Linking Fire Alarms

Add a relay to the alarm output in bldg A and run a normally closed contact pair from the relay to a zone on the alarm in bldg B. Repeat the other way around.

Sounds simple enough to me, but it's Saturday night and the highland waters are taking effect.

Logical really just break in to a loop of the opposite system.

Wire bldg B's siren or output terminal (or PGx / PGy) into a zone of bldg A Make sure zone used is set to NO

OR

Depending on distance, hook up a second siren and run the cables to the next building.

Thanks all for your input but back to Ton`s 2nd option. The distance between the bldings is not all that great approximately 30m from one siren to where I can install a second siren. Does this mean that I just have to loop the 2 sirens together? likewise do the same for the other set of siren from the other blding?

Yeah sure. Simply connect the sirenes in parallel. Just b sure you use sirene compatible with the system.

Dont do this. Fire alarms are not so "cut and dried" that you can just "add" things to them. Adding the sirens in parallel as suggested would, almost guaranteed, void the certification from the manufacturer. If something were to happen, your potential liability is large.

If you do proceed as suggested, bring in the manufacturer to re-certify the installs on both units. Go the input to a zone route.

I may have mis-read the intent. If you intend to keep the two alarm circuits separate, adding alarms in parallel is ok as long as the maximum drive current for the ouput is not met.

Do not tie the panels together using cross alarm contacts (each panel alarm contacts activate other panel input alarm zone). If this is done an alarm reset can only occur with someone standing at both panels. Adding alarm devices to either panel will require new power supply and standby battery calculations. Your desire to sound alarm in both buildings is not a code requirement, therefore you can treat each non-alarm building as an non-required annunciator. Install an interval delay relay in each panel and set the delay time to 1 second. The power to energize the relay comes from the other panel, switched through alarm contacts. The N/O contacts from the relay ties to an input circuit in the panel. You can even double lug an existing (used) input circuit as long as you don't add an end of line resistor to the relay. When Panel A goes into alarm it energizes the interval delay relay inside the other panel, placing that panel into fire alarm as well. After 1 second the relay contacts return to normal state, even though still energized. Now each panel can be reset independently.

Your better off treating them separately... No worries of voiding any warranties, no code violations, no complications, no headaches.

If you treat it as a "remote" or second sounder / annunciator you will not have to worry about each panels idiosyncrasies (and may even have a spare output on the TB to use). If there are wireless options then even better provided you have line of sight. 30 meters should not be a problem for 24 VDC.

I am assuming your gonna place the 2nd unit at the command center of bldg A (manned station)? You may wanna consider using a strobe so as not to panic people unnecessarily cause if wired into a zone then when one trips, all will trip. This may cause confusion/problems.

Cheers bro