Tarpaulins are critical supplies for disaster relief and humanitarian aid, serving as cover, shelter, carpet and all-round utility infielder.
Until 1996, aid groups either used cheap tarps that disintegrated quickly in the sun and wind, or splurged for high quality, high priced tarps from the Danish company Monarflex, which holds the patent on eyelets at the corners of tarps, and charged monopoly prices for their goods.
When the UN High Commission for Refugees decided to put out a spec for long-lasting tarps, it put Patrick Oger, a purchasing officer for Doctors Without Borders, in charge. Oger befriended a Monarflex engineer who tutored him on plastics manufacturing, and devised a set of improvised stress-tests for different kinds of tarp that helped him come up with a spec that is now in use all over the world: woven (not braided) tarps, made from black plastic that's been painted white, with unpatented fastener-bands.
Rubber is naturally white, but tires contain carbon black, a pigment that absorbs all visible light as well as UV light—which breaks down plastic. The pigment in the tarp's black fibers was absorbing the UV rays and protecting the plastic. No such luck for the clear fibers, though.
Solution: black tarpaulin. Right? But "if you have a house, nobody is going to be paint it with black paint," says Oger. "People don't live in black houses." Plus, black tents get sweltering in hot climates.
So Oger went out with a thermometer to a field near Doctors Without Borders' logistics center in Bordeaux, France and pitched tents in different colors: aluminized white and blue (for the UN), and a matte white. The aluminized colors kept the tent cool at first, but their reflectivity soon wore off, leaving them hotter than the white tents. The standard tarpaulin is now made of black fibers, painted white on both sides.
During his tests, Oger would also drive out to a military antennae field near the ocean, where he tied small rectangles of tarpaulin onto poles to flap in the coastal wind. Tarpaulin can be braided or woven, and the braided tarpaulins shredded in weeks. Woven it was. Finally, Oger got rid of the eyelets.
The Inside Story of an Aid Worker's Secret Weapon: The Tarp [Sarah Zhang/Wired]
