Using Geodatabases for Risk Calculation Query Policy and Considerations. EGUG Presentation Jason Bodily Nicor Gas Timothy P. Yost GL Noble Denton

Transcription

1 Using Geodatabases for Risk Calculation Query Policy and Considerations EGUG Presentation Jason Bodily Nicor Gas Timothy P. Yost GL Noble Denton

2 Agenda ArcGIS Pipeline Database Model vs Gas Distribution Database Considerations Parts of a Risk Model Steps in calculating a model Getting Risk Features Data Acquisition Math Calculation Data Acquisition Step Details Important Requirements 2

3 Alternative Data Models APDM vs Gas Distribution ArcGIS Pipeline Database Model Gas Distribution Database Model More Rigid Core Topology No real Core Topology Linear Referenced/Stationed Non-Stationed Station Series = Centerline Backbone Distribution Main Foreign Keys Less Feature Data Higher Volume in Feature Data More Survey Data Less Survey Data ILI Data Leaks 3

4 Some Working Definitions Risk Model = Consequence of Failure * Probability of Failure Structures Environmental Area Operating Pressure + Outside Diameter LOSS Min Responder Distance Fire Houses 4

5 Some Working Definitions Risk Model = Consequence of Failure * Probability of Failure Risk Formula = Consequence of Failure = (EN * (NUMRES / RESPDIST) * P * D * (5 + LOSS)) * 10^-4 Structures Environmental Area Operating Pressure + Outside Diameter LOSS Min Responder Distance Fire Houses 5

6 Some Working Definitions Risk Model = Consequence of Failure * Probability of Failure Risk Formula = Consequence of Failure = (EN * (NUMRES / RESPDIST) * P * D * (5 + LOSS)) * 10^-4 Risk Factors = the terms of the formula used to score each risk feature Each Risk Factor needs to resolve down to one value for each Risk Feature Structures Environmental Area Risk Factors Operating Pressure + Outside Diameter LOSS Min Responder Distance Fire Houses 6

7 Some Working Definitions Risk Model = Consequence of Failure * Probability of Failure Risk Formula = Consequence of Failure = (EN * (NUMRES / RESPDIST) * P * D * (5 + LOSS)) * 10^-4 Risk Factors = the terms of the formula used to score each risk feature Each Risk Factor needs to resolve down to one value for each Risk Feature Risk Features = the items to score (Lines, Points, or Polygons) Each Risk Feature will receive one score for each formula in the risk model In this case: Consequence of Failure Risk Features CP Area Distribution Main1 Distribution Main2 Distribution Main3 Valve 7

8 Nicor Transmission Risk Model Framework Nicor Risk Model Development ASME B31.8S Section 5 & Appendix A CFR Nine Probability of Failure Algorithms Consequence of Failure Algorithms External Corrosion Life & Property Internal Corrosion Throughput Stress Corrosion Cracking Environmental Manufacturing Construction Threat Equipment Threat Third-Party Damage Incorrect Operations Outside Forces Total Risk = (Probability of Failure x Consequence of Failure) 8

9 Model Summary Nicor Customized Risk Model Probability of Failure Algorithms Pec = (1/T) * CorrrosionRate * StressLevel * CoatingType * Soil * Temperature * StrayCurrent * MaterialType * SelectiveSeamCorrosion * Casings * MICInfluence * IncidentHistory * MITE Consequence of Failure Algorithms Clp = (CLASS * HCA * MOP * DFORM * (1+ (((MOP * DFORM) / ((2 * T) * 0.72 * SMYS)))^ * VCF * (1 + (VS/100)))) 100 Factors 90 Formulas 9

10 Parts of a Risk model Risk models are normally expressed as: Risk = Consequence of Failure * Probability of Failure X = Lets simplify this to just a Consequence Model But you ll need to consider which model Relative Ranking models (relative score/ordinal rank) Absolute Ranking models (probability/dist/time) GTI Model SGA Model ESRI Model Builder Model 10

