This safety tool designed by Los Alamos National Laboratory researchers locks fire-rated roll-up doors securely in place during maintenance, preventing them from closing unexpectedly when the power is turned off. The Challenge: Fire-rated roll-up doors — the large metal doors used in industrial or secure facilities — are designed to automatically close when power is lost to contain fires. However, this same safety feature makes it dangerous and nearly impossible to perform maintenance on the doors while they are open. If power is turned off for safety, the door will automatically uncoil and close, creating a serious risk of injury or damage. Existing safety procedures and manufacturer options did not provide a way to keep the doors open safely without altering the door's fire-certified design or risking damage to sensors and other components. Problems Solved: This invention provides a simple mechanical lock-out tool that attaches to the door's axle to physically prevent it from closing when power is off. It keeps the door safely open for maintenance or inspection. It works with existing Lock-Out/Tag-Out (LOTO) safety procedures so workers can easily secure and tag the tool during repairs. It avoids modifying the door or voiding its fire rating. It protects equipment and personnel, eliminating the need for unsafe props or energized work. The tool design is durable, easy to install, and can be adopted commercially by door manufacturers as essential maintenance equipment. In short, it transforms a previously unsafe maintenance task into a controlled, compliant, and safe operation for anyone servicing fire-rated roll-up doors. Market Applications: Industrial and Manufacturing Facilities Government and Defense Sites Commercial Buildings and Warehouses Critical Infrastructure and Utilities Door Manufacturers and Installers Maintenance and Safety Equipment Suppliers Fire Safety and Compliance Markets Development Status: Design complete, Implemented and tested for functionality and operations. US Patent No. 12,385,320 B1 LA-UR-25-31354 LANL Tech Partnerships: Unlock the Innovative Potential Los Alamos National Laboratory offers a wide range of cutting-edge technologies and capabilities that may provide your company with a competitive edge in the market and unlock the innovative potential that can enhance, refine, and revolutionize your products. LANL's licensing program focuses on moving inventions developed by our researchers to commercial innovations. Patented and patent pending inventions and copyrighted software are available to existing and start-up companies through exclusive and non-exclusive licensing agreements. For specific discussions, please contact licensing@lanl.gov. Note: This is not a call for external services for the development of this technology. https://www.lanl.gov/engage/collaboration/feynman-center/partner-with-us/licensing-technology https://www.lanl.gov/engage/collaboration/feynman-center/tech-and-capability-search