Drop Box

[BillConnerFASTC]

And no theatre technician would ever prevent a fire door from functioning as intended.

 

[Van]

The sort of door-holder magnet Bill illustrates, Van, doesn't work that way.

A permanent magnet holds the door open, and when you power it, the electromagnet, polarized in reverse, overcomes that magnetism, and releases the stopper. It's only powered while you're firing it.

Here's a standard trouble shooting cut sheet for an electromagnetic door holder-opener-thingy.
https://content.assaabloyusa.com/doc/AADSS1013820

Notice the first problem, 'Does Not Hold', first answer 'Power not turned on'.

The rest of this sheet goes on to describe the rest of the reason I don't like them i.e. buzzing, inconsistent holding power, etc. etc.

 

[Jay Ashworth]

Perhaps they come in both sorts, for different uses. I saw the instruciton sheet on the ones put in to allow an executive to close a door, 20 years ago where I worked, and they only pulled current when activated.

 

[Crisp image]

I created a 12v release form a car central locking solenoid. Advantages being low voltage, low cost or free from the wreckers. Disadvantages mounting them can be tricky. I also added a micro switch that cut power to them once activated so that the stage hand that operated the switch could reapply power or hold power on the device.
Worked a treat for me.
Regards
Geoff

 

[bobgaggle]

And no theatre technician would ever prevent a fire door from functioning as intended.

So big $$$ to the guy who invents a fire door that doesn't close with a loud click and doesn't latch unless there's a fire...

 

[BillConnerFASTC]

So big $$$ to the guy who invents a fire door that doesn't close with a loud click and doesn't latch unless there's a fire...

Some claims that this has been made but expensive and not truly quiet in my experience.

Generally the the solution is to include a sound and light lock at every entry to the stage or auditorium. Basically a vestibule that is included in the same fire compartment as the auditorium or stage. Thus, the door between the noise sensitive space and the vestibule is not required to be rated and therefore no latching hardware - just a push plate, a pull, and a closer. The door between vestibule and corridor/lobby/exterior/other would be rated and have latching hardware, but its a door removed from the noise sensitive spaces and usually not a problem.

I have at least on project where the entire corridor behind stage is the sound and light lock - with built in blue lights and all - but it takes careful planning to be sure that corridor is not a corridor serving as the required means of egress for other spaces. In effect, the corridor is just a part of the stage for code purposes.

I try to get this in control rooms, orchestra pits, etc., but those sometimes loose and will depend upon the relatively few users to plan their entries and exits.

 

[BillConnerFASTC]

Perhaps they come in both sorts, for different uses. I saw the instruciton sheet on the ones put in to allow an executive to close a door, 20 years ago where I worked, and they only pulled current when activated.

Jay -
I don't think you will find too many that work non-powered to hold and apply power to release. Generally, in means of egress, failing safe or in this case door closed, latched, but not necessarily locked is very desirable and simple. Perhaps some access control devices, like a strike plate that is activated - or retracted perhaps is a better word - to allow passage through an otherwise locked door.
Now, ETLs (electro thermal fusible links) sometimes used in stage smoke vents and fire safety curtains and on some fire doors and windows and fire dampers and such, do require power to be applied to release (coil heats link and it opens) but last time I checked they were like $50/link and one time use. There are now resettable ones but I have not researched. They might in fact be a viable release mechanism for a drop box.