My High Tech Research: Continued

One of the common tests used in my field is an ASTM E 96 Test ("Standard Test Methods for Water Vapor Transmission of Materials"). Vapor (er, vapour, here in Canada) permeance is basically how "breathable" a material is to water vapor--i.e., why Gore-Tex works, and using a plastic garbage bag as a raincoat sucks. Pemeance is measured in the most annoying units ever: the U.S. version (Perms) is grains / foot²*hour*inch Hg, while the metric version (Metric Perms) is nanograms / meter²*second*Pascal. The units of in Hg (inches of mercury) or Pa is the water vapor pressure difference across the material you're measuring. Ack.

So I'm running one of these tests myself, for the first time. What does this test look like? Well, something like this:



Yes, in fact, the test specimens are foil taped to off-brand tupperware (read: impermeable sample container) with openings cut through the lid; the lid is sealed to the container with foil tape. But hey--my results so far are pretty good.

Also, I had the nice experience of finding that my previous work is paying off. The Coke fridge that I turned into a temperature/humidity controlled chamber (story behind it here) is performing bang-on.

I have to babysit this experiment: I go in twice a day (typically morning and then after dinner). It's a bit annoying, but will only be a few more days.