PSA - Lezione 28 ottobre 2014 - RISK

Analisi del rischio: il caso

dell’incendio di strutture civili

CORSO DI PROGETTAZIONE STRUTTURALE ANTINCENDIO

1October 28 2014www.francobontempi.org

Konstantinos Gkoumas, Ph.D., P.E.

Franco Bontempi, Ph.D., P.E.

Facoltà di Ingegneria

Sapienza Università di Roma

http://www.francobontempi.org/

Index

• System approach to fire safety design

• Risk/fire risk/risk analysis

• Risk assessment process

• Risk analysis

• Hazard analysis

• Risk acceptance

• Risk reduction

• References

www.francobontempi.org


2ANALISI DEL RISCHIO:

IL CASO DELL’INCENDIO

DI STRUTTURE CIVILI




3ANALISI DEL RISCHIO:


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• System approach to fire safety design

• Risk

- fire risk

- risk types

- risk analysis



ANALISI DEL RISCHIO:


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System approach to fire safety design



MINOR

SPREAD

FIRE SPREADSTOP FIRE

suppressionY

MAJOR

SPREAD

STRUCTURAL

INTEGRITY

AVOID

CASUALITIES

LOCALISED

DAMAGE

STRUCTURAL

FAILURES

N

mitigation

Y

N

fire safe design

Y

N

FIRE

robust design

Y

N

MAJOR

COLLAPSE

AVOID

DIRECT

DAMAGE

AVOID

COLLAPSE

1

2

3

4

0 preventionOBJECTIVE

fire safety design -

structural

fire safety design -

non structural

GLOBAL

SAFETY

LOSS OF

GLOBAL

SAFETY

AVOID

INDIRECT

DAMAGE

NY

The fire safety is framed in different

“safety levels”, corresponding to

different safety objectives.





(Fire) Risk Estimation*

*(following SFPE Handbook of Fire Protection Engineering)

Provide answer to the following questions

1. What could happen?

2. How bad would it be if it did happen?

3. How likely is it to happen







What is risk?

Risk can be defined as the probability that the harm or damage from a particular

hazard is realized.

Risk is measured in terms of consequences and likelihood (a qualitative description

of probability or frequency). In mathematical terms risk can be defined as:

risk = f (frequency or probability, consequence) (1)

In the case of an activity with only one event with potential consequences, a risk (R)

is the probability (P) that this event will occur multiplied with the consequences (C)

given the event occurs:

R = PC (2)

The risk of a system is the sum of the risks of all harmful events of that system:

(3)





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𝑅𝑆 = 𝑅𝑖

𝑛

𝑖=1

7


Risk types• Life safety risks are normally presented in two ways:

- Individual risk and

- Societal risk

• Individual risk:

The purpose of the individual risk is to ensure that individuals in the society

are not exposed to unacceptably high risks. It can be defined as the risk to any

occupant on the scene for the event/hazard scenario i.e. it is the risk to an

individual and not to a group of people.

• Societal risk:

Societal risk is not looking at one individual but is concerned with the risk of

multiple fatalities. People are treated as a group, there are no considerations

taken to the individuals within the group i.e. the definition of the risk is from a

societal point of view.





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Source: Jönsson, 2007

8


What is risk analysis?

• A big family of different approaches, methods

and complex models combining various

methododical components for specific tasks

• Systematic analysis of sequences and interaction

effects in potential accidents, thereby identifying

weak points in the system and recognizing

possible improvement measures

• Risk analysis makes the quantification of risks

feasible







The risk assessment process







The risk assessment process





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Start

Definition of the system

Hazard identification

Probability analysis Consequence analysis

Additional safety

measures

Risk estimation

Risk evaluation Risk criteria

Acceptable

risk?

Stop

Risk analysis

Risk evaluation

YES

NO

Risk reduction

11


Definition of the system (context establishment)





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Define the operational environment and the context of the risk assessment

process

– Definition of the scope or the risk assessment process

• This includes determining the timeframe (e.g. from planning to dismantling),

the required resources and the depth of analysis required.

