BS5839

[Guest]

BS5839: Pt6: 1995 Fire Detection and Fire Alarm Systems for Buildings


Why do smoke alarms which derive their power from the mains lighting unswitched circuit have a battery back when new homes with a dedicated unswitched circuit don't?

Thanks

Mark

[Guest]

because a lighting circuit could fail before fire is detected. However, in Scotland and NI, you need battery back up anyway regardless of what mains circuit is, to comply with Building Regs.

[Guest]

Thanks for the info...but what is the difference between a lighting circuit and a mains curcuit...they could both fail ??

[colin todd]

The lighting circuit is more prone to failure in normal condition and fire condition. In normal condition as, say, result of bulb blowing (which can cause an mcb to trip). In fire, as a result of a fire in the room taking out the lighting circuit on that floor. The smoke alarm wiring will not be running ans exposed in the room.

[Guest]

Colin

Trust you to come up with the reasons why eh....Thanks for that, but where does is it state such requirements, I can't seem to see it in DOC B, 5446 or 5839.

Oh and not to confuse the issue but I am talking about the interconnect wire and not the sounding of an alarm in a domestic home grade D, E, and F

Thanks

[wee brian]

Now I am confused ---  I understand Colins explanation - I knew it was something like that but we don't all have photographic memories.

But what has this got to do with the interconnect wire??? and the need for battery backup.

[Guest]

Hi Wee Brian

We all know that smoke alarms must have battery back up for certain domestic systems especially if their is a mains power failure and Colin has kindly given the reasons why the difference of battery back on a lighting circuit is required *thxs again 4 that Colin*,.

My question is however, is there regulations that in the instance of power failure, and the system is running on battery back up, that the system must still be able to "interconnect" with other hard wired or  wireless alarms, and if so where can I find that information, i.e ADB, 5839 etc

I hope this is clearer however by all means feel free to call me direct if you wish.

Thanks for your interest

I can be contacted on 07960524308 and ask for Mark

[Guest]

The interconnect wire is separate. Is is nothing to do with the power wiring. The interconnect will work however the device is powered.

[colin todd]

sorry damn thing lost my name again

[Guest]

colin, when is the new pt 6 out or due (unless i missed it in all the excitement of njc meetings LOL)

thanks

dave bev

[colin todd]

Yo davey! Where have you been. Plotting the overthrow of democracy again, one hopes. It should be out later this month, as will my new book which is a guide to the standard. Signed copies (of the book not the standard) available at discounted rate to officials of the FBU on production of communist party membership card.

[Guest]

i can swap you a copy of forged in fire with forged signatures from anyone you want for a copy of your book 'light sleeping made easy' - i assume thats the title?

yes, i have been busy plotting though it was a nuisance plotting those begonias, though the the fuscia looks bright!

dave bev


ps - let me known when the document is out if you can - ta!

[colin todd]

I will try to remember but just recall who collaborated with the enemy come the revolution.

[Mark]

Does anybody know Is there is a review of ADB at the moment?

Mark

[colin todd]

Davey: It is published. Mark, yes but dont hold your breath for the new version.