What altitude = triple point of H20 on Earth?

[Cfidel99]

Just curious about this one:

Since we understand h20's "triple point" to be 0.006 atmospheres, and the fact that elevation has an effect on atmospheric pressure, at what elevation on Earth(if any) would h20's triple point occur?

[StusBlues]

Are you referring to this:

http://www.straightdope.com/columns/read/2162/how-can-water-turn-to-vapor-below-the-boiling-point

Pardon my ignorance of fluid dynamics, but you've lost me, mate.

[naita]

From this table it looks like it's close to 40 thousand meters altitude.

http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html

[naita]

While according to this: http://www.coolmath.com/calculators/atmosphere-calculator.htm

it's 34500m

[naita]

But you'd also need a heater...