Recently, Xcel Energy, a large energy company in the United States, selected the Sofis Power Wrench portable actuator as a tool to combat fatigue in manual valve operations.
The decision to use the Power Wrench portable actuators was based on an evaluation carried out by a committee of engineers, ergonomic specialists, and operators to address operational, worker-centric process safety principles.
Worker-centric process safety management (PSM) is a new approach to PSM that works to make systems, procedures, and tasks suited to the physical and psychological needs of humans. Just as ergonomics is the field of suiting equipment to the worker, instead of the other way around, worker-centric PSM seeks to remove error traps, inefficiencies in workflow, confusing procedures, and building plants to keep people safe, instead of relying on people to keep the plants safe.
Worker-centric PSM seeks to avoid or eliminate so-called ‘error traps’, which are circumstances that can increase the risk of an accident. Error traps make it more difficult to work safely and increase the likelihood of errors. When combined with humans’ innate tendencies, they create a likely opportunity for error to occur. Specific circumstances or ways of working can produce an environment conducive to human error. These are called ‘drivers of error’. Fatigue is an important driver of error.
Physical fatigue contributes to making mistakes, as the worker is excessively distracted by the discomfort of the environment, or the strain necessary to perform the task. This can lead to error because the worker is more focused on how to perform part of a task than anything else and increases the risk of injury to the worker as well as the equipment.
As a result of the evaluation, Xcel Energy considered the strategic use of equipment to overcome fatigue and physical operator stress during manual valve operations. A specific operation involved a valve on a newly constructed high-pressure valve set that required ~220 revolutions to actuate and often required actuation multiple times per day. Manual operation of large valves induces strained or fatigued arms, hands, shoulders, and backs, increasing the risk of injury and missed days of work. An on-site demonstration of the Power Wrench portable actuator found that using the Power Wrench allowed operators to operate these valves safely and quickly, reducing stress on the operators.