Hello,
Can anyone please explain the differences, benifits and disadvantages of the above systems?
Thanks
Can anyone please explain the differences, benifits and disadvantages of the above systems?
Thanks
2 wire and 4 wire fire alarm systems?
- Thread starter ipjodan
- Start date
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from what i know... ( seen on site, installed one or two.. )
2 wire is a system where the break glasses and detectors are on one set of cables back to the controller, and the sirens and bells and beacons are on another set of cables...
4 wire is one cable goes round to everything..
it's like 24v, input, output and 0v...
2 wire is a system where the break glasses and detectors are on one set of cables back to the controller, and the sirens and bells and beacons are on another set of cables...
4 wire is one cable goes round to everything..
it's like 24v, input, output and 0v...
There is a bit more to it than that.
Fire Alarm Systems fall broadly in to two groups - Conventional Systems or Analogue Addressable Systems.
'Conventional' Fire Alarm Systems, in their various forms, have been around for many years and have changed little in that time in terms of technology although design and reliability have improved significantly. However, Conventional fire alarm Systems are a well-proven technology protecting many hundreds of thousands of properties worldwide. A Conventional Fire Alarm System is often the natural choice for smaller systems or where budget constraints exist.
Conventional fire alarm systems are available in two types. There is the standard type which has a 2 core cable for each detector zone circuit, and a 2 core cable for each sounder circuit.
You can also get twinflex fire alarms which uses just one 2 core cable for both the detectors and sounders, and the sounders are often built into the detectors.
Analogue Addressable Fire Alarm Systems differ from conventional systems in a number of ways and certainly add more flexibility, intelligence, speed of identification and scope of control. For this reason Analogue Addressable Fire Alarm Systems are the natural choice for Commercial premises and more complex system requirements.
In an analogue addressable system detectors are wired in a loop around the building with each detector having its own unique 'address'. The fire alarm system may contain one or more loops depending upon the size of the system and design requirements. The Fire Control Panel 'communicates' with each detector individually and receives a status report e.g. Healthy, In Alarm or In Fault etc. As each detector has an individual 'address' the fire alarm control panel is able to display/indicate the precise location of the device in question, which obviously helps speed the location of an incident.
Addressable detectors are, in themselves, "intelligent" devices which are capable of reporting far more than just fire or fault conditions, for example most detectors are able to signal if contamination within the device (dust etc) reaches a pre-set level enabling maintenance to take place prior to problems being experienced. Addressable detectors are also able to provide pre-alarm warnings when smoke/heat levels, reach a pre-set level enabling investigation of the fire to take place prior to a full evacuation alarm and Fire Brigade signaling taking place.
Selection very much depends on the type of premises it is to be installed into.
Analogue addressable are by far the best, but most probably overkill and prohibitively expensive for a small commercial unit for example.
I personally do not like the twinflex stuff, and would opt for a proper system with separate sounder / zone wiring if a conventional system were called for.
Fire Alarm Systems fall broadly in to two groups - Conventional Systems or Analogue Addressable Systems.
'Conventional' Fire Alarm Systems, in their various forms, have been around for many years and have changed little in that time in terms of technology although design and reliability have improved significantly. However, Conventional fire alarm Systems are a well-proven technology protecting many hundreds of thousands of properties worldwide. A Conventional Fire Alarm System is often the natural choice for smaller systems or where budget constraints exist.
Conventional fire alarm systems are available in two types. There is the standard type which has a 2 core cable for each detector zone circuit, and a 2 core cable for each sounder circuit.
You can also get twinflex fire alarms which uses just one 2 core cable for both the detectors and sounders, and the sounders are often built into the detectors.
Analogue Addressable Fire Alarm Systems differ from conventional systems in a number of ways and certainly add more flexibility, intelligence, speed of identification and scope of control. For this reason Analogue Addressable Fire Alarm Systems are the natural choice for Commercial premises and more complex system requirements.
In an analogue addressable system detectors are wired in a loop around the building with each detector having its own unique 'address'. The fire alarm system may contain one or more loops depending upon the size of the system and design requirements. The Fire Control Panel 'communicates' with each detector individually and receives a status report e.g. Healthy, In Alarm or In Fault etc. As each detector has an individual 'address' the fire alarm control panel is able to display/indicate the precise location of the device in question, which obviously helps speed the location of an incident.
Addressable detectors are, in themselves, "intelligent" devices which are capable of reporting far more than just fire or fault conditions, for example most detectors are able to signal if contamination within the device (dust etc) reaches a pre-set level enabling maintenance to take place prior to problems being experienced. Addressable detectors are also able to provide pre-alarm warnings when smoke/heat levels, reach a pre-set level enabling investigation of the fire to take place prior to a full evacuation alarm and Fire Brigade signaling taking place.
Selection very much depends on the type of premises it is to be installed into.
Analogue addressable are by far the best, but most probably overkill and prohibitively expensive for a small commercial unit for example.
I personally do not like the twinflex stuff, and would opt for a proper system with separate sounder / zone wiring if a conventional system were called for.
B
breezer
one snag with addressable, you dont know where each detector is.
the panel will say for example "fault detector 2002" but unless ome one has left a list of where each detector is, its pot luck.
also when an extension is added (same make etc) it can realuy be confusing as some detectors may or may not have been moved from where they were in the first place, but overall i understand they are good
the panel will say for example "fault detector 2002" but unless ome one has left a list of where each detector is, its pot luck.
also when an extension is added (same make etc) it can realuy be confusing as some detectors may or may not have been moved from where they were in the first place, but overall i understand they are good
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For a short period of time in the early 90's, there was a two wire system where you connected all detection devices (conventional type) as you would usually, but connected the sirens (on the same +/- pair) REVERSE polarity.
When the panel was pushed into fire by a detector, the panel reversed the polarity on ALL zones, and the sounders went off.
The system didn't last long, as it will not signal a further detection to the panel.
When the panel was pushed into fire by a detector, the panel reversed the polarity on ALL zones, and the sounders went off.
The system didn't last long, as it will not signal a further detection to the panel.
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