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Hexayurt rapid deployment

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Hexayurt Project Header see: (3mb) for more information on the expanded hexacomb cardboard approach to rapid deployment

The Shipping Density Problem

Hexayurts are light, but they are not small. An 8' unit (160 square feet) takes 12 4' x 8' sheets, or a package four feet by eight feet by one foot. A 40 foot sea container will only fit 80 units, and that's just not nearly enough.

There is an answer: ship the buildings without the air which provides both strength and insulation, and expand the dense shipping form into buildings at the disaster site / war zone.

It involves developing some new technology, but it is clearly within the scope of the possible, and possibly even the easy, at least in one case.

Materials Options

There are two promising construction materials we have worked with.

The first is modified polystyrene coated with aluminium foil (commonly used in the construction industry for insulating houses - go to any Home Depot and ask for Tuff R by Dow.) That's what most of the units I've made were built from. Thermax HD (good) (cheap)

The other is hexacomb cardboard, used universally in the packaging industry. Hexacomb cardboard looks like an inch thick honeycomb, with the faces covered with nice thick craft paper. In a hexayurt context, a foil facer would be added for waterproofing, and there are a lot of options with this material for additional waterproofing and strengthening treatments. Hexacomb Cardboard from Pregis. These folks have been really nice to me over the years, and incredibly helpful, particularly Mark Jacobson, one of their salesmen with some long standing expertise in using this material in building applications (they used to do it in California in the 1980s).

Either one of these materials can be shipped in a much, much more compact form than 4' x 8' x 1" boards.

Foam Boards From Liquids

The insulation boards could, in theory, be shipped as liquids. The feedstock chemicals would then be mixed on site in a portable factory, either built in a sea container, or built on the back of a very rugged 18 wheeler truck. On site, in a camp or a disaster zone, the truck rolls in, the chemicals are mixed on site and foam up into the board mould, and are coated with the silver foil.

An 18 wheeler can carry around 36 tons of liquids. Assuming 10 lbs of chemicals per board, that's 7200 boards, or 600 units. At UN occupancy densities (3.5 square meters per adult, if I recall correctly) that's shelter for 2700-ish people per truck. That's beginning to look like a reasonable shipping density.

I discussed this idea briefly with Dow Chemical, who know their way around this stuff (Steve Harasim) and they say "it's not easy, but it's plausible. It's not trivial to get good quality consistent product, there are a lot of factors."

Flat Packed Cardboard

see: (3mb) for more information on the expanded hexacomb cardboard approach to rapid deployment

A simpler approach - and this one I'd go as far as to call "easy" is to work with the hexacomb cardboard. Like corrugated cardboard, Hexacomb is flat materials arranged into a 3D form which is much, much stronger. The honeycomb can be shipped "collapsed" - enough material to form the honeycomb center of a 4' x 8' x 1" board is only a few inches in depth. You stretch it out to it's full volume with a simple machine called an expander, which simply grabs the cells of the honeycomb and pulls them open from the flat pack core: it's basically a simple mechanical device.

Then the facing materials - something light, waterproof and tough - either tyvek or aluminium-faced kraft paper are stuck directly on to the open honeycomb, forming the panels. It's basically like shipping corrugated cardboard as a roll of cardboard, then corrugating it on site. Not hard - no fiddly chemistry, just paper, shapes and glue.

Mark Jacobson of Pregis thinks it would be "fairly easy." Fairly easy in this instance is still probably hundreds of thousands of dollars of R&D to a complete production system, but compared to the liquids-and-foam approach, that's cheap. And there are far fewer unknowns than trying to do that kind of chemistry in the field.

Densities for these buildings are going to be a lot lower than the liquid-ship form - my guess is 400 units a truck, but there are some significant unknowns in all of this.

Finally, add a container load of pedal-powered table saws (or a generator and portable table saws, $100 each retail price) to cut the boards, and a crate of tapes per truck.

Three containers of factory, plus one additional container of materials per 2,000-ish people. A chinook helicopter will carry about half what an 18 wheeler will, so we're talking about housing for 1000 people per chinook run.

That's the real approach, but it's a long haul to get there. It could take a generation to get to the point where nobody ships tents except in the rare circumstance that you know people are going to be taken care of in a few weeks.

Developing this kind of technology is, I think, a job for the military.

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