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					                  HAZARD ASSESSMENT OF
                  MAJOR ACCIDENTS TRIGGERED
                  BY INTENTIONAL ACTS OF
                  INTERFERENCE

Martina Sabatini a,c, Severino Zanelli a,c, Valerio Cozzani b,c

       (a)                        DICCISM
                              Università di Pisa

                                  DICMA
       (b)                Alma Mater Studiorum –
                           Università di Bologna
                                   CONPRICI
                   Consorzio Interuniversitario Prevenzione e
       (c)           Protezione dai Rischi Chimico-Indusriali
  INTRODUCTION (1)

    An increasing attention of the risk analysts in the last
  years was devoted to the evaluation of the risk brought by
        external sources, as natural events (floodings,
   earthquakes) or intentional acts of interference, in sites
   where relevant quantities of dangerous substances are
                      handled or stored

                            SVAs
                        PROCEDURES
                         (API-NPRA,
                            SFK)

• SECURITY                             SCARCE ATTENTION on
• LIKENESS of the                        CONSEQUENCES
  ATTACK                                        DICMA
                      DICCISM           Alma Mater Studiorum -
  CONPRICI
                  Università di Pisa     Università di Bologna   2
INTRODUCTION (2)

           From literature analysis the need of a
               NEW METHOD arises, able to
           estimate the CONSEQUENCES of an
                 attack to a process plant




    EMERGENCY                                RESOURCES
     PLANNING                               MANAGEMENT

                        SCREENING of
                             an
                         INDUSTRIAL
                            SITE                DICMA
                       DICCISM          Alma Mater Studiorum -
CONPRICI
                   Università di Pisa    Università di Bologna   3
   SCHEME of the PROCEDURE



                             CONSEQUENCES ASSESSMENT
                                      STEPS
       1.
Identification
 of attractive
                                                                          4.
    targets
                                                                     Evaluation of
                                                                     domino effect

                 2.
         Identification of                           3.
         credible acts of                    Identification of
           interference                         accidental
                                              scenarios and
                                              consequences
                                                    DICMA
                           DICCISM          Alma Mater Studiorum -
    CONPRICI
                       Università di Pisa    Università di Bologna               4
   FIRST STEP: ANALYSIS OF VARIOUS
                      REQUIRED    EXPECTED                               EXPECTED
        TYPE OF
      ACTS OF INTERFERENCEOF
     INTERFERENCE
                      LEVEL     RELEASE RATE                           RELEASE RATE
                                INFORMATION   (ATMOSP. EQ.)            (PRESSUR. EQ.)

   From the literature
DELIBERATE MISOPERATION review, a list of 10 acts of
                             C             R2        R1
     interference was developed. To carachterize them,
INTERFERENCE BY SIMPLE
                             C             R2
     some parameters are needed, in order to carry R1
        MEANS                                        on
     an analysis as
INTERFERENCE BY MAJOR quantitative as possible
          AIDS
                                         C           R3                     R2
  1. POTENTIAL IMPACT VECTOR (physical effects as
     radiation, overpressure,C             R3         R2
ARSON BY SIMPLE MEANS
                              projectile penetration)
 ARSON BY INCENDIARY
  2. EXPECTED RELEASE B
      DEVICES         RATE                         R4           R3
                                              (4 categories based on
     Purple Book)
   SHOOTING (MINOR)                      A           R1                     R1
  3. REQUIRED LEVEL OF KNOWLEDGE (how deeply
                                        R4
     the plant must be know A perform the attack, rankR4 3
  SHOOTING (MAJOR)
                            to                         of
     categories)
      EXPLOSIVES            B           R4            R4
    VEHICLE IMPACT                       B           R3                     R3
                                                      DICMA
                            DICCISM           Alma Mater Studiorum -
    CONPRICI
     PLANE     IMPACT                    A
                        Università di Pisa           R4
                                               Università di Bologna
                                                                            R4      5
 1. IDENTIFICATION OF ATTRACTIVE
     TARGETS (1)
  THE MOST SEVERE POSSIBLE CONSEQUENCES are
      aimed to be achieved by the executors of the attack

