel heats it expands. Granted a 50' sectional I-beam will expand 5+ inches at 1000+ degrees, what will an all steel structure do? how long will it take to fail? does anyone know of any studies?


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Stone35

[Dalmation90]

These scare me!

At least if you use them, you'll put sheetrock over them 'cause otherwise they'd be ugly, and there probably won't be very much fire in the walls...but I have to think steel that thin and under tension/compression from holding up the structure isn't gonna hold up to much heat if it gets in there!

If anyone hasn't seen them, go down to your local home depot and check 'em out...I can see why the contractors love them (much, much lighter than wood!)

[STA2]

The metal studs I have seen are thin. They look alot like the metal type used in strip shopping centers to hold up walls between occupancies. They are NOT solid, atleast not here. They have pre-cast or pre-drilled openings in them for their entire length. As far as metal rafters go they appear to be of the same grade and/or thickness of the studs of the same material. The reasons I have heard that they can be the same grade is because they can make up the difference with more of them to hold the weight of the roofing materials which is more than sheetrock. I have been to fires in metal studded businesses were fire DID travel within the walls because of the paper backed insulation. The one good fire I have seen DID have a very big impact on the studs and the non-load bearing wall bowed and then fell. Thank goodness it was only holding up sheetrock and was not load bearing. I have to believe that the same can be said of metal studs and rafters in private residences. I have also seen an aversion to METAL STUDDED BALLOON CONSTRUCTION if you can believe that. No horizontal fire stopping at all. Just my thoughts. Be safe.

Larry

[CFD SQURT81]

Remember the progression of the way buildings are being assembled. Todays buildings are built to burn and collapse early... metal studding and rafters are a product of economical, lightweight, yet strong building materials. Yes, they are stronger, and hold up better over time, but NO they are not firefighter friendly. They can be conductive of electricity, catastrophically failing under high heat conditions ( just like unprotected steel I beam or steel bar truss, which lose 90% of their strength at about 1400 F ) and being somewhat new, we haven't learned all to be learned about them. Remember, though... Metal trusses, shy of those bastardly gusset plates, are still trusses, and require full integrity to withstand collapse.
Also, as with any metal-use in building subjected to fire, metal E X P A N D S, which can hasten collapse of walls, floors, the roof, or all 3 at once. Expanding metal can also create spaces for fire to travel throughout a building, sometimes going unnoticed until it finds a place to vent.
Another point to ponder is fires within these buildings while they are under construction. While under construction, metal trusses are required to be braced, often by cabling or some other form of bracing. Sometimes, they may not be properly installed, esp. if the jobs isn't going according to schedule or such. Be very careful operating within or around a building currently under construction, as material collapses are possible.

[CFD SQURT81]

Oh yeah, one more thing. I do agree with truckie observation that a lot of the metal studding covered over by drywall/sheetrock have been on non-load bearing walls... especially in recently renovated offices, etc. Good call!

[friday]

There are different grades of metal studs with fall loosely into 2 different categories- structural and non-structural. The non structural stuff is very flimsey appearing and must be cross braced. It draws almost all of it's resistance to twisting and bending from whatever is used to sheath it. The stuctural stuff is a little stronger but is much more expensive (read "you can't make me spend that much"). Metal trusses are death just waiting for you to step under it due to the principle of "remove a truss member and you have no truss" and the characteristic expansion of metal. Ever seen Bar Joists come through the brick veneer of a strip mall? And Bar Joists are much heavier than the sheet metal nightmares available today as well as being welded instead of being pop-riveted or screwed together with sheetmetal screws. Be sure to note this stuff on any pre-plans you do. Capt. Dan