Alarm systems required in a building containing an atrium, must include a manual call point (break-glass) alarm at each door to a fire-isolated exit. The aim of this provision is that a person is able to break the glass setting off the alarm as they evacuate the building, in advance of the automatic activation of the alarm system.

Where a sampling type smoke detection system is provided, a staged alarm must be given. The stages are set out in S31C18(2)(a) to (c). The reason for the staged alarms is to minimise the occurrence of false alarms.

Under S31C18(3), beam and point type smoke detectors (as with a sampling type smoke detection system) must also operate as set out in S31C18(2)(a) to (c), but at the levels set in AS/NZS 1670.1. This provision only applies to beam and point type smoke detectors required by the BCA.