Lock Functions: Passage, Privacy, Storeroom, Classroom, and More

How Function Numbers Work

Function numbers live inside individual product standards. Bored (cylindrical) locks are covered by ANSI/BHMA A156.2 (current edition 2022) and mortise locks by ANSI/BHMA A156.13 (current edition 2022). Each standard numbers its functions separately.

A few points shape how the numbers are used:

• Same behavior, different number. A passage latch is F75 in Schlage's ND (bored) catalog and F01 in Schlage's L (mortise) catalog, because the two standards number their functions independently.
• Function is not grade. The A156.2 standard (2017 edition preview) states that function numbers do not identify grade, finish, or design, and that manufacturer catalogs must be consulted alongside them.
• Manufacturers add their own names and variants. A catalog listing usually shows the manufacturer's model number, a descriptive name, and the ANSI function number where one applies. Some catalog functions carry no ANSI number at all.
• Codes come first. A156.2 tells users to check applicable building codes for functions used on fire doors and doors in a means of egress.
• Editions change. Function lists are revised over time, and different catalogs may reflect different editions. For any specific product, the manufacturer's current function chart and its BHMA listing are the reference.

Common Functions at a Glance

The table lists only functions whose numbers agree across the manufacturer catalogs and BHMA material reviewed for this article. Descriptions are simplified; the standard's wording governs.

Passage

The simplest function: a latch with no locking at all. Either lever retracts the latch at all times. Passage sets are common on closets, corridors, and interior doors where closing the door is enough.

Privacy

A privacy lock lets the occupant lock the outside lever from inside. In Schlage's ND catalog, the bath/bedroom privacy lock (F76) is locked by a push button in the inside lever. Rotating the inside lever retracts the latch and releases the button, and closing the door also unlocks it to prevent lockout. An emergency release on the outside lets someone open the door if needed. Residential locksets have their own standard, ANSI/BHMA A156.39, which lists a related F77A patio or privacy lock.

Classroom

The outside lever is locked or unlocked with a key from the outside; the inside lever is always free. An ASSA ABLOY white paper on classroom locks notes that this was historically the standard classroom function. Its limitation is that locking the door requires someone to step into the corridor with a key.

Storeroom

The outside lever is always locked. A key retracts the latch for entry; the inside lever always allows exit. The ASSA ABLOY white paper notes that because the door relocks whenever it closes, there is no question about whether it was left unlocked.

Communicating

BHMA's A156.2-2022 summary describes F80 as a deadlocking latch operated by the lever from either side, in which turning the key in either lever locks or unlocks that lever independently. The summary adds that it should not be used on doors in rooms that have no other entrance.

Office, Entry, and Classroom Security Functions

Many locks add an inside push button, inside turn button, or inside key to the basic functions above:

• Office or entrance functions use an inside push button or turn button to lock the outside lever, while an outside key still opens the door. Several variants exist, depending on how the button is released.
• Classroom security functions put a key cylinder on the inside as well as the outside. An authorized person can then lock the outside lever from within the room without opening the door, while the inside lever still allows free egress.

F-numbers for these variants are not consistent across the sources reviewed, so the numbers below are one manufacturer's catalog listings, not general rules:

For any other product, check the manufacturer's function chart and the product's BHMA listing. State laws and the local authority having jurisdiction (AHJ) may also decide which classroom functions are acceptable.

Beyond Bored and Mortise Locks

Other hardware families have their own standards and numbering:

• Exit devices. ANSI/BHMA A156.3 (current edition 2025) numbers both exit-device types and outside trim functions. BHMA gives "Outside Trim Function 10" as an example. See panic hardware.
• Residential deadbolts. These are covered by ANSI/BHMA A156.40 (current edition 2025). See deadbolts for the single- vs double-cylinder distinction.
• Electrified locks. ANSI/BHMA A156.25 covers electrified locking devices. Electrified locksets are usually described by a mechanical function plus fail-safe or fail-secure behavior. See electric strikes for those terms.

How Function Relates to Keying and Grade

Function, keying, and grade are three separate decisions:

• Function: how the lock behaves (this article).
• Keying: which keys operate it. See master keying, interchangeable cores, and key control.
• Grade: how the lock performs in BHMA durability and strength tests. See ANSI/BHMA lock grades.

A storeroom function can come in different grades and keying arrangements, and in a mortise lock body or a cylindrical lock chassis.

Related Topics

• Door latches: spring latches, deadlatches, and deadlocking plungers
• Mortise locks: the lock body with the widest range of functions
• Cylindrical locks: bored locksets and A156.2
• ANSI/BHMA lock grades: performance classes that sit alongside function
• Panic hardware: exit devices and outside trim functions
• Master keying: keying hierarchy, separate from function

Sources