The United States banned the use of Halon under the Montreal Protocol because it is harmful to the environment. It contains CFCs that deplete the Ozone layer.
In Relation To CISSP Exam
There are fire suppression methods that you should use, and ones that you should not, depending on the types of fires. Check out my post on Fires and Suppression Methods for more info. Basically, just know that nobody uses Halon anymore because it has been mandated illegal by the federal government.
How Does Halon Work?
Halon comes in a liquified compressed form. It is used on chemical combustion fires because Halon prevents fires by stopping their chemical reaction.
Remember that fire requires three things to be created: oxygen, a fueling agent, and heat.
What Halon does is stop all three of these elements from mixing and dancing around with each other. Using Halon, molecules from a fueling agent like gasoline, won’t be able to mix with molecules from oxygen or heat.
This stops fires from becoming bigger fires.
Why Is It Banned?
The Montreal Protocol banned Halon in 1987 (I think?) because Halon contains CFCs. CFCs are TERRIBLE for the environment in regards to the ozone layer. It depletes the ozone layer. This is BAD, just ask anyone from Australia.
What Is A Substitute For Halon?
For the CISSP, they want you to know that FM-200 is a potential substitute.
Other substitutes include:
Anything approved by the Environmental Protection Agency