NEW GOVERNMENT LEGISLATION:
For existing dwelling from 1 January 2017, all property owners are required to replace all smoke alarms with the photoelectric smoke alarms, to comply with Australia Standards (AS) 3786-2014. Smoke alarms must be less than 10 years old (date of manufacture should be found on the back of the smoke alarm), not contain an ionisation sensor, function correctly when tested and interconnect with all other smoke alarm in the dwelling, so they all activate together.
Smoke alarms must be installed on each storey, bedroom and in hallways which connect the bedrooms to the rest of the dwelling. If there are no bedrooms on a storey, a smoke alarm must be installed on the most likely way you'll exit the dwelling. Smoke alarms must be either hardwired or powered by a non-removable 10-year battery.
New or renovated dwelling must comply with the above, as well as have their smoke alarms hardwired to the mains power with a secondary power back up. e.g. a battery.
Smoke alarms must be installed on the ceiling but not placed within 300mm of a corner of a ceiling, a wall, light fitting or within 400mm of an air-conditioning vent or the blades of a ceiling fan. Special requirements for stairways, sloping ceilings, and ceilings with exposed beams can be found in the Building Fire Safety Regulation 2008. Be aware shower steam and cooking fumes may activate smoke alarms, in this case the owner may find another suitable location.