Targeting Vulnerability in Process Safety and Asset Management seeing the wood for the trees

Transcription

1 Targeting Vulnerability in Process Safety and Asset Management seeing the wood for the trees Ian Travers Principal onsultant, Process Safety Information Systems & Global Solution

2 Background Identify and categorise both criticality and vulnerability of the component elements within a process safety management system. Developed by the author whilst in HSE and is used by them to focus regulatory programmes on the control measures that make the greatest contribution to preventing a major accident whilst at the same time representing the weakest parts of the control regime. Results in a clear risk profile and visibility of the functioning and performance of the most important aspects of a process safety management system. 2

3 Benefits Helps to prioritise resources and attention to those aspects of risk management that matter the most. In times of economic restraint allows business decisions to be based on relevance to a safe outcome and performance of critical assets. Brings visibility and focus to those involved in critical tasks and functions so they recognise the reason and value of the control measure. Ensures vital items of plant maintenance don t slip through the net against a background of maintenance backlogs. Easily links to KPIs and Performance Dashboard. 3

4 The 5 Key Questions in Process Safety How could it go catastrophically wrong? Where / when will most likely go wrong? What controls or systems are there to prevent a major incident? Which of these controls are most vulnerable to failure? What information do you have to show those systems continue to operate to the desired performance standard? 4

5 Monitoring performance HSG 254 Developing Process Safety Performance Indicators OED Guidance on developing safety performance indicators 5

6 How it works Select the main major hazard scenarios Identify how loss of control or loss of function can arise Set out the business process stages product or activity flow Map the failure mechanisms onto the flow diagram Set out the controls that should be / are present to prevent a failure / loss of control Ensure there are no gaps in control / mitigation Review each control against criticality and vulnerability Focus on high criticality and high vulnerability Map these to KPIs, asset registers and maintenance programs? Safe Fail 6

7 Process Safety Management 7

8 8

9 Stages of Analysis Toxic Flammable Reactive orrosive Explosive hemical Processes: Storage Reacting Separating, Distillation Mixing, Blending Product Transfer Temperature Pressure Solid Liquid Gas Substance: Hazardous- Property: ondition Volume Processes or Activities Undertaken Whole-Site Major Hazard Scenarios Site Risk Profile Probability Potential Impact/ onsquences hallenges to ontainment Most redible / Greatest Inpact MH Scenario Relevant Plant / Process High/Low Pressure High/Low Temperature Overfilling orrosion Human Error Physical Damage hallenges to Integrity on that Plant ontrol Systems to maintain integrity Preventive Barriers Mitigation Barriers Most Vulnerable ontrol Systems Loss of ontainment 9

10 How do things fail? Based on UK Health and Safety Laboratory s of loss of containment incidents: Human error Over filling Over pressure Over temperature Over speed Excessive current / load Static discharge / lightening Mechanical Failure orrosion internal / external Stress Fracture temp/pressure cycling / vibration / loading Embrittlement Wear friction Impact 10

11 ontrol Measures / Mitigation (from risk assessment) Plant Design Operating Parameters Operating Procedures Process ontrols: Temperature Pressure Level Flow Inspection & Maintenance ompetence Management of change Permit to work Procurement Emergency Shut Down Pressure Relief ooling / fire water Secondary ontainment Warning & Evacuation Refuge 11

12 ase Study Fuel Storage and Distribution 12

13 Servo Gauge RADAR Level Guage L Independent High Level Switch High High Level Alarm Articulated Gantry High Level Alarm Normal Fill Level Thermal relief Floating deck Scully level and meter control Vapour Recovery Unit Ship s pumps Ship / Shore coupling P ROSV Tank drain ROSV Flow meter Road Tanker Bottom Loading Gasoline Storage and Dispatch Process Description What can go wrong? Major Hazard Scenarios: Large scale spillage of gasoline & ignition Ship off loading Bulk tank Road Tanker filling Large scale spillage of diesel into harbour 13

14 Where can it go wrong? Ship off loading Bulk tank Road Tanker filling Ship loading How can it go wrong? orrosion Erosion Mechanical failure Overfilling Overpressure Over Temperature (thermal expansion) Human Error Impact Stress Static 14

