The Basics: Exit Devices, Door Alarms & Delayed Egress

Exit devices are one of the most important architectural door hardware items. In most cases exit devices are already there when you arrive to the site. They are permanent assets to a building which were specified at the time the building was built or the tenants took occupancy. I rarely have had to remove exit devices.

Generally speaking, exit devices are very reliable, and once properly installed, work indefinitely. They’re often referred to as ‘crash bars’ because that’s how people use them, by crashing into them with their bodies, forklifts, gurneys or whatever they are carrying. The reason the crash bar is there is so that the door may be readily opened for egress without having to grip and turn a lever or a knob, and it should be apparent enough so that anyone can figure it out, even if the room is full of smoke and they can’t even see the exit device.

The point is the exit device is designed to be abused and still continue to operate.

On the other hand, the exit device is not supposed to be abused while it is being installed, and that’s what I’ve encountered when arriving at new buildings where the contractor has already left town, but failed to address all the items on their punchlist. They figure “let the locksmith deal with it.” And that’s what I always did, and by doing so have won a lot of loyal customers and additional business for my employers.

One time, we were hired to install card readers on a newly constructed dormitory for a state university. The students hadn’t even moved in yet and the campus locksmith was getting apprehensive because the concealed rod exits on the exterior doors were not ready for card readers nor were they functioning. Additionally the doors were theoretically supposed to be handicapped accessible with low energy operators. These were also not working.

The goal was to have doors with properly working exit devices which could be opened from the inside for manual or automated egress with ‘knowing act’ pushplates or from the outside by use of a valid credential and then by pressing the pushplate.

All of this was well beyond the capabilities of both the general contractor or the door control contractor, but fortunately not beyond mine. We picked up a lot of additional work and were invited to bid on the rest of the doors for the planned entire campus-wide upgrade.

I’ve always worked closely with manufacturers, and when their equipment isn’t working, they get upset because they fear getting written out of the bid spec, or that another vendor will be allowed. Manufacturers work hard to get their products put into the bid specs and hate when the words  “or equivalent” are put into an addendum, because it opens the bid up to many other players.

Another time there was a big project where many of the exit devices were connected to card readers (by others) but would not open reliably. Another grand slam.

After a new project, there is usually a punchlist of things which do not operate as anticipated, and also a wish list set forth by various departments which expresses what they actually wanted in the first place and how the wanted things to work.

By demonstrating the ability to get the original hardware working, I won the respect and gratitude of the facility’s director who made sure that we did the specifying and were given the green light to install and deploy all the other electric locking equipment for the building. It was a lot of fun, and kept me and many of my co-workers occupied for quite a while as deficits were revealed and new work was rolled out.

Many security professionals do not know how to work with exit devices in all their manifestations. A few do, and it pays off for them. It also could for you.

I see a lot of exit devices at the home centers, but not for sale on the hardware aisles, but rather on perimeter doors to deter shoplifting.

Panic Bars vs. Exit Hardware

Fire Exit Hardware is UL Listed to be used on a fire door assembly.  One of the most significant functional differences between a panic bar and a Fire Rated Exit Device is that the Fire Rated exit device cannot have the dogging feature. This is because one of the cardinal rules of fire doors is that they are always closed and latched. Dogging is the process where the latches are retracted on the exit device so the door may be opened without having to use trim or push on the bar.

An interesting detail about exits is the electric dogging (or latch retraction) feature available from many manufacturers. Even though retracting the latch is dogging the exit device, fire rated exit devices are available with electric dogging. The requirement is that the latch automatically engage in the event of a fire. This is a detail which might warrant you contact your AHJ to confirm it is acceptable for your specific application.

Panic bars & (fire exit hardware) come in three types:

1. Vertical rods/cables  (surface mounted or concealed) These have two, or in some applications one latch (I’ll explain later in this article)

2. Mortise (the lock body in inside the door and there is a single latch)

3. Rim Exits (the device mounts on the surface of the door and there is one latch). Rim locks used to be very common lock items.

Please note: there are several specialized exit devices that provide multiple point locking which are not included in this discussion.

One Releasing Operation

In most situations, no other locks, bolts or other hardware can be installed on a door which has an exit device. (We’ll discuss delayed egress later in the article.)

The one releasing operation does not address the OPENING PRESSURE required to unlatch the exit device from the egress side, or how hard you must push on the door to open it. These parameters are largely governed by the door closer, although the condition of the door, the installation of the exit device and site conditions such as atmospheric wind and HVAC back pressure may affect how difficult it is to dislodge a closed door. An example would be a warped door which when closed applies pressure on the exit device’s latch preventing it from moving freely to unlock.

The codes vary on how much pressure should be required to retract the latch. Some codes and standards require panic hardware to operate with a maximum of 15 pounds of force, while other codes and standards limit the operable force for hardware to 5 pounds. A special UL listing indicates panic hardware that is certified to operate with 5 pounds of force or less.

These numbers correspond with the parameters found in the ADAAG (Americans with Disabilities Guidelines) a publication available on line or from the Department of Justice (DOJ) which states 15 lbs for exterior doors and 5 lbs. for interior doors.

You can obtain a door pressure gauge to measure these parameters.

Latch Throw

This refers to how far the lock’s latch must project from the door’s edge. This length is part of the fire door assembly’s specification.

How much of the latch will fall behind the strike will be in inversely proportionate to the gap between the door and the frame where the strike is installed.

The allowable gap between the edge of the door and the frame is also part of the fire door assembly’s specification.

Here are some tolerances from NFPA 80, Section 6.3.1.7.1 just to give you some idea how these two tolerances interact, and how easy it is to go wrong when working with worn doors and frames, or improperly specified or installed locks.

