New construction technique/materials

[efermann 28]

I was reading the newspaper today at school and came across the article linked below about cross-laminated timber (CLT) being used in construction in Europe. Seems very different than typical stick construction and different still from light-weight construction. Either way, it's allowing wood /timber buildings to be built taller than previously.

The article mentions that this construction hasn't taken off in the US, but if/when this construction works its way to the US, it will probably have an impact on tactics and fire spread (with the apparent lack of void spaces within walls).

1st link to the article: http://www.nytimes.c...gewanted=1&_r=1

2nd link to the large graphic image with some summary information for those that don't want to read the whole article: http://www.nytimes.c...tml?ref=science

[SageVigiles 1,194]

Thanks Cap, I'm going to post this in a few places as an FYI.

Anybody in the Fire Marshal world see anything like this coming down the pike?

[JetPhoto 626]

Very Interesting, I'll have to search YouTube later to see if thier are any videos the FD's may have made showing burn examles. I know it will eventually come to the US where it will have to pass test before it's used and then factorys would have to be tooled for the wood manufacturing and then put out on the market for people to build with where initially will be expensive. So I think it may be a few years before it becomes common in the states.

Good find.

[SageVigiles 1,194]

The diagram says the multiple layers of wood add strength under fire conditions, which from a fire science standpoint makes sense.

Personally I wonder what effect will the heating have on the glue that holds the panels together?

The panels get put together with metal brackets and screws, but will contractors try to cheat there and use cheaper screws? Will some form of oversized gusset plate get approved to use as an alternative?

The idea of a wooden high-rise building just doesn't sit right with me.

[rayrider 94]

It looks like a challenge for electricians running wire as well as plumbers doing piping. Less fire spread in voids but will this deck of cards type construction fail after intense fire?

[ny10570 745]

With this type of structural building material you can easily engineer the building to transfer loads in the event of failure. Its no different than using precast concrete or steel. I'm worried about the glue used to build these pieces. Large diameter timber is great because it is a solid contiguous material. This stuff is laminated. Is the glue flammable? Does the glue fail when exposed to heat? If the glue fails under heat then as you heat the material it will separate and no longer be a single solid member (bundle of sticks vs solid log). If the glue is flammable then you have a bundle of sticks coated in gasoline. Since this is the problem plaguing all current engineered lumber products I'm going to assume this stuff is another disaster waiting to happen. These structures are going to need serious sprinkler systems and multiple exits.

[SageVigiles 1,194]

I got an answer back from a Deputy Fire Marshal in CT.

The building code limits the height/number of stories in new construction based on construction type. Unless they come up with some approvals for pretty hefty fire rated assemblies with this stuff, that should cap the height of these buildings as no higher than any other wood framed structure.

[antiquefirelt 994]

This is interesting and likely will become viable here in the U.S. As has been mentioned the first concern that's pops up is the adhesives resistance to heat. The fact that the these panels provide a large single face for fire to attack vs. standard framing that allows multiple surfaces to be affected simultaneously lends to potentially higher inherent fire resistance ratings, but it's all for not if the adhesive fails and the pieces delaminate.

[16fire5 693]

Large diameter timber is great because it is a solid contiguous material.

Unfortunatly this is no longer a safe assumption. Tests done by UL show that contemporary dimensional lumber fails much earlier than the old dimensional stuff. An new 2X10 fails faster then an old 2X8 (I know the the old one is really 2X8). It has more to do with how lumber is harvested today(old growth vs. new growth). When the structure was built is a big size up factor. Although we love to complain about balloon construction it really dosen't have close to the collapse potential early in the inciden compared to the modern stuff out there. Of course you need to be aware it travels vertically and horizontally unimpeded. If you haven't done so go to UL's site and go through the self guided training programs. Some are dry material but it is essential stuff that could save your life.

http://www.ul.com/gl...ses/structural/

Edited June 8, 2012 by 16fire5

[ny10570 745]

Absolutely, old vs new old holds up much better. Old timber is substantially heavier and denser than anything sold today. Not to go off topic, but its the same reason instrument craftsmen go nuts for old reclaimed lumber. The old growth wood used to have a much denser and stronger structure.

I'm simply comparing new to new. Modern solid timber vs laminated engineered lumber.

[Stepjam 118]

I know a couple of European firefighter friends (Dutch) who were simply flabbergasted at our mostly-wooden residential construction. I won't repeat some of their comments here, but suffice to say that in Europe, load-bearing exterior walls and most especially, partition walls seldom rely on lumber and aren't faced with plywood, particle board, or sheet rock. But there are arguments to be made for either technique.

[Bnechis 3,961]

I know a couple of European firefighter friends (Dutch) who were simply flabbergasted at our mostly-wooden residential construction. I won't repeat some of their comments here, but suffice to say that in Europe, load-bearing exterior walls and most especially, partition walls seldom rely on lumber and aren't faced with plywood, particle board, or sheet rock. But there are arguments to be made for either technique.

They also make their telephone poles out of concrete. It is not because of fire, is because they cut down most of their forrests to burn, build ships etc. and how much was destroyed in multiple wars. That is the main reason that 200 years ago they wanted to control No. America...timber.

[wraftery 1,275]

Brannigan said that it is not necessarily the members that fail, it's the connections.

I think I would pay as much attention to how these members are connected as I would pay to what they are made of.

[Stepjam 118]

They also make their telephone poles out of concrete. It is not because of fire, is because they cut down most of their forrests to burn, build ships etc. and how much was destroyed in multiple wars. That is the main reason that 200 years ago they wanted to control No. America...timber.

True that. They also make their snow tires out of real snow.