// Hardware Basics
5 min read
Lock Functions Explained:
Which One Do You Need?
"Lock function" describes how a lock behaves — who can lock it, from which side, and whether a key overrides that. Picking the wrong function is the #1 reason a customer ends up locked out of their own bathroom, or with a front door that won't secure at all. Here are the six you'll run into most often.
The most common functions
|
Function
|
Behavior
|
Typical use
|
|---|---|---|
|
Passage 1
|
||
Passage
Never locks. Both sides turn freely at all times. Used for closets, hallways, and any door where privacy or security isn't a concern.
Privacy
Locks from the inside only, usually with a button or turn-button, and can be released from outside in an emergency with a small tool or screwdriver (not a key). Standard for bedrooms and bathrooms.
Entry / Office
Keyed from outside, with a thumbturn or push-button to lock from inside. The most common function for front doors and offices — you can lock it behind you with the inside turn, or use the key from outside.
Classroom
Keyed from outside on both sides, but the outside is normally left unlocked; a key toggles it locked or unlocked. The inside is always free to open (important for exit safety). Common in schools and offices where staff need to secure a room from the hallway side.
Storeroom
Outside is always locked and only opens with a key; inside is always free to turn and exit. No way to leave it unlocked from outside by mistake — used for storage rooms, mechanical rooms, and other spaces that should stay secured.
Communicating
Locks independently from both sides, each with its own key or turn. Used on doors that connect two separately secured spaces, like adjoining hotel rooms.
How to choose
Ask two questions:
- Does this door need a key at all, or just privacy? If it's a closet or hallway, you likely want Passage. If it's a bedroom or bathroom, Privacy.
- Who needs to be able to lock it, and from where? If only the person leaving needs to secure it (front door), that's Entry/Office. If it should never be left unsecured, that's Storeroom. If it needs to stay open from inside no matter what (fire code, classrooms), that's Classroom.