European Seminar

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EuropeanSeminar PPRT
RISK PREVENTION AND POLLUTION CONTROL
The French Approach to Risk Assessment
Risk Assessment Risk acceptability
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EuropeanSeminar PPRT
RISK PREVENTION AND POLLUTION CONTROL
Risk Assessment Risk acceptability
1- Vocabulary used in France 2- Major Principles
of risk assessment and risk acceptability 3-
The safety report deliverables 4-
Characterisation of the parameters
probability, intensity and gravity 5- Risk
acceptability
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Scenario / phenomenon / barriers
1- Vocabulary used in France
A dangerous phenomenon
EI
Scenario a "path"
or
EI
Dangerous phenomenon
EI
ERC
EI

or
ERC
effects
EI
EI
EI
ERC
or
EI
Several scenarios may lead to the same dangerous
phenomenon
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Phenomenon / accident
1- Vocabulary used in France
No consequences (human)
No targets (human)
Phenomenon
Effects of intensity I
Accident
BOOM
Presence of targets
Human Consequences gravity G
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1- Vocabulary used in France
Risk G F (as used in the safety report
) Risk on the territory A V (as used in the
PPRT)
kinetics
Vulnerability of the stakes
Risk
Intensity of the effects of the dangerous
phenomenon
Frequency of occurrence
contribution to the risk
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2- Major Principles of risk assessment
Risk assessment by the operator according to a
clear and recognised methodology
Principle of proportionality
Evaluation of the intensity of dangerous phenomena
Effects distances evaluated using national
thresholds No generic distances (leak duration,
weather conditions, breach sizes... adapted to
the site)
Evaluation of the probability
Need to evaluate the probability of dangerous
phenomena (several methods), preferably using the
barriers in place
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2- Major Principles of risk assessment
Zoom on the risk control measures
Points to analyze - Efficacy - Response time
(suitability to kinetics) - Testability -
Maintainability
Risk control measures may be taken into account
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2- Major Principles of Risk acceptability
Acceptability of the risk 1st step (before LUP
and PPRT)

• Based on the safety report
• Authorisation or continuous improvement
  (reduction of the risk at source) or refusal

National acceptability grid (probability, gravity)
Applicable to Seveso sites (Upper and lower tier)
Role of the various parties

• Safety report under the responsibility of the
  operator risk control demonstration

• Safety reports and sites verified by the
  Inspectors (DRIRE Classified Installations
  Inspection Body State representatives)

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2- Major Principles of Risk acceptability
Acceptability according to Probability - Gravity
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3- The safety report deliverables
Safety report
Exhaustive identification of representative
accidents through a risk analysis
Accidents classified according to the
acceptability grid (P,G)
The operator demonstrates his risk control
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4- Characterisation of the parameters

• A- probability
• B- intensity
• C- gravity

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4- Characterisation of probability
Estimation of the probability

• National regulatory scale
• Scale with 5 classes of probability
• Choice of characterisation method (qualitative
  or quantitative or semi-quantitative) - using
  feedback, expert data or "barriers approach"...

./year
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4- Characterisation of probability
Evaluation using the "barrier approach"
SCENARIOS
Ein 1
EM
EI
Ph D
AND
Ein 2
EM
ERS
Ein 3
EI
Ph D
OR
Ein 4
ERC
OR
Ein 5
EM
EI
Ph D
AND
EM
EC 6
ERS
Ein 7
EM
EI
Ph D
OR
EM
EIn
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Prevention
Protection barriers
Protection
Events tree
Failure tree

• Prevention barriers
• Protection barriers

• Technical barriers
• Organisational barriers

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4- Characterisation of probability
Evaluation using the "barrier approach" example
Pipe rupture
F4
F2
Reduced intensity
Barrier functions
RR 100
Limited release release time 30 s
F4
./year
F5
RR risk reduction
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4- Characterisation of intensity
Effects thresholds
- thresholds on humans and on structures (domino
effects)
gt Effects on humans

• Effect distances evaluated taking barriers into
  account (leak duration, etc.) together with
  specific site conditions (weather, breach size,
  etc.)
• Mapping of the effects (software)

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4- Characterisation of gravity
Gravity evaluated for the acceptability of the
risks
Intensity gt gravity

• Evaluation of the number of potential victims
• 3 effects significantly lethal,
• start of lethal effects
• irreversible injuries
• Traffic, stadium... intermittent presence -

Zone of lethal effects
Zone of significantly lethal effects
Zone of irreversible injuries
Site studied
Toxic effects calculation in the cloud
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4- Characterisation of gravity
National scale to appreciate the gravity of the
human consequences of an accident outside the
installations
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5- Acceptability of the risk
Presentation of major accidents according to
national grid
NON non authorizable MMR authorizable but
verify that Risk Control Measures (MMR) are in
place (non authorizable if more than 5 accidents)
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EuropeanSeminar PPRT
RISK PREVENTION AND POLLUTION CONTROL
For more information...
Regulatory texts
- order of 29 September 2005 regarding the taking
into account of the probability of occurrence,
the kinetics, the intensity of the effects and
the gravity of the consequences of potential
accidents in safety reports for classified
installations subject to authorisation - order of
29 September 2005 amending the order of 10 May
2000 regarding the prevention of major accidents
involving hazardous substance or preparations
present in some categories of installations
classified for environmental protection subject
to authorisation - circular of 29 September 2005
regarding the criteria for appreciation of the
risk control approach for accidents likely to
occur in "Seveso" establishments, governed by the
order of 10 May 2000 amended.
Internet sites
http//www.ecologie.gouv.fr http//aida.ineris.fr/