15 M F Servo Gauge RADAR Level Guage L M F Independent High Level Switch I O P M F S Articulated Gantry High High Level Alarm High Level Alarm H E Normal Fill Level Thermal relief S T O F Floating deck Scully level and meter control S T O F O T O P S Vapour Recovery Unit M F I P ROSV I ROSV O P Ship s pumps H E I E O P O T M F O P M F O T Flow meter M F M F S H E I Gasoline Storage and Dispatch hallenges to Integrity How & where? E M F O F O P O T H E I S S T hallenges to Integrity orrosion Erosion Mechanical Failure Overfilling Over Pressure Over Temperature (thermal expansion) Human Error Impact Stress Static 15

16 hallenges to Integrity How do things go wrong? 16

17 Servo Gauge RADAR Level Guage L Independent High Level Switch PL High High Level Alarm RI M Articulated Gantry V I T High Level Alarm Normal Fill Level Thermal relief L Floating deck Scully level and meter control L P Vapour Recovery Unit T Ship s pumps V I B E B P ROSV Mo V I E B ROSV Flow meter F PL V I B E B IL P E P ontrol Measures - Process ontrol Measures - Generic T Temperature ontrol Inspection & Maintenance P Pressure ontrol ompetence L Level ontrol Mo Management of hange PL Pre-loading checks E P Emergency Plan Gasoline Storage and Dispatch ontrol Measures F PT Flow ontrol Pressure Testing B M Barrier ommunication V I Visual Inspection RI Range Indicator E B Earth Bonding IL Interlock 17

18 ontrol Measures 18

19 Vulnerability analysis the system is safety critical that is, if it failed and there was an associated loss of containment would this potentially lead to a major accident or a serious incident? the control measure is towards or is the last in line using the bow-tie analogy, the system provides any early warning, of failure, there is opportunity to recover the loss of containment, and the correct functioning of the control measure relies partly or wholly on human intervention. 19

20 Vulnerable to failure Safety ritical 20

21 Analysis Table 1: Overfilling Gasoline Tank Safety ritical Low Medium High Vulnerability High Verification of products on the ship prior to off loading Ullage checks of Tanks prior to filling Inspection & maintenance of level gauges and associated control loops Inspection and maintenance of high level alarms Inspection & maintenance of high level trips Medium Low Pre-receipt paperwork from ship's agent Alarm checks prior to commencing loading Setting valve routing prior to tank filling Flow rates cross check Shift handover completed correctly High level Alarms fitted High Level shut off device fitted Appropriate number of personnel involved in the process Level gauges fitted 21

22 Analysis Table 3: Overpressure Vulnerability High Safety ritical Low Medium High Load arm hoses inspected & maintained Medium Pressure relief valves fitted Ship sets up pressure flow rate Pressure relief valves inspected and maintained Vehicle safe loading pass Low Pressure gauges fitted to pipelines Tanks designed to recognised codes / standards Pressure gauges inspected & maintained Road tanker vapour recovery system fitted Inspection & maintenance of vapour relief lines 22

23 Servo Gauge RADAR Level Guage L Independent High Level Switch RI Articulated Gantry PL High High Level Alarm High Level Alarm Normal Fill Level Thermal relief ULS Gasoline 27/28 Floating deck Scully level and meter control Vapour Recovery Unit T Ship s pumps M V I V I P ROSV E B ROSV V I Flow meter E B PL PT ontrol Measures - Process ontrol Measures - Generic T Temperature ontrol Inspection & Maintenance L Level ontrol ompetence PL Pre-loading checks M ommunication Gasoline Storage and Dispatch High Vulnerability / High riticality PT V I RI E B Pressure Testing Visual Inspection Range Indicator Earth Bonding 23