– Definition of the strategic and organizational context

• The nature of the organization in charge of the risk management and the

environment in which it operates is established

– Identification of the stakeholders and objectives

• The relationships that are interdependent with the organization are defined, the

impacts that might occur are accounted for, as well as and what each is wanting

out of the relationship

– Determination of the evaluation criteria

• Decide what level of risk the organization is prepared to accept

12







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a. What can happen

b. How can it happen

Means for hazard identification:

• Decomposition of the system into a number of

components and/or subsystems

• Identification of possible states of failure for the

considered system and sub-systems

• Identification of how the hazards might be realized

for the considered system and subsystemsSource: Faber, 2008

13






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Hazard identification – system decomposition

A. Structure

1. Main components

(d) Foundations

(c) Towers

(b) Anchor systems

(a) Main cables

(h) Cable saddle

(e) Railway girder

(f) Highway girders

(g) Expansion joints

(e) Non str.elements

(a) Steel

(b) Concrete

(c) Prestressed c.

(d) Alluminium/iron

3. Materials

(f) Coating

4. Systems

(a) Electrical

(c) Hydraulics

(b) Mechanical

(e) Bitumen

(e) Plastic

2. Secondary comp.

(d) H.R. attachments

(c) TMD

(b) Buffers

(a) Hanger ropes

B. Users

1. Highway traffic

(b) Commercial

(a) Private

2. Railway traffic

(b) Commercial

(a) Private

(a) Heavy

(b) Hazard mat.

(c) Military

3. Exceptional traffic

C. Facilities

1. Over the bridge

(b) Railway

(a) Highway

2. By the bridge

(a) Highway

(b) Railway

(c) Toll booths

(d) Control center

(e) Parking

(a) Maritime traffic

3. Under the bridge

D. Dependencies

1. Power

3. Financial

2. Communications

4. Supplies

5. Emerg. Responce

(a) First aid

(b) Police

(c) Fire brigade

(d) Hospitals

6. Ext. Contractors

E. Linkage

1. Economy

3. Military

2. Social

F. Operation

1. Authorities

(b) Management

2. Aspects

(a) Bridge authorities

(b) Goverment

(c) Region

5. Personnel

(c) Maintenance

(a) Financial

(b) Other

(a) Technical

G. Technology

(a) GPS

(b) Accelerometers

(c) Strain gauges

(e) Thermometers

(g) CCTV

(f) WIM

(d) Seismographs

(h) Field equipment

1. Monitoring

2. Control

(a) Cable control

(d) Railway traffic

(c) Highway traffic

(b) TMD

3. Data transmission

(b) Wireless

(a) Cable

4. Computer center

(b) Software

(a) Hardware

(d) Internet/LAN

(c) Data bases

4. Regulations

3. Policies

4. Location

(c) External

Hie

rarc

hic

al

Ho

log

rap

hic

Mo

del

s(H

HM

)

(Def

ined

in H

aim

es, 1

98

1)

14


Risk analysis: hazard identification





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• Qualitative methods

Studies based on the generic experience of personnel and do not

involve mathematical estimations.

• Quantitative methods

Mathematical estimations that rely upon historical evidence or

estimates of failures to predict the occurrence of an event.

• Semi-quantitative methods

Combination of the above (mostly, qualitative methods with

applied numerical values).

Source: Nolan, D. P. Handbook of Fire and Explosion Protection

Engineering Principles for Oil, Gas, Chemical, and Related Facilities, 1986

15






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Source: Aven, T. Risk Analysis: Assessing Uncertainties beyond Expected Values and Probabilities.

John Wiley & Sons, 2008

Risk analysis: hazard identification

16


Hazard identification. Qualitative Methods





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Checklist or Worksheet

A standardized listing which identifies common protection features required for typical

facilities is compared against the facility design and operation. Risks are expressed by

the omission of safety systems or system features.

Preliminary Hazard Analysis (PHA)

Each hazard is identified with potential causes and effects. Recommendations or known

protective measures are listed.

What-If analysis

A safety study which by which “What-If’ investigative questions (brainstorming

approach) are asked by an experienced team of a hydrocarbon system or components

under examination. Risks are normally expressed in a qualitative numerical series (e.g., 1

to 5).

HAZOP - HAZard and OPerability analysis (analisi di pericolo e operabilità)

A formal systematic critical safety study where deviations of design intent of each

component are formulated and analyzed from a standardized list. Risks are typically

expressed in a qualitative numerical series (e.g., 1 to 5) relative to one another.

