Benefits of customizing dust hazard controls to meet your needs

Abstract

The OSHA Combustible Dust National Emphasis Program (NEP), recent studies commissioned by the National Fire Protection Association (NFPA) Research Foundation and U.S. Chemical Safety and Hazard Investigation Board (CSB), as well as emphasis by insurance companies have brought more urgency to combustible dust safety. NFPA standards are being revised for consistency and clarity of standards for combustible dust safety. While that is a significant improvement from conditions of past decades, the situation can be improved even more by implementing risk‐based methods to help develop application‐specific explosion protection. Many facilities that handle combustible particulate solids follow prescriptive requirements of applicable NFPA standards, especially for new installations. Decisions are often driven primarily by meeting codes and standards with minimum capital cost. Legacy installations that do not meet current standards typically claim “grandfather” status as the reason for not implementing the current standard requirement or good engineering practice. The goal of this paper is to present a method of adapting the familiar process safety risk matrix to assess likelihood of a deflagration event rather than the overall the risk of a consequence. This method provides an objective basis to assist staff of a legacy facility to make decisions to prioritize capital improvement projects, to follow current good engineering practice, and to stop relying on “grandfather” status. This paper makes the broad, practical assumption that any deflagration event has serious consequences. The magnitude of those consequences may vary based on facility siting, deflagration area of effect, population of personnel in the affected area, or business criticality of affected equipment and structures. Decisions based solely on the likelihood matrix may inadvertently prioritize a more likely, but less consequential, concern over an event that may put multiple people at risk, or have serious commercial implications. Methods such as Hazard and Operability Study (HAZOP), Failure Modes and Effects Analysis (FMEA), Fault Tree Analysis (FTA) and Layer of Protection Analysis (LOPA) are useful to more comprehensively understand risks. Flexible, outside‐the‐box thinking in applying safeguards, Independent Protection Layers (IPLs), administrative controls, and facility siting may provide a better solution than merely following prescriptive code without making the effort to fully understand the hazard.