ANSI/ASSE Z244.1-2016 The Control of Hazardous Energy Lockout, Tagout, and Alternative Methods



When writing the latest edition of the Lockout Tagout standard The American National Standard Institute included examples of practical and useful applications of alternative risk reduction methods. Trapped Key is an example of such a method and is explored in more detail in this article. Certainly, access to ANSI/ASSE Z244.1-2016 is a must-have for factory and maintenance managers across the United States looking to implement Lockout Tagout procedures.




Employers are often faced with difficult decisions when employees do not follow Lockout Tagout procedures. It’s Human nature to forget to apply every step of such procedures. Therefore, is it better to apply disciplinary actions for Lockout Tagout violations? Or look at enhancing procedures with a more engineering controls approach that cannot be forgotten or avoided?  

Application Example Image of Trapped Key Application




Moreover, we can understand why Z244.1 includes examples of trapped key technology being used as an enhanced version of Lockout Tagout. In applications requiring mains isolation, a mechanical trapped key system can be used on access points to equipment. This ensures that full power isolation takes place before access is permitted.  

Example 2: Alternative Risk Reduction Measures for Mains Isolation for Machines/Equipment within ANSI/ASSE Z244.1 includes the following recommendations on how to incorporate trapped key for main isolations: 


First Recommendation

“Directly driving the contacts via a trapped key fitted to the shaft. This method would work on units that are small enough to allow the trapped key to drive directly.”

Second Recommendation

“Having a cam mechanism and bolt lock module for units that are too large for the trapped key to directly drive.”

Furthermore, Z244.1 includes a useful image of key switch and cam locking arrangements for readers to visualise an application to multiple access points.

Product Solutions

Product Solutions

Products Mentioned in this Article

mGard - Trapped Key Range

Key Switch

mGard - Trapped Key Range

Bolt Module