Door Entry Problem

[danrich123]

Hello there,

I recently installed a door entry system in a store in a shopping center. Easy job, mag lock, key pad etc.
However, the door needs to release when the fire alarm goes off. Normally I'd just wire into the NC/C relay on the fire panel then to mag lock etc. However the relay is already used in monitering the fire alarm at the main security office via the common/normally open connections.
I'm struggling to get the right solution to open the door when the alarm goes off.
I 've thought of the following possible solution: the NC connection will always be live with 24v from the common (from security office panel), so I take a wire from NC and have that as the trigger on a relay which either goes to the Mag lock @ 12v or the 240v power supply to the whole door entry system.
Any ideas on a relay that would do the job, or another solution

Thanks

 

[OwainDIYer]

The hold-open magnetic latches used with door closer springs, to hold doors open, release on fire alarm and usually wire into the local sounder circuit. Electrically they are what you want (magnet disable on alarm).

Alternative is to get the fire alarm installer to provide a second set of relay contacts. That way it's his responsibility to comply with fire alarm regulations.

Final resort is a break-glass-to-exit switch adjacent to the door, possibly with a local alarm buzzer for security.