Photoelectric or ionazation smoke detectors?

Merry Christmas
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inspector 102

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Northern Indiana
HAs anyone heard of the issues bewteen these two types of detectors. Apparently there was testing done in central Indiana by a group of fire dpeartments involving the detectors. It was found that the ionazation detectors typically would not detect a slow burning fire, such as a matress fire for time periods up to 78 minutes and in some cases, never set off an alarm. As a result, the local fire chief had an article run in the local newspaper advising people to be aware of the type of detector they are installing.
Has anyone heard of similar testing and what the result might be. Is this a safety issue that might become a code revision in the future as to the type of detectors allowable in residential installation? Any thoughts or comments on this issue would be greatly appreciated.
 
If this is a concern, line voltage or battery operated combo ion/photo smokes are available.

I've seen them at the supply house but they don't appear to be very big sellers. They're about triple the price of a regular inonization SD.
 
This is not that unheard of. Ionization is best for fast moving fires, photo for slow smoldering.

Too bad you don't get to choose what kind of fire you're going to have.

In Mass any detector installed within 20' of a kitchen or bath must be photo electric type.

To keep it simple many guys just go all photo, and combo photo-CO2 where required.
 
Due to the method of detection, photos don't do well with black smoke (usually fast developing fires) as the black smoke absorbs the light and doesn't reflect it to the receiver.
 
All I recall from the 2 types are:

Photoelectric: Uses a "beam" of light which gets reflected by the smoke particles.

Ioniation: Uses the conductive particles in the smoke to complete a "circuit".

Different types of smoke create different results.

I guess using both of them would be best.
Do they make an Ion. & Photo. combination?
 
I think one type is more sensitive false alarms due to high humidity, but I'm not sure which type it is. I know opf one case where there were some problems with some installed in a locker room - the steam from the showers would set them off.

Steve
 
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