Cabin pressurization is a process
In which conditioned air is pumped into the cabin of an aircraft
In order to create a safe and comfortable environment
For passengers and crew flying at high altitudes
This air is usually bled off from the gas turbine engines at the compressor stage
The air is cooled, humidified, and mixed with recirculated air if necessary
Before it is distributed to the cabin by one or more environmental control systems
The cabin pressure is regulated by the outflow valve
Pressurization becomes increasingly necessary at altitudes above 10,000 feet Above sea level to protect crew and passengers from the risk of a number of Physiological problems caused by the low outside air pressure above that altitude
Pressurization of the cargo hold is also required to prevent damage
To pressure-sensitive goods that might leak
Expand, burst or be crushed on re-pressurization
The principal physiological problems are listed below
Hypoxia, Altitude sickness, Decompression sickness and Barotrauma
Cabin Pressurization