It is DIY and professional term.
It means the detector needs to be activated twice within a certain time period. This can be used for troublesome detectors but is false method in any good engineers opinion. Especially to be avoided on door contacts. Or the dubious method of a PIR on entry/exit.
Why do you ask this, it is in the manuals that come with the panels ( well some anyway, not the professional systems that only come with manager and user manuals), did you not understand the terminology?
It is poor method of trying to cut down on false alarms and in my eyes and most insurers totally incorrect. If there is an issue, investigate and change detector if all seems fine. I won't go into fault finding here ATM. You could soak test a new device, still not the best answer but one allowed for a few days by insurers.
I assume you know what that is?
A detector that is log only and if passes test automatically comes live after a set period. Just in case you were not aware.
Many instances for this, new doors/conservatory ECT. Our job is detection, not false alarms. Hence ongoing training and knowing the equipment, which is proven and reliable. Risk assesments and customer budgets. Something people seem to miss on here, or make incorrect assumptions from what I have seen.
Of course we charge more than a one man side line, but we have efficiency insurance. Which is totally different to public liability if your unsure.
Looking back as this subject obviously interests me, I have yet to see anyone mention this when they quote numbers of systems fitted. May I add not even decent ones. A decent system does not cost a lot . Why spend £130 on something that is supposed to protect property and or life if fire detection when your trying to protect thousands of pounds of items?