Source: Nolan, D.P. 1986. Handbook of Fire and Explosion Protection Engineering Principles for …. Noyes, New Jersey

17


Hazard identification. Qualitative Methods





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Event Trees (ET) –albero degli eventi

A mathematical logic model that mathematically and graphically

portrays the combination of events and circumstances in an

accident sequence, expressed in an annual estimation.

Fault Trees (FT) – alberi dei guasti

A mathematical logic model that mathematically and graphically

portrays the combination of failures that can lead to a specific main

failure or accident of interest, expressed in an annual estimation.

Failure Modes and Effects Analysis (FMEA)

A systematic, tabular method of evaluating the causes and effects

of known types of component failures, expressed in an annual

estimation.

Source: Nolan, D.P. 1986. Handbook of Fire and Explosion Protection Engineering Principles for …. Noyes, New Jersey

18


• Risk analysis

• Qualitative risk analysis

• Quantitative risk analysis











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Risk analysis

• Risk analysis

– Probability- as the likelihood of the risk occurrence

– Impact - consequences if the risk occurs

• risk proximity, meant as the point in time during which

a risk will impact

• Risk analysis - methods

– Qualitative Risk Analysis, in which numbers and

probabilities are used not extensively or at all

– Quantified Risk Analysis (QRA)

– Probabilistic Risk Analysis (PRA), in which the system risk

is represented as a probability distribution

20






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Risk analysis and system complexity

High-Probability/

Low-Consequences

(HPLC)

Low-Probability/

High-Consequences

(LPHC)

High-Probability/

Low-Consequences

(HPLC)

Low-Probability/

High-Consequences

(LPHC)

High-Probability/

Low-Consequences

(HPLC)

Low-Probability/

High-Consequences

(LPHC)

High-Probability/

Low-Consequences

(HPLC)

Stochastic

Complexity

Deterministic

Analysis

Methods

Qualitative

Risk

Analysis

Quantitative/Probabilistic

Risk

Analysis

Pragmatic

Risk

Scenarios

Stochastic

Complexity

Deterministic

Analysis

Methods

Qualitative

Risk

Analysis

Quantitative/Probabilistic

Risk

Analysis

Pragmatic

Risk

Scenarios

21






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Qualitative Risk analysis

• Qualitative Risk Analysis is the simplest method of risk analysis, and

generally is used during the preliminary analysis phases.

• It consists in using subjective assessments of risks, and consequently, in

ranking them in a subjective manner.

• Sources for information to be used in the analysis can be drown from

previous experiences, history of events and consultation of experts.

• The ranking of risks is qualitative, e.g. risk (1) > risk (2) > risk (3),

while a description can be added. Eventually, a likelihood-consequence

matrix can be constructed.

• The biggest drawback of QRA is that there is neither a clear indication

of the risk’s magnitude nor an absolute scale of how serious the risk

might be, so, for a comprehensive risk analysis of more complex

systems, quantitative methods should be preferred.

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Qualitative risk analysis methods: risk matrix• A risk matrix typically provides a discrete partitioning of relative consequences

along one dimension and relative likelihood along the other.

• The entry in each matrix cell may include a description of hazards known or

believed to have that combination of consequence severity and likelihood.

Source: NFPA, SFPE Handbook of

Fire Protection Engineering,

3rd edition, 2002

Source: Furness, A., Muckett, M.

Introduction to Fire Safety

Management. Elsevier, 2007.

23






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Qualitative risk analysis methods: SWOT analysis

24

Strengths: characteristics of the

business or project that give it an

advantage over others.

Weaknesses: characteristics that

place the business or project at a

disadvantage relative to others

Opportunities: elements that the

project could exploit to its

advantage

Threats: elements in the

environment that could cause

trouble for the business or project






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Quantitative Risk analysis

• Quantified (or quantitative) Risk Analysis (QRA) combines

the consequences and frequencies of accident scenarios to

estimate the level of risk.

• In respect to the Qualitative method, QRA implicates the

acquaintance of probabilities that describe the likelihood of

the outcomes and their consequences.

• QRA started with the chemical industries from the 70s and

the offshore industry from the 80s.

• QRA is traditionally expressed through the decomposition

of the system. This frequently is done by the use of event

trees and fault trees.

