fire alarm circuit classifications?

[sheldon_ace]

hi guys

I just wanted to know if anyone could shed some light on how they classify fire alarms. All the classes like class "A", and so on confuse me. I have never had any formal training on fire alarm. I basically went to the school of hard knocks and teach myself. I am always looking for reasons why things are done the way they are. Any help would be great!!

 

[ron]

Re: fire alarm circuit classifications?

FA circuits are divided into two main categories, Class A and B. Class A means that the circuit begins at the control panel and after the last device goes back to the control panel. The fire alarm code further divides class A into other numbers (and capabilities of the circuit to function under certain conditions). Class B circuits do not return to the control panel after the last device. Again the code further divides the Class B category regarding functionality.
There are extensive tables indicating capabilities and circuit types in NFPA 72