Urbanisation control UC in France since 2003

1
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
Urbanisation control (UC) in France since 2003
Technologic al Risk Prevention Plans (PPRTs)
2- Characterisation of aléas
2
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
Characterisation of aléas

• 1- Characterisation of dangerous phenomena
• 2- Selection of dangerous phenomena for the PPRT
• 3- Definition of the zone of study
• 4- Analysis of aléas
• 5- Mapping of aléas

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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
1- Characterisation of dangerous phenomena
Safety report by operator 1
Safety report by operator X
Dangerous phenomena lists (P,I,C)
Dangerous phenomena lists (P,I,C)
The DRIRE uses these data to characterise
technological aléas
Dangerous phenomena lists for the different
sites (P,I,C)

• Selection of dangerous phenomena (DPs) for the
  PPRT
• Definition of the zone of study

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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
1- Characterisation of dangerous phenomena
Summary table of dangerous phenomena
DPNo.
Comment
Probability Index
Type of effect
Very serious effect
Serious effect
Significant effect
Broken windows
Kinetics
1
SOO-Fire, Vat 1
E
thermal
40
55
80
0
Fast
2
SOO-BOIL-OVER Vat 1
E
thermal
200
350
430
0
Slow
3
SOO-Burst, Vat 1
E
overpressure
25
60
180
360
Fast
4
SOO-Fire, Vat 2
E
thermal
40
55
80
0
Fast
5
SOO-BOIL-OVER Vat 2
E
thermal
200
350
430
0
Slow
6
SOO-Burst, Vat 2
E
overpressure
25
60
180
360
Fast
7
SOO-Fire, Vat 3
D
thermal
40
55
80
0
Fast
8
SOO-BOIL-OVER, Vat 3
E
thermal
200
350
430
0
Slow
9
SOO-Burst, Vat 3
E
overpressure
25
60
180
360
Fast
4 parameters required for the PPRT

• probability (class) min. E, i.e. lt10-5/year
• type of effect (thermal, overpressure, toxic)
• - intensity (4 levels) expressed in terms of
  effect distance
• gravity
• kinetics

5
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
1- Characterisation of DPs probability
Probability assessed according to a national scale
./year
Data derived from the safety report
No generic values (values dependent on the method
used in the safety report)
- use of fault and consequence trees, with
barrier identification - feedback data -
otherwise, generic data (ERC, probability of
ignition)
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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
1- Characterisation of DPs Intensity
Intensity defined according to 4 national
thresholds


Significantly
Lethal effect
Irreversible effect
Indirect effect
Effects on humans

lethal effect
thresholds
thresholds
thresholds
thresholds



broken windows



Thermal effects of

_

2
4/3
2
4/3
1000 (kW / m
)
.s

600 (kW / m
)
.s

2
4/3
short exposure

1800 (kW / m
)
.s

Thermal effects of

_

2
2

2
prolonged exposure
8 kW / m

5 kW / m
3 kW / m



20 mbar

Overpressure effects

140 mbar

50 mbar

200 mbar

LC 5

_

Acute toxic effects

LC 1

SEI

Corresponding

Very serious effects

Serious effects

Significant effects

wording in law
(PPRT)


The effect distances are calculated in the safety
report and are specific to the site (no generic
values) - valve closure time, - weather
conditions and roughness, etc. - breach
conditions (size of leak, etc.)
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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
1- Characterisation of DPs Kinetics
2 cases
Slow if the kinetics allow for the
implementation of adequate safety measures under
the framework of an external emergency plan,
before the effects spread and reach the public
outside the facility otherwise Fast
Treated differently in the PPRT
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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
2. Selection of dangerous phenomena for the PPRT
Summary table of dangerous phenomena
DP No.
Comment
Probability index
Type of effect
Very serious effect
Serious effect
Significant effect
Shattered windows
Kinetics
1
SOO-Fire Vat 1
E
thermal
40
55
80
0
Fast
2
SOO-BOIL-OVER Vat 1
E
thermal
200
350
430
0
Slow
3
SOO-Burst Vat 1
E
overpressure
25
60
180
360
Fast
4
SOO-Fire Vat 2
E
thermal
40
55
80
0
Fast
5
SOO-BOIL-OVER Vat 2
E
thermal
200
350
430
0
Slow
6
SOO-Burst Vat 2
E
overpressure
25
60
180
360
Fast
7
SOO-Fire Vat 3
D
thermal
40
55
80
0
Fast
8
SOO-BOIL-OVER Vat 3
E
thermal
200
350
430
0
Slow
9
SOO-Burst Vat 3
E
overpressure
25
60
180
360
Fast

• Dangerous phenomena selected if potential
  effects outside the site
• Possible elimination depending on probability
  barrier conditions

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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
2. Selection of dangerous phenomena for the PPRT
Dangerous phenomenon elimination conditions

• ? Only dangerous phenomena with a sufficiently
  low probability level (class E i.e. lt 10-5/year
  conditions) can be excluded from the PPRT
• The Conditions are
• The probability classification is based on the
  implementation of a passive safety measure for
  each identified scenario
• or
• The probability classification is based on
• the implementation of at least two technical
  safety measures for each identified scenario,
• the maintaining of the probability class in the
  event of a failure of an existing or recommended
  technical or organisational safety measure.

