FRA extras

[Steve_gb]

If a fire risk assesment asks for extra sounders and beacons to be added on a non addressable system, depending on the zone capacity what would be the maximum allowed (as a rule of thumb)?
If the number exceeds capacity is it possible to keep adding more sounder modules to the system?

[kurnal]

Steve this may attract more responses in the technical forum. Chris may move it across if we ask nicely.

[Steve_gb]

hmm i might be in the right place and have had 70 views but as yet no opinions...does nobody know???

[AnthonyB]

I would assume the number varies based on the age, design, brand & capability of the panel & its batteries.

In one building they've had to replace a system as the building needs several more sounders due to partitioning, but the panel can't take any more devices on it's available circuits.

Another building I've visited has a similar problem with being expanded as far as possible with extra modules power supplies and bells (which surely use more power than electronic sounders?)and is so stretched it could fail.


So it appears (this is from engineers reports, different companies, different regions) that there is a finite capacity as to how far you can add  to a panel with sounders and that some panels cannot be extended this way at all.

[Graeme]

it can be easily done by using a sounder extender unit which will give another 4 additional monitored sounder circuits powered by a seperate power supply unit.

[GregC]

Another way may be to source sounders and beacons that have a lower power consuption and replace the exsiting sounders/beacons to lower the overall load on the panel.

A quick calcualtion
1 no. bell @ 30ma, 1 no. xenon beacon @ 45ma = 75ma  
1 no. combined sounder/beacon = 33ma
or
1 no. sounder @ 20ma
1 no. LED beacon @ 5ma

This would give you virtually double the capacity if you currently have bells and Xenon beacons