Exit Device Outside Trim 2026: Every Trim Function Compared, Dogging Rules, and Why the Bar Is Never the Decision

Short answer: the bar inside always opens an exit door; the outside trim decides who can open it from outside. Fit a blank plate on a pure escape door, a night latch where a key should give momentary access and relock, an entrance trim (the key unlocks the lever until it is relocked) on doors open in business hours, and passage only where the door never has to be secured. An exit device is two products that ship as one. Inside is a bar that always releases the latch, and that half is not a decision, it is a life-safety requirement, and it behaves identically whichever device you buy.

HYDE (Canton Hyland, Zhongshan, since 1998) makes the 307 and 311 covered in this article.

Outside is the trim, and that half is the entire specification. It decides who can get in, whether the door can be left unlocked during trading hours, whether a key is needed, and what the opening does when the power fails.

A schedule that names an exit device and not its trim has specified the half that was never in question.

Every outside trim function, compared

The two that get confused are night latch and entrance. A night latch gives momentary access and relocks; an entrance trim can be left unlocked. On a shop that props its exit doors open all day, the first is wrong and generates a workaround; on a staff door that must never be left open, the second is wrong for the same reason in reverse.

Passage is the simplest function and the one most often chosen by default. The outside lever or knob always retracts the latch and there is no cylinder, so the door opens from both sides at all times and the exit device only does its job from inside. It is right on a door that must never stop anybody: a cross-corridor door, a stair door where people must be able to re-enter the floor, an internal door that needs an exit device only for egress. It is dangerous on any door that also has to keep people out, because a passage trim cannot be locked: anyone can walk in, at any hour, and nothing short of changing the trim alters that.

Classroom and classroom-security functions

Classroom is a function name from North American lockset practice, and ANSI/BHMA-style function lists use it. A key from the corridor side locks or unlocks the outside lever, and while it is unlocked the lever retracts the latch for anyone. Classroom security adds a second key point on the inside, so the teacher can lock the outside lever without opening the door and stepping into the corridor. That difference is why classroom security spread through schools: locking a door from the corridor side means standing in the corridor.

On an exit device the inside half is the push bar, and it always lets people out whatever the outside trim is doing. So on an exit device the classroom question is only about the outside: who can lock the trim, and from which side. Trims that lock with a key from outside are common; locking the outside trim from the room side needs a device and trim designed for it, so ask for that by function rather than assuming it. None of our trim records publishes a classroom or classroom-security function.

Door by door: which outside function fits

The pattern across all four: decide first whether the door is ever an entrance, then who enters, then whether it may ever be left unlocked. Each answer removes rows from the comparison table above, and the one left is the function to write on the trim line.

The four device types, and which trims each one takes

Before the trim function there is the device type, and it constrains which trims are even available.

The row that catches projects out is the last one. A concealed vertical rod device needs a door built to take it, the rod channels are inside the leaf and cannot be added later. Specifying one on a door already on site is specifying a new door.

The vertical rod rows also carry a maintenance consequence worth knowing before selection rather than after. Rods latch at head and threshold, which means the bottom latch lives where the floor is, and floors collect grit, water and cleaning chemicals. A bottom rod that has stopped engaging is the commonest fault in this whole category, and on a pair it means the inactive leaf is being held by one latch instead of two.

Where that is a real risk (a wet entrance, a loading area, anywhere mopped daily) ask about a device with no bottom rod, or accept that the opening needs inspecting rather than assuming.

Pairs: the part that is not about the device at all

A pair of doors with exit devices raises two questions the device cannot answer by itself.

Which leaf is active, and does the inactive leaf need to open? If it does, it needs its own device or flush bolts, and if it does not, flush bolts alone may be enough, but flush bolts on an escape route are constrained, because a leaf that needs a second action to open is a leaf that people cannot use in a crowd.

Do the leaves need to close in order? They do if they overlap, and that is a door coordinator rather than a device, a separate product, on a separate line, that nobody remembers until a pair of fire doors is found sitting open at the meeting stile.

Both of these are why a pair costs more than twice a single door in hardware terms, and why the schedule line for a pair should be written as a set rather than as two copies of a single-door line.

Dogging: what it is, and the one rule that is absolute

Dogging holds the latch retracted so the door pushes open freely from both sides. A shop with a dogged exit door during trading hours has a door that works like a push-plate and locks properly at night with one action.

There are two mechanisms. Mechanical dogging uses a hex key or similar tool on the device itself. Cylinder dogging uses a keyed cylinder in the device, so the same key management as the rest of the building controls it.

