Armstrong limit
The Armstrong limit ( Armstrong limit or Armstrong's line ) describes the altitude in the earth's atmosphere at which the air pressure is so low that water begins to boil at a human body temperature of approx. 37 ° C. It is named after the US Air Force officer and doctor Harry Armstrong.
At sea level at normal air pressure of 1,013.25 hPa , water boils at 100 ° C. The Armstrong limit is around 18,900 to 19,350 meters above sea level , where the atmospheric pressure is around 63 hPa (0.0618 atm ). At this point, body fluids such as tears or lung fluids begin to boil at 37 ° C, and ebullism occurs. That is why humans cannot survive above the Armstrong limit without a pressure suit or a pressurized cabin .
Atmospheric pressure at different heights above sea level :
| Place (height) | Air pressure |
|---|---|
| Sea level (0 m) | 1013.25 hPa (1 atm) |
| Zugspitze (2,962 m) | 691 hPa (0.68 atm) |
| Mount Everest (approx. 8,848 m) | 314 hPa (0.31 atm) |
| Armstrong limit | 63 hPa (0.062 atm) |
Web links
Ebullism at 1 million feet. geoffreylandis.com, accessed October 29, 2015 .
Individual evidence
- ↑ Thin air on Mount Everest. In: LEIFI Physics. Retrieved September 6, 2018 .