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  1. #1
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    Default Truss Roof Video

    Good video got passed to me today on a demonstration done with a wood truss roof and its collapse under fire condition with a load placed on the roof also.

    Link to view video is http://fire-forums.com/forums/showthread.php?t=654


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    just further reinforcement that you shouldnt stand directly over, or under, a roof thats on fire.


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    Forum Member volfirie's Avatar
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    Not just a roof - trusses are being used for 'support' of floors in multiple storey residences. Here they are lightwieght pine with gang-nail gussets, not exactly confidence inspiring. For the USA I've seen pictures of seemingly equal lightweight trusses with 'groove and finger' joints, glued of course.

    I think the construction industry is out to kill us my friends...
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    Quote Originally Posted by volfirie View Post
    Not just a roof - trusses are being used for 'support' of floors in multiple storey residences. Here they are lightwieght pine with gang-nail gussets, not exactly confidence inspiring. For the USA I've seen pictures of seemingly equal lightweight trusses with 'groove and finger' joints, glued of course.

    I think the construction industry is out to kill us my friends...
    Just over 400 degrees F. That's the temp at which the glue fails. The newest trend in light-weight construction here is NO gang-nails or gusset plates...Just the damn glue!

    Trying to kill us? Hell, they ARE killing us!
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    Quote Originally Posted by volfirie View Post
    For the USA I've seen pictures of seemingly equal lightweight trusses with 'groove and finger' joints, glued of course.

    I think the construction industry is out to kill us my friends...
    Here is a youtube video of what you are talking about http://www.youtube.com/watch?v=KWc8TSaDIG8

    We have a group of townhouses that just went up in our area built with these for the floor, and we have it in our preplan for that area that these are whats supporting the floor and not the regular gusset plate trusses.
    NJ FFII/EMT-B

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    MembersZone Subscriber dadman's Avatar
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    The first video is a good demonstration of truss vs. stick.
    A better comparision could have drywall to simulate a ceiling and to enclose the 2 open side areas. Have four enclosed walls to contain the heat.

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    Forum Member ThNozzleman's Avatar
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    Trying to kill us? Hell, they ARE killing us!
    Baloney. We're killing us...not the evil construction industry.

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    Forum Member Slaytallica45's Avatar
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    Quote Originally Posted by ThNozzleman View Post
    Baloney. We're killing us...not the evil construction industry.

    Not always, I dont think its our fault that we get on scene to a fire in 5 minutes and roof is already gone, or close to being...
    NJ FFII/EMT-B

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    Forum Member ThNozzleman's Avatar
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    Not always, I dont think its our fault that we get on scene to a fire in 5 minutes and roof is already gone, or close to being...
    It is our fault for not recognizing the signs and knowing what and what not to do in that situation. Most of the hysterics about the dangers of truss roofs is just that...hysterics.

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    MembersZone Subscriber dadman's Avatar
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    Fire Performance of Wood Trusses
    http://www.carbeck.org/fire_performance.php

    Information for Firefighters
    http://www.carbeck.org/info_for_firefighters.php

    A CD and info packet which I got for free or cheap from somewhere in FF Close Calls(?).
    Wood Truss Construction and Fire Performance on CD: This CD addresses some long-standing misconceptions on trusses and presents the facts on wood trusses and how they behave under fire conditions. Topics include an overview of truss history, truss manufacturing and applications; exposure to fire; ASTM and fire testing; standardized fire testing; and information for firefighters to help them more safely fight fires in buildings constructed with wood truss components. (18 modules, total of 3 hours)
    http://www.carbeck.org/pubs/catalog....tegoryID&ID=18

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    Quote Originally Posted by dadman View Post
    Fire Performance of Wood Trusses
    http://www.carbeck.org/fire_performance.php

    Information for Firefighters
    http://www.carbeck.org/info_for_firefighters.php

    A CD and info packet which I got for free or cheap from somewhere in FF Close Calls(?).
    Wood Truss Construction and Fire Performance on CD: This CD addresses some long-standing misconceptions on trusses and presents the facts on wood trusses and how they behave under fire conditions. Topics include an overview of truss history, truss manufacturing and applications; exposure to fire; ASTM and fire testing; standardized fire testing; and information for firefighters to help them more safely fight fires in buildings constructed with wood truss components. (18 modules, total of 3 hours)
    http://www.carbeck.org/pubs/catalog....tegoryID&ID=18
    +1 alot of good info at carbeck!

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    MembersZone Subscriber dadman's Avatar
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    Quote Originally Posted by LeatherHed4Life View Post
    +1 alot of good info at carbeck!
    Looking at the info there, videos and pics, it appears the sheathing failure may be what gives trusses their bad name. Also, subfloor material may be a factor.
    Drywall covering, or lack of it, is a factor in truss failure.
    From what I saw there, the trusses tested were the gusset plate type.
    I'm not aware if they did any glued truss testing.
    Would like to see some similiar thorough testing on engineered wood I-beams.
    The floor fire test on top of a boxed furnace was realistic and impressive.

    Be careful of whatever the floor or roof is made of.

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    Forum Member KEEPBACK200FEET's Avatar
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    I posted this sometime ago, but it's always a good refresher and a great video for anyone who hasn't seen it before.
    Just know, I chose my own fate. I drove by the fork in the road and went straight.

    Quote Originally Posted by FlyingKiwi View Post
    Go put your pussy 2 1/2" lines away kiddies.

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    By the way KEEPBACK200FEET, you're so dramatic!