Cylinder dogging costs more and is usually the right answer in any building where more than one person opens up, because a hex key that lives on a hook is a hex key that anybody can use, including after hours.

The absolute rule: a fire exit device must not be dogged: a fire door works by staying latched, and dogging holds the latch retracted, the two are directly contradictory. Devices intended for fire doors are built without a dogging facility for exactly this reason, and a device with dogging fitted to a fire door is a non-compliant opening whatever else is correct about it.

If a fire-rated door needs to be free-swinging during occupied hours, the answer is an electromagnetic hold-open released by the alarm system, not a dogged latch. Our fire door hardware page covers why.

The two questions the trim has to answer before anything else

Does the door need to be securable from outside without a key? If the answer is no (and it usually is) then any trim with a thumbturn or a free lever is wrong, however convenient.

What happens when the power fails? Only relevant for electrified trim, and it is the question that gets deferred to commissioning. Fail-safe releases on power loss; fail-secure stays locked. Which is correct is a decision for that specific opening and two doors in one corridor can legitimately differ.

Free egress is not affected by any of this

Worth stating explicitly because it is the source of most anxiety about exit device specification.

No outside trim function (not storeroom, not electrified, not a blank plate) changes what happens when somebody pushes the bar from inside. The bar retracts the latch and the door opens. That is the point of the device and it is not configurable.

So the trim decision is a security and convenience decision, not a safety one, provided the device itself is the right device for the opening. The safety decisions were made earlier: whether the opening needs an exit device at all, and which standard it has to meet.

Trim and device are ordered together, and often are not

The single most common ordering error in this category: a device ordered without its trim, or a trim ordered for a device from another range.

They are matched products. The trim's spindle or tailpiece has to engage the device's mechanism, the fixing centers have to align, and on many ranges the trim is handed. A trim that looks identical from a catalog photograph may not engage at all.

So order them as a pair, by model, and state the function on the trim line rather than assuming it from the device. Our order code page covers how the function suffix is written (ET entrance, PS passage) and a trim ordered without one arrives as whatever the default is.

What we publish on our own trims

Our panic and exit hardware records cover the devices themselves and the outside trims that go with them. Each trim record publishes its type (lever or knob), material and finish, and some add door thickness, rose and knob dimensions or projection.

On the trims, the function row is the gap. Some records publish one (entrance with a key outside, passage, or a safety lock with cylinder); the rest publish dimensions and finishes but leave the function to the inquiry.

That is the honest state, and on this category it matters more than on most, because as this page has argued the function is the entire point of the trim. We are publishing the half that was never in question and leaving the half that was.

It is being fixed by measurement and confirmation rather than by inference, a trim's function is a property of its mechanism, and writing a plausible one into a specification table would be the same error as writing a plausible dimension. In the meantime, ask, and the answer comes back per model.

Knob trims, and what each record states

The 037 is an outside knob for a panic bar. Its listing gives iron and stainless steel as the material, a door thickness of 35–55mm and a spindle whose length is adjusted to the door, and states that the key locks and unlocks the knob. It does not list a function row, so whether that keyed knob behaves as an entrance, classroom or storeroom trim in the terms of the table above is not listed; ask before scheduling it.

The 037 PS is the passage version. Its function row reads "Passage: outside knob always free, no cylinder", so from outside the knob always opens the door and the push bar opens it from inside. The listing gives an iron knob on a stainless steel rose, satin nickel plating with other finishes on request, a 75mm rose, a 57.5mm knob, a projection of 78.5mm from the door face and a door thickness of 35–55mm. Everything said above about passage applies: it is for doors that must never keep anyone out.

The 027 is a lever, not a knob, and is listed here as a keyed lever trim to compare the knobs against. Its listing states key-operated locking and unlocking but has no function row. The listing gives zinc alloy, a 122mm lever and a door thickness of 35–55mm; ask for the function to be confirmed.

The four lines an exit device order needs

The device model, and whether it is rim, mortise, surface vertical rod or concealed vertical rod.

The trim model and its function, named.

Dogging: none, mechanical, or cylinder, and if the door is fire-rated, none, with the fire rating stated so the device selected is one without the facility.

The door width and handing, because push bar length follows the door and the trim is frequently handed.

Our 307 and 311 exit devices do not hold certificates today. Until certificate numbers exist, nothing we publish will imply they hold a fire rating, an ANSI grade or a UL listing, which is also why this page talks about the fire dogging rule in general terms rather than pointing at a product.