Wood That Reaches New Heights(nytimes.com)
nytimes.com
Wood That Reaches New Heights
http://www.nytimes.com/2012/06/05/science/lofty-ambitions-for-cross-laminated-timber-panels.html
6 comments
> 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.
By that logic, so are gas and oil. Earth itself is carbon-neutral.
Gas and oil are very slow to be regenerated. wood takes significantly less time. I wasn't clear enough originally; I really meant neutral with a short cycle duration.
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.
> The earth itself would probably be fine though
I giggle at your ethnocentrism and hubris.
I giggle at your ethnocentrism and hubris.
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.
It was the "probably". :)
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.
With laminated woods you also have to take into account the glues used in the lamination process. While there might be some carbon-neutral glues out there, how many laminated wood products actually make use of them?
Hello from Finland. Our country produces more wood than we cut. With paper industry going down, I'm sure we are happy to export.
Could you suggest better alternatives to shelter ourselves ?
Old growth forests are not suitable for building material. All of these wood panels came from plantations that are re-planted immediately after harvesting, often from places where there was no forest before.
Exactly, that's why engineered wood products are so appealing. Where old style construction would require long, single timbers from 80+ year old trees, products like MDF, OSB and this thing can be done with much younger trees, which yield more net wood volume per acre of farmland per year.
True. But MDO and CDX can both be made from younger trees and although they are more expensive they are much more durable due to being layers of wood as opposed to glued fibers. LVLs are another good example.
Edit: For DIY projects never use MDF or OSB. These products are for production building and are very unforgiving for weekend projects. And dustier.
Edit: For DIY projects never use MDF or OSB. These products are for production building and are very unforgiving for weekend projects. And dustier.
The amount of carbon which could be sequestered, or otherwise, in all the buildings of all of the world is a miniscule portion of the Earth's total carbon budget.
You're being disingenous here. Human emissions are also a miniscule proportion of the Earth's total carbon cycle.
In the United States in 2008, CO2 emissions per capita were 17.5 tonnes. That equates to roughly 4.76 tonnes of carbon, which requires 9.53 tonnes of wood to capture (wood is about 50% carbon).
If the US could grow 9.53 tonnes of wood per capita per year, and sequester it, it would be carbon neutral. For comparison, US wheat production in 2008 was 218kg.
The US has 190 million acres of forests, which according to the EPA grow about 2 tonnes per year until they mature at ~200 tonnes (probably not linearly). This is only 1.22 tonnes per person per year, even if you devoted all the current US forests to the task. However, tree farming could likely grow a significantly higher tonnage of wood per year with the same land.
Using 9.53 tonnes of wood per year, if you've got access to it, is actually not that hard. A decent sized house can easily weigh 100-200 tonnes, and current home builds are trying to minimize weight (and thus cost).
It's not a silver bullet, but it would make a noticeable difference to the bottom line.
I haven't listed references here (I'm on my laptop and it's quite cumbersome), but I urge you to do back of the envelope calculations before you talk about this stuff. There's already way too much misinformation flying around.
In the United States in 2008, CO2 emissions per capita were 17.5 tonnes. That equates to roughly 4.76 tonnes of carbon, which requires 9.53 tonnes of wood to capture (wood is about 50% carbon).
If the US could grow 9.53 tonnes of wood per capita per year, and sequester it, it would be carbon neutral. For comparison, US wheat production in 2008 was 218kg.
The US has 190 million acres of forests, which according to the EPA grow about 2 tonnes per year until they mature at ~200 tonnes (probably not linearly). This is only 1.22 tonnes per person per year, even if you devoted all the current US forests to the task. However, tree farming could likely grow a significantly higher tonnage of wood per year with the same land.
Using 9.53 tonnes of wood per year, if you've got access to it, is actually not that hard. A decent sized house can easily weigh 100-200 tonnes, and current home builds are trying to minimize weight (and thus cost).
It's not a silver bullet, but it would make a noticeable difference to the bottom line.
I haven't listed references here (I'm on my laptop and it's quite cumbersome), but I urge you to do back of the envelope calculations before you talk about this stuff. There's already way too much misinformation flying around.
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.
Wood. Good stuff.
a lot more info here (technical + photos) - http://eoinc.weebly.com.nyud.net/uploads/3/0/5/1/3051016/mur...
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.
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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.
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.
> 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.
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.
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.
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.
I really don't get the down-voting here. Did I say something that is no true?
possible in NYC/SF? given the fire-safety regulations. How are the regulations in the UK, given this article?
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.