Pushing Back The Boundaries Of Uncertainty

Click here to load reader

  • date post

  • Category


  • view

  • download


Embed Size (px)

Transcript of Pushing Back The Boundaries Of Uncertainty

  • 1. Pushing back the boundaries of uncertainty

2. Overview - uncertaintyUncertainty should be avoided in anyengineering projectLack of certainty will often cost money andreputationThis discussion outlines how reducing the levelsof dimensional uncertainty can save significanttime and money for a given engineering project 3. Example No 1Double jointed pipesMust be straightWhy? To reduce stress at joint, to ensure fit inJLay tower, to ensure pipe ends are square forweldingHow straight and how measured?How could such a simple thing involve anyuncertainty? 4. Description of uncertaintyTypically pipes are measured intwo locations at 90 degreesapartUnfortunately the actual out ofstraightness can be 1.4 timeslargerPipes are flexibleSupport of pipe is also important 5. SolutionBetter understanding by engineersBetter specificationsBetter tools 6. Example No 2Pipe shapePipes are accepted by a welding contractor as fitfor weldingA Hi-Lo mismatch is specifiedPipes are measured using a ruler graduated inmmPipes to all be welded offshore Africa 7. Description of uncertaintyUOE pipes have many shapefeatures (flatter sections,peaking, more curved sections,ovality, expander marks)Pipes also have a differentaverage diameter and each endof the pipe is usually differentSample measurements are taken 8. SolutionMeasure the pipesUnderstand theproblem usingsimulationProvide an on-boardsolutionSave several days at$500k per day 9. Example No 3Land pipe project in the USSeveral hundred miles ofpipePipes supplied with manydefectsAll pipes required rebevellingClient unwilling to pay forthis additional work 10. Description of uncertaintyNumber, quantity anddegree of defects notunderstoodLevel of inspectioncarried out was notsufficient to resolvedispute 11. SolutionDeployment of qualified teamTraceable equipment forevery measurement (ovality,pitting, paint overspray,gouges, bevel land thickness,bevel angle)Client wins case worth $10M+ 12. Example No 4Owner/OperatorProblems with contractorsworking to the letter of thespecificationSpecification leaving gapsfor contractors to exploitleaving client with a bill oran issue 13. Description of uncertaintyContractors and suppliers notalways supplying requirementsSome areas not specifiedproperlySome tools not appropriate orused inappropriatelyAccuracy of tools not specifiedproperly 14. SolutionSupply of educational materialTop quality clear diagramsSimple specificationsTools specifiedReportingQualification tests identifiedAccuracy specified rigorously 15. Example No 5Pipe welding can be compromisedby poor pipe fit-upA poor fit-up can result in a poorweld which has to be cut out orreworkedEach welding problem slowsproduction and costs the client orthe contractor money 16. Description of the uncertaintyPipe shapes are veryvariable 1When fitted togetherthe mismatch can belargeIt is uncertain which2pipe joint is going to bea problem 17. SolutionMeasure each pipe endRotate the pipes to fit ifpossibleSort the pipes into abetter orderImplement this systemon-site prior to welding 18. ConclusionsUncertainty can exist in many areasThere is usually a cost to each uncertaintyGood specifications are required to eliminateareas of ambiguityOMS has provided many unique solutions(services and tools) to the problems that ariseThe amounts of money saved total far morethan the cost of using OMSs tools and services