Fire alarm relay

[cristafar]

Any of you guys know if it is ok to activate a relay using the sounder output of a fire alarm. It's operating a mag lock obviously when the alarm goes off the mag lock breaks. Thanks in advance.

 

[telectrix]

most fire panels have a relay built in for that very purpose.

 

[bawall]

All fire alarm panels should have 2 volt free relays for fire and fault though these are often used and so it is possible to get a relay that will run off a fire alarm sounder circuit have a look here Fire Alarm Ancillaries

 

[Darkwood]

NO! to your query as its a monitored critical circuit and mustn't be used other than for the purposes it was designed for which is sounder circuit, as already pointed out all modern panels have dedicated outputs or volts free contacts that you can utilize for this purpose.

 

[telectrix]

as darkwood has amplified my comment, the sounder output is monitoring the end of line device ( usually a resistor ) . if you add a relay coil across the o/p, this will cause the panel to "think" there is a fault on the circuit.

 

[bawall]

Yes the circuit is monitored and you can get relay interfaces as the ones in the link on my previous post that will not interfear with the monitoring of the circuit if installed correctly

 

[cristafar]

Thanks for all your replies guys. I am currently working for a firealarm company and noticed that the alarm we serviced had a relay that was operating using the sounder output terminals, all the other relays in panel were in use and the 24v aux. so I was just wondering if this was to go down on the certification. The firealarm engineer I was working with seems a little laid back and seemed to think it was ok because it will activate the relay on firealarm activation, but I just don't think it was right still.

Thanks anyway guys

 

[telectrix]

well, in that case, you could use the panel relay to do both jobs. loading being OK. maybe activate a separate relay with it.

 

[jaresquire]

It's ok and very common, especially with conventional panels. The relay should be polarised ie have a diode in circuit to enable the monitoring to work correctly.

 

[Moses]

Thanks for all your replies guys. I am currently working for a firealarm company and noticed that the alarm we serviced had a relay that was operating using the sounder output terminals, all the other relays in panel were in use and the 24v aux. so I was just wondering if this was to go down on the certification. The firealarm engineer I was working with seems a little laid back and seemed to think it was ok because it will activate the relay on firealarm activation, but I just don't think it was right still.

Thanks anyway guys

You need to rememebr, that if you use the sounder output to activate the relay and unlock the door, then when the alarm is silenced, by the silence button for any reason, before the evacuate is given, then the mag lock will lock the door, as its a non-latched output, unlike the fire output/relay.

 

[alarm man]

You need to rememebr, that if you use the sounder output to activate the relay and unlock the door, then when the alarm is silenced, by the silence button for any reason, before the evacuate is given, then the mag lock will lock the door, as its a non-latched output, unlike the fire output/relay.

the sounders going is the given to evac

 

[cristafar]

Thanks for all the usefull information guys, much appreciated.

 

[Engineer54]

This is a very common arrangement to operate magnetic fire door hold backs!!

Especially on systems that don't have conventional operation layouts!! Projects in the Middle East, have a tendency to get changed because some high manager want's it to work differently!! lol!! And NO, they will then not then conform to any recognised standard, but it still gets done!! lol!!

 

[Adam]

This is a very common arrangement to operate magnetic fire door hold backs!!

Especially on systems that don't have conventional operation layouts!! Projects in the Middle East, have a tendency to get changed because some high manager want's it to work differently!! lol!! And NO, they will then not then conform to any recognised standard, but it still gets done!! lol!!

Magnetic hold backs are a little different to a door mag lock.
The hold backs release (allowing doors to close) on sounder activation.

The maglock will release on Sounder Activiation, but as mentioned earlier the door will lock again if the sounders are silenced.

 

[Darkwood]

could always fit standard maglocks with a green break glass if its suitable for the situation, this depends if the maglocks are holding doors open or closed for security.