Control Engineering

Peter Welander

An interesting safety resource
June 18, 2007

One of the plenary sessions at Honeywell's User Group was with Dr. Nancy Leveson on plant safety. She is from MIT and was the only presenter who spoke to the total group who was not with Honeywell or a member of the steering committee. (She has launched her own safety company, Safeware Engineering.) For the time she spoke, Dr. Leveson had the audience focused on her presentation.

She made some very interesting points about leadership:

• Safety at the plant level requires passionate leadership.
• It's the tone at the top that makes it happen (or not happen) at all levels.
• Safety and productivity are not in conflict if you are looking at the bigger picture.

Companies make some critical mistakes:

• Reductions in injury rates is not a valid metric to indicate safety.
• Redundancy is not a real protection given the frequency of common mode failures.
• Just because something doesn't happen does not reduce its likelihood of happening.

The nature of errors:

More sophisticated automation puts higher demand on operators. As processes become more complex, there are more complex relationships that operators have to understand. Under those circumstances, operators are more likely to make errors of omission than errors of commission. Hence the importance of training, now more than ever. People investigating accidents have a tendency to blame operators for not following procedures, even though the written procedures have nothing to do with what really has to happen to make things work. Consider these two facts:

• When air traffic controllers want to muck up the system to make a point, they run by the book. The system couldn't work if they followed procedures.
• During the Three Mile Island crisis, operators followed written procedures.

Now that's something to think about.

Posted by Peter Welander on June 18, 2007 | Comments (0)