Product Spotlight: Safe-T-Lock Door Monitor

March 8, 2022

Elevators have come a long way from the days when operators manually controlled doors and activated the cab’s vertical motion, helping keep passengers safe every step of the way. Over the years, technologies like light curtains, multi-dimensional sensors, infrared, and more, have been deployed, just in and around the doors. Still, we hear news of trappings, collisions and other contact related injuries. It’s estimated that the average elevator door opens a shocking 200,000 times a year.

Among the worst of the serious situations happen when an elevator cab begins moving vertically when it shouldn’t. If passengers are attempting to use the cab, the worst of all outcomes is possible. Enter Safe-T-Lock solution. The ADAMS Safe-T-Lock monitor provides complete protection against car operation in the case the following faults are detected, eliminating the risk of the car moving when it absolutely should not:

  1. Door not fully closed – This type of fault indicates the car gate switch and/or hoistway door lock are closed but the car door is not physically fully closed.
  2. Shorted door lock or car gate switch – This type of fault indicates inconsistent performance of the door fully open signal, car gate switch, hoistway door lock, inspection and Fire Phase 2 signals.
  3. Hardware failure detection – Safe-T-Lock monitors itself against hardware failure for redundant protection.

The Safe-T-Lock monitor is a PLC based design, that includes a display screen to indicate monitor status and specific door fault codes for trouble shooting. It also includes a terminal block system to easily interface with most controls on the market, new and old. Technology advancements like Safe-T-Lock are important within the elevator industry as they keep passengers safe. In recent years, we’ve heard shocking stories of injury and even death caused by elevators. Unsurprisingly, those kinds of serious situations have spurred a new round of stricter safety codes.

The A17 Ad Hoc Committee on Door Protection, for example, worked for years to develop the new requirements in the 2019 code update, ASME A17.5/CSA B44.1 Safety Code for Elevators and Escalators. New York City was one of the first large municipalities to adopt, and mandate some of the new guidance on 1/1/2020. New York City’s building code, 3.10.12, reads in part, with a handful of exceptions:

Means shall be provided to monitor the position of power-operated car doors that are mechanically coupled with the landing doors or power-operated car doors with manually operated swing-type hall doors, while the car is in the landing zone, in order

(a) To prevent the operation of the car if the car door is not closed (see Section 3.4.2(c) of ASME A17.3), regardless whether the portion of the circuits incorporating the car-door contact or the interlock contact of the landing door coupled with car door, or both, are closed or open.

(b) To prevent, except as permitted by inspection operation, the power closing of the doors if the car door is fully open.

This requires an extra level of security, fault detection that prohibits automatic car operation. While not all codes are as stringent as New York City’s, things are trending that way in cities big and small; these codes have since been adopted in Alabama and Florida. No matter where you are, if you operate any of the hundreds of thousands of elevators built before 2017, you want to consider a superior solution like Safe-T-Lock. It ensures the strictest requirements are met if new codes are implemented and, more importantly, that passengers are kept safe.

Visit our Safe-T-lock product page or get in touch with an ADAMS product expert to learn how easy it is to install.