It’s funny how some things stick in your mind, and even funnier that I have “hardware memories” from way back. I remember a rumor going around my 7th grade Home Ec class that another class had locked our teacher, Mrs. Cross, out of the classroom, and that she had cried. So sad!
I’m sure that’s why classroom function locks were invented…to protect all of the Mrs. Crosses of the world. I’ve recently been asked how classroom function locks and deadlocks work, so here goes…
A classroom function lockset is controlled by using a key in the outside cylinder. The inside lever always provides free egress. The outside lever can be locked or unlocked only by someone with the key. There is no pushbutton or thumbturn on the inside that could be used by a rowdy band of 7th grade seamstresses. This function is not just for classrooms…it can be used in any location where control over the locking/unlocking is more important than the convenience offered by a pushbutton or thumbturn (office function).
Several years ago a new type of classroom function lock was introduced, called the “classroom security function” or “security classroom function,” depending on who you’re talking to. This function has two cylinders, which can cause a case of mistaken identity when it’s assumed to be an institutional function (locked on both sides, preventing access AND egress). The inside cylinder on a classroom security lock actually controls the outside lever – the inside lever always allows free egress. The ability to lock the outside lever without opening the door or stepping out into the corridor protects teachers from exposure during a lock-down emergency.
A classroom function deadlock is often used with push/pull hardware on entrance doors to multi-stall bathrooms, and I’ve had several code officials question their use over the years. In all cases, once I explained how the lock worked, the code official allowed the application. To lock a classroom function deadlock, you need to use the key to project the bolt. The key can also be used to retract the bolt. There is a thumbturn on the inside, but it will not project the deadbolt; it will only retract it. Similar to a classroom function lockset, only the person with the key has control over locking the door. If someone is accidentally “locked in,” they can use the thumbturn to retract the bolt for egress.