Ionisation and optical smoke alarms - Which where?

[andyfr]

We have two mains smoke alarms interconnected, one in the hall and one on the landing. One kept going off in the middle of the night, and as they were about 14 years old, we thought it best to replace them.

After reading about the different types we got one of each, ionisation and optical but not sure which one should go where. I have done a search of the forum but haven't found the answer.

Thanks in advance.

 

[yaleguy3]

optical downstairs hallway ionisation upstairs landing.

optical supposedly less sensitive to cooking smoke

 

[andyfr]

Thanks for the reply.

 

[andyfr]

As I had been getting conflicting advice I contacted the local fire station and asked the community fire officer. He said optical upstairs and ionisation downstairs.

Confused??? I know I am.

 

[aptsys]

We have an optical in the hall and ionisation on the landing. The hall one never goes off, but any cooking smoke immediately sets off the landing one!

 

[yaleguy3]

Optical are less sensitive to flaming fires ie fires with a roaring flame such as cooking or burning wood.
They are more sensitive to smouldering fires such as the smoke from hot electrical wiring or a slow starting fire.
They are marginally less likely to be started by normal cooking.
Ionisation are less adept at recognising smouldering fires but more sensitive to flaming fires.

There's not much in it really other than the suggestion of one of each.
The optical one I would put downstairs to try and avoid false alarms from normal kitchen activity.
However someone has suggested differently on here..
I don't suppose you will go far wrong either way.

 

[Spark123]

Optical are generally more sensitive than ionising, optical will detect thin smoke whereas ionising require a bit more smoke to alarm.