Automist can be interconnected with many existing alarm systems, however, some caution is required to ensure the right system is being connected to the right alarm output from the panel utilised. To avoid such mistakes, it's preferable that Automist activation and domestic / residential fire detection for early warning purposes be kept completely separate. Just because Automist uses detection for triggering suppression it does not mean it is performing as a detection system too.
The interface varies for the different Automist products:
Automist fixed and Smartscan
These have a 3 wire input which can be driven from a volt-free NO-NC relay output from a panel, flame detector or any other detection device which is deemed adequate for the application. Automist will monitor whether the NC is kept closed on the 3 wire input so a 2 wire output only will generate a fault on Automist when installed.
If these systems are to be initiated by an addressable panel then an output addressable device must be used to trigger Automist which is able to provide a NC and NO input to Automist and do the swap-over when alarming.
Hydra uses a 24V DC 2 wire conventional detector as its initiating device connected to one of the spray heads in the zone to be protected. A fire alarm panel can therefore be used instead of the detector to simulate that input as long as the number of output relays on the alarm panel match the number of zones being protected by Hydra.
To simulate a detector it is necessary to use a pair of resistors as per the diagram below to replicate the high impedance state of a stand-by detector and the low impedance state of an alarming detector. In the same way a Hydra installation would work, the relay output (with resistors) must be connected to a Hydra head in the zone it is protecting.
Caution must be used in utilising higher sensitivity detection, such as aspiration systems, which will cause heads to scan for a fire (but not to spray water) in case of sensitive detection of smoke. By altering the detection method utilised on the fire testing of Hydra against BS 8458, and if the application is to meet Building Regulations, the specifying installer is taking responsibility to ensure the activation time of detection is no longer than the time it would take an EN54 multi-criteria smoke + heat detector to detect a fire.
If linked to an addressable fire then an output addressable device must be used to simulate a conventional detector 24V DC impedance (either through an addressable device that carries this functionality or using a volt-free output relay and the resistor combination below).
For more details refer to the DIOM