84195 - Process Safety Engineering M

Academic Year 2023/2024

  • Teaching Mode: Traditional lectures
  • Campus: Bologna
  • Corso: Second cycle degree programme (LM) in Chemical and Process Engineering (cod. 8896)

Learning outcomes

After the course students will be able to assess the risks due to industrial installations (i.e. chemical and process industries), through the application of basic concepts about: classification of hazardous substances, hazard identification, probabilistic assessment of top events and consequence assessment.

Course contents

1) Introduction to loss prevention and risk analysis

Risk and risk assessment. The risk assessment procedure. Risk matrixes. Risk acceptability criteria. Risk mitigation. Introduction to relevant regulation.

2) Hazardous properties of substances

Introduction to the hazardous properties of materials. Flammability. Toxicity. The GHS classification system. The material safety data sheet. Labelling.

3) Hazard identification

Introduction to hazard identification. Hazard identification techniques: past accident analysis analysis; checklists; safety review; index methods; what-if analysis; FMEA / FMECA; HazId analysis, HazOp analysis. How to choose the most suitable technique.

4) Consequence and damage assessment

Introduction to consequence assessment models. Source models: introduction; typical storage conditions of substances; schematization of the releases; some source term models (liquid outflow, gas outflow, flash, evaporating and boiling pool models). Fire models: introduction to fires in the process industry and to their modeling; radiation models for poolfires, jetfires, fireballs. Dispersion models: introduction and classification of models; meteorological parameters (atmospheric turbulence and wind); Gaussian dispersion model for steady state releases (isopleths for flammable and toxic clouds, mass in the explosivity range); Gaussian dispersion model for instantaneous releases; dispersion of heavy gases. Explosion models: classification of explosions (physical explosions and BLEVEs, chemical explosions, UVCEs); the TNT model; TNT models for physical explosions and UVCEs; consequence assessment of VCFs. Post-release event trees. Damage models for heat radiation, overpressure and toxic exposure (thresholds and probit models).

5) Frequency evaluation and reliability engineering

Introduction to frequency evaluation and reliability engineering. Standard frequency values and parts count. Elements of Boolean Algebra. Reliability of components. Reliability of systems. Fault Tree Analysis. Quantified event trees. The bow-tie diagram.

6) Risk recomposition

Local risk. F-N curves.


Reference books:

  • Lees' Loss Prevention in the Process Industries, S. Mannan editor, IV ed., Butterworth-Heineman, Oxford, UK, 2012
  • R.Rota, G. Nano, Introduzione alla affidabilità e sicurezza nell'industria di processo, Pitagora Ed., Bologna, I, 2007
  • D.A.Crowl, J.F.Louvar, Chemical process safety: fundamentals with applications, IV ed., Pearson Education, USA, 2020
  • Centre for Chemical Process Safety of AIChE, Guidelines for chemical process quantitative risk analysis (II ed.), New York, USA, 1999
  • Center for Chemical Process Safety of AIChE, Guidelines for hazard evaluation procedures (III ed.), AIChE, New York, USA, 2008
  • TNO, Methods for the calculation of physical effects (Yellow book). Report CPR 14E (III ed.), The Hague, NL, 2005
  • H. Kumamoto, E. Henley, Probabilistic Risk Assessment and Management for Engineers and Scientists, 2nd edition, IEEE Press, New York, 2000

All these books (in some cases in one of the previous editions) can be found at the Library F.P.Foraboschi in via Terracini 28; for information about the availability of the books, please contact the librarian (Annalisa Neri, annalisa.neri@unibo.it)

Teaching methods

The teacher adopts a traditional teaching method: all topics of the course contents are explained during the classes, with the support of slides. In the slides both theoretical concepts and the solutions of simple exercises are reported. Interactivity is welcome during the classes: students are invited to ask questions to clarify doubts or if they want the teacher to repeat the explanations, as well as to answer the questions asked by the teacher. Furthermore, homework can be done by the students within specific deadlines.

The course is focused mainly on theory. Practical activities (e.g., use of software for consequence assessment) are offered in the Laboratory of Process Safety M – prof. A.Tugnoli).

Assessment methods

The exam consists in a written proof, specifically a quiz with multiple choice answers, open questions, simple numerical exercises, questions with words to fit in, true or false questions,.... Sets of quizzes for each topic and an example of the written proof (with its solution) are available in the teaching material. More information on the written proof is reported in the teaching material and given by the teacher during the classes.

In order to avoid disapponting the teacher, it is strictly forbidden to sit the exam just "trying" to pass it. Students have to sit the exam only when their preparation has reached a sufficient level. In the teaching material there are lots of exercizes and quizzes on theory  to to allow students to evaluate if they are able to solve the exercizes and to answer the questions accurately and quickly.

For all those issues concerning the exam not explicitely mentioned in the webpage of the PSEM course and not reported in the teaching material, the indications of the Teaching Regulation (regolamento didattico) of UniBO are valid. In the unfortunate case that exams are online, the teacher will consider the possibility to introduce changes to the assessment methods. These changes will be valid for students sitting the exam online and for those sitting it in the classroom, so to avoid differences in the exam due to the mode the exam is taken.

Teaching tools

  • Slides explained during the classes
  • Additional teaching material
  • Books on the course contents
  • Videos of some major accidents
  • Numerical exercises
  • Quizzes
  • Homework
  • Example of an exam proof

All the material mentioned above is made available on the Virtuale platform for 1 year (access is limited to the students having the course in their study plan). The teacher will NOT make available the audio/video recordings of the classes. The warm reccomandation to students is to directly follow all the classes, taking notes personally, writing the notes directly on the slides (which are made avaibable in advance), revising the slides and the notes after each class.

Office hours

See the website of Sarah Bonvicini


Good health and well-being Industry, innovation and infrastructure Sustainable cities Responsible consumption and production

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.