3 Jul
2011
3 Jul
'11
5:44 p.m.
Not in space, but on a plane. The air pressure in an
aircraft cabin at
altitude is significantly less than 1atm, so most good air-tight equipment
cases will have one of these knobs. The military even has air-insulated
boots for use in the arctic that have a valve on them so they don't crush
your feet when you're flying.
Not only that, but with such a good seal, if the cases are opened then
closed at low pressure (high altitude), then shipped to sea level,
they will not open without pressure equalization.
--
Will