Process Equipment Selection and Risky Operation: The Consequences of Not Asking: “What If?”

A fire that rapidly spread throughout and eventually destroyed a large food processing facility, originated at a batch-type heated mixing unit.  The fire cause and origin investigation revealed how the fire started at the mixing unit and why it grew so rapidly.  The failure of a double-walled externally heated kettle, used to mix a batch of ingredients, was studied using a root cause analysis. This analysis indicates that a combination of poor equipment and materials selection, maintenance and fire hazards mitigation contributed to the fire initiating event, which was ultimately caused by the over pressurization  of the non-rated jacket of the mixing kettle.  Although the food processing facility was not required to perform a Process Hazard Analysis (PHA) for this particular operation, the root-cause analysis investigation showed how a simple “What if?” study would have identified the main failure modes and alerted the various departments involved in the plant operation about the ongoing hazard. Multiple lessons for the chemical and process industries can be drawn from this food industry incident; in particular in the areas of pressure rating for process equipment, pressure relief valve and heat transfer fluid selection, management of change, routine use of gas burners for product heating on production floors, and use of PHAs.