Communal flats, smoke alarms

[shed69]

Hi all,

I need help... I have spoken with fire officer today regarding smoke detection in 3 storey flats....

The flats have a smoke and heat in each of them...

The supply authority haven't brought their service in yet but I'm assuming they will be bringing 3 phase into building....

FO has advised that he wants a heat detector inside the doorway of each flat door, ie hallway.... to be interlinked throughout communal areas etc... Fine yeah....

My problem is this, if my flat is fed off Phase L1 and the communal smoke circuit is fed off phase L2 then I have potentially 400volt between my light in hallway and heat detector from communal.....

Advice appreciated.....

 

[Engineer54]

Is there any problem keeping the communal side of the Fire Alarm system on one phase??

 

[shed69]

It will be on one phase...... there are 12 flats across 3 storeys.... so i can't avoid it??

 

[Engineer54]

Sorry, i don't understand your concern, the heat detectors won't be apart of any of the flats electrical installations, so can you explain what your worried about ??

 

[shed69]

No, but they are to be installed in the hallway of each individual flat.... So if flat 1 is on brown phase and my communal area heat detector is on the black phase , I will have 400v between the flat hallway light and the communal heat detector.....

 

[Engineer54]

But they won't be in anyway connected via a common raceway, so any contact between the two is non existent!! Unless for some unknown reason you link the light and heat detector together, ....your not going to do that are you?? In that case, you can safely sleep soundly at night, .....unless of course the heat detector sounds off the alarms!!!....

 

[shed69]

So are you telling me its okay to have 400v in a domestic dwelling then, cos I think otherwise.... I know they won't be connected but it just doesn't seem right...!!!!

 

[Engineer54]

To be honest, in a multi dwelling building, i wouldn't even be considering mains voltage interlinked detectors. I would say, this should definitly be a conventional fire alarm system installation, bringing all the benefits of such a system to the building....

 

[Engineer54]

I have 3 phase running around my house Shed69, as do many larger house installations in the UK. There is absolutly nothing in the Reg's saying you can't have 400 volts in a domestic installation. In your case it will be at one single point, and between two totally different installation systems!!! You have nothing whatsoever to worry about mate...

 

[shed69]

I expected the FO to say the same thing, Its not straight forward as the plans were submitted years ago so he is relaxing what we would need to do if it was a new project..... They are going to housing association and it is proper rough! They would set off call points every day!!!!

 

[briand]

You are making the assumption they will feed different phases in - doesn't have to be so, but you can't control that. I've had same problem with no communal area - in your case it would need panel in communal area and all detectors ELV on their own areas on panel - my earlier post on here may help.