   ATTRACTIVENESS
                                           DAMAGE DISTANCES
(likeness of the attack)
       TYPE OF HAZARD
       (flammable, toxic or both)
       PHYSICAL CONDITIONS
       (post-release behaviour: adiabatic expansion, pool
       vaporization, etc.)
       AMOUNT OF SUBSTANCE IN THE UNIT (hold up:
       devices having the same volumes may contain different
       quantities of hazardous materials)
             ATTRACTIVENESS RANKING
                    from 1 to 4
                                                   DICMA
                          DICCISM          Alma Mater Studiorum -
  CONPRICI
                      Università di Pisa    Università di Bologna   6
   1. IDENTIFICATION OF ATTRACTIVE
       TARGETS (2)
                ATTRACTIVENESS RANKING TABLE

                                FLUIDS WITH LOW
                LIQUEFIED GAS
                                VAPOR PRESSURE                   CRYOGENIC
                STORED UNDER
                                STORED IN LIQUID   GAS                       LIQUID
                  PRESSURE                                        STORAGE
                                     PHASE



  TANKS              4                   3           3                 2      1
   LARGE
 DIAMETER            4                   3           2                 2      1
 PIPELINES


COLUMN-TYPE
EQUIPMENTS           3                   2           2                 2      1
 REACTORS /
   HEAT              3                   2           1                 1      1
EXCHANGERS
                                                           DICMA
                               DICCISM             Alma Mater Studiorum -
     CONPRICI
                           Università di Pisa       Università di Bologna         7
    2. IDENTIFICATION of CREDIBLE ACTS OF
        INTERFERENCE (1)
        ACT of                          VULNERABILITY
                   DAMAGE VECTOR
  INTERFERENCE                             MODELS
          PROBABILITY OF SUCCESS OF AN ATTACK
Deliberate Misoperation,                   Availability on demand for
   Interference using    EXTERNAL ACTION   protection and mitigation
 Simple or Major Aids
 MODE OF INTERFERENCE            PHYSICAL VULNERABILITY of the
                                                     systems
                                                             device
                                                 Equipment vulnerability
Arson using Simple or
                                  RADIATION       models and reliability
         DAMAGE
 Incendiary Devices                       STRUCTURAL RESISTANCE,
                                                        models
          VECTOR                                     depending on the
                                                  Equipment vulnerability
   Shooting (1) o (2)                    OPERATING CONDITIONS
                            MISSILES IMPACT        models and reliability
                                                         models
                                       (pressurized devices are more
                                             resistant than atmospheric ones)
                                                          Equipment vulnerability
      Explosives             OVERPRESSURE                  models and reliability
            PROBIT FUNCTIONS: simple                      way to models
                                             some
   Vehicle evaluate success probability forEquipment vulnerability
           or Plane
                        VEHICLE IMPACT
       Accident     modes of interference DICMA  models
                            DICCISM                Alma Mater Studiorum -
      CONPRICI
                        Università di Pisa          Università di Bologna           8
 2. IDENTIFICATION of CREDIBLE ACTS OF
     INTERFERENCE (2)
 SCHEMATIZATION OF
    the LAYERS
  PROBABILITY OF of
     SUCCESS                                      PROTECTIONS that may
     PROTECTION
                                                  affect the success of the
 (esp. for Sabotage
                                                            attack
   interferences)


             LOPA (Layers of Protection Analysis)
                  approach may be useful

                                           PROTECTION LAYERS (passive
  PROBABILITY of an
                                           and active protections: pressure
ACCIDENTAL SCENARIO
                                           relief systems, alarms, dikes etc.)

