Report: Slipshod monitoring caused costly fire, explosion

A new government report reinforces the importance of making sure piping systems are regularly inspected for defects, particularly in vulnerable areas such as elbows.

The factual report from the U.S. Chemical Safety Board (CSB) detailed the June 2019 fire and explosion at the Philadelphia Energy Solutions (PES) refinery in Philadelphia. The report revealed that the incident was caused by a corroded pipe elbow that ruptured.

According to the report, a vapor cloud began forming after a corrosive chemical leaked through the failed elbow. A short time later, the cloud ignited. There were two additional explosions. All told, five workers suffered minor injuries and about 3,271 pounds of a hazardous chemical were released into the atmosphere. Shortly after the incident, PES shut down the refinery and declared bankruptcy.

The CSB said the elbow that failed was part of the original piping system installed in 1973. Although the piping circuit that included the ruptured elbow was subject to regular ultrasonic thickness measurements at designated locations, the elbow itself wasn’t actively monitored. As a result, managers didn’t know that the chemical in the system had corroded the elbow to 0.012 inches, which is thin enough to have prompted PES to replace the elbow.

What it means to you:

Now is probably a good time to talk to production managers about your process safety management plans for corrosion monitoring of piping systems. Make sure that the monitoring is as comprehensive as possible, and that it includes vulnerable piping sections such as elbows.

(From the Oct. 28, 2019 issue of OSHA Compliance News)