ARE YOU CARRYING OUT VIBRATION ANALYSIS FOR ROTATING EQUIPMENT TO PREDICT FAILURES?

On May 15, 2023, at 9:32 a.m., an accidental release of naphtha caught fire, fatally injuring one worker at a Refinery in Texas. The company estimated that this event resulted in $829 million in property damage.
On the morning of the incident, two employees were completing an equipment oil change on an elevated platform above a pump that was supplying naphtha to downstream equipment. The pump’s coupling failed, reducing outlet flow and creating high vibration that broke a small bore (¾-inch) piping section, releasing flammable naphtha. Employee 1 was on the platform cleaning up the work area while Employee 2 was carrying a bucket of oil down the stairs from the platform. Employee 2 smelled the released hydrocarbon and saw what looked like a steam cloud. Within minutes of the release, the flammable vapor ignited 

The heat from the fire ruptured piping and damaged other equipment. Employee 2 was able to exit the unit before the flammable naphtha ignited. Employee 1 did not escape from the elevated platform and was fatally injured by the fire.
The company's investigation found that a pump inspection in June 2022 had identified damage to the coupling of the pump but did not recommend any repairs. During the release in this incident, the pump’s motor continued to operate and spin the damaged coupling. The heat generated by the friction ignited some of the released naphtha, resulting in the fire. The investigation also found that according to the company’s mechanical integrity program, vibration analysis should be performed every two months to predict pump failures, including coupling failures. The last vibration analysis test on the pump was completed in October 2022, seven months before the incident. The company reported that approximately 102,000 pounds of naphtha and light hydrocarbons were released.

Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the incident was a pump coupling failure that created high vibration, breaking a section of small-bore piping and releasing flammable naphtha. With the pump’s motor continuing to operate, the coupling failure also created enough heat (friction) to ignite some of the released naphtha vapor, creating the fire.
The company's mechanical integrity program contributed to the incident by not repairing the damaged coupling identified by the inspection. Additionally, the company did not perform its required vibration analysis on the pump, which could have predicted the coupling failure. 

Source:CSB.gov