Guidelines for Applying Process Hazard Analysis Techniques to Combustible Dust Applications

Combustible dust safety in processing applications has moved to the forefront of public and industrial awareness due to major combustible dust explosion fatalities and government agency emphasis. The U.S. Occupational Safety and Health Administration (OSHA) recently implemented a combustible dust National Emphasis Program to inspect workplaces that create or handle combustible dusts.   In addition, the National Fire Protection Association (NFPA) has been revising and developing new standards that cover combustible dusts and are requiring hazard assessments be conducted to identify combustible dust hazards through the use of process hazard analysis (PHA). As a result, manufacturers and users are scrambling to evaluate and improve their dust collection systems and safety practices as well as to understand the hazardous characteristics of their dusts.  An important element for the improvement of safety is identification and evaluation of potential hazards of dust-related processes. A means to do this is by the application of a process hazard analysis (PHA).  PHA involves a  systematic review of potential hazards using a set of prescribed methodologies (i.e. Hazard and Operability (HAZOP) studies, What If studies, etc.). The traditional PHA methodology is typically used in chemical processing and petrochemical facilities and is not routinely applied to combustible dust hazards.  As a result, we have found a wide disparity in PHA applications to dust-related processes throughout industry. This paper attempts to provide guidance related to the application  of PHA to combustible dust hazards using a series of case studies and examples of practical considerations and applications of PHA techniques.