Risk Analysis - Prof Carpignano - Appunti di Fabio Galizia

Corso di Laurea Magistrale

in

Risk Analysis

Prof. Andrea Carpignano

Appunti di

Fabio Galizia

Lezione 1

Introduction to Risk Analysis

POLITECNICO DI TORINO DIPARTIMENTO ENERGIA

Safety and Risk Analysis

Andrea CARPIGNANO

andrea.carpignano@polito.it

Francesco GANCI

francesco.ganci@polito.it

Anna Chiara UGGENTI

anna.uggenti@polito.it

Introduction

The course is hold for students in Energy

Engineering

Five lectures (including Monte Carlo) per

week (1.5 hours each)

Rooms:

Wednesday 13.00-16.00 Room 29

Friday 10.00 - 13.00 Room 29

Friday 16.00 – 17.30 Room 27

Ed. 2011/12

Rooms

Rooms 8.30 10.00 11.30 13.00 14.30 16.00 17.30

Schedule Sep 30 MC MC AR

Oct 5 MC MC

7 AR AR AR

12 MC MC

White cells means AR AR AR

14

19 MC MC

lectures (MC 21 MC MC AR

Monte Carlo, AR MC MC

26 AR AR AR

28

Risk Analysis) Nov 2 MC MC

Yellow cells are MC MC AR

4 AR

9 AR

exercises split 11 AR AR AR

into 2 groups 16 MC MC

18 AR AR AR

(Room 27 and 23 MC MC

Aula Capetti), 25 AR AR AR

30 MC MC

Dec 2 AR AR AR

7 MC MC

14 MC MC

16 MC MC AR

21 MC MC

Jan 11 MC MC

13 AR AR AR

18 MC MC

20 AR AR AR

Rules for the exam

Rules for Safety and Risk Analysis

exam must be downloaded from the

didactic portal

pls. read them carefully!

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Introduction to the course

Practical Lectures are hold by Francesco Ganci and

Chiara Uggenti

Lecture notes will be at disposal of the students on

the “Portale della didattica”, the Polito web site for

the students.

I will give you also some references for books,

papers that can help you to deep some specific

topics or to use them in your future working

activity (most of them are available in the POLITO

Library).

Ed. 2011/12

GOALS Students are required to join their skills in

GENERAL GOAL:

different topics (gained in previous courses) to face an

engineering project, by a professional approach

Clarify concepts & definitions

Introduce to the RISK BASED approach for the everyday

life

Provide methodologies and techniques for safety and

risk assessment

Provide sensibility versus regulations

Address students to a professional approach to

industrial safety by practical case study

Ed. 2011/12

CONTENTS OF THE COURSE

Introduction to terminology

1. The “Risk” concept

2. Risk perception and acceptability

3. Risk analyses methodologies (probabilistic

4. and damage analyses)

Reliability theory

5. Fundamentals on consequence

6. assessment (fires, explosions, gas

dispersion, …)

Ed. 2009/10

CONTENTS OF THE COURSE

SAFETY and RISK ANALYSIS

Introduction to terminology

1. The “Risk” concept

2. Monte Carlo methods

Risk perception and acceptability

3. Risk analyses methodologies

4. (probabilistic and damage analyses)

Reliability theory

5. Fundamentals on consequence

6. assessment (fires, explosions, gas

dispersion, …) Localizzazione e

Impatto Ambientale

Ed. 2009/10

Introduction to the “RISK” concept

What is SAFETY? damage free.

Situation where you are

What is RISK? distance to safe.

Is the We are not able to

risk to zero.

reduce

Which is the relationship between Safety

and Risk? The risk is the measure of our distance from

fully safety.

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Introduction to the “RISK” concept

What is SAFETY?

A condition characterised by the absence of possible

damages (abstraction)

What is RISK?

A technical “measure” able to assess the distance

from safety of a system/situation

Which is the relationship between Safety and Risk?

Risk can be seen as the distance from the “full” safety

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Introduction to the “RISK” concept

SAFETY

RISK

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Introduction to the “RISK” concept

Which kind of damages we are interested in?

Damage to people (deaths, injuries)

Damage to environment Authorities

Economical damage

direct damage (cost for asset recovery)

indirect damage (los of production)

Damage to reputation Company

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In the past the worst damage was related to damage to people.