  NO WAY to evaluate FREQUENCY of the attack, but we can
           estimate the LIKENESS of SUCCESS
                                                         DICMA
                          DICCISM                Alma Mater Studiorum -
  CONPRICI
                      Università di Pisa          Università di Bologna          9
  3. IDENTIFICATION OF ACCIDENTAL SCENARIOS AND
      CONSEQUENCES EVALUATION

               From the previous phases
   RELEASE RATES for each ACT OF INTERFERENCE can be
                        obtained

         TRADITIONAL SAFETY ANALYSIS METHODS
 may be used to assess the consequences of loss of containment

                                         CONVENTIONAL EVENT
ACCIDENTAL SCENARIOS
                                          TREES may be used

              SPECIFIC ACTS OF INTERFERENCE
              (Arson or Explosives) may affect the
               probabilities of the scenarios, since
                IGNITION is largely more probable
                     than in usual conditions
                                                 DICMA
                        DICCISM          Alma Mater Studiorum -
   CONPRICI
                    Università di Pisa    Università di Bologna   10
  4. EVALUATION of DOMINO EFFECT

                   PROVEN CORRELATIONS
                    for the EVALUATION OF
                      PHYSICAL EFFECTS
                      (Yellow Book ones )


                                             PHYSICAL EFFECTS on
                                                   DEVICES
  PHYSICAL EFFECTS on
          PEOPLE
(proper thresholds provided                External attacks may trigger
       by Seveso III)                        ESCALATION EVENTS
                                             Conventional escalation
                                         thresholds (defined by literature)
                                            may be successfully used


                                                     DICMA
                        DICCISM              Alma Mater Studiorum -
   CONPRICI
                    Università di Pisa        Università di Bologna       11
CASE STUDY

 ACRYLONITRILE                                  METHANOL
  ATMOSPHERIC                                  ATMOSPHERIC
     TANKS                                        TANKS

           1                                                     1


                                                             4
                                                 LPG
                                             PRESSURIZED
                                             HORIZONTAL
                                                TANKS

                                            DICMA
                   DICCISM          Alma Mater Studiorum -
CONPRICI
               Università di Pisa    Università di Bologna           12
    ASSESSING THE CONSEQUENCES
      ACT of                                           RATE of               DAMAGE
                        ITEM          SCENARIO
  INTERFERENCE                                        RELEASE              DISTANCE (m)
DELIBERATE       THRESHOLDS for PHYSICAL
          PROPERPV-1/2   VCE       R2
                                                                 EFFECTS
                                                                      354
MISOPERATION
INTERFERENCE
   DAMAGE             PV-1/2        VCE            R2                  354
USING SIMPLE AIDS
   INTENSITY → HIGH              FATALITY        IRREVERSIBLE         REVERSIBLE
INTERFERENCE      FATALITIES     THRESHOLD       DAMAGES              DAMAGES
   SCENARIO ↓         PV-1/2        VCE            R2                  354
USING MAJOR AIDS
   Pool fire, Jet
ARSON USING       12.5 kW/m2     7 kW/m2         5 kW/m2              3 kW/m2
   Fire, Fireball     PV-1/2        Jet fire        R2 (PSV)           183
SIMPLE MEANS
   Flash fire     LFL            0.5 LFL                  ----                   ----
ARSON USING
INCENDIARY
   Overpressure       PV-1/2         Jet fire       R2 (PSV)           183
DEVICES           0.3 bar        0.14 bar        0.07 bar             0.03 bar
   (VCE)
                                     Toxic
SHOOTING (MINOR)LC50 (30
  Toxic release    AT_T-1/2/3                     R1                      118 ----
                min.)
                                       ----
                                     Dispersion IDLH

SHOOTING (MAJOR)    PV-1/2           Jet fire      R3                     249

EXPLOSIVES          PV-1/2           VCE           R4                     2318
VEHICLE IMPACT      (Unlikely)       ----          ----                   ----
PLANE IMPACT        PV-1/2  DICCISM VCE            R4 DICMA
                                                 Alma Mater Studiorum -
                                                                          2318
     CONPRICI
                        Università di Pisa        Università di Bologna                 13
CONCLUSIONS


A method to evaluate consequences of an external
attack was developed
Expected release rates, likeliness of the success of
the attack and impact distances (also considering
domino effect) may be estimated
A ranking of the “attractiveness” of the equipment
may be performed




                                           DICMA
                  DICCISM          Alma Mater Studiorum -
CONPRICI
              Università di Pisa    Università di Bologna   14
  HAZARD ASSESSMENT OF
  MAJOR ACCIDENTS TRIGGERED
  BY INTENTIONAL ACTS OF
  INTERFERENCE


THANK YOU FOR YOUR
    ATTENTION

				
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posted:3/11/2010
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