On 25/11/2018 20:55, Tim Lamb wrote:
In message , ARW
writes
On 25/11/2018 18:11, wrote:
Unfortunately fire protection by combustion detectorsÂ* is one of the
fields where too many people believe that more = better and fail to
understand that if there are too many (and too many is a small number)
nuisance alarms then occupants will both ignore and later disable the
alarms. "I've put lots of sensors in so its much safer" often really
means "I've put lots of sensors in so its much less safe but I've
created a really good illusion of safety".
Â*You and most people are wrong on one point. Ionisation alarms can
cover kitchens with no significant false alarms IF positioned
correctly. Obviously 'correctly' there means something different than
for other alarm types or in other locations.




That goes against the advice from every manufacturer.

We seem to be going round this again:-)

Slightly sideways and pertinent to why detectors may be disabled.....
battery life?
Set of 3 linked detectors. Batteries all failed within 2 weeks after
about 6 months use! PP3s are not cheap!

Seems a bit odd if they were alkaline.

Anyhow, have you considered NiMH? I've been running linked detectors
with NiMH PP3s for the c.8 years since the original Alkaline expired.
I've had to replace one or 2 of the NiMHs (from Lidl) but so long as I
can manage the ladders every 6 months[1] it's economical.

What I'm dithering over, with the detectors approaching their end of
life, are the pros and cons of alkaline battery vs rechargeable lithium.
The choice'd be easier if I knew my expiry date but that just shifts
it to another decision...


[1] for pre-emptive recharges: something that I don't begrudge after
the time it started beeping at 02:00 after a heavy night
--
Robin
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