25






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FTA and ETA

• ETA (event tree analysis) provides a structure for

postulating an initiating event and analyzing the

potential outcomes

• FTA (fault tree analysis) begins with a failure

and provides a structure to look for potential

causes

26






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Event tree analysis

• Event trees pictorially represent the logical order in which

events in a system can occur. Event trees begin with an

initiating event, and then the consequences of the event are

followed through a series of possible paths.

• Each path is assigned a probability of occurrence. Therefore,

the probability of the various possible outcomes can be

calculated.

• Event tree analysis is based on binary logic, in which an

event has either happened or not, or a component has failed

or has not.

• It is valuable to analyze the consequences arising from a

failure or undesired event.

27






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Event tree analysis: illustration (1)

28

Event trees are helpful in

considering all the possible

outcomes (on the right-hand side)

from an initiating event (on the

left-hand side), which is usually

ignition for fire risks.

The frequency of the initiating

event can be estimated from fire

report data, and the conditional

probabilities of the sub-events can

be quantified from fire report data

or fault trees.






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Event tree analysis: illustration (2)

Source: Fire Risk in Metro Tunnels and Stations Hyder Consulting

29






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Fault tree analysis

30

Fault trees are helpful in

quantifying the

probability of a top

event of concern (such

as the failure of a fire

protection system) from

all the potential root

causes (at the bottom),

again quantified from fire

report data.






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Fault tree analysisgeneral conclusion (event)

• Fault trees look like a complement

to event trees.

• The idea is to begin with a general

conclusion (event) and, using a

top-down approach, to generate a

logic model that provides for both

qualitative and quantitative

evaluation of the system

reliability.

Source: google pictures search “Fault tree”

31






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Fault tree analysis - symbolsBasic event - failure or error in a system component or element

(example: switch stuck in open position)

Initiating event - an external event (example: bird strike to aircraft)

Undeveloped event - an event about which insufficient information is

available, or which is of no consequence

Conditioning event - conditions that restrict or affect logic gates

(example: mode of operation in effect)

Intermediate event: can be used immediately above a primary event to

provide more room to type the event description.

Source: Fault Tree Handbook. Nuclear Regulatory Commission. NUREG–0492

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Fault tree analysis – gate symbols

OR gate - the output occurs if any input occurs

AND gate - the output occurs only if all inputs occur (inputs are

independent)

Exclusive OR gate - the output occurs if exactly one input occurs

Priority AND gate - the output occurs if the inputs occur in a specific

sequence specified by a conditioning event

Inhibit gate - the output occurs if the input occurs under an enabling

condition specified by a conditioning eventSource: Fault Tree Handbook. Nuclear Regulatory Commission. NUREG–0492

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Advantages and disadvantages of FTA

• Disadvantages

1. There is a possibility of oversight and omission of significant failure

modes.

2. It is difficult to apply Boolean logic to describe failures of system

components that can be partially successful in operation and thereby

affect the operation of the system, e.g. leakage through a valve.

3. For the quantitative analysis there is usually a lack of pertinent failure

data. Even when there are data they may have been obtained from a

different environment.

• Advantages

1. It provides a systematic procedure for identifying faults that can exist

within a system.

2. It forces the analyst to understand the system thoroughly.Source: Hasofer et al. 2007, Risk Analysis in Building Fire Safety Engineering

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Cause – consequence diagrams

• The combination of fault trees and event trees leads to the creation of

cause-consequence diagrams.

Time

Revealed from the

Monitoring system

S3

S2

S1

Consequences

Infraction of traffic law

Improper speed

Road condition

Vehicle flow

blocked

YES

YES

NO

NO

Other

Iniziative event

Road

Accident

35






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SCENARIO PROBABILITY

A1 PA*P1

A2 PA*(1-P1) *P2 *P3

A3 PA*(1-P1) *P2*(1-P3 )

A4 PA*(1-P1) *(1-P2)*P3

A5 PA*(1-P1) *(1-P2)*(1-P3)

B1PB*P1

B2PB*(1-P1) *P2 *P3

B3PB*(1-P1) *P2*(1-P3 )

B4PB*(1-P1) *(1-P2)*P3

B5 PB*(1-P1) *(1-P2)*(1-P3)

