73499 - Safety and Loss Prevention M

Learning outcomes

The aim of the course is to give students the basic theoretical notions and the technical tools for:
- the identification of hazards;
- the evaluation of the consequences of accidents (through the consequence analysis and the damage models);
- the evaluation of their occurrence frequency (through preliminary elements of reliability engineering);
- the assessment of risk measures as a combination of frequencies and consequences.
The knowledge of these issues is necessary to manage safety problems during the whole lifetime of a plant and also to assure compliance with the safety regulations of the process industries.

Course contents

REQUIREMENTS - PRIOR KNOWLEDGE

First of all, the student should possess the basic skills relating to the Italian language, to mathematics and to English that are typically acquired during high school:

1. with reference to the Italian language, it is advisable for the student to have a C2 level knowledge of the Italian language, according to the Common European Framework of Reference for Languages (CEFR), so as to be able to:

- to easily understand complex texts and specialized topics;

- to express oneself spontaneously, fluently and precisely, using a rich and varied language, with a mastery of the nuances of meaning and textual coherence, even in a formal context;

- to write with coherence, clarity and precision, demonstrating full mastery of grammar and vocabulary;

- to summarize information from different sources, restructuring it in a coherent and concise way;

2. with reference to mathematics, it is in particular appropriate for the student to be able to easily solve algebraic and transcendent equations, also with the aid of a scientific calculator;

3. with reference to the English language, a knowledge of C1 level and in any case no lower than B2 level would be desirable.

In addition, the student should possess the skills that are typically acquired during engineering degree courses, i.e. an adequate mastery of the knowledge and tools of the basic sciences applied to engineering as well as the methodological-operational aspects of engineering, with particular regard to engineering modelling.

The course is offered during the last year of the master degree. This implies that it is in some way "recapitulatory" with respect to the whole study plan. In fact, the analysis of the safety aspects of the process industries and of their risk quantification requires an overall view of the features of these installations, and this view is usually gained only at the end of the studies (not during the studies, not at their beginning).

To fruitfully attend the classes and to fully understand the course contents and to pass the exam without sitting several times, it is necessary to have a robuts knowledge of the fundamentals of termodynamics (specifically, of the mass and energy balances - even in presence of phase transitions and chemical reactions - and of the vapour-liquid equilibria), of fluidodynamics (specifically, of the Bernoulli equation and of the outflow of gas in choked conditions), of the transport phenomena (specifically, of the local balances of mass, energy, momentum), of Boolean algebra, and of the calculus of probabilities.

Classes are in Italian: to fruitfully attend classes, a good comprehension of Italian is necessary (at least a B2 level in Italian is required). For students not understanding Italian, it is possible to study the course contents on readings and bibliography fully in English (however, at least a B2 level in English is required).

COURSE CONTENS for a.y. 2025-2026

1.Introduction to the course

Risk: the process industry and the Chemical Process Quantitative Risk Analysis (C.P.Q.R.A.), the concepts of risk and safety, risk definitions, risk classification methods (individual risk / collective risk; natural risk / anthropic risk, with the sub-categories of technological risk and industrial risk); industrial risk (conventional risk, specific risk, risk of major accident); elements on the Italian legislation on occupational risk; the Seveso I, II and III directives; the Legislative Decree 105/2015 with its annexes and the relevant implementing decrees; the risk of major accidents in the context of HSEQS disciplines; the risk of major accidents in the context of green chemistry and sustainability. Risk indices: the concepts of frequency and probability; individual / local risk; social risk, with calculation examples (f/N curves (simple frequency / number of fatalities), F/N curves (cumulative frequency / number of fatalities), the expected number of deaths or Potential Life Loss, histograms local risk / number of people present); risk matrices. The procedure for calculating risk: the three phases of the calculation; risk acceptability criteria, with examples of application to local risk, social risk, risk matrices; safety measures (preventive and protective; according to the Swiss cheese model, according to the "shell" model, according to T.Kletz); residual risk and the tools for its management (internal and external emergency planning, land use planning, investigation of accidents, inspections). The subjectability of establishments to Legislative Decree 105/2015: art. 3 and annex 1; lower tier and upper tier major accident establishments; the notification; the safety report; the safety management system for the prevention of major accidents.

