The role design error plays in chemical industry accidents

What proportion of chemical process incidents have design as a contributor? This study soon to be summarised explored these links.

They analysed 284 major equipment-related accident cases from a database.

What I liked about the definition of design in this study is that it went beyond just the literal plant/equipment view.

Here, a “design error is deemed to have occurred, if the design or operating procedures are changed after an incident has occurred”.

NB. This is one of ‘tabulation of error’ studies. Don’t read too literally into the specific percentages, but I think there’s something to the findings about the significant role design plays; also not helpful to simply shift blame from the frontline to the designers/managers. But also remember that WYLFIWYF.

Results:

· Design errors were divided into 11 categories

· 79% (224 of 284) had at least one error

· 72% had multiple design errors, giving an average of 2.35 design errors per case

· ~59% of design changes involved changes in equipment or process, like minor structural modification, change in layout, replacement of construction material, safer heat transfer material or installing safety protection systems

· 41% were non-hardware related changes, including equipment setting, adjustment of automation limits, design documentation, and more

Wrapping up, they argue that nearly 80% of accident cases had at least one design error, and most had more than one.

These findings “shows that nearly 2/3 of design errors are done in basic and detailed engineering phases.

Authors: Kidam, K., & Hurme, M. (2012). Design as a contributor to chemical process accidents. Journal of Loss Prevention in the Process Industries, 25(4), 655-666.