C1PC*P1

C2 PC*(1-P1) *P2 *P3

C3 PC*(1-P1) *P2*(1-P3 )

C4 PC*(1-P1) *(1-P2)*P3

C5 PC*(1-P1) *(1-P2)*(1-P3)

Triggering

event

Fire

ignition

1. Fire

extinguished

by personnel

2. Intrusion of

fire fighters

Arson

Explosion

Short

circuit

Cigarette

fire

YES (P1)

NO (1-P1)YES (P2)

NO (1-P2)

Scenario

Other

A1

A2

A3

A4

A5

3. Fire

suppression

YES (P3)NO (1-P3)

YES (P3)NO (1-P3)

Fire

location

AREA A

(PA)

YES (P1)

NO (1-P1) YES (P2)

NO (1-P2)

B1

B2

B3

B4

B5

YES (P3)NO (1-P3)

YES (P3)NO (1-P3)

AREA B

(PB)

YES (P1)

NO (1-P1) YES (P2)

NO (1-P2)

C1

C2

C3

C4

C5

YES (P3)NO (1-P3)

YES (P3)NO (1-P3)

AREA C

(PC)

Quantified Risk Analysis: cause – effect diagrams

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F (frequency) – N (number of fatalities) curve

• An F–N curve is an alternative way of describing the

risk associated with loss of lives.

• An F–N curve shows the frequency (i.e. the expected

number) of accident events with at least N fatalities,

where the axes normally are Logarithmic.

• The F–N curve describes risk related to large-scale

accidents, and is thus especially suited for

characterizing societal risk.

Source: Aven, T. Risk Analysis: Assessing Uncertainties beyond Expected Values and Probabilities. John Wiley & Sons, 2008

37






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Source: Aven, T. Risk Analysis: Assessing Uncertainties beyond Expected Values and Probabilities. John Wiley & Sons, 2008

38






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Source: NFPA, SFPE Handbook of Fire Protection Engineering, 3rd edition, 2002

39


Index

• Risk acceptance

- ALARP

- Human life (!)











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Risk acceptance

Source: Persson, M. Quantitative Risk Analysis Procedure for the Fire Evacuation of a Road Tunnel -An Illustrative Example. Lund, 2002

41






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Risk acceptance – ALARP (1)

RISK MAGNITUDE

INTOLERABLE

REGION

As

Low

As

Reasonably

Practicable

BROADLY ACCEPTABLE

REGION

Risk cannot be justified

in any circumstances

Tolerable only if risk

reduction is impracticable

or if its cost is greatly

disproportionate to the

improvement gained

Tolerable if cost of

reduction would exceed

the improvements gained

Necessary to maintain

assurance that the risk

remains at this level

As

Low

As

Reasonably

Achievable

RISK MAGNITUDE

INTOLERABLE

REGION

As

Low

As

Reasonably

Practicable

BROADLY ACCEPTABLE

REGION

Risk cannot be justified

in any circumstances

Tolerable only if risk

reduction is impracticable

or if its cost is greatly

disproportionate to the

improvement gained

Tolerable if cost of

reduction would exceed

the improvements gained

Necessary to maintain

assurance that the risk

remains at this level

As

Low

As

Reasonably

Achievable

42






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Risk acceptance – ALARP (2)

Source: google pictures search “ALARP”

43





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Monetary values – cost of human life (!)

• What is the maximum amount the society (or the decision-maker) is willing

to pay to reduce the expected number of fatalities by 1?

• Typical numbers for the value of a statistical life used in cost-benefit analysis

are 1–10 million euros. The Ministry of Finance in Norway has arrived at a

value at approximately 2 million euros.


