The Science and Art of Door Closer Arms

July 1, 2021
Know the different types and how each is aimed at different applications.

Door closers, the mainstay of a safe door, control a door and protect the security and safety of a building and its occupants. Door closer arms are the unsung heroes of door closers, because they transfer the control from the door closer to the opening and closing of the door. The best door controls (closers and arms) work together and are designed to complement the full spectrum of door functionality from heavy to light duty.

Surface-applied door closers do an admirable job of storing kinetic energy when a pedestrian opens a door. They then discharge energy to close the door. Store-discharge, store-discharge, store-discharge. In some ways, they’re the rechargeable batteries of door control.

But they can’t operate independently. Like an automobile engine that doesn’t connect with a transmission, door closers are useless without a physical connection — a drive shaft that conveys energy, like an automobile’s transmission. That’s where door closer arms come in. Arms permit the transfer of energy from the closer to the frame or the door, which results in a controlled opening and closing of the door.

The usefulness of arms extends beyond the rudimentary physics described above. As an integral part of a door system, arms can deliver a variety of functions that augment and complement a door closer’s operation.

Each manufacturer offers a selection of arms, so choosing the proper connection for each door closer, mounting configuration and desired function within a building can be downright challenging.

Door closer arms and closers also should provide a consistent, harmonized look from opening to opening. Some manufacturers produce interchangeable arms that support this uniformity across their door closer line. Interchangeability gives locksmiths fewer products to stock, adds flexibility and simplifies field installation. Interchangeability streamlines the ordeal of specifying and ordering products. Given how complicated the process can be, any measure of simplification is welcome.

Here’s a look at different types of arms.

Standard Arms

Standard arms provide a simple physical link between the door closer and the door or frame. They’re used with regular mount, top jamb mount or parallel-arm configurations when no additional functionality is desired, such as on a typical interior or exterior door.

Still, most manufacturers offer a couple of standard-arm options. Some are pinned or riveted at the elbow. Riveted arms deliver a more solid linkage and generally are preferred for security reasons, because they don’t come apart.

Conversely, standard arms are available in an unpinned configuration. These arms can be disassembled for quicker and easier installation. In addition, standard arms generally are available in a utilitarian rounded form or a more eye-pleasing flat-form style. Also, most companies offer a high-security arm that can withstand the use and abuse in certain facilities, such as corrections and educational buildings.

Dead Stop Arms

As the name implies, a dead stop arm is designed to assist in stopping the opening movement of the door in conjunction with a strong hydraulic backcheck in the closer to help to slow the door prior to engaging the dead stop. These arms are structured to work in a parallel-arm mount or top jamb mount on the push side of the door and a regular mount on the pull side to prevent damage caused by a pedestrian pushing the door into a wall.

Dead stop arms in a parallel-mount configuration often accommodate aesthetic demands for out-swinging doors. However, an in-swing museum gallery door or in-swing hotel or motel doors shouldn’t have a closer and arm on the hallway side. The hardware might look conspicuous on the hallway side of the door. Meanwhile, the owner probably has to protect the wall — particularly if a mural or display were there. A stop in the middle of the display simply wouldn’t be an option. A dead stop arm limits the movement of the door and would be appropriate in this application.

A frequent option with dead stop arms is a spring shock absorber. They’re used in high-traffic applications where dead-stop functionality is required but a floor stop or wall stop isn’t an option. In normal traffic, a door closer’s backcheck feature slows a door before it hits a stop, but during high-volume traffic, such as when students leave a study hall when the class bell rings, pedestrians pushing on the door can cause it to hit the stop repeatedly.

A spring absorber takes the load off the mechanical door stop. The spring acts as a cushion and transfers the force back to the entire door so it isn’t as abusive on the individual components, such as the hinges and frame, which results in a more reliable and longer lasting application.