2.Hazardous properties of chemicals

The hazardous properties of chemical substances: flammability, explosiveness, toxicity, corrosivity, reactivity. In-depth study of the “flammability” property. In-depth study of the "toxicity" property. The CLP regulation. The GHS system (origin and development, classification of chemical substances, pictograms, H-statements, P-statements, hazard phrases, the group of physical hazards and its main classes, the group of health hazards and its main classes, the group of environmental hazards and its class, examples of subdivision of classes into categories, differences between the CLP regulation and the GHS system). The safety data sheet and labeling of chemical substances. The REACH regulation (origin, structure, registration and evaluation of chemical substances, authorization for the production of SVHC substances (with definition of PBT and vPvB substances, endocrine disruptors, PMT and vPvM substances), restrictions on chemical substances).

3. Hazard identification

Introduction to hazard identification. The main hazard identification techniques: historical analysss; checklists; safety review / safety audit; index methods; HazId analysis; HazOp analysis; what-if analysis; FMEA / FMECA. Criteria for choosing the hazard identification techniques to apply.

4.Damage models

Introduction to damage assessment models (input and output data; targets of major accidents and damage levels; the domino effect; the physical effects of fires, toxic clouds, explosions, and their spatial representation). Damage models based on probit equations: the mathematical model; examples of probit equations for fires, toxic clouds, and explosions; the spatial representation of the probability of death). Damage models based on threshold values: examples of threshold values for fires, toxic clouds, and explosions. Use of threshold values for external emergency planning and land use planning around major accident hazard establishments in Italy.

5.Source models

Introduction to the consequences analysis of accidental scenarios (source models, fire models, atmospheric dispersion models, explosion models, with related input and output data). Types of storage tanks and typical storage conditions of chemical substances, the Antoine equation and the gas liquefaction modes. The schematization of accidental releases, with examples of schematizations reported in C.P.Q.R.A. guidelines and schematizations deriving from HazOp analysis. Source models: for liquids released from a hole on a pipe pipe and on a tank; for gases released from a hole on a pipe or a tank; for liquefied gases under pressure (flash of instantaneous releases and continuous releases); for evaporating and boiling pools.

6. Fire models

Introduction to fire models (definition of fire, the methods of transmission of thermal power and the role of radiation, damage produced by fires, the "single point source" and the "surface emitter" fire models, atmospheric transmissivity). Typical process industry fires (poolfire; jet-fire; fireball; Vapor Cloud Fire (VCF)), with description of the related physical phenomena and their mathematical modeling.

7. Dispersion models

Introduction to atmospheric dispersion models (what they are; the damage produced by toxic clouds and flammable clouds; classification of dispersion models based on the density of the gas, the speed of release, the duration of the release, the dimensions of the source, the height of the source; differences between dispersion of polluting emissions and dispersion of accidental releases). The meteorological parameters in the planetary boundary layer at the basis of passive dispersion (the wind: module and direction; the atmospheric turbulence and its classification according to Pasquill). Gaussian dispersion models: model for continuous stationary releases, with determination of concentration profiles, isopleths of flammable and/or toxic clouds, mass in the flammability range; model for instantaneous releases, with calculation of the passage time of the cloud. Elements on the dispersion of heavy gases.

8. Explosions models

Introduction to explosion models (definition of explosion, classification of explosions (physical / chemical); classification of chemical explosions (confined / unconfined; deflagrations / detonations); run-away reactions; damage produced by explosions; mathematical modeling of explosions; TNT equivalence models). Physical explosions, with in-depth analysis of BLEVE: causes, description of physical phenomena, mathematical modeling. Unconfined chemical explosions (VCE): formation and fate of flammable vapor clouds; mathematical modeling of VCEs.

9.Event trees

Typical post-release event trees (trees for continuous or instantaneous releases of flammable liquids and cryogenically liquefied flammable gases, for continuous releases of flammable gases and flammable gases liquefied under pressure, for instantaneous releases of flammable gases liquefied under pressure; quantified event trees for calculating the probabilities and frequencies of the final accident scenarios). Event trees and safety measures: some examples.

Elements on software codes for consequence analysis.

10. Introduction to reliability theory

Introduction to reliability theory (distinction between components and systems). Standard failure rates. Standard release frequencies. Elements of Boolean algebra and probability calculus.

11. The reliability of components (topic that will almost certainly not be discussed due to lack of time)

Introduction to the reliability of components. The non-repairable component. The repairable component. The component subject to preventive maintenance.