Guideline values for the cost to

avert a statistical life (euros), used

by an oil company

Source: Aven, T. Risk Analysis: Assessing

Uncertainties beyond Expected Values and

Probabilities. John Wiley & Sons, 2008

44





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F-N diagrams: case study on a 180m road tunnel

www.francobontempi.org 45

1 20MW Fire [fat+inj/year] 0.00E+00

2 100MW Fire [fat+inj/year] 0.00E+00

3 Bleve of 50kg propane cylinder [fat+inj/year] 0.00E+00

4 Motor spirit pool fire [fat+inj/year] 0.00E+00

5 VCE of motor spirit [fat+inj/year] 0.00E+00

6 Chlorine release [fat+inj/year] 0.00E+00

7 BLEVE of 18t propane tank [fat+inj/year] 0.00E+00

8 VCE of propane [fat+inj/year] 0.00E+00

9 Propane torch fire [fat+inj/year] 0.00E+00

10 Ammonia Release [fat+inj/year] 0.00E+00

11 Acrolein in bulk release [fat+inj/year] 0.00E+00

12 Acrolein in cylinder release [fat+inj/year] 0.00E+00

13 BLEVE of a 20t CO2 tank [fat+inj/year] 0.00E+00

All scenarios [fat+inj/year] 0.00E+00

1+2 20MW - 100MW FIRES [fat+inj/year] 0.00E+00

3+13 BLEVE (except propane in bulk) [fat+inj/year] 0.00E+00

4+5 Flammable liquids [fat+inj/year] 0.00E+00

6+10+11+12 Toxic products [fat+inj/year] 0.00E+00

7+8+9 Propane in bulk [fat+inj/year] 0.00E+00





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𝐹𝑁 =

𝑖=1

𝑛

𝑓𝑖

𝐸𝑉 =

𝑖=1

𝑛

𝑓𝑖 ∙ 𝑁𝑖

EVENTEvent

Frequency

Event

Consequence

Cumulative Frequency

(per year)

E1 f1 N1F1 = f1

E2 f2 N1 F2 = f1 + f2

E3 f3 N2 F3 = f1 + f2 + f3

E4 f4 N4 F3 = f1 + f2 + f3 + f4

..... ..... ..... .....

En fn Nn Fn = f1 + f2 + f3 + f4+.....+ fn

F-N diagrams: case study on a 180m road tunnel





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Case study: 180m road tunnel


Trial 1 BASIS calculation

Trial 2 Total traffic [veh/h] 7200 72000

HGV ratio [-] 0.01 0.99

TrDen (traffic density) [-] 0.78 3.79

Bus/Coaches ratio [-] 0.01 0.99


HGV ratio [-] 0.01 0.99

Bus/Coaches ratio [-] 0.01 0.99


Trial 6 Light vehicles average speed [km/h] 80 179

Trial 7 HGV/Bus average speed [km/h] 60 119

Trial 8 Delay for stopping approaching traffic [s] 9000 1

Trial 9 Area (Urban/Rural) [-] urban rural

Trial 10 Average density of population [hab/km2] 0.01 999000

Trial 11 DG-HGV traffic [veh/h] 5 10000

Trial 12 Average number of people in a light vehicle [-] 2 10

Trial 13 W (effective width) [m] 10 5

Trial 14 H (effective height) [m] 6 3

Trial 15 VnN (volume flow rate along tunnel at nodes) [m3/s] 120 0

Trial 16 VnE (volume flow rate along tunnel at nodes) [m3/s] 210 0

Trial 17 tE (Time taken to activate emergency ventilation) [mins] 0.2 60

Trial 18 Xe (average spacing between emergency exits) [m] 90 1000

Trial 19 Cam (camber) [%] 0 100

Trial 20 Ad (open area of discrete drains) [m2] 0.075 0

Trial 21 Ecom (emergency coms) → 1, 2 o 3 [-] 3 1

Type of construction → 1 o 2 [-] 2 1

trad (internal radius) [m] - 6

dlin (lining thickness) [m] - 0.3

trad (wall thickness) [m] 0.2 -

dlin (roof slab thickness) [m] 0.2 -

Ns (Number of segments) [-] 6 15

Xs (Segment lengths) [m] 30 12

Nsub (number of sub-segments per segment) [-] 3 2

total number of sub-segments [-] 18 30

Xsub (actual sub-segment lengths) [m] 10 6

Trial 24 Number of lanes [-] 2 5

Trial 4

Trial 3

Trial 22

Trial 5

Trial 23

1 20MW Fire [fat+inj/year]

2 100MW Fire [fat+inj/year]

