73197 - Safety and Loss Prevention M

Learning outcomes

Il corso si propone di fornire agli allievi le nozioni fondamentali e gli strumenti tecnici per identificare i pericoli nell'industria di processo e per valutare le conseguenze degli incidenti rilevanti (tramite i modelli della consequence analysis ed i modelli di danno) e stimarne la frequenza di accadimento (tramite la teoria dell'affidabilità), onde poter quantificare il rischio. La conoscenza di tali argomenti è infatti necessaria per affrontare i problemi relativi alla sicurezza nello sviluppo dei progetti e nella conduzione degli impianti, anche in riferimento agli adempimenti normativi richiesti alle industrie di processo.

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 reliability engineering);
- the assessment of risk measures as a combination of frequencies and consequences.
The knowledge of these themes 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

INTRODUCTION
Basic notions about: risk; CPQRA and QRA; individual risk and societal risk (F/N curves, expected number of deaths, IR-N histograms, risk matrixes); risk acceptability criteria.

HAZARDOUS SUBSTANCES

Introduction. Hazardous properties of substances. Toxicity. Flammability. Classification of hazardous substances. The Safety Data Sheet. Labeling. The REACH regulation.

HAZARD IDENTIFICATION
Introduction. Analysis of case histories. Checklists. Safety reviews. HAZOP analysis. What-if analysis. FMEA and FMECA.

DAMAGE MODELS
Introduction. Damage of fires, explosions, toxic clouds. Models based on threshold values. The probit equations model.

CONSEQUENCE ANALYSIS
Source models. Storage conditions in the process industries. Outflow of liquid: through a hole; through a hole in a tank; through a pipe. Outflow of vapour: through a hole in a tank. Flashing liquids. Outflow of pressure liquefied gases. Pools.
Fires. Introduction. Poolfire. Jet-fire. Fireball. Flash-fire.
Dispersion. Classification of models. The dispersion of neutral gases (from a steady-state source; for an instantaneous source; form a punctual source; form a source with finite dimensions; the evaluation of the dispersion coefficients; the dispersion in case of non-homogeneous soil roughness; concentration profiles; concentration contours; mass in the flammable range; plume rise models; puff passage time). Basic notion about the dispersion of heavy gases. Basic notions about transformation and removal phenomena.
Explosions. Introduction and classification. Unconfined vapour cloud explosions (UVCE). Physical explosions and BLEVEs.
Post-release event trees: for flammable liquids; for flammable liquefied gases.
Software for consequence analysis.

RELIABILITY ENGINEERING
Introduction. Basic notions about probabilities. Non repairable components: probabilistic parameters of the repair-to-failure process (R, F, lambda, f, MTTF) and their relationships. Repairable components: probabilistic parameters of the failure-to-repair process (G, g, mu, MTTR); probabilistic parameters of the whole repair-failure-repair process (A, Q, lambdar, mur, w, v, W, V, MTBF, MTBR) and their relationships. Basic concept about: reliability data-bases; the Markov model; human reliability. Systems reliability. Introduction. Simple systems: components in sery; components in parallel; stand-by systems. The analysis of complex systems by means of fault trees.

THE CALCULATION OF RISK MEASURES
Exemple of calculation of individual and societal risk of a distillation column.

OTHER TOPICS:

INHERENT SAFETY. Basic concepts.

RUNAWAY REACTIONS. Basic concepts.

THE ITALIAN LEGLISLATION FOR THE CONTROL OF MAJOR ACCIDENTS.

Readings/Bibliography

Reference books:

• Lees' Loss Prevention in the Process Industries, S. Mannan editor,  IV ed., Butterworth-Heineman, Oxford, UK, 2011
• 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, III ed., Prentice Hall, New Jersey, USA, 2011
• 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, 1997
• H. Kumamoto, E. Henley, Probabilistic Risk Assessment and Management for Engineers and Scientists, 2nd edition, IEEE Press, New York, 1996

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 of DICMA (Annalisa Neri, annalisa.neri@unibo.it)

Teaching methods

- Notes personally taken during the lessons

- Copy of the dias used during the lessons available on the  web site of the Digital Library of the University of Bologna Alm@DL till the endo of July 2015 (the access is limited to the students of the mailing list of the course, a.y. 2014/2015) http://almadl.cib.unibo.it/

- Notes prepared by prof. Spadoni for the ASIP course

Assessment methods

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

- knowledge of the risk indexes adopted of major accident hazards and of the methodological approach for their estimate;

- 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 an oral proof, generally of about 45 – 60 minutes. During the oral proof the student can be required to sketch out simple numerical exercises related to the course contents. "Simple" means that the use of a PC is not necessary, nor it is necessary to retrieve data about the chemical, physical and hazardous properties of the substances, or to perform difficult conversion of unit measures. Students should refer, as an example, to the exercises explained by the teacher during the lessons. At the exam students can (but are not forced to) present a free choice topic. The topic can be selected among those explained by the teacher or it can be a different one (but related to safety and risk aspects). In the latter case the student can prepare a brief computer presentation to support the oral exposition, which should be limited to 10 minuets. The same topic can be selected by more than one student, each one preparing his own exposition or, alternatively, a single topic can be presented by a group of 2 – 3 students presenting themselves for the exam on the same day. The topic can be a theoretical one or a numerical simulation.

No dates are fixed for the exam. Student have to ask the teacher for an appointment (by phone or e-mail), at least 2 days before the day they would like to make the exam. The teacher will try to satisfy the request, with a variability of 1 or 2 working days. The teacher will communicate longabsences form work on her webpage, in the section of the notices (avvisi): http://www.ing.unibo.it/SitoWebDocente/default.htm?NRMODE=Published&UPN=sarah.bonvicini%40unibo.it&news=740&TabControl1=TabAvvisi

The exam will be performed in the office of the teacher, at DICAM - Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali in via Terracini 28 (II floor, after the stairs door on the left).

Students retiring during the exam or not obtaining a positive mark can present themselves for a new exam after at least 14 days. The teacher registers the exam some days after the examination, inserting the date in which the student has been examined. The teacher doesn't register negative marks if it's the first time the student makes the exam.

Teaching tools

• Lessons performed with the aid of power point presentations
• Audio files for specific topics non explained during the classes
  
• Seminars on specific topics
• Highlights about specific software tools
  
• Numerical exercises

Office hours

See the website of Sarah Bonvicini