The Challenge of Risk Control in a Hydrogen based Economy, Part I

Transcription

1 The Challenge of Risk Control in a Hydrogen based Economy, Part I Hans J. Pasman Chemical Risk Management What are the risks, how can we determine them, How can we avoid, how to reduce, when can we be satisfied? We shall look broader than just hydrogen risks sec: Domino effects Summer School UofU 1

2 Definitions: Hazard" and Danger ; Risk. Hazard: inherent physical or chemical characteristic that has the potential for causing harm to people, property or the environment. Combination of a hazardous material, an operating environment, and certain unplanned events that could result in an accident. Risk: occurrence of undesired events, the effects resulting from such events, and the probabilities or likelihood that both the undesired events and their consequences do indeed occur: Probability Consequence Probability an event happens over time: Frequency [per time unit] 03 October

3 Preventive barrier Protective barrier Mitigative barrier Initiating action = Trigger Barrier Hazard, Potential, Danger LOP 1 LOP 2..n Effect / damage on target Enabling condition / event Elements in a accident situation, which form together a scenario; LOP stands for Layer of Protection 03 October

4 1. Hazard identification Process Safety analysis Data banks Checklist Index methods 3. Quantification of failure frequency Fault tree analysis Mitigation 5. Risk reduction Safety Management System Layer of Protection Analysis HAZOP Hazardous Process Effect analysis Event tree analysis Human factors Damage analysis Reliability Risk evaluation Emergency planning Safe conditions Risk communication Source terms Risk presentation Risk comparison Risk perception 2. Quantification of consequence 4. Risk assessment 6. Risk appraisal Ishikawa or Fish bone diagram QRA sequence 4

5 Why do a risk assessment? Land Use Planning Licensing plant Operational safety Emergency planning 03 October

6 Group or Societal Risk: F, N -curve F = Frequency of accident resulting in N or more prompt fatalities N = number of fatalities 03 October

7 RA : Qualitative Quantitative Deterministicprobabilistic 03 October

8 Trivial problem: Dispersion in results EU project 1990: Ammonia tank release scenario Scenarios Dispersion Damage models Failure frequencies Human factor??? Effectiveness of management 03 October

9 ARAMIS: EU project MIMAH Identification Hazards MIRAS Reference Accident Scenarios Risk= Severity Vulnerability Severity= Frequency Intensity 03 October

10 Bow tie: old-fashioned man s tie in the shape of a butterfly: Q AND n = Q i= 1 Q = 1 (1 Q ) OR n i i= 1 i UE = Unwanted Event e.g. human act CU E = Current Event condition, direct cause IE = Initiating Event e.g. pump fails CE = Critical Event, 12 types: leak, start of fire SCE = Secondary CE, escalation DP = Dangerous Phenomena, 13 types VCE, pool fire, jet fire etc. ME = Major Event, 4 types: overpressure, heat radiation, toxic load, pollution Barriers: Preventive, Protective, Mitigative 03 October

11 ARAMIS : Severity and Vulnerability Indexes m m n m n Sd ( ) = ( fce SCE ( d)) = CE ( DP DP ( )) ( DP, DP ( )) j j f P S d j i i = f S d i j i, j j= 1 j= 1 i= 1 j= 1 i= 1 V = V V V global H E M VH = V V V V op tr tox poll H H H H VE = V V V V op tr tox poll E E E E VM = V V V V op tr tox poll M M M M S DP negligible, reversible, irreversible effects and lethality or domino effects 3 Target categories, each 4 sub-categories weighing factors; MCA, 38 experts, 6 countries Quite a nuanced risk map can be produced 03 October

12 Risk Presentation: grid on GIS map Example for Materiel targets 03 October

13 How to use Risk Assessment : Effect distance: dispersion model Group risk of an activity Criteria NL 1985: Individual risk 10-6 (10-5 ) /yr RISKS UNACCEPTABLE Group Risk F( N) 10-3 /N 2, N 10 Transport F( N) 10-2 /N 2 /km ALARA and ALARP USA 1996: RMP rule Worst Case Scenario Community committee PROBABILITY (per year) RISKS TOLERABLE 100 1,000 10,000 France 2006: LUP: ARAMIS + committee, barriers EFFECT (number of fatalities) 03 October

