I appreciated your article on door holder relays. We have fire doors on our nursery and toddler doors that are held open by magnets. The workers have to "pop" the door off the magnet when church starts. Some of the workers are older and have difficulty closing the door. They have asked if we could install a push button under the magnet that would stop the magnet field when pressed, allowing the door to close. Is there a problem with doing this if we use an auxiliary relay as you stated in your article?
Adding a switch to interrupt power to the magnet should not be any problem. As a matter of fact, some manufactures install these buttons on the above-the-door door holders. The worst that can happen by installing the power interrupting switch is that if the switch fails, the door closes.
Basically, if the switch fails, it will fail safe.
This means that if the switch fails and continues to apply fire alarm system supplied power to the door magnet, the fire alarm system will still be able to close the door in case of fire, it will just be difficult to close it manually.
On the other hand, if the switch fails and turns off the fire alarm supplied power to the door magnet, the door will close whether or not the fire alarm system has detected fire, someone just has to hold it open for the door to stay open.