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Commercial Lock Function Codes Explained
Jun 5th 2026
A function code defines how a commercial lockset behaves: which side locks, whether the outside lever is rigid or free, and whether a key or thumbturn controls it. You cannot order a commercial lock without choosing one. The ANSI/BHMA function names (Office, Classroom, Storeroom, Privacy, Passage, and a dozen more) are standardized in A156.2 (cylindrical) and A156.13 (mortise), but each manufacturer also assigns its own catalog number (Schlage uses three letters like ND53PD; Sargent uses a number like 8205; Corbin Russwin uses CL/ML numbers). This guide maps the most-used functions to what they do, which door they belong on, and the ANSI F-number that lets you cross-reference any brand.
What a function code controls
Every cylindrical or mortise lockset has the same four variables. The function is the named combination of those variables:
- Outside lever: locked (rigid), unlocked (free), or controlled by key.
- Inside lever: almost always free for egress (life safety requires free egress on occupied spaces).
- Locking method: key outside, thumbturn or pushbutton inside, or both.
- Latchbolt vs deadbolt: storeroom/entrance functions use a latch; deadbolt functions add a separate bolt.
The inside lever is the part code rarely changes: it must retract the latch and allow exit without a key or special knowledge. That is why almost every commercial function is a variation of what happens on the outside.
The function codes you will actually order
| Function | What it does | Typical door | ANSI F-number (cyl / mortise) |
|---|---|---|---|
| Passage | Both levers always free, no lock | Corridors, closets, non-secured rooms | F75 / F01 |
| Privacy | Inside pushbutton/thumbturn locks outside; emergency tool unlocks | Restrooms, exam rooms, dressing rooms | F76 / F19, F22 |
| Office / Entry | Outside lever locked/unlocked by key or inside pushbutton; inside always free | Private offices, conference rooms | F82, F109 / F04, F05 |
| Classroom | Outside lever locked/unlocked by key only; inside always free | Classrooms, labs | F84 / F05 |
| Classroom Security (Intruder) | Key locks/unlocks the outside from the inside without opening the door | K-12, lockdown-required rooms | (mfr-specific; see below) |
| Storeroom | Outside lever always rigid, key retracts latch; inside always free; no inside locking | Storerooms, mechanical/electrical, IT closets | F86 / F07, F09 |
| Entrance / Apartment | Key outside, turn/button inside, deadlocking latch | Apartment entry, suite entry | F81, F88 / F13, F14 |
| Communicating | Both sides keyed or one side keyed, no deadbolt | Adjoining rooms, suites | — / F20, F21 |
| Dormitory / Exit | Inside thumbturn projects deadbolt, outside key retracts | Dorms, hotel-style | — / F12, F13 |
| Institutional | Both levers locked, key both sides | Detention-adjacent, high-control | — / F30, F32 |
The single most common error is ordering Office when the spec needs Storeroom. Office function lets a user leave the outside unlocked by pressing a button; Storeroom never unlocks from a button, so the door is always secure and only a key gets in. Secured rooms (IT, mechanical, supply) are almost always Storeroom — a unit like the Schlage L9480 storeroom mortise lock with deadbolt is a typical spec for those doors.
Classroom vs Classroom Security (the lockdown question)
Standard Classroom function locks and unlocks the outside lever with a key inserted from the corridor. The flaw: during a lockdown, a teacher would have to step into the hallway to lock the door. Classroom Security (also called Intruder or Classroom Holdback) adds a second cylinder or an inside key/thumbturn so the outside can be locked from inside the room without opening the door. Most modern K-12 specs require Classroom Security. Confirm the function name on the spec; the catalog numbers differ by brand even though both are loosely called "classroom."
How brand catalog numbers map to functions
The ANSI F-number is the Rosetta Stone. Every major brand publishes its functions against the ANSI list, so you can substitute across brands by matching F-numbers.
| Function | Schlage (cyl) | Sargent (mortise) | Corbin Russwin (mortise) | Yale |
|---|---|---|---|---|
| Storeroom | ND80 | 8204 | ML2057 | 5305 |
| Office | ND50 | 8205 | ML2051 | 5307 |
| Classroom | ND70 | 8237 | ML2055 | 5308 |
| Privacy | ND40 | 8265 | ML2030 | 5402 |
| Passage | ND10 | 8215 | ML2010 | 5401 |
These are representative, not exhaustive; always confirm the exact suffix (lever style, cylinder, finish) on the manufacturer's current price book.
Where deadbolt functions fit
Function codes also cover deadbolt-bearing locksets. A mortise lock can combine a latch and a deadbolt in one case (the F13/F14 entrance and apartment functions). Standalone auxiliary deadbolts are a separate order under A156.36. If the opening needs a deadbolt plus a latch in one chassis, specify a mortise entrance or apartment function rather than adding a surface deadbolt.
Common function-spec mistakes
- Office where Storeroom belongs: secured rooms get left unlocked by the pushbutton. Use Storeroom for IT, mechanical, and supply.
- Standard Classroom in a lockdown jurisdiction: specify Classroom Security so the door locks from inside.
- Privacy on a door that needs key override for staff: hospitals and senior care often need Privacy with an outside emergency key, not a coin-slot tool.
- Passage on a fire/egress door that needs positive latching: passage latches still latch, but confirm the fire rating; never downgrade a fire door to a non-latching function.
- Mismatched function across a substitution: when swapping brands, match the ANSI F-number, not the marketing name.
FAQ
What is the difference between Office and Entrance function? Office function uses a key or inside pushbutton and is designed for a single private room. Entrance/Apartment function (F13/F14) adds a deadlocking latch and a thumbturn for suite or apartment doors. Entrance functions are built for higher security at a unit door.
Is Storeroom function ADA compliant? Yes. Storeroom keeps the outside lever rigid but the inside lever is always free, so egress meets ADA and life-safety code. The lever itself must still meet ADA shape and operating-force rules.
Can I change a lock's function in the field? Sometimes. Mortise locks often allow function changes by repositioning internal parts or swapping a cylinder/thumbturn; cylindrical locks usually do not. Plan the function at order time rather than relying on field conversion.
What ANSI standard defines function codes? A156.2 defines cylindrical (bored) lock functions and A156.13 defines mortise lock functions. Both list standardized F-numbers.
Next step
Choose the function before you choose the brand: it dictates which catalog number you order. Start from the cylindrical lever locks or mortise locks category, confirm the ANSI F-number against your spec, and pick the finish. Our commercial desk cross-references function codes across Schlage, Sargent, Corbin Russwin, and Yale so a brand substitution keeps the exact behavior the spec called for.