Key takeaways
- A lock function describes behavior from each side of the door; a lock family describes construction, and the two are specified separately.
- Storeroom function cannot be left unlocked from the outside, which makes it the default for storage and mechanical rooms.
- Classroom function keeps the inside lever free at all times while a key sets the outside lever locked or unlocked.
- Office function trades key-only control for convenience, so it can also be left unlocked unintentionally.
- Free egress from the inside is preserved by every standard commercial function and must not be altered in the field.
- Never assume a function from appearance; operate both sides of the door and test the key before and after any lock work.
First distinction
A lock function is not a lock family.
Commercial locks are specified along two separate axes, and property teams get better quotes when they keep them apart. The family describes construction: cylindrical locks bore through the door face with a separate latch at the edge, mortise locks recess a rectangular case into the door edge, deadbolts add bolt-only security, interconnected locks link a lever and deadbolt so both operate together, and exit devices provide egress through a push pad. The function describes behavior — what each side of the door does when it is locked, unlocked, or operated with a key.
The same function exists across families. Storeroom behavior is available in a cylindrical lock, a mortise lock, and exit-device trim, and each acts the same way at the door even though the hardware looks different. A hardware schedule therefore names both: family for the door and its prep, function for the way the room should work. Neither can be inferred from the other, and neither can be inferred from a photo of the lever.
Function is also only one layer of the opening. The door, frame, hinges, latch, strike, and closer behave as one system, and the correct function still fails if the door does not close and latch.
Decision table
What does each lock function do from each side of the door?
Five functions cover most commercial interior and entry doors. Read each row from the outside first, then the inside; the inside behavior is what protects egress.
| Function | Outside (key side) | Inside (room side) | Typical rooms |
|---|---|---|---|
| Passage | Always unlocked; the lever simply retracts the latch | Always unlocked; no locking function on either side | Closets, corridors, and non-secure rooms |
| Privacy | No key in normal use; an emergency release allows authorized entry | Occupant locks and unlocks the door from inside | Restrooms and dressing rooms |
| Storeroom | Always locked; a key retracts the latch for each entry | Lever is always free for egress | Storage and mechanical rooms |
| Classroom | A key sets the outside lever locked or unlocked | Lever is always free for egress | Classrooms and controlled rooms |
| Office / entry | Can be left locked or unlocked | Inside control sets the outside state; lever stays free for egress | Offices and general entry doors |
Non-keyed functions
Where do passage and privacy functions belong?
Two common functions have no key in daily use, and each solves a different problem.
Passage: no locking function at all
A passage set latches the door but never locks it; both levers retract the latch at all times. It belongs on closets, corridor doors, and other rooms that must never be secured. Choosing passage deliberately matters: putting a keyed function on a door that should never lock invites propping and wedging, which defeats the closer and wears the latch.
Privacy: inside control with an outside emergency release
A privacy set gives the occupant a simple inside control — typically a push button or thumbturn — and provides an emergency release on the outside so staff can reach someone in trouble. It suits restrooms and dressing rooms. Privacy is an occupancy signal, not a security function: it manages momentary use of a room and should not be asked to protect property or control keys.
Keyed functions
Storeroom, classroom, or office: which keyed function fits the room?
The keyed functions differ in one thing: who can change the state of the outside lever, and how.
Storeroom: the outside is always locked
The outside lever stays rigid at all times; a key retracts the latch for each entry, and the door relatches behind the user. No one can leave the opening unlocked from the outside, which is why storeroom is the default for storage rooms, mechanical rooms, and anywhere access should equal holding a key. The tradeoff is deliberate friction: every entry requires the key.
Classroom: a key sets the outside state
A key turns the outside lever locked or unlocked. Staff can open the room for a scheduled period and relock it afterward, while the inside lever always allows egress. It fits classrooms and other rooms that operate on a schedule under staff control. The risk to manage is human: a keyholder can leave the outside unlocked at the end of the day.
