Mains powered smoke alarms

[HarryDewickEisele]

Hi Bernardgreen
Sorry, I misread the question. I thought it was all about the radio-activity from an ionisation smoke alarm affecting radio transmission. Yes, in the extreme, a fire's ionisation could affect transmission, although the units I mentioned are digitally coded, so they send a digital message rather than just a modulated frequency, so should not be affected to my knowledge. What is your view?
Harry

 

[bernardgreen]

Way back in the 1980's some test were carried out on digital signals to radio paging receivers used on fire grounds. The results did show that thick smoke reduced the signal strength significantly but not to the extent that the safety critical system would be compromised in use.

However that was with a transmitter with more than 10 watts of transmitted power and very sensitive receivers giving a free field range of over 15 miles. The domestic smoke alarms are very different in both transmitted power ( much lower ) and receiver sensitivity ( less sensitive ). And a domestic building is not free field as there are walls and/or floor between units.

I am sure they will work in 99% of the time they are required to work and have good batteries fitted if not mains. But that 1% possible failure worries me.

 

[Sparky1970]

Can anyone recommend any mains radio linked alarms?

 

[Taylortwocities]

Can anyone recommend any mains radio linked alarms?

I thought we already did.

OK
Get this mains powered radio base
http://www.tlc-direct.co.uk/Products/TLSD168.html
add a series 140 or 160 alarm to each base and you're done.

 

[Sparky1970]

Seems pricey!

 

[Taylortwocities]

It often works out cheaper than pulling up all of your flooring, chasing walls and redecorating.

Your call.

 

[bernardgreen]

Seems pricey!

Money can be replaced. A life lost due to a cut price installation cannot be replaced.

 

[mfarrow]

Money can be replaced. A life lost due to a cut price installation cannot be replaced.

Indeed.

The mains interlinked AICO's I bought recommended in the instructions not to collect them to circuits containing dimmers and/or fluorescents (can't remember which now), which rules out connection to any form of lighting circuit these days.

Also, with the majority of lighting circuits in existing installations requiring an RCD due to unprotected switch drops, I would prefer to have a smokes on a circuit which has some form of withstand level before cutting out.

Of course, nothing's better than fire-tuf or pyro...

 

[Sparky1970]

Seems pricey!

Money can be replaced. A life lost due to a cut price installation cannot be replaced.

True, my previous installation must have been a 'cut price' installation as whoever wired it in used 6 core alarm wire designed for 12v dc and not 240vac. This is now disconnected and I have temporary battery alarms in place, some protection is better than no protection, will be installing linked alarms very soon though.