Hold Open Arms

Hold open arms fix the door in an open position, typically between 70 and 120 degrees, although some arms provide a 180-degree opening. These arms are helpful when the entryway has to accommodate high traffic over time or when pedestrians carry objects and want an unobstructed path. Applications might include storefront doors, glass front entrances and interior shopping mall doors.

An important note: Mechanical hold open arms can be used only on nonfire-rated doors. If hold-open functionality is desired on a fire-rated door, you must use an electrified hold open, such as an electromagnetic holder or stop and closer, or a Fire Life Safety closer or holder combination.

The three primary types of hold open arms differ in how the function is engaged:

1.     Friction hold open arms are available in all three mounts: regular, top jamb and parallel arm. Friction hold open arms allow the door to be placed in the hold-open position automatically until the user puts force on the door to disengage the friction hold and cause the door to close. A friction hold open arm, in most cases, can be used with the standard template and would be a simple replacement. Typically, friction hold open arms must be coordinated with auxiliary stops to prevent damage to the door closer, arm, door and frame.

2.      Thumbturn or twist-turn hold open arms are used in parallel-arm, top jamb or regular-mount applications, depending on the manufacturer. You have to know the maximum degree of door swing and the desired hold-open angle: Is it 120 degrees, 90 degrees or what? The hold-open angle will affect the templating when the door closer is installed, so the angle has to be determined before installation.

3.      Plunger hold open arms are designed with a cam-type mechanism in the arm to allow the arm to be adjusted to any hold-open position. The plunger hold open arm doesn’t include a positive stop, but it has a bypass (breakaway) feature, so the arm won’t break if the door is pushed beyond the hold-open point. The plunger hold open design prevents overtravel and damage to the door closer, arm, door and frame.

Specialty Arms

Of course, special applications require a specially engineered arm. For example, narrow profile arms are ideal for low headframe conditions, such as a drop ceiling that abuts the top of the door frame. After all, some movement of the arm is in the vertical plane when the door opens, but without ample space, the arm can hit the ceiling or trim when the door opens or closes.

A narrow profile arm also might be necessary to provide attachment when narrow top rails on doors are used on glass doors. Attachment of standard arms would put the closer or arm into the glass and not provide adequate fastening.

These conditions can be resolved by using a flat or low-profile arm. A low-profile arm can buy enough room (about one-half of an inch) to permit the arm to travel over the top of the door or under the frame without contacting other surfaces and secure the surface closer and arm properly to the door or frame.

Track Arms

Unlike other arms, track arms don’t have an elbow or shoe. They consist of a single link of metal that connects to a track on the door or frame. The arm moves along the track as the door opens and closes.

Because they don’t have an elbow, track arms are used frequently in moderately abusive situations, such as the inside door of a school bathroom. (Considering that protruding arms have been known to be used as chin-up bars in schools and universities, a track arm removes the enticement to hang from the hardware.)

They also can be used in special applications, such as a luxury box-seating area where a protruding arm isn’t as desirable or a curtain might cause a conflict with installation and interference. Pocket installations that require doors to be flush with the wall and close only to direct a path of egress during an emergency are another viable application.

Track arms are ideal for when aesthetics are considered, because they provide a clean, minimalist look. However, their simple nature renders them less efficient across the opening and closing of the door cycle. It typically takes more force to open a track arm-configured door, and less closing force is available. This situation can be remedied by using a cam-and-roller door closer design. Simply put, the cam and roller are engineered to match the required opening or closing force with the angle of the opening. It’s a perfect match for track arms.

As with an automobile engine and transmission, without the “drive shaft” arm, a door closer is nothing. The two pieces of hardware work together to transfer energy during the closing and opening cycle. Together, they perform dozens of functions depending on the requirements of each entryway. Spend time with your local door hardware distributor or sales representative to choose the right door closer hardware for your specific application.

George Nimee is a learning leader at dormakaba Americas. He has more than 40 years’ experience as an access control design engineer and trainer for various security product manufacturers.