Process Safety
Topic outline
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Process Safety is about saving lives, avoiding injuries and protecting the environment. News bulletins remind us constantly that accidents occur all too often in industrial processes. The industries concerned range from small-scale fine chemical production to oil refining to food processing to processing agricultural waste products.
The problems can be summed up as the “big three”: fires, explosions and releases of toxic materials. Understanding the causes of such accidents is essential to avoiding them in the future.
Your role, if you accept it, is to do just that and to advise plant managers and designers of industrial installations on how to avoid such accidents. As a Process Safety Engineer you will have a pivotal role in risk management. Following the online course is your first step on the road to getting there. -
Unit 1. Introduction to hazards of chemical industry
This first Unit introduces “Process safety”. It highlights the importance of this topic from the lessons learnt from major accidents. It then covers some of the most important types of incident observed in the process industries, especially loss of containment, fires and gas phase explosions.
For each type of incident, it gives real examples, together with determining parameters and an outline of methods of prevention and protection.
Unit 2. Various explosions
The second unit continues the presentation of the most important types of incident observed in the process industries. It covers physical explosions, dust explosions and condensed phase explosions, including runaway reactions. For each type of incident, it gives real examples, together with determining parameters and an outline of methods of prevention and protection.
Unit 3. Reduction of risk of fires and explosions
The third unit looks at the various ways to reduce the risk of incidents. It explains how and why we draw up plans of classified hazardous areas or “explosive zones” and what we should do in such areas to reduce the risk level. It covers the control of ignition sources in order to prevent fires, gas phase explosions and dust explosions. It also covers the issue of pressure and vacuum relief.
Unit 4. Consequence modeling
The fourth unit looks at how we estimate the effects of incidents such as leaks, fires and explosions. For a given type of incident, it presents the methods used to estimate distances to pre-defined threshold levels of toxicity, thermal radiation and overpressure. It shows how such studies can help to define the areas where there is a risk of injury or death.
Unit 5. Risk assessment principles
The fifth unit outlines the main methods used to identify hazard scenarios for a given industrial process unit. The methods presented incorporate HAZard and OPerabilty Studies (HAZOP) and Layers of Protection Analysis (LOPA), as used in the Solvay group of companies.
Unit 6. Risk assessment details and tools
The sixth unit details how we assess the risk level of a hazard scenario in the Solvay group of companies. It shows how we prioritize risk and deal with in a timely fashion. The method we use has some features that are unique to Solvay, but it is still firmly based on the established literature, so the material will be useful to engineers working for other companies.
Unit 7. Risk assessment of fire and explosion scenarios
The seventh unit shows how we carry out a risk assessment of a fire or explosion scenario. It includes how to assess, in a semi-quantitative way, the frequency of potential ignition sources. The ignition sources covered include electrostatic discharges, hot surfaces, electrical equipment, rotating machinery, electromagnetic radiation and lightning. The ignition frequency depends the flammable gas or dust, the extent of the zone where a flammable mixture is present and the type of equipment in that zone.
Unit 8. P&ID Diagram
Many engineers work on the same industrial facility. They fulfil a variety of functions: design, commissioning, operation, maintenance, etc., and of course safety. A common modelling means is therefore essential, in particular for ensuring safety. This Unit introduces the Piping and Instrumentation Diagram (P&ID) modelling tool. After clarifying the tagging and shape conventions, examples make it easier to understand the notations and benefits of P&ID.Unit 9. Instrumentation
Instrumentation in chemical facilities plays an essential role when implementing safety devices. Sensors communicate the most important physical values either to a control loop to regulate a process (including its shutdown), or to a simple display. Sensors are also a key component of Safety Instrumented Systems (SIS). This Unit addresses the principle of a control loop and the role of sensors. Sensors must be chosen carefully according to the context of their use. The various characteristics enabling the appropriate selection of the following sensors are studied: temperature sensors, pressure sensors, flow rate sensors, and level sensors.
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Simon EGAN is a recognized Process Safety expert with 30 years industrial experience Rhône-Poulenc, Rhodia and now Solvay. He is a member of several committees responsible for international standards on static electricity and pressure relief systems. He has spent the last three years working on the Process Safety module of INSA’s online course in Safety Engineering and Management. He is the author of Units 1 to 7.
Fulbert Baudoin is an Associate Professor at the University of Toulouse (France). His research deals with the electrical characterization of dielectric material, to identify the mechanisms leading to ageing or breaking. They apply to energy, transport and aerospace sectors. He teaches instrumentation for chemical facilities as well as various diagrams used to represent a process of chemical industries. He is the author of the Units 8 (P&ID diagram) and 9 (Instrumentation).