Intruder Locks: An Extra Level of School Security

These locks protect classrooms because the teacher is able to lock the exterior trim without leaving the interior of the classroom.

When deadbolt is projected, the trim inside retracts both latchbolt and deadbolt simultaneously and the outside trim remains locked.

The fourth model is a double cylinder mortise lock equipped with a deadlatch, deadbolt and holdback. The function description for the Schlage L9077/LV9077 Classroom Security Holdback Lock is:

Latchbolt retracted by lever from either side unless outside is locked by key from either side.

When locked, latchbolt retracted by key outside or lever inside. Auxiliary latch deadlocks latchbolt when door is locked.

Depress inside lever and turn key 360° for holdback feature.

Inside lever is always free for immediate egress.

Note: Activating the Holdback function turns the door into a push-pull (latchbolt retracted) operation. The purpose of the Holdback function is to reduce the wear and tear on the lock mechanism (same as dogging an exit device) and eliminates the latching noise when the door closes.

The Holdback function lock cannot be installed onto a fire rated door.

A number of offline and online electromechanical locks provide the ability to lock the exterior trim, not allowing access into the classroom. Each lock manufacturer or access control software (online) has its own methodology for “Intruder” protection.

Some standalone, offline electromechanical locks are available with an inside privacy button that locks the outside trim and/or the methods of access.

Some Simplex mechanical pushbutton locks including the 1021 cylindrical and R8148 mortise are available with the Privacy or lockout functions. When activated, the inside keyed cylinder disables the pushbutton operation. Access is available using the outside key override only.

On the inside trim, the R8148 keyed cylinder has three positions; “L” Lockout, “P” Passage and “C” Code. This way, when you are inside the classroom, there is visible indication of the condition of the lock.

Alarm Lock Trilogy 4100/4500 standalone offline locks are equipped with a privacy pushbutton on the top of the inside lock assembly. Pressing this button automatically disables free passage, locking the lock mechanism and at the same time, locks out general PIN user codes. Access can be gained using the lockdown override code or mechanically using an override key. Inside lever is always free for immediate egress.

Schlage CO Series offline locks have an available privacy (40) function. This button, located on the interior assembly, can lock down the keypad and/or outside credential reader to standard user codes. Inside lever is always free for immediate egress.

Kaba E-Plex locks can have an optional privacy function with a thumbturn on the inside. When the thumbturn is thrown, no access codes or cards are valid. Access can only be gained using the key override or the master code.

Online or networked electromechanical locks have a distinct advantage as they are interconnected electronically. A single command can lockdown every lock on the network. For example, the Alarm Lock Trilogy Networx lock’s factory software has been upgraded to include an emergency global lockdown command. According to Alarm Lock, lockdown of all the programmed Networx Locks occurs within ten seconds of being issued. It will supersede all scheduled programming or updates unless individual locks are otherwise programmed.

For just about every school, college or university, whether they have mechanical or electromechanical locks installed, a lock manufacturer probably makes a compatible “Intruder” lock.

The following is a partial list of lock manufacturers that offer mechanical and/or electromechanical Classroom “Intruder” cylindrical and/or mortise locks, along with their web site addresses.

Arrow Lock:

Best Access Control Systems:


Corbin Russwin:

Dorma Architectural Hardware:


Kaba Ilco Corp.:

Marks USA:



Yale Commercial Lock and Hardware:

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