White Papers

Making Sense of Combustible Dust PHAs

Process hazard analyses (PHAs) have been conducted for decades in many industries. First conceived at ICI in the 1960s (Kletz, 2009), they have been refined and adapted for various applications, now finding their way into combustible dust hazard management. No matter the industry, the premise is the same, identify hazards, understand their causes and consequences, implement safeguards, and risks will be managed. The CCPS Guidelines for Hazard Evaluation Procedures, Third Edition, states: “A hazard evaluation is an organized effort to identify and analyze the significance of hazardous situations associated with a process or activity.” (Center for Chemical Process Safety, 2008) Keeping these in mind, a simple inclusive approach can be developed and applied. Several NFPA standards on combustible dust contain provisions for conducting process hazard analyses. The newest standard, NFPA 652, Standard on the Fundamentals of Combustible Dust, 2016 Edition, (NFPA, 2016) became effective on September 7, 2015. It requires that dust hazards analyses (DHAs) be completed on existing facilities and large modifications. The legacy standard, NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids, 2013 Edition, (NFPA, 2013) contains requirements for process hazard analysis that includes hazard assessments. If the facility falls under an industry- or commodity-specific (dust specific) NFPA standard (e.g., metals, agricultural and food, wood processing and woodworking, and sulfur) different hazard analysis requirements may apply. All of these competing recommendations and requirements can make it difficult to know where to start and what approach to use. This article will summarize the specific requirements in the standards and present some guidance to meet them. The result is a basic, easy to apply approach that will guide implementation of this critical technique. Read more

No Nonsense Approach to Addressing the Combustible Dust Hazard

February 7, 2008, was the pivotal point where recognizing the severity of dust hazards was pushed to the forefront of industry concerns. This was the date that a huge explosion occurred at the Imperial Sugar refinery in Savannah, Georgia. There were 14 deaths and 38 injuries, including an additional 14 serious burns. Read more

Overpressure Protection of Battery Energy Storage Systems (BESS)

Increased awareness of sustainable development objectives is encouraging the uptake of different energy storage media. Technologies are also now rapidly developing to a point where they can be a practicable alternative to combustion engines for public and private modes of transport. Lithium-ion (Li-ion) batteries are one technology widely used to meet those targets, for use in electric vehicles and energy storage installations. Read more

Polymerization Reactions Inhibitor Modeling - Styrene and Butyl Acrylate Incidents Case Studies

High levels of inhibitor can improve long term storage stability but may be detrimental to operational safety in the case of a fire, loss of cooling, or an external heating induced runaway reaction. Read more

Predicting Dust Deflagration Behavior Using A Burn Rate Model

NFPA 68 (2013) provides simple calculation methods for sizing vents for combustible dust deflagrations. These methods have limited applicability to process operations. For systems outside of the applicability limits of NFPA 68, Murphy and Melhem presented in 2016 a methodology using a burn rate model for deflagration vent sizing. It involved estimating a reference laminar burning velocity and then using this velocity to simulate behavior at different operating conditions. The paper introduced the methodology and derived a laminar burning velocity for Niacin from measurements in an explosion severity test in a 20-liter sphere. Read more

Pressure Relief Design for Reactive Systems

Pressure relief design for reactive systems requires a different way of thinking than standard non-reactive designs. Reactive systems are in a constant state of flux: compositions, mixture properties, temperatures, and pressures are all changing throughout the relief event. Being able to safely vent a reactive system requires careful consideration of the mixture properties before reaction, the pressure and temperature rates during the reaction, and the mixture properties after reaction. To understand how these system properties effect the sizing of pressure relief systems requires careful experimentation, analysis and scale-up application. This presentation will explain a model-based approach to reactive pressure relief system design. Read more