Oxygen masks – things that a plane has to have but hopefully not being used. If you’ve been flying, you know oxygen mask is a precaution for the loss of cabin pressurisation.
A typical commercial aircraft fly at around 31,000-38,000 feet. At this altitude, oxygen is so thin that the human’s body will not sustain. Cabin is pressurised to provide us with enough oxygen to breath while flying. If there is a sudden loss of this pressurisation, we need supplemental oxygen in which this oxygen mask will be our lifesaver.
So, what is behind the oxygen mask? It is not the actual oxygen gas. Why? First, oxygen cans are too heavy for the airplane to carry for all passengers. Second, oxygen gas can be fuel in the event of fire.
So, what is behind the oxygen mask? It is actually a solid source of oxygen known as oxygen chemical generator. Like its name, it is a chemical reaction that produces oxygen.
Above every row of seats on the airplane is the oxygen generator. The generator consists of a safety pin that will unplug when passengers tug their oxygen mask. Inside the generator, it’s a mixture of sodium chlorate, iron powder, less than 5% barium peroxide, and less than 1% potassium perchlorate.
The mixing between sodium chlorate and iron powder in the chamber trigger the decomposition reaction of sodium chlorate produces sodium chloride and oxygen. This is the oxygen gas that we need to survive. However as sodium chlorate has chlorine atom, there is a small chance that gaseous chlorine can be produced. This is why we have barium peroxide that will absorb chlorine.
This reaction is an exothermic one, meaning it produces heat, thus it is normal for the generator to get hot during the time. Smoke can also probably seen too. Not to be panic if you caught up in this situation.
Once the reaction has started, it can’t stop, this oxygen generator will last for about 12 minutes. Short time huh? Not really, it is enough time for pilots to bring the plane to safety, around 10,000 feet where supplementary oxygen is no longer necessary.
Lastly, in the event of an emergency make sure the oxygen mask is covering both of your nose and mouth. Breathe normally and don’t worry if the bag is not inflated.