Stick Or Truss Frame, Fire And Collapse Issue

nywoodwizard

I',m listening to the news the other day, half heartedly, and there is a story about a fire started by a lightning strike on an apartment building, the fire chief makes a remark pointing to some of the collapse because it was a truss style building. never gave it much thought until now , but is truss style build more prone to collapsing in that type of scenario?
I would say yes, all truss components are structurally inferior when separated or burned, one small piece of the puzzle fails ,the whole truss is useless. then when compared to stick frame. I would say mostly for the fact the truss lumber material is much smaller in dimension hence making it more prone to burning up faster and failing?
When i look at new floor truss systems, I'm thinking I'd rather have a 2x10 or better for that very reason. Not a bunch of 2x4's strapped together.

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toolwiz93

Wallmaxx posted a thread with a video about this very topic not too long ago. Look on page two of the threads in the framing section. Looking back on these threads i saw the one about wallmaxx's next roof. I wonder how that one is coming??

neolitic

I always figured that it is an issue
of all the bracing making fire stops
so hard to do properly, that they
are rarely done properly.

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Cole

I agree, here is the thread:
http://www.contractortalk.com/f14/stick-built-roof-vs-trusses-38391/

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nywoodwizard

Thats a pretty interesting video, and basically confirms my beliefs. Kind of worries me a bit for the simple fact that lately there is a small boom of apartment housing going up around me, and it appears most of it is for seniors, guess you can see where I'm going with this, there not exactly the quickest on there feet. 100% is truss, everything prefabbed including the joist/floor system. Almost all are two story probably 4-6 apartments up and down

A fire in these type of floor systems can spread extremely quick. I know all the apartments are equipped with a smoke detectors, but as we seen in the video it only took two a few min for something catastrophic to happen. I wonder if a flame retardant applied on the wooden materials in this type of housing has ever been thought of. The principle of retarding fire on doors, slowing it down with thicker drywall why not consider truss framing as well.
I can't see a confused or disoriented senior making it out of there apartment in under 5 min without some help, some would probably be like others and try to collect and save valuables. Just a thought.

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Chris Johnson

Well this is going to sound very biased...concrete walls and floor systems give you a min. 3 hr fire rating...something to dwell on next time you are concerned about fire hazards and designing a project.

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joasis

I am with Chris....but what would you expect from an ICF builder.

I will have to go and read all this again, but generally, if a fire is that intense, I doubt it would matter that much in roof structures for residential, since interior walls would carry the load in a failure situation....the open floor joists are another matter....however, code requires fire rock or 5/8 rock, like the lower ceiling, and 3/5 or thicker subfloor above, seems like that would be a non issue.

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nywoodwizard

http://www.cdc.gov/niosh/docs/2005-132/

The fire endurance testing is hardly adequate for this type of framing,as admitted by many. it by far does not represent a real life scenario, not for stick framing either but the truss buildings are far more dangerous. I guess cheap and fast over rule safety.

Here i am thinking about the safety of the apartment dwellers and i left out the concern for the firefighters who have to deal with an actuall collapses on themselves as well. The link above has some great insight on this matter.

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Chris Johnson

Did I mention we can do concrete roof systems as well

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cooks

alot of fire departments now days will not let there men enter a building if they know that certain building components are used. such as trusses. the old timers dont agree with it because they were taught to go and give it your all on a fire, but now they just contain the blaze

joasis

I am not buying into this. Sorry, but engineering beats stick built, in my opinion. The example from the video in the past post is great.....but how many homes truly have clear span applications like the example? My point is interior walls and spaces tend to break the span, plus insulation, plus sheetrock are all variables. The examples posted from the CDC report should be compared to the number of fires for the same period, and fire related deaths.

This hasn't changed my opinion, I will continue to use truss systems, and hope no one piles up a bunch of pallets and sets them on fire before the rock is hung.....I wonder how it would go if it was tested in a "finished" scenario, rather then exposed?

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concretemasonry

At least it was not a steel truss system.

Just look at some of the insurance rates for property inside a building with a steel truss system.

Wood systems can be observed and give the fire fighter more time to assess and save people/property because much of the strength loss is proportional to the charring. Steel is a instant, unpredictable failure when it gets hot so fire fighters have to back off sooner.

Still not equal to concrete, of course.

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wallmaxx

Most apartments I have built had sprinkler systems.

Also, the head of the county codes dept. told me that the county fire marshal wanted to get with him to develop a marking / identification system that would be included in the property address to inform the fire dept what type of roof structure the burning building had as they approached the building.

Stick framed by a competent framer - GOOD.
Trusses - bad.

Maybe more stick framing roofs are in my future. That's always a good thing.

PS...according to some fire chiefs...new homes burn more quickly due to all the "ENGINEERED" wood products in them.

nywoodwizard

The pallet comment was funny as hell but, i think most of my concern would actually start at the roof system still, the second story does not have the luxury of a floor system to hold up the roof when it collapse as the first floor would. like i said in my original post, all it took was a stupid lighting bolt. There is no finished burn test for that.
I may not be the brightest candle on the cake but are lightning rods a thing of the past ?
Lets not kid ourselves here, when it comes to cost, we all know sometimes safety is put at the back of the line. slap it up and get paid. keep labor down and profits high?

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joasis

I had coffee today with one of our State inspectors.....and we were talking about waterproofing a basement....I am thinking about using 3lb. spray foam with a PU sealer and then backfilling...so anyway, I tell him that if it wasn't so costly, I would like to do spray foam in my new home, and he said they are doing studies now on it's accelerant properties....like how flammable it is, and in his opinion, he would like to see it outlawed in residential applications...I don't know if all spreay foam is toxic, but the ones based on any polyethylenes are ..food for thought.

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nywoodwizard

After a bit of research i have discovered there is an interior wood available with a fire retardant, trusses also. If i read this right the chemical creates a char making the wood harder to burn thru, in a nut shell.
Seeing something like this is available for all framing and truss parts, I'd like to know the cost comparison with non-treated wood. A few companies involve in wood with fire retardant, but this one caught my eye.


http://www.biewerlumber.com/dricon/dricon.htm also list lumber yards and states that sell it.

I've always had concerns about the spray foams+fires ,nothing good can come from that.

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chris klee

the city of Wilmington, DE banned the use of spray foam fire proofing. it has a UL rating but they think it still burns. dont know if you can insulate with foam as we have not done it.
I have always wondered it there were bad side effects from spray insulation if the house burnt