I'm sure you are aware of the preliminary findings of the Philadelphia Energy Solutions (PES) Refinery explosion. If not, have a look at the video below. It is very interesting, but sad. I think we all can learn a lot from it.
The PES refinery is one of the largest refineries on the East Coast (processing 335,000 barrels per day of crude oil into gasoline, jet fuel, propane, home heating oil and other products) and one of the oldest in the US at 150 years old. The explosion of the Hydroflouric acid unit was the result of a rupture in the elbow bend of a pipe. According to the CSB, the investigators found the remnants of the failed elbow pipe, which they said had worn to .012 inches, which is about half the thickness of a credit card. The result of which was the likely contributing factor to the release of the flammable vapor. Even though thickness monitoring stations were installed, to measure pipe thickness and corrosion, there were none near or around the elbow joint that fractured. Incredibly, it was established that the piping had not been inspected for corrosion for 45 years. In addition to the explosion and fire there was about 3,200 pounds of hydrofluoric acid released into the atmosphere during the incident, although there were no reported ill-effects from the surrounding population.
The CSB report also noted that both the 2012 Chevron Richmond refinery fire in California and the 2009 Silver Eagle refinery fire in Utah were similarly caused by ruptured pipes that had thinned due to corrosion.
It's incredible to think that companies still don’t follow basic mechanical integrity which should include visual inspections of piping and valves for corrosion and/or unauthorized modifications, as well as checking wiring for corroded terminals and/or loose connections. From a functional safety perspective, visual inspection for clogged impulse lines, corrosion on piping and blocked filters, is a must. This is an area we cover as part of our operation and maintenance course, as well as our flagship FSE100 course. In the case of the PES explosion and fire, it was lucky that there were no fatalities. The unfortunate result of this is that the refinery has closed, resulting in the 1,100 workers losing their jobs.
How many more incidents have to occur before companies wake up and realize that the cost of implementing process and functional safety is nothing compared to the cost of an accident and the ensuing fallout. It will be interesting to read the final report from the CSB on this incident.