Many people don't realize that the air in the air tanks on the backs of firefighters or those worn by divers is not oxygen, but the same air we breathe every day. The difference is that the air is compressed as it is put in those tanks but the properties of the air are the same. The purpose is to allow firefighters and divers to breathe as normally as possible in the environment they operate in so keeping the contents of the tank just like the air we breathe daily is important.
Air Filtration And Purification
One difference that the air in SCBA (self-contained breathing apparatus) and SCUBA (self-contained underwater breathing apparatus) tanks contain is that it is filtered. Because dust and other particles can settle in the compressor intake lines, the air is run through a high-grade filter that will take out foreign matter. The idea is not to purify that air, it is simply to ensure that the air does not contain debris that could cause the regulator or hoses to become clogged and inoperable. A diver down 100-feet with a stuck regulator is in serious trouble. Likewise, a firefighter in a burning structure would very likely be injured or even killed if his SCBA did not work properly. The filtration is important and if you have tanks being filled without it, find a new location to fill your tanks. It is not worth the risk that comes with it for a paper filter that likely costs a couple dollars.
Drying The Air
One of the side effects of compressing air is the creation of condensation or water. When the air is compressed, if there is no dryer in the system, that condensation or water ends up inside the tank being filled. There is no way to get it out so it comes out through the hoses and regulator. Compressed air is cold and as it is released from the tank, it can cause the water in the air to freeze. If that happens, the regulator can become frozen and the moving parts inside will not work, causing a complete failure of the unit. Without a working regulator, the wearer will not be able to get air from the tank. The air must be dried as it is being compressed so, in most systems, the dryer is installed just upstream from the hose used to fill the tank.
Ensuring You Are Getting Filtered And Dried Air In Your Tanks
While it is true that most people will not be running into a burning building anytime soon, the possibility that you may want to take a scuba class or do some sports-diving is very real. The best way to ensure that the air in your tanks is dry and clean is to ask. Don't be afraid to talk to the operator of the dive school or shop about the compressor and whether or not they are using these items in their system. Anyone operating a compressor for the purpose of filling these types of tanks should be well aware of the risks and how to prevent them.
For more information, check with places like the Kruman Equipment Company.