Motorized Latch Retraction

An Exit Device Option Providing Peace of Mind & Peace and Quiet

By David Karley, Exit Device Product Manager, DORMA Americas

As safety, security, and end-users’ needs remain in the forefront of developers’ and property owners’ minds, door hardware manufacturers need to stay vigilant in their efforts to design new—and improve existing—products and components. Introduced several years ago, Motorized Latch Retraction (MLR) is one innovation that has helped satisfy all three top-of-mind concerns.

What Is MLR And Why Was It Developed?

MLR (also known as “electrified latch retraction”) provides electronic control of an exit device via a quiet motor. It was created as an option for use in noise-sensitive environments that need the security of access control. Functioning very quietly, it’s an ideal solution for facilities such as hospitals, doctors’ offices, museums, theaters, libraries, and child care centers. Really, any facility that would benefit from a motor-driven device and where ambient noise would be distracting could find value in an exit device with MLR.

How Does MLR Work?

In an MLR-equipped exit device, the concealed motor inside the device’s rail draws in the touch bar. This action retracts the latch, allowing the door to open. This sequence is activated upon presentation of a valid credential previously entered into the access control peripheral such as a card reader or keypad. MLR exits can also be integrated with access control systems and peripherals (remotely or locally) to have latches held retracted (“dogged”) electronically during non-secure hours.

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What Are Some Advantages Of MLR?

  • Versatility
    You can use MLR in a broad range of applications, including on single and double doors, as well as on double egress doors.
  • Energy-efficiency
    MLR typically operates on low power consumption, making it less costly to operate and safer than standard solenoid-driven latch retraction products.
  • Quiet Operation

With a low amperage requirement (generally under 1 AMP), MLR operates smoothly and very quietly.

  • ADA Compliance

MLR devices can be paired with an ADA operator on an opening. (Note that for compatibility reasons, you will likely need an ADA operator and an MLR device made by the same manufacturer.)

  • Compatibility With Fire-Rated Doors

Most MLR options work with fire-rated doors, which is crucial for employee and public safety.

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Examples Of MLR In Action

Early in 2013 at DORMA, we introduced an MLR option for our DORMA 9000 Series exit device. Customers in several market segments were looking for an access solution that would provide not only security, but also subtle operation so as not to disturb their environment.

In the health care market for example, one project that was up for bid presented several scenarios that would be well-served by MLR-equipped exit devices:

  • Double doors (with ADA operators) from a hallway to a patient elevator and double doors from a hallway to exam rooms—These doors needed to give authorized staff members a way that didn’t require manual labor to take patients in wheelchairs and hospital beds to secured areas where the elevators and exam rooms are located. Upon personnel presenting their valid access card to the reader, the reader would communicate with the exit device and operator to unlock and open the doors—a sequence taking just seconds to complete.  That would enable the staff to easily take patients to wherever they’d need to go (radiology, CT, lab, etc.) or to the floor where their room is located.
  • Single door (no ADA) linking public areas to patient rooms—When patients are trying to recover, the last thing they need are loud-latching doors disturbing their rest. MLR’s quiet operation offers a perfect solution in scenarios like these where both staff and visitors will frequently go in and out through the doorways.

In the financial institution market, DORMA has provided MLR devices to a bank that has been using them for retrofit work on existing glass doors with pull handles on the exterior (secure) side of the door. Rather than change the trim to something electrified (with glass, there’s no way to conceal the wire inside the door), they converted the exit device on the push side of the door to MLR. Because of the shorter distance from the end of the device to the jamb, the wires could be concealed with a door loop.

MLR: A Solid Solution

Those are just a few examples of how MLR can solve issues that specific types of facilities in different industries face.

MLR has proven to be a complete, reliable security solution for architects, building managers, and end users. Safe, secure, and user environment-friendly, it’s a feature that delivers multiple benefits in a broad range of applications. As developers and property owners seek to improve the security and life safety of their facilities, MLR will surely gain popularity and become a frequently requested option.