24 High riticality HIGH Vulnerability 24

25 KPIs Table 2: KPIs for high criticality and high vulnerability controls Threat Barrier Leading KPIs Lagging KPIs Overfilling Gasoline Tank Ullage checks of Tanks prior to filling hecks undertaken according to procedure Any loss of containment of gasoline during off loading, bulk storage or road tanker filling Overfilling Road Tankers Inspection and maintenance of high level alarms Inspection & maintenance of high level trips Inspection & maintenance of level gauges and associated control loops Driver checks ullage prior to loading Inspection & maintenance of emergency shut off system Inspection & maintenance completed to agreed schedule Inspection & maintenance completed to agreed schedule Inspection & maintenance completed to agreed schedule hecks carried out in accordance with procedures Inspection & maintenance completed to agreed schedule Any occasion where a gasoline tank is overfilled Any occasion where a road tanker is overfilled 25

26 Visibility of Performance 26

27 Other examples 27

28 LPG LPG O O P Mo Napha feed stock 7/10 barg Heat Exchangers D6 Water removal High Level Alarm P L NST 1 9 barg 145/ 150 o L Heavy Products Light products Mo D O High reflux O P L NSD1 Pressure reduction ondenser Emergency isolation valve Mo E P Mo D L P NFT1 1 barg 80 o Supports P NFD1 D Mo Reflux Light Naptha Re-boiler L Emergency Shut Down E P Mo Heavy Naptha ontrol Measures - Process ontrol Measures - Generic T Temperature ontrol Inspection & Maintenance P Pressure ontrol ompetence L Level ontrol Mo Management of hange F Flow ontrol E P Emergency Plan Naptha Stabilisation & Fractionation Unit Vulnerability D O P Design Operating parameters O Operating controls 28

29 Flue Gas Gas 4 Reactor T P O P Gasoline Mo Fresh atalyst Regenerator Spent atalyst Steam Injection L Fractionator Light Gas Oil Oxygen O Heavy Gas Oil F O P Riser o T O F ombustion Air O F Regenerated atalyst O P O P O O rude Oil F Slurry Settler Mo O O P F Fired Heaters T rude Oil T ontrol Measures - Process Temperature ontrol ontrol Measures - Generic Inspection & Maintenance Fluid atalytic racker Unit Vulnerability P L Pressure ontrol Level ontrol Mo ompetence Management of hange F Flow ontrol D Design O P Operating parameters O Operating controls 29

30 Auto shut off High Pressure Inlet I&M OP Pig Trap PW Ph I&M 67 bar(g) P I&M Slam Shut Valve P I&M I&M Filter Meter Water Bath Heater I&M OP Ph Regulators I&M Odourant Tank I&M 32 bar(g) P P Auto shut off valve LGT Pump P Diagram 4: Key: I&M NTS Take Off Installation ontrol Measures Vulnerability Inspection & maintenance P athode protection OP Operational Procedures P/ Painting & oating T Temperature ontrol PW Permit to Work L Level ontrol Ph ontrol of Plant hange P Pressure ontrol PB Physical Barriers / Layout 30

31 How could it go catastrophically wrong? Where / when will most likely go wrong? What controls or systems are there to prevent a major incident? Which of these controls are most vulnerable to failure? What information do you have to show those systems continue to operate to the desired performance standard? Servo Gauge RADAR Level Guage L Independent High Level Switch High High Level Alarm Articulated Gantry High Level Alarm Normal Fill Level Thermal relief Floating deck Scully level and meter control Vapour Recovery Unit Ship s pumps Ship / Shore coupling P ROSV Tank drain ROSV Flow meter Road Tanker Bottom Loading Servo Gauge RADAR Level Guage L Independent High Level Switch Gasoline Storage and Dispatch Process Description RI Articulated Gantry PL High High Level Alarm High Level Alarm Normal Fill Level Thermal relief ULS Gasoline 27/28 Floating deck Scully level and meter control Vapour Recovery Unit T M V I P ROSV E B ROSV Vulnerable to failure Ship s pumps V I V I Flow meter E B PL PT T ontrol Measures - Process Temperature ontrol ontrol Measures - Generic Inspection & Maintenance L Level ontrol ompetence PL Pre-loading checks M ommunication Gasoline Storage and Dispatch High Vulnerability / High riticality PT V I RI Pressure Testing Visual Inspection Range Indicator Safety ritical E B Earth Bonding 31

32 Thank You Questions? Ian Travers Principal onsultant, Process Safety Information Systems & Global Solution 32