This post deals with a Rotary Screw Air Compressor coupling failure and the Field Service Report documenting this event. Normally a grid type coupling is considered pretty much bulletproof with the exception of grid wear due to misalignment or lubrication issues, so this failure 
was a surprise; the coupling halves were totally destroyed.
Great latitude is given to individuals in modern industry to act independently and handle issues as they arise and without direction. This is good, as we always need people that can identify a problem before it’s a disaster and act to correct or just handle it to completion.
The plants narrative went that at some point in the past, workers had made a mistake and then taken it upon themselves to cover up their error by modifying the equipment as discussed in the report. Unfortunately, the changes were not well thought out and the result of those modifications was this failure. Even if we could be assured that sound judgment would be applied, this action would still be a half measure as we’re dealing with people and unfortunately, even the best-intentioned people screw-up.
The plant had no Change Management Process while also attempting to push decisions to the lowest level. With a CMP all equipment changes (with the exception of incidental changes) are to be submitted for approval to a competent individual, preferably with an engineering background. These modifications would never have been considered incidental, they would never have been approved. It’s imperative that the CMP not be viewed as a roadblock or delaying tactic by the workers on the floor. If an issue is raised and an approval is needed in the middle of the night, the duty approver is expected to get up and go see what the issue is.
In fairness to the workers, the plant was understaffed and had very little engineering support for anything other than major projects. I also can’t believe a couple of guys on a second shift were changing the motor and got into this mess on their own. Falk couplings were hard to come by as stores stocked a minimum of parts so it was probably a special order item for that job. Looking at the total of the work done, it would most likely have run the job beyond a couple of shifts. It wouldn’t surprise me at all if some management wasn’t involved in some way, at some point. Yes, even supervisors and managers need to have all but incidental changes to the equipment approved within a Change Management Process.
I think it’s important to note; as a consultant, my job was not to fix blame but to help the plant understand what had happened and why, what should have happened, and how do we stay out of this kind of mess in the future. You can read the full report with the link below.