Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
addressable via radial circuits
#1
If a conventional fire alarm is converted to addressable by using addressable devices/loop isolators on the existing radial circuits:

1 - is it a variation for the comm. cert?

2 - is there anything special set out in writing (e.g. in bs5839) that has to be done? do they have to have isolators between each radial circuit? can they use radial spurs? or can they effectively do whatever they want and no variations for anything like this are needed?

we have a site where 4 conventional panels have been linked together with kentec and hochiki with a comm. cert stating 'no variations' and not all info. shows on all panels...
Reply
#2
(13-11-2019, 12:59 PM)alonso Wrote: If a conventional fire alarm is converted to addressable by using addressable devices/loop isolators on the existing radial circuits:

1 - is it a variation for the comm. cert?

2 - is there anything special set out in writing (e.g. in bs5839) that has to be done? do they have to have isolators between each radial circuit? can they use radial spurs? or can they effectively do whatever they want and no variations for anything like this are needed?

we have a site where 4 conventional panels have been linked together with kentec and hochiki with a comm. cert stating 'no variations' and not all info. shows on all panels...

1 - No.

2 - Yes 12.2.2 b) A single short circuit or open circuit fault on an automatic fire detector circuit should neither disable protection within an area of more than 2 000 m2, nor on more than one floor of the building plus a maximum of five devices (automatic detection, manual call points, sounders or a combination of these) on the floor immediately above and five devices on the floor immediately below that floor.

and

12.2.2 c) Two simultaneous faults on a manual call point or fire detector circuit should not disable protection within an area greater than 10 000 m2.

so if a conventional zone is put onto a addressable loop this still applies. so will need isolators in the correct place
www.fia.uk.com

Technical Manager FIA

All comments and views are mine own and may not reflect the views of FIA
Reply
#3
(13-11-2019, 01:12 PM)Will Lloyd Wrote:
(13-11-2019, 12:59 PM)alonso Wrote: If a conventional fire alarm is converted to addressable by using addressable devices/loop isolators on the existing radial circuits:

1 - is it a variation for the comm. cert?

2 - is there anything special set out in writing (e.g. in bs5839) that has to be done? do they have to have isolators between each radial circuit? can they use radial spurs? or can they effectively do whatever they want and no variations for anything like this are needed?

we have a site where 4 conventional panels have been linked together with kentec and hochiki with a comm. cert stating 'no variations' and not all info. shows on all panels...

1 - No.

2 - Yes 12.2.2 b) A single short circuit or open circuit fault on an automatic fire detector circuit should neither disable protection within an area of more than 2 000 m2, nor on more than one floor of the building plus a maximum of five devices (automatic detection, manual call points, sounders or a combination of these) on the floor immediately above and five devices on the floor immediately below that floor.

and

12.2.2 c) Two simultaneous faults on a manual call point or fire detector circuit should not disable protection within an area greater than 10 000 m2.

so if a conventional zone is put onto a addressable loop this still applies. so will need isolators in the correct place
thanks will i will check for isolators tomorrow. i thought running a loop as a radial would need a variation but clearly not. thanks for the advice!
Reply
#4
What Will said.
The only reason a loop is a loop is so it can have a cable fault without losing too many devices.
The only reason a zone is a zone is so that a cable cut before the first device won't lose you too many devices. 

An isolator before each radial circuit will protect the system just as well as each radial being a physically separate circuit so as long as you're installing it properly then it's still fully compliant. Good idea to document the setup in the panel though in case anyone coming behind you makes a break in for a new extension or something.
Reply
#5
(13-11-2019, 06:49 PM)Monkeh Wrote: What Will said.
The only reason a loop is a loop is so it can have a cable fault without losing too many devices.
The only reason a zone is a zone is so that a cable cut before the first device won't lose you too many devices. 

An isolator before each radial circuit will protect the system just as well as each radial being a physically separate circuit so as long as you're installing it properly then it's still fully compliant. Good idea to document the setup in the panel though in case anyone coming behind you makes a break in for a new extension or something.

My common sense issue was the lack of a mention in the comm. Cert. E.g. 'conventional system rewired to addressable spurs'. Still a rare setup i believe. Thanks all
Reply
#6
Iv done a couple upgrades in this scenario. Do you know what panel you will be installing? Choose a panel that has some room in it for the short circuit isolators.

On both of my jobs I used the 16 Zone Ctec XFPs. The main PCB on these are at the front and there is quite a bit of space behind it. I bought the Apollo mini din-rale switch monitors, used them as Isolators and mounted them at the back of the panel. Keeps the installation tidy.
Nothing is foolproof to a sufficiently talented fool...   24

Reply
#7
Next time I go back to one of these jobs il take some photos and put them on the forum.
Nothing is foolproof to a sufficiently talented fool...   24

Reply
#8
(13-11-2019, 11:09 PM)Dan Wrote: Next time I go back to one of these jobs il take some photos and put them on the forum.

If you have more than a few zones, to isolate it properly, I wouldn’t have thought you have enough room to fit them all in the back of the panel?
Reply
#9
I prefer the dual din mounted isolators.
Reply
#10
(13-11-2019, 11:51 PM)Monkeh Wrote: I prefer the dual din mounted isolators.

I’ll 2nd that
Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  Zonal indication on addressable panels. Tilly 9 1,954 28-09-2018, 06:22 PM
Last Post: luggsey

Forum Jump:


Users browsing this thread: 1 Guest(s)