An Air System Is Improved and a Vessel Blows Up

Talented supervisors often need to make improvements, but with their zeal to improve they may fail to see the need for all of the fanfare of a committee review for a small change in a utility system. In a previous example, the operating team made a small change in just a waste water line that yielded damages of over a half-million dollars. 

This case involves a 50 psig (345 kPa gauge) utility air system. It was probably easy to justify not initiating a committee review for decreasing moisture within a 40-year-old compressed air system. No one envisioned this improvement could create a problem. It is easy to see the narrow focus of the innovators now. 

These creative individuals had set up a scheme to purge through the top of the air dryer and out of a partially opened ball valve on the lower piping. They, no doubt, failed to realize that the dryers were not individually equipped with safety relief valves. The overpressure protection was on the compressors. A new operator to the area did not open the exit valve sufficiently during the cool-down step. 

This equipment was over 40 years old and was purchased by the previous owner. Documentation was very limited. The dryers were not even protected from overpressure from the possibility of a high-pressure steam-coil leak. After this incident the entire system was dismantled and scrapped. 

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