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    Quote Originally Posted by dadman View Post
    Looking at the info there, videos and pics, it appears the sheathing failure may be what gives trusses their bad name. Also, subfloor material may be a factor.
    Drywall covering, or lack of it, is a factor in truss failure.
    From what I saw there, the trusses tested were the gusset plate type.
    I'm not aware if they did any glued truss testing.
    Would like to see some similiar thorough testing on engineered wood I-beams.
    The floor fire test on top of a boxed furnace was realistic and impressive.

    Be careful of whatever the floor or roof is made of.
    EXACTLY! that and floor truss systems are required and designed to hold less PSI than a roof truss. I have been told that a new std in roof construction is the truss system is required to hold 1.5 times the load needed, in case of failure, it can maintain the load.

    Fire engineering did an article on the engineered wooden i beams with 2x6 cords and osb in the middle. the results were NOT good. less than 10 minuted to failure after exposure to fire conditions. That is not to say 10 mins total, but when was the last time you saw 1 hr drywall last 1hr ? hell, even 15 min.

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    Forum Member volfirie's Avatar
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    Truss-built house fires are easy and safe to fight! Just surround and drown...
    "Professional" means your attitude to the job...

    Nullus Anxietas ..... (T Pratchett)

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    Quote Originally Posted by ThNozzleman View Post
    It is our fault for not recognizing the signs and knowing what and what not to do in that situation. Most of the hysterics about the dangers of truss roofs is just that...hysterics.
    While we should all recognize the hazard of truss roofs, I beg to differ about being hysterical about the danger of truss roofs.

    The Hackensack Ford Fire: Five Brothers killed in a truss roof collapse.

    Orange County, Florida: Two Brothers killed in a truss roof collapse.

    Houston, Texas: A Brother and a Sister were killed in a truss roof collapse at a McDonald's.

    There are many more, I just can't remember them all.

    The key is getting the asses out of the recliners and driving around your first due districts noting any new construction and what they are building the structures with. Information has to be shared with other companies!

    We had a fire in a McMansion in February. The first due engine arrived within 3 minutes; the Lt. reported heavy fire showing and went defensive right away. A scant 2 minutes later, the roof collapsed, sending the second floor down crashing into the first floor level!!!

    The house was built using lightweight wood construction.

    There are those with the "booksmarts" and certifications up the wazoo who will not attack a fire in a balloon frame becuase it is "dangerous", yet they will charge into a McMansion as if it were a doghouse on fire!
    ‎"The education of a firefighter and the continued education of a firefighter is what makes "real" firefighters. Continuous skill development is the core of progressive firefighting. We learn by doing and doing it again and again, both on the training ground and the fireground."
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    Forum Member ThNozzleman's Avatar
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    While we should all recognize the hazard of truss roofs, I beg to differ about being hysterical about the danger of truss roofs.
    All aspects of firefighting can be dangerous. It is not the responsibility of the construction industry to keep us safe. Just how far do we go in blaming an inanimate piece of engineering for our mistakes or operational choices? It's not like we don't know truss construction isn't out there in abundance. Most of the scientific based studies I've seen have shown that stick built roofs perform pretty much the same, or worse than truss construction with modern day lumber (light weight pine, usually). The houses and buildings out there with good ol' sawmill oak framing are disappearing rapidly. We burned one old house with oak rafters that we had been using for training this past weekend. I was surprised at how quickly the roof above the seat of the starter pile went once the fire moved into the attic. Of course, the shingles and tar paper were removed, allowing the fire to get a grip around the exposed pine planking as it vented through the cracks. The much ballyhooed ridgepole in this seventy year old house was a mere 1" x 6" plank that was scabbed over in several places. So much for relying on that to support much of anything.
    We had a fire in a McMansion in February. The first due engine arrived within 3 minutes; the Lt. reported heavy fire showing and went defensive right away. A scant 2 minutes later, the roof collapsed, sending the second floor down crashing into the first floor level!!!
    Good call on the Lt.'s part. Anything that collapses like that, lightweight or not, would have to have been burning for some time, I would think.
    There are those with the "booksmarts" and certifications up the wazoo who will not attack a fire in a balloon frame becuase it is "dangerous", yet they will charge into a McMansion as if it were a doghouse on fire!
    Never figured that one out, either. Of course, over the years, the same irrational reaction towards the behavior of trusses in fire has been applied to balloon frame construction as well.
    The key is getting the asses out of the recliners and driving around your first due districts noting any new construction and what they are building the structures with. Information has to be shared with other companies!
    Exactly. I guess I tire of firefighters coming back from training sessions at academy terrified to death of a truss. "Don't trust a truss" they are told...over and over. Does this mean they trust a rafter? Or a floor beam? Or any piece of engineering subjected to fire? As you wrote, information and awareness is the key...along with experience and responsible training. Not irrational fear of a piece of engineering. The truss (and other engineered structural components) is here to stay.

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    Forum Member DeputyChiefGonzo's Avatar
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    In a fire condition, I will trust the structural integrity of a rafter and solid floor joists over engineered wood anyday of the week!
    ‎"The education of a firefighter and the continued education of a firefighter is what makes "real" firefighters. Continuous skill development is the core of progressive firefighting. We learn by doing and doing it again and again, both on the training ground and the fireground."
    Lt. Ray McCormack, FDNY

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    Are you suggesting that the construction industry should receive no input from the fire service? It's not just firefighters that are endangered, it's also the occupants of the building. Regardless, you know as well as I do that we're going in if we think viable victims are inside. When I see industry websites like this (lightweight steel trusses):

    http://www.precisionsteeltrusses.com...el_trusses.php

    it doesn't engender much respect for the construction industry.

    For those who don't feel like clicking on the link:

    "Reduce or eliminate attic sprinkling systems and other code requirements needed with combustable materials"

    So yes, of course we should have a voice when it comes to building codes.

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