fire alarm types

[electrofelon]

I have been getting to know fire alarm basics lately and Need some clarification on a few terms. First, I know what class A and B are but I am a bit confused on how Class A and B relates to addressable and non addressable systems. Can you have a class B addressable system and a class A conventional system? Second, what are two and four wire smoke detectors? Does four wire just mean it has terminals for "daisy chaining" more initiation devices on a loop and is independent of whether it is class A or B? Thanks.

 

[LEO2854]

I have been getting to know fire alarm basics lately and Need some clarification on a few terms. First, I know what class A and B are but I am a bit confused on how Class A and B relates to addressable and non addressable systems. Can you have a class B addressable system and a class A conventional system? Second, what are two and four wire smoke detectors? Does four wire just mean it has terminals for "daisy chaining" more initiation devices on a loop and is independent of whether it is class A or B? Thanks.

"daisy chaining" Yes that is what it means.

 

[tbballou]

Terminology

Terminology

Need to start with smoke alarm and smoke detector. A smoke detector is a device connected to a control panel, a smoke alarm is a 120Vac device with no control panel.
The term "2 wire smoke detector" means the device receives it's power from the same conductors monitoring its condition.
The term "4 wire smoke detector" means it's a powered detector and its condition is monitored via a set of dry contacts with in the device.

Need to be very careful with retrofitting systems, 2 wire smoke detectors receive their operating voltage from the control panel You need to make sure the detectors in the field are Listed for use with the manufacturer's control panel.

 

[electrofelon]

Need to start with smoke alarm and smoke detector. A smoke detector is a device connected to a control panel, a smoke alarm is a 120Vac device with no control panel.
The term "2 wire smoke detector" means the device receives it's power from the same conductors monitoring its condition.
The term "4 wire smoke detector" means it's a powered detector and its condition is monitored via a set of dry contacts with in the device.

Need to be very careful with retrofitting systems, 2 wire smoke detectors receive their operating voltage from the control panel You need to make sure the detectors in the field are Listed for use with the manufacturer's control panel.

Thanks that makes sense. Am I correct that we are referring to conventional systems when talking about 2 vs 4 wire? Addressable stuff doesn't seem to have that option...

 

[iwire]

Addressable or not addressable can be class A or class B, it can also be two wire or four wire detector.

For instance the last Lowes I did was addressable, it was class A. The room smoke detectors would be considered two wire, they got their power from the addressable loop. However the duct smoke detectors where four wire non-addressable.

This means we had to run auxiliary power to each duct smoke and install an addressable monitor module to interface the conventional four wire duct smoke to the addressable loop.