Door locks behave differently based on their lock function. Do you want a lock that always locks every time the door closes? There’s a lock function for that. Do you want a lock that cannot be locked from the inside (only the outside) so that you never get locked out of a room? Yep, there’s a lock function for that too. Here are the most common types of lock functions.
Passage locks are used when doors do not need to be locked. There is no keyhole in a passage lock and no means to lock it. You’ll find these metal door locks on hall closet or bedroom closet doors, pantries, supply rooms, etc…. Their main purpose is simply to prevent a door from swinging open once the door is closed.
Privacy locks can be locked from the inside to lock a room, but privacy locks do not require a key to unlock them from the outside.
Instead of a key, there is usually a simply tool that unlocks the lock. In homes, you see these most commonly installed on bedrooms and bathrooms.
In businesses, like retail clothing stores, you typically see them on dressing room doors. Just like the name implies, the offer privacy to the user but they are easily bypassed in case someone needs to get in for an emergency.
To lock a privacy set there is usually a thumb turn or a push button/turn. Some privacy locks installed in bathrooms on commercial buildings have an indicator to show the locked or unlocked status of the bathroom.
Entrydoor locks are controlled by a key in the outside cylinder and by a thumbturn, key or push button/turn on the inside. The use of the thumbturn/button provides the ability to lock the door or keep the door unlocked so a key is not required to enter for convenience to the user.
This type of lock should be used where unauthorized access is not a concern most of the time – like an office, home or storage closet door that you don’t want to be locked at all times.