About ten years ago I had a situation where the company I was working for was considering adding smoke detectors to automated robot battery charging stations. I was given the task of testing their effectiveness at detecting the beginning of an ABS plastic fire and to compare ionization and photoelectric types. I had very interesting results although my memory is a bit hazy, I think what I found was that neither type was better than the other overall. If I recall correctly, the photoelectric one was usually much faster to trip but sometimes never tripped, depending on how smoky the fire was (Some of my tests had a hot piece of metal in contact with the plastic, causing it to char but not visibly burn. Others had visible flames coming from the plastic). The ionization one almost always tripped but it sometimes took much longer to do so. My conclusion is that you really want both types in your house. This seems to be vindicated by the advice I've seen given to the public recently, as well as the prevalence of dual-action (photo/ionization) types for sale now= .. Sean On Tue, Nov 27, 2018 at 5:33 AM RussellMc wrote: > Interesting. > I've had good results over decades with ionisation type detectors and hav= e > found photoelectric ones less sensitive than I'd like. > > I had intended to do an informal test of various detectors and locations > "sometime" / manana (manana manana?) . > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .