(128c) Calcium Stearate Deflagrations – A Series of Unfortunate Events

A series of deflagrations occurred in a plant unloading Calcium Stearate from bulk bags. Each one had a different root cause and illustrates the importance of management systems for ignition control and the need to evaluate a system for many  types of ignition sources.  The first event was caused by static discharge from an ungrounded tote. When upgrading the system Type C bags were specified for the product and a second deflagration occurred due to static discharge from and ungrounded bag. In the third deflagrations cause was most likely a conical pile discharge. The presence of fines and coarse material plus the use of a cubic vessel probably enhanced the likelihood of the brush discharge.