Exit Devices, Exit Bolts, Panic Devices, Panic Bars and Crash Bars are some of the names given to the door-mounted security and safety devices that allow free egress at all times for outswinging doors. These devices are commonly used as the lock mechanism on commercial and institutional building’s exterior doors.
The first “panic bar” was developed in the beginning of the 19th century. The invention was said to be a result of the 596 deaths that occurred during the Iroquois Theater Fire in Chicago. Panic bars were developed prevent this type of tragedy from occurring.
The unique feature of the “panic bar” versus the standard locks of the day was the ability to open the door – even when it was locked - simply by pushing the “bar” on the inside of the door. This type of release mechanism allows people to exit without having prior knowledge of operation. There was no need to know how the lock operated. With the “panic bar” pushed, the lock mechanism would unlock and the door could be opened. Therefore, the door could be opened by any horizontal force on the “bar,” especially if there was a panic causing people to “crash” into the doors in hopes of escaping a dangerous situation.
Building owners and tenants did not want to leave their doors unlocked or made easily accessible from the exterior. The basic design of the exit device permitted the door to remain locked from the outside to prevent unauthorized access.
The “panic bar” mechanical lock consisted of a tubular bar extending just about the full width of the door that was attached to two small hinging mechanisms. The hinging mechanism on the lock side of the door was connected to a locking mechanism that would lock and secure the closed door within the jamb.
Over the years, the designs of these devices evolved in a number of directions. The most common version is a bar assembly with push rail mechanism exit device. One of the reasons for the design was the development of surreptitious entry tools that could hook onto the bar and when pulled, retract the locking mechanism and permit the door to be opened from outside.
NOTE: To accommodate Life Safety Codes, the push rail portion of the bar assembly exit device must extend at least halfway across the width of the door.
There are four different types of exit devices: rim, mortise, concealed vertical rod and surface vertical rod exit devices. Exit devices come fire rated or non-fire rated.
Life Safety Codes determine the fire door locations requiring fire rated exit devices. Fire rated exit devices offer most of the same features as non-fire rated exit devices including design, finish and operation*. However, fire rated exit devices must be constructed of specific materials. This is because the exit device must be tested by a testing agency to keep the door locked for up to and including 3 hours under test conditions as determined by the various testing agencies.
*Exit devices equipped with dogging feature are not permitted on fire rated doors.
Rim exit devices are surface-mounted exit devices that are mounted on the secured side of a door in order to permit free egress. The latching mechanism for most rim exit devices is a Pullman bolt. Unlike cylindrical and mortise lock latches and bolts, the Pullman bolt swings out and in. The Pullman bolt has a less angled shape than a latch. To increase locking capability, the strike has a contoured shape that increases the locking strength of the Pullman bolt.
Mortise exit devices rod or bar assembly devices are designed to operate a mortise locking mechanism.
The basic vertical rod exit device has two-point latching into the jamb above the device and into the threshold/floor beneath the door. As an alternative, a one-point latching (top rod only) rod can extend vertically from the latch assembly. The vertical rod exit device top rod usually has a Pullman style bolt that locks against the top strike plate and the bottom rod usually has a deadbolt that slides into tubular bottom strike. Fire rated top rod only vertical rod exit devices will usually have some type of secondary independent lock mechanism that secures the door in place during a fire. Surface-mounted vertical rod exit devices have the rods and lock mechanisms mounted onto the secured side face of the door.
Concealed vertical rod exit devices have the rods and lock mechanisms within the body of the door. Most concealed vertical rod exit devices are installed in hollow core metal doors that have been built to accommodate this type of lock mechanism.
Over the years, a number of variations to the basic exit device have been developed. For example, Yale developed the SquareBolt latch in the mid 1990s. Similar to a cylindrical lock latch, the SquareBolt extends directly out from the assembly, unlike the Pullman Bolt that swings out.
There are exit devices equipped with a motor or solenoid mechanism that permits remote unlocking. Remote unlocking can be accomplished by having a button at a receptionist’s desk. This can eliminate the need for someone to go and unlock the door and relock the door once access has been gained.
Exit devices can be equipped with built-in panic alarms that sound when the door onto which the device is mounted is opened. The purpose of the panic alarm-equipped exit device is twofold. First, it provides life safety by allowing the device to unlock the door while notifying that there could be an emergency situation. These devices can be connected to a monitoring center. The second is to notify that the door is being opened without authorization. Many panic alarm-equipped exit devices require a key to reset.
Another variation is the delayed egress exit device. The delayed egress feature restricts the ability to press the bar and immediately open the door. Depending upon the Local Authority Having Jurisdiction (LAHJ), a delayed egress exit device can delay the unlocking of the authorized door for 15 or 30 seconds. Contact your locksmith distributor, factory or LAHJ for more information.
Exit devices are designed to be mounted onto the secure side of a door that swings out towards the unsecured side. Yale YM Series exit devices are available in three sizes, 36”, 42” and 48”. These measurements are not the actual size of the device; they are the width of the door they accommodate. A 36” exit device actually measures 32-3/8”. A 42” exit device measures 38-3/8”. A 48” exit device measures 44-3/8”. This is because most doors fit into a jamb whose stops cover a portion of the door face.
NOTE: Although there is no consensus between lock hardware manufacturers, the exit device is mounted approximately 39” to 42” above the finished floor. This range should satisfy ADA as well as codes and local ordinances.
I was invited to the retrofitting of the lock hardware on a pair of wide stile aluminum doors equipped with rim exit devices latching onto a mullion.