If required, fire detectors should be installed as detailed in AS 1670. There are special exceptions and variations.
Detectors should be provided throughout all areas of a building, and must be installed in any sleeping areas and circulation spaces leading to exits.
Where areas are divided into sections by wall, partitions or storage racks reaching within 300 mm of the ceiling, each section must be treated as a room and have detection. Accessible service tunnels, not fire isolated, that provide communication between sections or buildings must be protected.
A clear space of at least 300 mm radius, to a depth of 600 mm, shall be maintained from the detector. Protection should be provided in all concealed spaces. Cupboards with a capacity exceeding 3 sq m need to have detectors.
Please note: the above are necessarily general requirements and the precise requirements for each building have to be determined by a professional installer, following a site survey.