On 25/11/2018 13:14, Peter Parry wrote:

Unfortunately fire protection by combustion detectors 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".


I agree with the message in the para. above. but wonder if some might
take it as an argument against multiple detectors per se. Eg I took the
view that smoke detectors were best placed in the usual circulation
spaces which here gave 3 (above stairs, rear landing and downstairs
gall) and in rooms where electrical kit was routinely left on and
unattended which gave another 3. Most people think that's a lot in a 3
bed terrace house. The more so as 2 are only 2m apart. But there's a
closed door between them so I reckoned it was a price worth paying for
earlier warnings. And we've had perhaps 3 nuisance alarms in 10+ years
- and that includes those from neighbours' summer barbecues


--
Robin
reply-to address is (intended to be) valid