A function code says what the lock does from each side
A lock function code, set out in ANSI/BHMA A156.2, describes how the lock behaves from the outside and from the inside. Two locks that look identical on the door can carry different codes and behave differently.
The code, not the brand, decides whether the door secures itself behind you, whether a key is needed from outside, and whether the inside can be locked at all. It is easy to get wrong on a replacement, because the person ordering describes the lever instead of the behavior. On almost every commercial function the inside lever is always free, so anyone can leave without a key or a code.
Makers number some functions differently: BEST’s own chart, for example, calls its entrance lock F109 where this chart says F82. Order by the function name, and your quote gives the maker’s own code with the part number.
Classroom vs storeroom lock: what is the difference?
A classroom lock can be left unlocked and a storeroom lock cannot. On a classroom lock (F84), a key in the outside lever locks or unlocks it. On a storeroom lock (F86), the outside lever is always fixed and the key only draws back the latch to let you in. On both, the inside lever is always free, so nobody needs a key to get out.
| Classroom, F84 | Storeroom, F86 | |
|---|---|---|
| Outside lever | Locked and unlocked by turning the key in the outside lever | Always fixed; cannot be unlocked |
| Entry from outside | The lever, when it is not locked by key; otherwise the key | The key, every time |
| When the door closes | Stays locked or unlocked, as the key last left it | Locked |
| Inside lever | Always free | Always free |
A classroom lock is locked with the key from the corridor side, so the door has to be opened to lock it. Where a room must be locked from inside, the answer is a lock keyed on both sides, the classroom security function above. On a storeroom lock, anyone who steps out without a key is locked out. BEST makes both in the BEST 9K Series cylindrical lock: function R is classroom and function D is storeroom (BEST 9K catalog, page 6).
The usual answer by door type
Conventional pairings on existing commercial openings, not a specification for your building.
| Door | Usual function | Why |
|---|---|---|
| Corridor or interior office door | F75 passage | It needs to latch and stay shut. Security sits at the suite door. |
| Restroom | F76 privacy | Locked by the occupant, released from outside without a key. |
| Exterior entrance | F86 storeroom | Secures itself on closing, so nobody has to remember to lock it. |
| Classroom | F84 classroom, or classroom security | Locking is held at key level. Classroom security adds a keyed inside cylinder for lockdown. |
| Storeroom, closet or mechanical room | F86 storeroom | Entry by key only, and it cannot be left on the latch by accident. |
| Janitor closet | F86 storeroom | Same reason, and it keeps chemicals and equipment behind a locked door. |
| Stairwell door | F86 storeroom, or a listed stairwell function | The egress side is always free. Re-entry from the stair depends on the building, and some stairwells require controlled re-entry hardware. |
We supply listed hardware and confirm in writing the part number and options you have chosen. We are not code consultants; your Authority Having Jurisdiction (AHJ) makes the final call.
Six details decide the part number
- Function. What the lock should do from each side. If you are unsure, describe what should happen when the door closes behind you.
- Backset. Door edge to the center of the bore, commonly 2-3/4 inch on commercial doors, 2-3/8 inch on lighter ones. It has to match the prep already in the door.
- Door thickness. Standard commercial doors are 1 3/4 inch. Anything else changes the part number or needs a spindle kit.
- Finish. 626 satin chrome is the default on commercial locks, with 613 oil rubbed bronze and 693 black common alternates. See the finish code chart.
- Handing. Read from the outside, meaning the keyed side. Exit device trims and some mortise lock functions and lever designs are handed at the factory and cannot be reversed on site. See the door handing chart.
- Keying. Keyed alike across a group, or keyed to an existing system, has to be told to us before the order is placed. Cut keys cannot be returned.
Handed, keyed and electrified items ship only after you confirm handing, finish, keying and voltage in writing. Stocked lines ship the same or next business day after payment; a special order ships on the lead time stated on your quote.
Which of our listed locks come in these functions?
Three of the parts we list are ordered by function: the function is part of the part number.
| Part | Functions the maker lists |
|---|---|
| BEST 9K Grade 1 cylindrical lever lock | Passage N (F75), privacy L (F76), entrance AB (BEST’s F109, the F82 above), classroom R (F84), storeroom D (F86), dormitory T (F90) and intruder IN, keyed on both sides |
| Alarm Lock Trilogy DL2700 keypad lever lock | The cylindrical DL2700 opens by code or by its key override. The mortise DL2700CR is a classroom function and the DL2700DB a deadbolt function |
| Accentra 2100 rim exit device | Outside lever trim (620F series) in exit only, night latch, classroom, storeroom, passage or dummy functions. Rim trim 213F is a night latch, 214F a dummy pull and 217F a pull with a key |
Each function is as its maker describes it, in the catalog listed on the part’s own page. In every BEST 9K function on that page the inside lever is always free.
Send a photo of the lock and the door
The lever, the inside of the door and the door edge are usually enough to read the function, the backset and the handing. You get part number, grade, finish, price and lead time back within one business day.