Now in the engineering the risk include 4 type od damage:

Damage to people

• Damage to environment

• Economical damage Indirect,

• (Direct, amount of money have to spend to recovery the damage,

loss of production due to a damage cause the plant doesn't work for a time). Usually

indirect>>direct: loss of production is more important compared to repair of component.

Damage to reputation

• social damage

The first 2 damage are the most important and are and are regulated by legislation.

R=f(scenario, probability, death)

R=frequency X damage expected

[event/year] [death/event]

Risk is the possibility that undesired and uncertain event occurs.

Our final results will be always affected by uncertainty.

Rtot= R1+R2+R3+...+Rn= f*d1+f*d2+...+fn*dn

The total risk is due to the sum of all the risk:

(Sum of damage weighted by its probability occurs) difference between frequency

The estimation of the risk must be in a period of time and this is the

and probability.

Introduction to the “RISK” concept

Definition of RISK

“The possibility that an undesired and uncertain

event occurs”

R (deaths/y) = f (events/y) x d (deaths/event)

Road Accident: 240.000 acc/y * 1/40 (death/acc) = 6000 (deaths/y)

Ed. 2011/12

Introduction to the “RISK” concept

Different ways to interpret “Risk”:

It is an estimation of damages, weighted by

their probability of occurrence

(R =R +R + … = f *d + f *d +…)

tot 1 2 1 1 2 2

It is the social cost of an incident (technical

failure, human error, natural event …)

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Introduction to the “RISK” concept

Social cost means:

The cost paid by the community deriving

from the introduction of a new technology

2 kinds of social costs:

Routinely cost: the cost in terms of daily

environmental impact (e.g. air pollution,

noise, …)

Probabilistc cost: the cost deriving from

potential accidents (loss of life due to an

explosion)

Ed. 2011/12

Introduction to the “RISK” concept

Environmental Impact Assessment

A procedure aiming to obtain the authorisation to

the construction and operation of a new

installation in Europe

It must deal with: EEC Directive 85/337

Soil and underground impacts EC Directive 96/61

Impact on water reserves, rivers, lakes, … EC Directive 97/11

Emissions to the atmosphere

Noise and vibration

Ionising and non ionising radiations

Impact on the landscape

Impact on public health (routinely and accidental)

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Plant authorisation processes

Major Accident installations Other installations

• Process safety (Safety • Fire prevention (DPR

Report+ Fire prevention, 151/2011, DM 7/8/2012, DM

DLgs. 105/15 (2012/18 UE), 3/8/2015)

DLgs. 145/15 (30/2013 UE) • Environemntal Impact

• Environemntal Impact Assessment (not for all,

Assessment (DLgs 152/06) includes risk analysis, DLgs

152/06)

In Italy (and EU) all the authorisation processes are split in two stages:

• For construction (NOF, VIA, Esame Progetto)

• For operations (PTC, AIA, CPI)

Other important regulations:

• Safety and Health for workers (DLgs 81/2008 -1989/391 CE)

• –

Safety for Machinery (DLgs. 17/2010 2006/42 CE)

LEGISLATION

MAJOR ACCIDENT INSTALLATION: people and anvironment

the damage to are outside the

major

plant. The amount is important to determine if it is or not.

SEVESO DIRECTIVE: Accident that moves the european community to have a specific legislation.

3º Seveso

Dlgs 145/15 (30/2013 UE) 1º Seveso

Dlgs 105/15 (2012/18 UE)

ON SHORE, OFF SHORE

1º Seveso was for the 2º for

Preliminare design

• of plant and parallel perform the risk analysis to verity the design.

Authorization

• of plant/project by authority (NOF Nulla Ostadi Fattibilità, VIA Valutazione Impatto

Ambientale, Esame progetto) for construction, ( PCT ParereTecnico Costruttivo, CPI Certificato

Prevenzione Incendi, AIA) for operator.

• Safety for machinery (marchio E cerchiato)

Introduction to the “RISK” concept

Type of RISK:

Social / Individual

Immediate /Delayed

Voluntary / involuntary

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SOCIAL/INDIVIDUAL

IMMEDIATE/DELAYED

VOLUNTARY/INVOLUNTARY

Introduction to the “RISK” concept

ATTENTION PLEASE

…the final risk figure is not so interesting it could be

affected by big uncertainties, it is a tool, not the truth…

Risk analysis aims to:

Investigate a system in terms of failures and errors in

Reduce the

order to increase it robustness frequency

Identify and suggest the PREVENTIVE MEASURES

(design review, preventive maintenance,, etc.) reducing

the probability of occurrence Reduce the damage

Identify and suggest the MITIGATION MEASURES

(design review of protection systems, land use

planning, emergency planning, etc.)

