The fire brigade did attend and charged $800+ and this is apparently going up to $1200+.If it is optical, can one or more detectors be changed to what? without all being changed?
In my building the same brand of smoke detectors are available in both optical and ionizing models. They are electrically and physically identical, so can be interchanged. It seems that optical ones are more likely to false alarm from steam and should not be located near bathrooms. Your installer should be able to advise further.
It does seem strange that the detectors inside each apartment sets off a Fire Brigade alarm. That’s going to be very expensive for the OC! False alarms happen quite a lot. Like JimmyT’s apartment, in our building the interior apartment smoke detectors are stand alone. The detectors in the common areas are linked to the Fire Indicator Panel and cause a full building alarm. But we have water sprinklers in every room and only a trigger of one of those will cause the Fire Brigade to be alerted