It is an acceptable and frequently used option to protect an opening in a fire wall by a sliding fire door held open by an electromagnetic device. However, sliding fire doors tend to be quite large and heavy, presenting a potential danger to occupants passing through while it is closing. To reduce the danger to building occupants the rate of the door’s closing is limited and must be by the deactivation of an electromagnetic device (see C4D7(1)(a)).

In the event of a power failure, the electromagnetic device must also fail-safe so that the door closes thereby maintaining the integrity of the fire wall (see C4D7(1)(b)).

Warning lights and signs are required to be installed on each side of the door by C4D7(1)(c) and (d) to indicate the presence and operation of the fire door. C4D7(2) and C4D7(3) requires the electromagnetic device to deactivate and the warning system to operate when there is a fire in a fire compartment on either side of the fire wall. This process must be activated by either smoke detectors or heat detectors (in specific circumstances) installed in accordance with the relevant provisions of AS/NZS 1905.1 and AS 1670.1 (see C4D7(2)).

The activation of any other required suitable fire alarm system (including a complying sprinkler system) in either of the fire compartments must also cause the automatic closing of the fire door (see C4D7(3)).

A smoke detector can give false alarms (see comments on C4D6). Heat detectors complying with C4D7(2) should be used in these circumstances.