Every time I specify hardware for a door that swings into a pocket, a little alarm sounds in my head because at least 50% of the time there will be a problem that urgently needs to be fixed at the end of the job. This application requires coordination between the architect designing the pocket, the contractor building the pocket, and the distributor supplying the doors and hardware, and that’s a lot harder than it sounds. The other problem is that when one pair on a project goes south, in most cases ALL of the pairs are a problem.
The doors I’m talking about are usually cross-corridor pairs, and when they swing open to 90 degrees they sit in a pocket and the face of the door is flush with the face of the wall. In order for this to happen, the door needs to swing out of the opening so the door edge is aligned with the face of the frame, rather than sitting out in the clear opening width. I have occasionally seen this done with swing clear hinges, but that leaves a large gap between the face of the frame and the door edge. The best way to hang the door in this application is with pocket pivots.
If a standard surface-mounted or concealed closer is supplied, the arm will be visible when the door is standing open. I like to specify a wall-mounted closer that sits in the pocket, like the LCN 4000T. When the door is open, the closer is completely hidden behind the door. These doors are almost always held open and only closed upon fire alarm actuation. The coordination problem that arises is that the pocket has to be the correct size. A pocket that’s not deep enough won’t leave enough room to mount the closer, and a pocket that’s too deep will result in the wrong geometry for the closer to work properly. The length of the pocket also needs to be coordinated, so there is enough space to open the door but without a large gap.
The magnetic holder and the projection of the lever handle also need to be considered. The lever handle has to fit within the allowable pocket depth, and the magnetic holder ultimately controls where the door will sit when it’s fully open, and whether it will be flush with the wall or not. It also affects whether there is enough space for the door closer and lever handle.
In the 4000T section of the LCN catalog, there’s a handy graphic to help with this coordination. —>
- Dimension 1 is the distance from the centerline of the closer shaft to the centerline of the hinge or pivot. For pocket pivot or total door hinge, 9 1/2” (241 mm). For butt hinge 8” (203 mm). For center pivot 10” (254 mm).
- Dimension 2 is the distance from the centerline of the pivot or hinge to the cylinder mounting surface. For pocket pivot 4 1/2” (114 mm). For total door hinge 3 7/8” (98mm) For butt hinge 2 7/8” (73 mm). For center pivot 4 1/2” (114 mm).
- Dimension 3 is the distance from the centerline of the pivot or hinge to end of the track. For pocket pivot or total door hinge, 3 7/8″ (98mm). For butt hinge 2 3/8″ (60mm). For center pivot 4 5/8″ (117mm).
I saw a great example of this application the other day, and I thought it was interesting that the UL label was on the lock edge instead of the hinge edge. It makes perfect sense since you wouldn’t be able to see a label on the hinge edge, but I’ve never seen it that way before. I would have used a less-conspicuous finish on the hardware, but the pocket was perfectly coordinated.