Rim, Surface Vertical Rod, Concealed Vertical Rod: Choosing an Exit Device
, by United Doors and Locks, 6 min reading time
Rim, surface vertical rod, concealed vertical rod or mortise. The door configuration decides, and a removable mullion is often the cheapest answer to a pair.
Exit devices are the most expensive line on most hardware schedules, and the four types are not interchangeable. The right one is decided by the door configuration first, the security requirement second, and the budget third — in that order, because a device that does not suit the opening cannot be made to work.
Rim device
The latch is mounted on the surface of the door face and latches into a strike on the frame or on a mullion.
The rim device is the simplest exit device and the one to specify unless something rules it out. There is one latch point, so there is one thing to align and one thing to service. It mounts to the door face with through-bolts, needs no special door prep, and is therefore by far the easiest retrofit — a rim device can go on a door that has never had an exit device before.
It suits single doors, and pairs of doors fitted with a mullion. The 8300B Heavy Duty Rim Device covers 28 to 36 inch doors with a Grade 1 rating; the Accentra 2100 Series is non-handed and available in both standard and fire-rated configurations; the Von Duprin 99EO is the specification you will see written on institutional work.
Its limitation is that it cannot secure a pair of doors on its own, because there is nothing in the middle for the latch to catch.
Surface vertical rod device
Rods run up and down the face of the door to latches at the head and the threshold.
This is the answer for a pair of doors without a mullion. Each leaf latches into the frame above and the floor below, so neither leaf depends on the other, and the opening between them stays clear — which is the whole point of a pair without a mullion.
The 8400B Surface Vertical Rod is a typical Grade 1 specification, and the F2000V is the fire-rated equivalent for rated pairs.
Two things to know. The rods are exposed, so they collect abuse and can be bent. And the bottom latch fires into the floor, which means it fills with grit in dirty environments and stops latching. Where the floor is a problem, a less-bottom-rod variant latches only at the head.
Concealed vertical rod device
The same top-and-bottom latching, with the rods inside the door.
Everything the surface version does, without the exposed rods. The door looks cleaner, the rods cannot be kicked or bent, and the mechanism is protected. Architects specify it on visible entrances for exactly these reasons.
The cost is real and it is not only the purchase price. The door must be factory prepped with a channel for the rods, so this is a new-work or new-door decision, not a retrofit. Servicing means opening the door up. And if the door is a rated assembly, the prep has to be part of the listing.
Mortise exit device
A mortise lock case in the door edge, operated by a push bar.
The highest-security option and the most expensive. The latch is a mortise lock bolt engaging a frame strike, so the resistance to forcing is far better than a surface-mounted latch, and the device can carry the full range of mortise lock functions. A device such as the Von Duprin 9875EO-F is a fire-rated mortise exit device for rated high-security openings.
It needs a mortise prep in the door edge, so it carries the same retrofit constraint as any mortise lock.
The mullion option worth considering first
If you have a pair of doors and you are choosing between surface and concealed vertical rod, price a removable mullion with two rim devices before you decide. A mullion turns a pair into two independently secured single doors, so both leaves can take the simpler, cheaper, more reliable rim device. When the full width is needed for moving equipment, the mullion lifts out.
It is frequently the cheapest and most durable answer to a pair, and it is regularly overlooked because the question is framed as which vertical rod device to buy.
Trim: what happens on the outside
The device handles egress. Getting back in is the trim's job, ordered separately.
- EO (exit only): no outside trim at all. No entry from outside.
- Night latch (NL): a cylinder and pull; the key retracts the latch. See the 1000R x 2P-03NL.
- Keyed lever: a lever with a cylinder, as on the 1000R x KIL. The usual choice for a staff entrance.
- Electrified trim: a keypad or card reader, such as the CO-100 keypad trim, where access needs to be managed rather than keyed.
Deciding in order
- Single door? Rim device.
- Pair with a mullion, or one you can add a mullion to? Two rim devices.
- Pair that must stay clear, retrofit? Surface vertical rod.
- Pair that must stay clear, new doors, appearance matters? Concealed vertical rod.
- High security or complex function needed? Mortise device.
Then confirm the fire rating separately, because every type above exists in both panic-only and fire-rated versions and they are not the same part.
Send us the door configurations, ratings, and how people need to get back in, and we will specify the devices and trim as matched sets.