3 Bleve of 50kg propane cylinder [fat+inj/year]

4 Motor spirit pool fire [fat+inj/year]

5 VCE of motor spirit [fat+inj/year]

6 Chlorine release [fat+inj/year]

7 BLEVE of 18t propane tank [fat+inj/year]

8 VCE of propane [fat+inj/year]

9 Propane torch fire [fat+inj/year]

10 Ammonia Release [fat+inj/year]

11 Acrolein in bulk release [fat+inj/year]

12 Acrolein in cylinder release [fat+inj/year]

13 BLEVE of a 20t CO2 tank [fat+inj/year]

All scenarios [fat+inj/year]

1+2 20MW - 100MW FIRES [fat+inj/year]

3+13 BLEVE (except propane in bulk) [fat+inj/year]

4+5 Flammable liquids [fat+inj/year]

6+10+11+12 Toxic products [fat+inj/year]

7+8+9 Propane in bulk [fat+inj/year]

Societal Risk

EV (Expected Value of the dead)

Societal Risk

30m (distance from the route) [fat+inj/year]

80m [fat+inj/year]

200m [fat+inj/year]

500m [fat+inj/year]

30m [fat+inj/year]

80m [fat+inj/year]

200m [fat+inj/year]

500m [fat+inj/year]

Individual Risk

Direction A

Direction B

Individual Risk

4 analysis for every trial

Grouping


Risk reduction











DI STRUTTURE CIVILI

Risk reduction

Source: Brussaard et al. 2004. The Dutch Model for the Quantitative Risk Analysis of Road Tunnels.

49






DI STRUTTURE CIVILI

Risk reduction (2) - monitoring and system response

Time

1

3

2

Accident Accident evolutionPre-accident

situation

Pre-accident

Monitoring

Pre-accident

System Response

Accident

Localization

Evolution of System Response

Accident evolution Monitoring

System

Response

50






DI STRUTTURE CIVILI

• NFPA, SFPE Handbook of Fire Protection Engineering, 3rd edition, 2002

• Jönsson, J. Combined Qualitative and Quantitative Fire Risk Analysis – Complex Urban Road Tunnel. Arup partners, 2007.

• Faber, M.H. (2008) Risk and Safety in Civil, Environmental and Geomatic Engineering. ETH Zürich, lecture notes, available

online on 01/2011 at: http://www.ibk.ethz.ch/fa

• Haimes, Y. Y. (1981). Hierarchical holographic modeling. IEEE Transactions on Systems, Man, and Cybernetics, 11(9), pp.

606– 617.

• Nolan, D.P. 1986. Handbook of Fire and Explosion Protection Engineering Principles for Oil, Gas, Chemical, and Related

Facilities. Noyes, New Jersey

• Aven, T. Risk Analysis: Assessing Uncertainties beyond Expected Values and Probabilities. John Wiley & Sons, 2008

• Furness, A. , Muckett, M. Introduction to Fire Safety Management. Elsevier, 2007.

• Fire Risk in Metro Tunnels and Stations, Hyder Consulting, available on 05.2011 at

http://hkarms.myftp.org/web_resources/Conference_Presentation/Fire_Risk_Metro_Tunnels_Stations.pdf

• Fault Tree Handbook. Nuclear Regulatory Commission. NUREG–0492

• Hasofer et al. 2007, Risk Analysis in Building Fire Safety Engineering

• Persson, M. Quantitative Risk Analysis Procedure for the Fire Evacuation of a Road Tunnel -An Illustrative Example. Lund,

2002

• Brussaard et al. 2004. The Dutch Model for the Quantitative Risk Analysis of Road Tunnels. Available on 05.2011 at

http://www.rws.nl/rws/bwd/home/Tunnelveiligheid/dutch%20model.pdf

• Gkoumas, K. 2008. Basic aspects of risk-analysis for civil engineering structures. Handling Exceptions in Structural

Engineering: Robustezza Strutturale, Scenari Accidentali, Complessità di Progetto, Roma, 13-14 novembre.

http://www.francobontempi.org/handling_papers.php

References

51


http://www.ibk.ethz.ch/fa

http://hkarms.myftp.org/web_resources/Conference_Presentation/Fire_Risk_Metro_Tunnels_Stations.pdf

http://www.rws.nl/rws/bwd/home/Tunnelveiligheid/dutch model.pdf

http://www.francobontempi.org/handling_papers.php

PSA - Lezione 28 ottobre 2014 - RISK

Education

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