I know Gent do proprietary interface devices, I assume other manufacturers do the same.
From BS 5839:
The following recommendations are applicable in the case of systems intended to actuate other fire protection systems or safety facilities (e.g. by triggering an automatic fire extinguishing system, closing fire resisting doors, shutting down an air handling system or grounding lifts).
d) The other equipment or systems should not draw power from the fire alarm system in the non-fire state, other than for indicators and interface devices (e.g. relays). The power consumption of any such indicators and interface devices should be taken into account in the calculation of battery capacity
[This message has been edited by TeesdaleSparkUK (edited 03-03-2007).]