12. The realibility of systems

Introduction to the reliability of systems (typologies, schemes, states of a system). Simple systems describable with the "parts count" methodology. Complex systems describable with the fault tree: construction of the fault tree, qualitative analysis, elements on quantitative analysis. The bow-tie diagram.

13. The calculation of risk

Calculation of local and societal risk: examples.

Readings/Bibliography

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, II ed., Bonomo Ed., Bologna, I, 2024
• 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, II ed., IEEE Press, New York, 2000

You can find all these books (in some cases in one of the previous editions) 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

- Notes personally taken during the classes

- Material available on the e-learning platform of the University of Bologna (Virtuale) (the access is limited to the students having the couurse in their study plan for a.y. 2025/2026 or for one of the previous years)

- copy of the slides explained during the classes

- supplementary readings

- exercizes and quizzes for each topic

- an example of the written exam text

- audio / video files on specific topics

- specic software tools

The teacher does NOT make available the video recordings of the classes. The warm reccomandation to students is to follow personally all the classes, taking notes directly on the slides explained by the teacher (made available before the classes) and revising them after each class. It is aboslutely to avoid sitting part of other exams or entire exams during the classes of the course or just after the end of the classes, if this requires to suspend attending the classes of the course.

Assessment methods

The exam has the aim to verify that the student has achieved the following goals:

- knowledge of the risk indexes adopted for the quantification of the risk of major accidents and of the methodological approach for their evaluation;

- knowledge of the most important techniques for hazard identification;

- knowledge of the different kinds of accidental scenarios arising form a loss of containment of flammable and/or toxic fluids;

- knowledge of the consequence analysis models for the evaluation of the consequences of accidental scenarios and of the reliability engineering models for the estimate of their occurrence frequency.

The exam consists in a written test followed by an oral test (to be sit one after the other, if possible on the same day or, if not, on consecutive workind days). To sit the oral test, a positive mark in the written test is necessary. In case the oral test is not positive, it is necessary to sit again also the written test. The written test consists of questions about theory and simple numerical exercises related to the course contents. "Simple" means that neither the use of a desktop is necessary, nor it is necessary to retrieve data about the chemical, physical and hazardous properties of the substances, nor to perform difficult conversions of units of measurement. Students should refer, as an example, to the exercises explained by the teacher during the classes and to the example of exam test made available in the teaching material.

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.

To obtain a passing grade, students are required to demonstrate a knowledge at least of the key concepts of hazardous substances, of the indexes to express the risk of major accidents, of the successive steps of the risk analysis methodology and of their connections, of the main mathematical models of each step and of the meaning and units of measurement of the most important parameters of these models, also being able to solve simple exercises. Higher grades will be awarded to students who demonstrate an organic understanding of the subject and a high ability for critical application, a clear presentation of all the course contents and the ability to face more complex problems related to safety aspects and risk quantification, appropriately applying the expertise aquired in the whole duration of the studies. A failing grade will be awarded if the student shows knowledge gaps or superficial knowledge of several topics, confusion in distinguishig the accidental scenarios one from the other, poor knowledge of the key-concepts of relialibility engineering. Penalties will be given to those students who are not able to retrieve information about the course there where this information is made avalable (web pages of the teacher and of the course, Virtuale platform, copy of the slides expalined during the first classes) and to those writing unnecessary emails to the teacher to get the information about the course reported elsewhere.

Six exam dates per year are fixed and published on AlmaEsami.

To avoid disapponting the teacher, it is strictly forbidden to sit the the exam just for trying to pass it. In fact, students should sit the exam only when their preparation has reached a sufficient level. Since there are lots of exercizes and quizzes (both on theory and on exercizes) available on Virtuale, each student can verify by himself / herself if his / her preparation is sufficient, being able to solve the exercizes and to answer the questions on Virtuale accurately and quickly.

More information about the AfSIP M exam is reported in the regulation for sitting the AfSIP M exam and in the introduction to the AfSIP M course, both available on Virtuale.

For all those issues cocerning the exam not explicitely mentioned in this webpage of the AfSIP M course and in AfSIP M exam regulation available on Virtuale, the indications of the Teaching Regulation (regolamento didattico) of UniBO are valid.

Teaching tools

• Lessons performed with the aid of power point presentations
• Watching of videos 
• Highlights about specific software tools
• Numerical exercises

Office hours

See the website of Sarah Bonvicini