Compare different design solution in order to choose

the safer one

Ed. 2011/12

Introduction to the “RISK” concept

Problems related to the Risk Assessment:

Merging of several disciplines

Complexity of the phenomena we must study

Uncertainty of the estimations

Need to cover all the operational configurations

(risk depends on equipment, human, environment)

Need to follow the system evolution (ageing,

design review, etc.)

Political and social implications

Ed. 2011/12

GLOSSARY

RISK (RISCHIO)

PROBABILITY/FREQUENCY

HAZARD (PERICOLO)

INITIATING EVENT or INITIATOR

ACCIDENTAL SEQUENCE

CONSEQUENCE

VULNERABILITY

DAMAGE

Ed. 2011/12

GLOSSARY

RISK (RISCHIO)

PROBABILITY/FREQUENCY

HAZARD (PERICOLO): a situation of potential

damage

INITIATING EVENT: the event able to “activate”

the hazard

ACCIDENTAL SEQUENCE: the sequence of events,

staring from the initiating event, describing all the

accident evolution

CONSEQUENCE: the physical effects of the accident

VULNERABILITY: the capability of the context to

transform the consequence in damage

DAMAGE: the final ecffects of an accident int erms

of loss of lives, injuries, money, etc.

Ed. 2011/12

Security: is against the volontary act.

Safety: is against unvoluntary act

Hazard: is the physical situation that is able to produce damage. The risk is only the evaluation of

the hazard. (Hazard=pericolo)

Before we have to list all the hazard and then the relative risk.

Vulnearbility: capacity to transform the consequences to real damage.

Glossary

absence of any possible damage (an unreachable goal!)

SAFETY a situation that could be potentially dangerous (e.g. the presence

HAZARD of a storage of dangerous materials, high pressures, …)

possibility that a dangerous event occurs, i.e., possibility that the

RISK HAZARD becomes DAMAGE CONSEQUENCE DAMAGE

ACCIDENTAL S (e.g. mg/m3)

SEQUENCE

INITIATING

EVENT

HAZARD

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TYPES OF INITIATING EVENTS

Technical failures (e.g. pipe break, valve

stuck, pump failures, electronic

malfunctioning, …)

Operational/Maintenance errors

Software errors (leading to a

malfunctioning of the control system)

External events (plane crashes on the

plant, earthquakes, external fires, flooding,

etc.)

Ed. 2011/12

Accident evolutions & Safety Critical Barriers

Technical failures DAMAG

(design, operations,

Human errors E

maintenance, organisation)

Software errors

External events https://www.youtube.com/watch?v=SFGfRtfsp-w

Ed. 2011/12

RISK ASSESSMENT

Approaches to Risk Assessment

QUALITATIVE assessment 4 8 12 16

F 4 F

PROBABILITY DAMAGE 3 6 9 12

1 - Not expected: … 1 - Negligible: … 3

2 - Rare: … 2 - Light damage: … 2 4 6 8

2

3 - Occasional: … 3 - Major damage: … 1 2 3 4

1

4 - Probable: … 4 - Catastrophic: … 1 2 3 4 D

F (ev./anno) The manager of company decide which is the

5.0 E-5 too high rick and which is the acceptable risk

NOT QUANTITATIVE assessment

NON ACCETTABILE

ACCEPTABLE

5.0 E-6 ALARA Statistical approach

ACCEPTABLE

ACCETTABILE Analytical approach

5.0 E-7 1 10 100 D (morti) (When there are no statistic elements to discuss)

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RISK PERCEPTION

People feel the risk in this way:

D

R

= F x

They have an high perception of damage

They don’t take into particular account the

frequency of occurrence

… some people are afraid to take the plane

but drive every day their car…

Ed. 2011/12

RISK PERCEPTION

USA interview

year) Cancer

per Heart

(deaths diseases

Flooding

Tornados

interview

the

of

Results REAL number of deaths per year

Ed. 2011/12

RISK PERCEPTION

To respect people perception we could

usethe following relationship for risk:

R= F x D

k

With k>1

The Nederland uses K=2!

The value of K is a socio-political matter,

not a technical point!