11 Simplified Risk Formula Consequence of Failure = (EN * LS * P * D * (5 + LOSS)) * 10^-4 EN = Environmental Score (Environmental Impact) Highly Sensitive Area = 3 Moderately Sensitive Area = 2 Normally Sensitive Area = 1 LS = Life Safety Score (People and Property Impact) = NUMRES / RESPDIST NUMRES = Number of Residential Structures RESPDIST = Responder Distance (minimum distance to E.R.) P = Operating Pressure D = Outside Diameter LOSS = Loss of Service Score (Relative business impact of a service outage?) No customers shut-off and shipper's needs are not affected = 1 Major impact on industrial customers or minor impact on residential customers = 2 Major impact on industrial, commercial, and residential customers = 3 11

12 Let s look at the model in action Feature1 = (EN * (NUMRES / RESPDIST) * P * D * SOF * (5 + LOSS)) * 10^-4 Step #1 Data Acquisition resolve every factor to a single value or score Factor Current Values Structures 2 Environmental Area Wetland=3 Minimum Responder Distance 3mi Operating Pressure 400psi Outside Diameter 18in Loss Major impact to industrial customers = 3 Structures Environmental Area Operating Pressure Outside Diameter LOSS Feature1 Min Responder Distance 12

13 Let s look at the model in action Feature1 = (EN * (NUMRES / RESPDIST) * P * D * SOF * (5 + LOSS)) * 10^-4 Step #1 Data Acquisition resolve every factor to a single value or score Factor Current Values Structures 2 Environmental Area Wetland=3 Minimum Responder Distance 3mi Operating Pressure 400psi Outside Diameter 18in Loss Major impact to industrial customers = 3 Step #2 Evaluate The Math simple, plug in the factor values, let the computer do the work! Feature1 = (EN * (NUMRES / RESPDIST) * P * D * (5 + LOSS)) * 10^-4 Feature1 = (3 * (2 / 3) * 400 * 18 * (5 + 3)) * 10^-4 =

14 Data Acquisition Step Details Getting the Risk Features Dynamic Segmentation Dynamic Aggregation Risk Feature to Risk Factor Relationships Risk Factor Query Policies Defensive Model Coding 14

15 Nicor Transmission System Dynamic Segmentation Select Area of Focus Du Page County, Illinois Probability and/or Consequence of Failure Algorithms for Case Study Probability of Failure due to External Corrosion Segment Area of Focus on all factors associated with Chosen Risk Algorithms Install Year, Class Location, MAOP, Coating Type Pipe Segment Install Year DOT Class Class Location Operating Pressure MAOP Coating Coating Type Coal-Tar FBE 250 Felt Coat 500 Coal-Tar Segmentation Hypothetical Data 15

16 Nicor Transmission System Dynamic Segmentation Full Risk Analysis Nicor Transmission Miles = 1,174 Full Segmentation of Transmission System results in 3,627 Segments HCA Risk Analysis Nicor Transmission HCA s = miles (23% of Transmission System) HCA segmentation = 618 segments (17% of Full System Segmentation) 16

17 Getting the Risk Features Dynamic Aggregation Query By Attribute or Spatially 17

18 Alternative calculation considerations Features vs Areas Risk Feature scored = Polygon area Risk Factors usually queried spatially inside each area Stage Gates? Region CP Based Grid or Based Operational Area Based 18

19 Nicor Distribution System Potential Dynamic Aggregation Method Risk Analysis Nicor Distribution Miles = 32,949 Nicor Services = 1,998,323 Line Segments = 719,201

20 Nicor Distribution System Potential Dynamic Aggregation Method Risk Analysis Counties = 37 Townships = 445 Public Land Survey System = 5,130 Nicor Atlas Page Grid = 20,521 20

21 Risk Feature to Risk Factor Relationships Relationship between the Risk Feature and the Risk Factors Structures Environmental Area Consider the following. Online Features (APDM) Online Features (Gas Dist) Offline Features (Gas Dist or APDM) Operating Pressure + Outside Diameter LOSS Object Tables (records, no feature shapes) Min Responder Distance Fire Houses 21