14 Dutch peculiarities group risk: CUMULATIVE FREQUENCY, F( N), per year Fictitious fireworks storage Schiphol airport F N Freq. F( N), per year Dutch risk of flood disaster and drowning -average -scatter bandwidth Public safety risk by NL process industry ,000 10,000 EFFECT (number of fatalities, N) N, number of fatalities 03 October

15 A factor that helped safety to improve: Legislation Seveso I (1982/501/EEC) Seveso II (1996/82/EC IPPC 1996 Pressure Equipment Directive ATEX 100 (1994/9/EC) ATEX 137 (1999/92/EC) 03 October

16 Safety Management System 1. Accountability, 2. Process documentation, 3. Critical project review 4. Process risk management, 5. Management of change 6. Equipment integrity 7. Human factors (KISS) 8. Training and performance 9. Incident investigation 10.Standards, codes and laws 11.Audits and corrective actions 12. Enhancement of process safety Policy and objectives Organization, responsibilities and resources Practices and procedures Implementation and compliance monitoring Verification / assessment auditing Management review Control Correction Improvement 03 October

17 LOPA effectiveness tree example L1 PFD = Probability of Failure on Demand Failure, PFD = 0.05 L2 0.2 L3 L4 Crit. alarm Pressure relief Water curtain Fire brigade 0.15 Consequence class 0.33 Explosion, rebuilding plant 0.67 Fire; heavy damage to process equipment Inci - dent? Yes No Success P = Fire, quickly extinguished; damage Light damage, Short repair stop No process interruption, some off-spec product Normal course L1-4 = Independent Protection Layers: Length of arrow represents severity, thickness frequency

18 Conse- Plant Community Environment Financial quence personnel loss, k Class I / II 10 1 No lost time No hazard No notification < 100 III 10 2 Single injury Odor/ noise Permit violation > 100 IV 10 3 >1 Injury Injuries; Serious impact > 1000 local news V 10 4 Fatality Severe injuries; Severe, short >10,000 regional news term effects 10 5 Multiple Fatality; Disastrous effects, >100,000 fatalities int l news long term 10 6 Catastrophe Fatalities Disastrous effects >1,000,000 Public image severely damaged long term 18

19 Risk Matrix Action at once Freq. [ /yr] 10-1 Consequence class Action at next occasion A A 10-4 Optional No further action p D B B If class 10 4 or 10 5, or Freq. > 10-1 a semi-quantitative hazard study is required. If or a management review is required; if uncertainty exists, a QRA is needed. Line piece AB represents the public group risk criterion FN 2 < 10-3, A B includes worker fatalities.

20 k 10 Personal injury, lost time accident k 60 Plant damage k 90 Other incidents, lost production Typical Cost Pyramid After T.J. Webster, 1st Int l Symp. Loss Prevention, Delft, NL, October

21 Overall life cycle cost optimization Costs Total costs C t (C ins + p D) / f AP C ΣFC + C m / f AP Risk (p D) C t = C ΣFC (p, D) + C m (p) / f AP + C ins (p,d) / f AP + (p D) / f AP Costs Safety investments Maintenance Insurance Residual risk f AP = { (1 ) n n i + i }/{(1 + i) 1} = Annuity Present Worth factor 03 October

22 How safe is safe enough? Quantification: Suppose initiating event 1 per year Protection Concept 1: Base case 1,E+01 PC 2: Improvement IPL1 and 2 Frequency [events/year] 1,E+00 1,E-01 1,E-02 1,E-03 1,E-04 1,E Frequency [events/year] 1,E+01 1,E+00 1,E-01 1,E-02 1,E-03 1,E-04 1,E ,E-06 1,E-06 Damage = Capital + Revenue Loss [1000 ] LOPA points Action Threshold Limit Max. Acceptable EAL Damage = Capital + Revenue Loss [1000 ] LOPA points Action Threshold Limit Max. acceptable EAL 22

23 Conclusions, Part 1: For large scale technological systems such as Hydrogen economy, it pays to perform risk assessments Identification is a difficult step if no accidents have happened yet Concepts and methods are ready to be applied Improvements are to be developed in the human factor, management effectiveness measurement Consequence analysis is a separate chapter: Part 2 03 October