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RISK TOLERABILITY

Which is the acceptable/tolerable level of

RISK? R<R

max

?

R

max

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INDIVIDUAL RISK TOLERABILITY

Individual risk

CAUSES (deaths/y*person)

All causes

Cancer

Accident Individual risk

Type of accident deaths (deaths/y*person)

Car accident

Falls

Fires

Drowning

Poison

Weapon

Machines

Naval transport

Airplane

Dropping objects

Electric shock

Rail transport

Ed. 2011/12

SOCIAL RISK TOLERABILITY

Rischio

Risk

Social Risk R1

F (ev./anno)

F (ev./y) R2

5.0 E-5 €

C1 C2 €

NON ACCETTABILE

UNACCEPTABLE

5.0 E-6 ALARA

ACCEPTABLE

5.0 E-7 1 10 100 D (morti)

D (deaths)

Ed. 2011/12

SOCIAL RISK TOLERABILITY

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OVERALL RISK ASSESSMENT

NATURAL RISKS

Hydro-geological (land slips, flooding, …)

Forest fire

Exceptional meteo events (hurricanes, tornados)

Snow (snow slips)

Seismic (earthquakes)

TECHNOLOGICAL/ANTROPIC RISKS

Transportation

Industrial Risk

Health Risk (virus, bacteria)

Nuclear Risk

Ed. 2011/12

RISK AND LEGISLATION

IN ITALY:

In the past, the technical laws were prescriptive

(e.g. road code: the max speed is 50 km/h)

The new technical regulation, based on EU

Directives, is “goal setting” or “performance

based” (prestazionale) (i.e. based on the risk

analysis)

At the moment we have in EU good performance

rules for industry while transportation is still

based, mainly, on prescriptive rules (some

exception, for instance the new regulation for the

risk analysis of tunnels)

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ON SHORE: 105 Directive Seveso/2015

OFF SHORE: 145/2015

PERSPECTIVE RULE: set of rules that must be follows the legislation has decides the good

approach for safety.

Starting from '20 there was changing in legislation; there is no precise rule but the organization can

"goal based rule" prestazionali)

decide the rules of safety with (leggi within the risk analysis.

This is the situation for industry. is not local problem.

For transport is different because

Must be agreeded the uniform change.

The evolution of legislation in transport is very low infact.

ADR License: International agreement and gives the rules for transportation (rules for construction

of truck and for the hours to transport: night or day).

RID: for trains.

IMO/SOLAS: marittim transportation.

ICAO: planes transportation.

Free prevention: is still prescriptive rule but there are some changing to goal based within risk

analysis.

Molte volte non si possono seguire le regole (museo con dipinti importanti alle pareti e non si

possono aprire uscite di emergenza) tramite risk analysis si può garantire e dimostrare la sicurezza

pur non seguendo le direttive.

FIRE FIGHTING: is not to shutdown

The goal of water

the fire but to cool the surround to

avoid the propagation.

FOAM: Useful if we have liquid that is flammable, to separate the vapor fase from liquid fase.

Other way to fire fighting:

We remove the air and insert CO2.

The fire is shutdowned; it must be

done if there is no people inside

(there is usually a door protection)

RISK AND LEGISLATION

Aims of the main rules

To check and guarantee the safety and

health in work environment (89/391 EC, …,

2004/40 EC, DLgs 81/2008).

To check the safety for the community in

Major Hazard Installations: Refineries,

Chemical plants, (2012/18 EU, DLgs

105/2015 “Seveso Directive") Nuclear

plants, Oil&gas plants (2013/30 EC, DLgs

145/2015)

Ed. 2011/12

RISK AND LEGISLATION

In transportation…:

To check and guarantee the safety

still

for the transportation of people (

prescriptive rules )

To check and guarantee the safety

for the transportation of dangerous

goods (flammable, explosive, toxic

substances …) (2004/54 EC for road

tunnels, DLgs 2006/264)

Ed. 2011/12

RISK AND LEGISLATION

In fire fighting…:

To design “ad hoc” fire emergency systems

prescriptive

where the regulation is not

applicable (e.g. historical buildings) (DPR

151/2011, DM 9/5/07)

During the machinery design and construction:

Risk analysis to identify the residual risk and

to prepare the technical documentation for the

commercialisation of the machine (2006/42 CE

- DLgs. 17/2010)

Ed. 2011