
Wood That Reaches New Heights - J3L2404
http://www.nytimes.com/2012/06/05/science/lofty-ambitions-for-cross-laminated-timber-panels.html
======
anusinha
The tricky thing about wood is that it's carbon neutral but still (often) a
bad material to use.

It's carbon neutral because when you burn it, all the CO2 released from the
combustion reaction originally came from the air. But it's often a bad
material to use because many forests aren't harvested in a sustainable manner.
The situation is better in Europe and North America, but in many parts of the
world, far more trees are cut down than are planted which is clearly a bad
thing. Using it as a building material is certainly a good "sequestration"
technique.

~~~
sneak
> It's carbon neutral because when you burn it, all the CO2 released from the
> combustion reaction originally came from the air.

By that logic, so are gas and oil. Earth itself is carbon-neutral.

~~~
ktizo
But your atmospheric concentration can vary. We could get back to the same
atmospheric concentration of CO2 as it was when the oldest oil was laid down,
but that doesn't mean we would like it. The earth itself would probably be
fine though, and on a long enough timeline it might give a chance to some
giant intelligent spiders, or something.

~~~
sneak
> The earth itself would probably be fine though

I giggle at your ethnocentrism and hubris.

~~~
ktizo
Why, thank you. If I can manage to be ethnocentric and hubristic, while
simultaneously putting forward the idea that we are unimportant on a long
timescale and that giant intelligent spiders might eventually be the dominant
form, then I must be doing especially well, even by the exceptional standards
of our particular group of apes.

~~~
sneak
It was the "probably". :)

~~~
ktizo
I'm not ruling out giant marauding space worms that get attracted to the CO2
enriched atmosphere and end up breaking down the entire crust into sterile
lumps no bigger than a tortoise, before then leaving for fresh new planets to
scour of all life. Not over that sort of timescale anyway. Over that sort of
timescale, 'probably' is all we've really got.

------
RandallBrown
This seems somehwat similar to the way that Intamin (a rollercoaster company)
builds their wooden coasters. They machine all the sections of track in their
factory, then send them to the construction site, just like with steel tracked
coasters. Before, the way they did it was to just build the track using
boards, which led to a rougher ride that made it harder to do some things like
crazy banked turns and sharp drops.

Wood. Good stuff.

------
andrewcooke
a lot more info here (technical + photos) -
[http://eoinc.weebly.com.nyud.net/uploads/3/0/5/1/3051016/mur...](http://eoinc.weebly.com.nyud.net/uploads/3/0/5/1/3051016/murray_grove_case_study.pdf)

~~~
nosse
They actually made "floating floors" from concrete panels. I was wondering if
it's still possible with wood. Question is what will happen if some water gets
below the concrete. I guess it's self drying as there is void between ceiling
and wood structure.

------
nosse
Given weight of wood against same weight of steel have equal strength. Large
wood structures do not collapse in temperatures over 600C like steel. Wood is
not as brittle as concrete, which greatly reduces dangers of earthquakes.

Problems come from large fires, where wood can act as a fuel. Western world
hasn't seen a city burning for a long time and even then it was because of
napalm. That might change if wood takes on.

Second big problem is moisture, wood can change it's shape greatly with
moisture.

~~~
ajross
> Large wood structures do not collapse in temperatures over 600C like steel

Um, no... no, they don't. :)

Wood turns into a blackened crust of carbon at about 250C. That is, before it
erupts into a tower of flame. It's true that it won't collapse before it will
burn. But it will burn _long_ before an equivalent steel structure collapses.

But that seems treatable to me. Fire suppression is pretty robust in modern
buildings. I think this is great too. But... not at 600C.

~~~
nosse
The point is that in typical apartment fire, the temperature rises to at least
to 800C. Steel has good thermal conductivity, and therefore steel structures
start to bend greatly when temperature hits 600C in a single floor. This
usually causes a collapse. It's very important to quickly evacuate steel
building if it's on fire.

With massive wood structures the situation is different. The wood is very good
heat insulator, so if the skin gets to 1000C the inside might still be lot
less than 250C. Wood doesn't burn that quickly as it has to evaporate first
(we usually call this smoke) before it can burn.

Of course this is all dependent of scale. If you try this out at your
fireplace with something that fit's there, the story is completely different.

My info comes from Helsinki university of technology construction material
lectures. So I can't really paste sources here.

~~~
nosse
I really don't get the down-voting here. Did I say something that is no true?

------
balsam
possible in NYC/SF? given the fire-safety regulations. How are the regulations
in the UK, given this article?