10
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
2. Selection of dangerous phenomena for the PPRT
Remarks (cf. LUP guidance principles) 1/2
gt P1 intensity, frequency conditions on
barriers gt selection of dangerous phenomena
gt P2 aggravating scenarios only excluded if
conditions on probability and barriers
gt P3 Slow kinetics elimination if condition
on probability and barriers. Otherwise retained
for the PPRT
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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
2- Selection of dangerous phenomena for the PPRT
Remarks (cf. LUP guidance principles) 2/2

• P4 Condition on barriers requires the accurate
  identification of barriers. Barriers concerned
  are passive technical human barriers.
• P5 Safety report prior to the PPRT. Validation
  of barrier performance.

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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
3- Definition of the zone of study
The zone of study of the PPRT is defined by the
envelope curve of the effects of dangerous
phenomena selected according to the Probability
rule
The following are taken into account - the 3
effects (overpressure, toxic, thermal) - the
kinetics (slow and fast)
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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
4- Analysis of aléas
One study per type of effect (overpressure,
thermal, toxic) to

• outline PPRT regulations
• target further investigations

2 different treatments according to kinetics
Fast kinetics
The identification of an aléa level consists in
assigning one of the 7 aléa levels defined for
each type of effect to each point in the zone of
study, based on the maximum intensity of the
effects expected at this point and on the
cumulative probability of occurrence.
Low M M H H VH VH
Slow kinetics
The analysis is not based on aléas, but on the
envelope curves of the effects produced by all
the slow-kinetic phenomena selected for the PPRT.
14
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
4- Analysis of aléas
Aléas for fast kinetics
Example of mapping
Slow kinetics envelope curve
PPRT of Fictive Sous Bois Aléa map thermal
effects
Aléa level
Low M M H H VH VH
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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
4- Analysis of aléas
Principle

• Intensity (very serious, serious, etc.)
  calculated at a given point the maximum
  intensity is retained

• Calculation of cumulative probability in a
  geographic area, per intensity level (very
  serious, serious, etc.)

3 Cumulative probability classes
Cumulative probability classes
Cumulative prob. gt D
5E lt Cum. prob. lt D
Cumulative prob.lt 5E
Probability level D is equivalent to 10 dangerous
phenomena with a probability level E 
The cumulative probability of occurrence of 4
dangerous phenomena with a probability level E is
expressed as 4E
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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
4- Analysis of aléas
Definition of the 7 aléa levels resulting from
a combination of the maximum level of intensity
cumulative probabilities
Maximum intensity of the toxic,
thermal or overpressure effects on
Indirect
Significant
Very serious
Serious
humans at a given point
Cumulative probability
distribution of dangerous
lt5E
gtD
lt5E
gtD
lt5E
All
5E to D
gtD
5E to D
5E to D
phenomena at a
given point
Aléa level
VH
H
M
M
H
Low
VH
Practical action
Development of SIGALEA?, SIG software for spatial
analysis and 2-D technological aléa mapping.
17
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
4- Analysis of aléas
Example (1/3)
DP 2 (
Toxic
)
(Toxic)
DP 1

Very serious effects
800 m
Very serious effects
350 m
Probability D
Probability E
DP 3 (
Toxic
)
Very serious effects
650 m
Probability E
18
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
4- Analysis of aléas
Example (2/3)
DP 2 (
Toxic
)
(Toxic)
DP 1

Very serious effects
800 m
Very serious effects
350 m
Probability D
Probability E
DP 3 (
Toxic
)
Very serious effects
650 m
Probability E
19
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
4- Analysis of aléas
Example (3/3)
VH toxic aléa
VH toxic aléa
H toxic aléa
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Three aléa maps, one per type of effect
EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
5- Mapping of aléas
PPRT of Fictive Sous Bois Aléa map
overpressure effects
PPRT of Fictive Sous Bois Aléa map thermal
effects
PPRT of Fictive Sous Bois Aléa map toxic
effects
gt requirements differ according to the type of
effect
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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
Conclusion aléas

• All DPs are taken into account
• No implicit elimination of DPs (conditions on
  probability and barriers)
• Slow kinetics taken into account for the future
  gt specific requirements
• Specific features of the site taken into
  account
• - for DP probability and elimination (barriers)
• - to determine intensity levels
• Measures adjusted according to type of effect
  (detailed analysis)
• Justification of PPRT decisions (on which rough
  zoning and locally specific choices are based)
• Multi-establishments taken into account

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EuropeanPPRT Seminar
RISK PREVENTION AND POLLUTION CONTROL
After the aléas the stakes
Safety report / risk management
and control process
Technical study
sequence
Definition of the zone of study
aléas
Characterisation of aléas
Characterisation of stakes
.
stakes
Finalisation of the study sequence