Clothing Definitions — definitions of garments and clothing terms from Apparel Search
A pressure suit is a pressurised suit worn by high-altitude fighter pilots and others who may fly so high that breathing pure oxygen at the surrounding pressure would not provide enough oxygen to function, the condition called hypoxia. One type of pressure suit is the spacesuit, which is designed to operate in complete vacuum. The pressure suit exists because the human body needs pressure as well as oxygen: above certain altitudes the air is so thin that oxygen alone, at ambient pressure, cannot pass into the blood fast enough, so the suit supplies the missing pressure mechanically, squeezing the body or enclosing it in pressurised gas.
One type of pressure suit is a spacesuit, which is designed to operate in complete vacuum.
| The above article is licensed under the GNU Free Documentation License. From Wikipedia, the free encyclopedia ( https://en.wikipedia.org/wiki/pressure_suit ). Apparel Industry definition modified by Apparel Search 8/3/06 |
Pressure suits come in two strategies. A partial pressure suit squeezes the body mechanically, with capstans and bladders that tighten the garment against the torso and limbs, countering the body's tendency to swell and forcing air into the lungs under pressure through a mask. It is lighter and less cumbersome, an emergency garment meant to keep a pilot alive during descent after a cabin failure. A full pressure suit encloses the whole body in pressurised gas inside a sealed suit and helmet, a wearable atmosphere that can sustain work for hours. Full pressure suits are bulky and tiring to wear, their joints stiffened by the pressure inside them, which is why suit joint design, constant-volume joints that bend without changing the suit's internal volume, became a discipline of its own in the space programme.
The pressure suit's history runs from the stratosphere balloonists and high-altitude test pilots of the 1930s, through the jet test programmes of the 1950s, directly into the first space suits, which were adapted from high-altitude pressure suits before purpose-built space suits took over. The line of descent is visible in the special suits family: the flight suit provides the base garment, the g-suit adds acceleration protection, the pressure suit adds altitude protection, and the space suit completes the set as a self-supporting environmental suit. Modern high-altitude reconnaissance and test flying still issues pressure suits on the same principle stated in the definition: where a human flies higher than unaided breathing allows, the clothing itself must bring the pressure along.
Because breathing depends on pressure, not just on oxygen content. At great altitude the surrounding pressure is so low that even pure oxygen arrives at the lungs at too low a pressure to pass into the blood in sufficient quantity, and the result is hypoxia: impaired judgement and consciousness. A pressure suit restores the pressure around the body or the airways so breathing works.
They answer different problems of high-performance flight. A g-suit fights acceleration, squeezing the lower body to keep blood in the brain during manoeuvres. A pressure suit fights altitude, maintaining pressure for breathing where the air is too thin. High-altitude flight crews may need both protections, and the suits are worn as parts of one flying clothing system.
Yes, the most complete type. A pressure suit for high-altitude flight works against a thin atmosphere; a spacesuit is a pressure suit designed to operate in complete vacuum, and so it must also be a complete environmental suit, supplying all breathing gas, temperature control and micrometeorite protection as a self-contained system.