22 Risk Feature to Risk Factor Relationships Online Features (APDM) by Station Series and Station Range Risk Feature Station Series = X Select Pipe Segment Outside Diameter Where Station Series = X and Begin/End Station Between 0 and 100 Pipe Segment Outside Diameter Risk Feature Begin Station=0 Risk Feature End Station=100 22

23 Risk Feature to Risk Factor Relationships Online Features (Gas Dist) by Foreign Key Select Leak Where Leak Distribution Main ID = Risk Feature Distribution Main ID Leak Distribution Main ID = X Distribution Main ID = X 23

24 Risk Feature to Risk Factor Relationships Offline Features (Gas Dist or APDM) by Spatial coordinates only Buffer the Risk Feature X Distance Select Target Features Where they Spatially Intersect the Buffer Structure Count Environmental Area Type Leaks X Buffer Dist Min Responder Distance Fire Houses 24

25 Risk Feature to Risk Factor Relationships Object Tables (records, no feature shapes) By Foreign Key Flood Plain Lookup Table Distribution Main ID = X, Flood Plain Ranking = Y Risk Feature Distribution Main ID = X Select Lookup Table Where Distribution Main ID = X Lookup Value = Y 26

26 Nicor Risk Feature to Risk Factor Relationships Online Feature Approach 33 Direct Data Queries Stress Level = * ((MOP * D) / (2 * T * SMYS)) MOP = Maximum Operating Pressure from the MOP attribute from the Operating Pressure feature Class D = Diameter from the Outside Diameter attribute from the Pipe Segment feature class T = Wall Thickness from the Wall Thickness attribute from the Pipe Segment feature class SMYS = Specified Minimum Yield Strength from the Grade attribute on from the Pipe Segment feature class 27

27 Nicor Risk Feature to Risk Factor Relationships Online Feature Approach Pipe Install Year 22 Data Transformations Material Toughness Dual Data Transformation All Other Values Pipe Wall Thickness All Other Values Present Longitudinal Seam Weld Method Data Transformation Database Value Transformation Score All Other Values 0.60 Unknown 0.60 Continuous Butt Weld 0.60 Double Submerged Arc Weld 1.00 Electric Fusion Weld 0.85 Electric Resistance Weld - High Frequency 1.00 Electric Resistance Weld - Low Frequency 0.85 Flash Butt Weld 0.85 Lap Weld 0.80 Magnetic Arc Weld 1.00 Seamless Weld 1.00 Single Submerged Arc Weld 1.00 Spiral weld

28 Risk Feature to Risk Factor Relationships But wait.. What about factors we have no database data for? Structures Operating Pressure + Outside Diameter Loss Environmental Area LOSS = 1 if no cust are shut off and shipper s not affected LOSS = 2 if major impact on industrial customers or minor impact on residential LOSS = 2.5 if major impact on industrial and commercial customers but minor on residential LOSS = 3 if major impact on all users, industrial, commercial, residential Min Responder Distance You ll need some way to collect these scores as well Fire Houses LOSS 29

29 Defensive Model Coding Combating the inevitable imperfect data! Unavailable/Offline Data SME Input/Questionnaires Missing Data/Missing Attribution defaults, default policies Incomplete/Online-gap Data statistics, transformations and stratifications Extra/Overlapping Data statistics, value rankings and multi-value policies Spatial Relationships ability to query spatially Spatial Statistics Max/Min/Average Distances Incorrect Data allow for user intervention scenario and source correction Foreign Key Availability ability to traverse/join tables by foreign keys 30

30 Risk Feature to Risk Factor Relationships Unavailable/Offline Data SME Input/Questionnaires You ll need some way to collect these scores as well, some suggestions User prompts or constants? Lookup tables? Questionnaires that collect, score and log the answers best approach. Includes Audit Trail of Who/When 31

