“Armaments, universal debt and planned obsolescence — those are the three pillars of Western prosperity.” — Aldous Huxley, from the utopian novel, Island
Planned obsolescence, in particular, is something that we have come to expect. We buy a car or a television set, and we’re not too surprised if ends up in the junk heap after a decade or so. And up until now, there have been cheap fossil fuels to build new stuff and endless land to deposit it under when it wears out.
It wasn’t always like that, however. Us baby boomers (and our parents) remember when things were made more out of aluminium and steel, and less out of plastic.
And way off in the distant past, we have evidence of things built out of rock and cement that have survived not only centuries, but millennia. There are hundreds of Roman bridges, for example, that are still standing. And many of them are still in use.
In my work, I deal extensively with bridges that have a lifespan of only about 50 years. This is mainly due to a wooden substructure, which even when full of creosote, tends to rot away with the presence of humidity and air.
Nowadays, the use of creosoted wood around water bodies is discouraged, since it is a carcinogen (even though as “coal tar” it is still a significant ingredient in my shampoo bottle . . . go figure).
The other popular wood preservative is chromated copper arsenate. This the greenish hued wood that you find at the lumber yard, often used for constructing outdoor decks, etc. As the name indicates, it contains arsenic, commonly used as poison in old Cary Grant movies.
But an older technology has resurfaced which may allow new bridges to endure the ravages of time in an environmentally sustainable manner. The acetylation of wood was first tried in Germany in 1928. It is a very simple process involving vinegar (acetic acid) and not much else. I have a small chunk of acetylated wood in my office and indeed it does smell like vinegar.
The amazing thing is that if you soak it in water for a week, it won’t swell. It doesn’t uptake water and so it doesn’t expand and contract with humidity. This makes it an ideal material for making doors and window frames, which a company in B.C. is doing.
And the same underlying chemistry that makes it dimensionally stable with humidity also makes it unpalatable to fungus.
Besides window frames, you can make bridges out of it. You can even set a world record for making a 32-metre (105-foot) span wooden bridge with a load capacity of 60 tons (54 metric tonnes).
And you can make it beautiful, since you can work with curvy glulam beams, which is like plywood on steroids (and which in Red Deer, can be seen in the sanctuaries of at least two churches that I know of: Sunnybrook United and Deer Park Alliance).
How beautiful can you make a huge glulam bridge? Check out “bridge”, “Sneek” (the location of the bridge in the Netherlands), and “accoya” (the acetylation process) in a search engine. If you like the aesthetics of a woven basket, you’ll love the aesthetics of this bridge.
The final advantage of acetylated wood is that it effectively sequesters CO2 into a structure that will last many decades, if not centuries (as mentioned above, the process was only developed 82 years ago, so we really don’t know how long the wood will last). And unlike tropical hardwoods, which are used to make tough, long-lasting items, acetylation can be done with fast growing boreal species such as pine.
So, not only do you get a useful structure, but you have the assurance that it won’t be fouling up the environment or requiring a replacement in the near future. I think our great-grandchildren would approve.
Evan Bedford is a local environmentalist. Direct comments, questions and suggestions to wyddfa23@telus.net. Visit the Energy and Ecology website at www.evanbedford.com