Office or entry: inside control without a key
An inside button or turn lets the occupant leave the outside lever locked or unlocked without a key. That convenience suits private offices and general entry doors during business hours. The same convenience means the outside state is set by whoever was last in the room, so after-hours walk checks matter more with office function than with any other.
Life safety
Free egress comes before convenience.
Every standard function above keeps the inside lever free: one motion retracts the latch regardless of what the outside is doing. On doors that serve required egress, that behavior is not a courtesy — adopted code generally requires occupants to exit without a key, special knowledge, or special effort, and the authority having jurisdiction has the final word on any exception.
A function choice never authorizes trapping occupants. Arrangements that require a key to leave an occupied room, or field modifications that pin, block, or disable the inside lever, do not belong on commercial openings. Where a door is fire-rated, part of a required exit path, or on an accessible route, approved plans, product listings, manufacturer instructions, and the adopted code control the selection.
If an existing door on your property needs a key to get out of a room, treat it as a finding, not a feature, and have the opening reviewed.
Verification
How do you confirm which function is installed?
Appearance does not reveal function. Two identical levers can be storeroom on one door and office on the next, and a swapped chassis or replaced cylinder can quietly change the behavior a room depends on. Verification takes under a minute with the door open.
- Operate the outside lever with the door open and note whether it is unlocked, locked, or key-only.
- Operate the inside lever and confirm one motion retracts the latch with no key or extra step.
- Test the key and note whether it retracts the latch directly (storeroom) or sets the lever locked and unlocked (classroom).
- Check for inside controls: a push button or thumbturn indicates an office or privacy function.
- Compare the observed behavior with the work order or hardware schedule before and after any lock work, and reject substitutions made for convenience.
- Record the confirmed function on the property's door list so future service does not start from a guess.
Scope check
What should a lock-work quote state before you approve it?
A quote that names the function protects both sides. Before approving lock work, confirm it states:
- The function by name — passage, privacy, storeroom, classroom, or office — not just a product line or a generic new lever lock.
- The lock family and grade proposed for the door, and whether the existing prep supports it without modification.
- The keying plan: which key system the cylinder joins, who receives keys, and how issue and return are recorded.
- Whether the opening is fire-rated, part of required egress, or on an accessible route, and how that was verified.
- A closeout test covering both levers, the key, latch engagement at the strike, and one-motion egress from the inside.
Common questions
Questions about commercial lock functions
What is the difference between a storeroom lock and a classroom lock?
Both keep the inside lever free for egress. A storeroom outside lever is always locked, and the key retracts the latch each time someone enters, so the door cannot be left unlocked. A classroom outside lever is locked and unlocked with the key, so a keyholder can open the room for a period and relock it later.
Can an office-function lock be left unlocked by mistake?
Yes. The inside control sets the outside state, so the door stays however the last occupant left it. That is acceptable on doors staffed during business hours, but it argues for after-hours walk checks. If a room must never stand unlocked from the outside, specify storeroom function instead.
Do lock functions apply to mortise locks, exit devices, and electronic locks too?
Yes. Function describes behavior, and the same behaviors are available across lock families, including mortise cases, exit-device trim, and electronic levers. That is why a hardware schedule names both the family and the function: the family must match the door's preparation, and the function must match how the room should work.
How can I tell which lock function is on a door right now?
Open the door and test it. Operate the outside lever, operate the inside lever, and run the key. Always-locked outside with a key that retracts the latch is storeroom; a key that sets the lever locked or unlocked is classroom; an inside button or turn indicates office or privacy; no locking at all is passage.
Will changing the lock function affect emergency exit from the room?
It should not, and that is worth verifying. Standard commercial functions keep the inside lever free so one motion retracts the latch. On fire-rated doors and required egress paths, the adopted code and the authority having jurisdiction control what may change, so confirm one-motion egress from the inside after any lock work.
Sources and further reading
These references support the general technical guidance. The right answer for a specific opening still depends on the property and the authorities responsible for the project.