31 Risk Factor Query Policies Missing Data/Missing Attribution defaults, default policies Return a factor default = 18 Outside Diameter (Worst-case) Risk Feature Station Series = X? No Pipe Segment Found for this Risk Feature! Risk Feature Begin Station=0 Risk Feature End Station=100 32

32 Risk Factor Query Policies Incomplete/Online-gap Data statistics, transformations and stratifications Statistic: Return Maximum Risk Segment Operating Pressure = 640 Pipe Segment 1 Operating Pressure = 540 Pipe Segment 2 Operating Pressure = 640 Pipe Segment 3 Year Installed = <NULL> Gap here! 33

33 Risk Factor Query Policies Extra/Overlapping Data statistics, value rankings and multivalue policies Statistic: Return Maximum Pipe Segment Outside Diameter = 24 Value Rank: Return the worst-case From a ranked list of Environmental Areas: Highly Sensitive, Moderately Sensitive, Low Sensitivity Pipe Segment 1 Outside Diameter = 18 Pipe Segment 2 Outside Diameter = 24 Lo w Moderate Lo w 34

34 Risk Factor Query Policies Spatial Statistics Max/Min/Average Offline Distances Ability to buffer and measure off distances between objects Spatial Statistic: Minimum Offline Distance to a Structure Point within the Buffer, Where Type = Firehouse Min Responder Distance Fire Houses 35

35 Risk Factor Query Policies Incorrect Data allow for user intervention, scenario and source correction Ability to intervene and modify a copy of the queried results before final analysis User can modify queried source data before final scores are calculated Risk Feature ID Begin Station End Station EN NUMRES RESPDIST P D SOF LOSS

36 Defensive Model Coding Overall Goals Calculate the model making best use of the database data you DO have Optimally, update database to reflect as-built drawings Monitor risk model s output for missing/defaulted data Supplement, fill, or default what you DON T have When in doubt, take pessimistic assumptions Keep audit trails of what was supplemented or defaulted 37

37 Nicor Transmission Defensive Modeling Approach Foreign Key Availability Add all required data into the database avoids the need for Foreign Key Relationships Spatial Relationships or Offline Required data associated to online features when added to the database; Minimal Spatial Queries Incomplete or Online Data Gaps Database editing Overlapping Data Database editing Unavailable Data SME Input & Questionnaires for 39 Factors Missing or Incorrect Data Default policies for 33 Data Queries 38

38 Nicor Transmission Defensive Modeling Default Policies Stress Level = * ((MOP * D) / (2 * T * SMYS)) MOP = Default = 1,250 (Maximum MOP in Nicor Transmission System) D = Default = 36 (Maximum Pipe Diameter in Nicor Transmission System) T = Default = (Minimum Pipe Wall in Nicor Transmission System) SMYS = Default = 24,000 (Minimum SMYS in Nicor Transmission System) 39

39 Nicor Transmission System Risk Model Analysis Iteration 1 Iteration 2 Iteration 3 Transmission Pipeline Industry Incident by Cause Third Party Damage Construction External Corrosion Equipment Failure Internal Corrosion Incorrect Operations Manufacturing Outside Forces Stress Corrosion Cracking 40

40 Transmission System Risk Analysis Prescriptive - Based Integrity Management Program Threat Identification HCA Risk Rankings Baseline Assessment Priorities Audit Trail of Evolving IMP Longer Term Business Decisions Prioritize System Improvements Assessment Methodologies Prioritization Frequency Develop Appropriate Preventative & Mitigative Measures HCA Name # Segments HCA Distance (ft) HCA Distance (mi) Total Risk Risk * Miles Risk Ranking AAG , AD , W , S , X , P , AR , U , AG , V , AJ E H H AN AA AA H AO H

41 Important Requirements Flexibility Growth and adaptability to changing data? Does it require re-programming or just reruns? Staffing is risk modeling in the hands of GIS or Engineering? Can your framework support what-if or mitigation analyses? Audit Ability and Security Can your framework support your audit needs easily? 42

42 Questions? Jason Bodily Nicor Gas Timothy Yost GL Noble Denton