Process upsets involve towers that go down due to process problems or maintenance issues. It is imperative that you know the root cause of your process upsets in order to defer future upsets. This will save both time and money.
Root causes of upsets are rarely obvious. Causes of process problems can go undetected for years. It was simply assumed that upsets were a natural part of operations. Engineers seem surprised when they find out they have been merely working on symptoms, not the actual root cause, in the process upset.
Taking the time to find the root cause—not just fixing the symptoms—of your process upsets will save your tower from going down. Make sure you have an efficient SOP and training program for anyone that would be involved with fixing these upsets.