Gap Allowances for Fire Doors made of Wood:

• Clearance for under the bottom of the door maximum is 3/4”
• Clearance between door and frame is 1/8”
• Clearance for meeting edges for a pair of doors is 1/8”

Gap Allowances for Fire Doors made of Steel:

• Clearance for under the bottom of the door maximum is 3/4”
• Clearance between door and frame is 1/8”, +/- 1/16”
• Clearance for meeting edges for a pair of doors is 1/8”, +/- 1/16”

Latch throw (no longer in NFPA 80, but must conform to manufacturer’s recommendations) between ½-inch and ¾-inch

I’ve been on many sites where the conditions on the door were such that the door could be dislodged from its locked position by shaking the door. Shaking the door is not part of the fire door inspection, but maybe it should be. The door, frame or hinges can shift; the latch spring and keeper, or electric strike gate can weaken over time and might contribute to malfunctions of the exit device and affect the performance of the door assembly as either passive fire protection or as a security device.

The label on every fire door shows the detailed specifications of the door and assembly. The label may over time be removed or painted over, but this is not usually acceptable to the Fire Marshal who is trying to determine whether the door assembly is properly rated for the opening.

Exit devices are factory labelled as either Panic Hardware or Fire Exit Hardware. Fire exit hardware must conform to UL 10C and UL 305.

Less Bottom Rod

This special setup is used with surface mounted vertical rod devices in healthcare and other situations where bottom rods may prove problematic because the can become damaged and inoperable from being hit by objects, or because they create an obstruction across the face of the door which interferes with wheelchairs, walkers and other similar devices used by handicapped or disabled individuals.

NFPA 80 requires that a fire door be equipped with an active latch bolt to ensure the fire door positively latched during a fire. Vertical rod devices are sometimes used on pairs of doors, or where additional strength and rigidity two latches (one at the top and another at the bottom of the door will provide.

On some openings, if the bottom rod is not used, an auxiliary fire pin must be provided. An auxiliary fire pin is installed in the edge of the door and will be actuated at an extremely high temperature, causing the pin to pop out and engage the other door of the pair to hold the pair of doors closed to mitigate the spread of fire or smoke. The theory is that if the door becomes that hot, no one will still be alive to escape thru it.

Electronic Access Control And Egress Control

Electric latch retraction, electric strike and electrified trim are the three methods used to electrically control openings with exit devices with EAC (electronic access control)

Latch retraction’s electrical mechanisms (often solenoids, sometimes servos) are installed in the exit device and pull back the exit device’s latch when power is applied. The solenoid type has the advantage of always releasing the latch when the actuating power is removed. The disadvantage is the latch may not retract properly when power is applied. Many models of this type of retraction require a large amount of power to actuate the bolt which may be on a strong spring, or being bound up because of improper door adjustment, wind pressure or individuals pushing against the door while it is being retracted. The latch should retract regardless if the exit device is properly designed, but sometimes they do not. This can be due to inadequate power reaching the solenoid which can be caused by several other different issues.

Some latch retraction makes a loud noise when it is energized which is objectionable in certain surroundings. So silent latch retraction was born. It uses servos which are quiet operating motors that require relatively little power to operate and are virtually silent when the operate. Servos are being used more often for latch retraction because of the lower power requirement and quieter operation.

Electric strikes can also be used for adapting traditional exit devices to EAC. For vertical rod devices, the strikes are installed at the top and bottom of the door, unless it is a LBR situation.

For mortise exit devices, the electric strike is similar to the type used with any mortise type lock, only there is not likely be a provision for a deadbolt which is frequently used in a passage door mortise box lock. Strikes for use with rim exit devices  are relatively easy to install and adjust.

Electrified trim is often used to control access on doors with exit devices. They are quiet and draw little current to operate. However the exit device must use  trim which is adoptable to this conversion. Usuallt lever trim. Many exit devices use fixed handles and rim cylinders on the exterior of the building. There are specialty manufacturers who can supply operable electrified trim to upgrade this type of exit device. This approach is highly desirable because it uses a portion of the customer’s existing hardware thus saving money, and reduces the blemishes and damage to the door which an exit device swap could entail.

Delayed Egress

Delayed egress describes a special locking arrangement which allows for two different functions: the electrical unlocking of the door, and a security feature referred to as a special locking arrangement. Delayed egress is intended to protect the premises and its occupants from unauthorized use of a door for egress by preventing the door from opening immediately when the exit is attempted in order to give security or healthcare personnel time to respond to the point of egress.

Delayed egress hardware prevents a door from being opened from the egress side, usually for a period of 15 seconds. This type of device is used for a variety of purposes, such as

• In retail to prevent theft;
• In healthcare to prevent patients from eloping;
• In education to prevent students from taking unscheduled breaks
• Inc to force the use of a card reader to bother enter and egress to accurately track personnel movements while maintaining life safety.

The system is most commonly comprised of an exit device incorporating delayed egress features, or an electromagnetic lock and power supply, one of which would contain delayed egress circuitry. When the device is actuated, the door remains locked on the egress side for 15 seconds, and then releases to allow egress.

Some excellent exit devices have the delayed egress incorporated into their design. By using the crossbar as an actuator and also to unlock the door, the safety of the delayed egress system is, IMO actually enhanced.

Delayed egress system also are offered as component systems, but when the whole system is in a single housing it simplifies the installation and you know the different elements of the system are deigned to work together.

NFPA 101 SPECIAL LOCKING ARRANGEMENTS explains delayed egress in detail and is used by many code officials throughout the country as a reference.

Because of their versatility, because exit devices are used in non-residential premises, and because they are an essential life safety tool, exit devices are one of the more exciting types of architectural hardware which the locksmith can offer.