ROFU 8920 Magnetic Door Holders, Floor Mount Cast Iron Housing With Reset Button

That's exactly what it's built to do. The 8920 is a fail-safe holder: it drops the door the instant power is cut, with no residual magnetism keeping it stuck to the armature. Tie it into the fire alarm circuit and activation of the alarm releases the door so it can close. If you need a holder that keeps holding through a power loss, this is the wrong device.

It's designed for that. The 8920 draws power to hold and releases when that power is interrupted, so it goes on a circuit the fire alarm system drops on activation, either a panel output or a dedicated releasing supply. Match the circuit to the unit you order, 12 VAC/VDC or 24 VAC/VDC, and size the supply against 120 mA per holder at 12 VDC or 60 mA at 24 VDC when several are on one run.

The DORMA EM501 is the closest cross-brand equivalent: it is an electromagnetic door holder, floor mounted, for a single door, and it belongs to Dormakaba's EM Series. The ROFU 8920 covers the same floor mounted single opening application with a cast iron housing and an integral reset button, holds at 80 LB, and releases instantly on loss of power with no residual magnetism. Both are wired holders that drop the door on a fire alarm signal rather than mechanical stops, so either one fits an opening where the door is held open electrically and must close on alarm.

80 lb of holding force. That's sized for holding a normally-closed door open against its closer, not for securing a door against forced entry. A magnetic holder is a hold-open device, not a lock, so if you need the opening secured, that's a separate maglock or lockset.

Floor mount is the answer when the wall behind the door swing is too far away, isn't there at all, or is glass. The 8920 mounts to the floor, so the holder stands up from the deck and catches the door near its bottom rail regardless of what the wall does. Wall mount units are the cleaner choice in a corridor where the door swings flat to a solid wall at a usable height. The tradeoff on floor mount is the unit sits in the walk path, so keep it clear of the traffic line and out of an accessible route.

After a fire alarm release drops the door, the holder won't re-grab the armature until it's reset. The button on the 8920's housing is what does that, at the unit, so a maintenance tech walks the building and restores each hold-open by hand rather than the doors silently re-latching open after a false alarm. On a multi-door floor, factor that walk into your post-alarm reset routine.

The 8920 uses an adjustable swivel armature, so the strike plate on the door face pivots to meet the magnet flat instead of catching on one edge. That's the difference between a holder that grabs at full force and one that holds at half. Doors that are slightly out of plumb, or floors that aren't dead level, are the normal case in an older building and the swivel is there for exactly that.

Yes, and that catches people out. A holder like the 8920 only holds the door open; it has no ability to shut it. When power drops or the fire alarm trips, the magnet lets go and gravity does nothing useful on a swing door. The closer on the opening is what actually pulls it shut and latches it. If the door you're holding open doesn't have a working closer, order one as part of the same job.

The ROFU 8920 carries a reset button in its cast iron floor housing, so an opening that has released on alarm can be re-armed at the door. The DORMA EM501 is also a floor mounted single door electromagnetic holder in the EM Series, and is the choice where reset is handled centrally rather than at the holder. For a property manager standardizing corridor and stair openings across a building, that difference decides who has to walk the floor after a test.

Not with the ROFU 8920. It is ordered in either 12 VAC/VDC or 24 VAC/VDC, drawing 120 mA at 12 VDC and 60 mA at 24 VDC, so a contractor can spec the same holder and the same floor prep across a building and pick the voltage per circuit at order time. The cross-brand alternative in the same floor mounted single door format is the DORMA EM501 in the EM Series. Confirm the voltage of each holder against the power supply feeding that leg before ordering, since a holder wired to the wrong supply voltage will not hold reliably.

The housing is cast iron and the unit is rated commercial, which is what you want on a floor-mounted part that gets kicked, mopped into, and hit by carts. A floor holder takes abuse a wall unit never sees, and a plastic or thin-shell housing in that spot is a callback. For institutional standardization across a facility, the 8920 is ordered by voltage only, so you'd spec one voltage building-wide and stock a single part.