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  1. 1. PREDICTING FAILURESIr. Gan Chun ChetAugust 2007
  2. 2. The Concept and Practice In the Meeting RoomFigures Are ShowingBetter Outlook The Ability to Know BadResults Before ItHappens, Would BeGood to Know Before ItOccurs Hence, A ScientificMethod to Measure PastRecords to Achieve theRequired Future TargetsEmergeI havedoneenough.EngineerEverythingSeems to BeOK.PlantManagerProfitisRisingIm ImpressManagingDirectorPREDICTINGFAILURES
  3. 3. Predicting Failures What is Predicting? The ability to know something before ithappens What are Failures? Something that does not pass the requiredresults
  4. 4. Predicting Failures Some items that are highlighted in this talk- Plant Noise- Pumps and Compressors Vibration- Machine Setup Time- Redundancy- Partial/Full Stroke Testing- Review/Check Activity
  5. 5. Predicting Failures Introduction Passes, Failures and Predictions Some Examples To Serve as A Guide Some Counter Measures to Overcome Conclusion
  6. 6. Introduction Practices in General Industry EngineeringProject and Maintenance Services- Engineering Best Practices Oil and Gas Consultancy and ContractingServices- Requires High Safety Standards- Requires High Reliable Products
  7. 7. Introduction Some of the Issues Addressed in General Industry(Manufacturing and Processing)- Hearing Losses- Pumps and Compressors Concerns of A Breakdown- Long Machine Setup Time Which Contributed toUneasiness Among Production Personnel (ProductionPlanning, Production Morale, Machine Change Over,etc.) Some of the Practices from the Oil and Gas Industry thatworth while knowing- Redundancy- Partial/Full Stroke Testing- Review Check Activities
  8. 8. General Industry - EngineeringProject and Maintenance Services Improve Plant Conditions- Safe Working AreasInhabitants in the plant are able to work in a healthy andconducive environment Reduce Breakdowns- Continuous Batch OperationThe production purpose is to ensure continuous supplyto the market due to demand (to operate profitably)
  9. 9. Oil and Gas - Consultancy andContracting Services Query Services- Latest DevelopmentClient would like to know whether the latest product ispurchased Design and Engineering Services- Specify the Right Requirements- Integrating ProperlyEngineered correctly to enable the platform or plantoperating within the design production output, a properdetection system, the best way to fight a fire, equipmentare maintain to it best performance, etc.
  10. 10. What Causes Failures? Causes of Failures- Wear and Tear (Bath Tub Theory)- Vibration- Exhaustive Operation Are Failures Detectable?- Can it be Spotted and Rectified?- Are there Methods to Detect Failures?(i.e. To know before something happen)
  11. 11. Passes, Failures and Predictions 100% Passes- Is This Achievable(Take note of Process Variance) 0% Failures- Is this achievable(Perfection? Good Engineering Design) T+1 Prediction- Based on Facts and Past Data
  12. 12. Passes National or University Examination Results- Number of Students with DistinctionIs increasing the passing rate an indication of betterquality students?University in the search of glooming student that are ableto meet todays challenges Productivity- Operation OutputThe measurement of productivity is to achieve betterresult each year until it reaches its best performance.Business/Management will begin to look for otherperformance parameters
  13. 13. Passes Upper Range Limit- Highest Acceptable SpecificationValue Lower Range Limit- Lowest Acceptable SpecificationValue1201008060 Is it possible to increase the40limit, hence more will pass Take note of design quality20 Take note of process(machine) limit 0LRL URL0 5 10 15
  14. 14. Failures Bath Tube Theory- Failures Occur Beginning of DesignLife.- Sporadic Failures During Normal LifeStage.- Failures Begins to Occur Towardsthe End of Design Life. Is This ActuallyHappening in RealOperation?765432100 10 20TimeFailure RateInfantMortalityStageWear-outStageNormal-lifeStage
  15. 15. Failures Off-Spec Rejects- Not MeetingSpecification- A Known ProcessVariation Sporadic Peaks- SuddenOccurrences- Unpredictable15010050030020010001 2 3 4 5 6 7 8 9 1
  16. 16. Failures Shutdown/Detection System Fail ToOperate- Not Able to Detect or Shutdown Valves Unable to Function- Stuck- Cannot Close
  17. 17. Failures Failure Rate= Number of Failures X 100Total Number of Products Tested(p776, Operations Management Nigel Slack et al, Pitman Publishing) An equation to know the number of actual failure coming out of theproduction line Measurement of the percentage of product failure
  18. 18. Failures Mean Time Between Failure (MTBF)= Operating HoursNumber of Failures(p776)The average time between failures, measured in actual operation.The number of breakdowns over the operation duration.(To Determine Time Before a Failure, Average of Past Record)
  19. 19. Prediction Threshold Limit- Above a Set Horizontal Line WillTrigger a Warning. Review of past data shows that a limithas to be set. Anything above this setlimit must need to be attended. E.g. Noise (Hearing) Level876543210ThresholdLimitWarning0 5 10 15
  20. 20. Prediction Analysis- Frequency Spectrum An analysis of the pump orcompressor vibration behaviour.Because the pump and compressorrotate at fixed angular rotation, thefrequency of the pump or compressorcan be calculated.The spectrum shows the frequency ofthe pump or compressor, etc.FrequencyAmplitudef 2f 3f
  21. 21. Prediction Trend Line- A Straight Line Can Be Drawn on The Collected Data.- The Straight Line Can be Extended to Know the NextValue.E.g. A Linear Relationship Between X and Y and beConcluded, Case of reduction in setup time.Line of Regression10500 5 10
  22. 22. Prediction Moving Average- Average of Past Data and MovingForward The moving average line of 2 past datais the average of 2 past data. The moving average line of 2 past datais more reactive than 5 past data. Moving average is the record of past90807060504030historical data. With this type of trendline, the future up or down trend can20be know, provided all factors remainunchange.10(E.g. Monitoring Setup time) 05 past data2 past data0 5 10 15
  23. 23. Real Examples Threshold Shift (Noise Study) (Factoriesand Machinery, Noise Exposure)Regulations, 1989(A Real Noise Reduction Project) Noise Level Collected and Recorded at 500, 1000, 2000,3000 & 4000Hz Sampled of Production Workers at Floor Level
  24. 24. Real Examples Less than 10 yearsservice 2 Clusters Results- Below 20 dB(Cluster 1)- Below 30 dB(Cluster 2)
  25. 25. Real Examples More than 10 yearsservice 1 Cluster Results- Below 30 dB
  26. 26. Counter Measures Hearing Conservation Program- Engineering Control(To Install Enclosure At Rotating Equipment, To ReduceDevice Noise e.g. Control Valve & Relief Valve, ToPrevent Noise From Traveling Into The Control Room)EnclosureMachineLimit noise out of theenclosureControl RoomLimit noise to the controlroom
  27. 27. Counter Measures - Administrative Control(To Move Workers In And Out Of Noisy Area (take noteof threshold shift, very dangerous, so act mentioned tolimit daily exposure to noise by control of work schedule,very difficult to practice), Constant Monitoring, Do NotAllow People To Enter Noisy Areas, Sign Board of HighNoise Areas, etc.)HIGH NOISEAREA- WEAR EARMUFFLE
  28. 28. Counter Measures Required by law that the Permissible Exposure Limit is- 85 dB(A) for 16 hours duration per day,- 90 dB(A) for 8 hours duration per day, etc per schedule- Nobody shall be exposured to noise level exceeding115 dB (A) at any timeFactories And Machinery (NoiseExposure) Regulations, 1989 Employees need to check for a baseline reading(required by law) Take note of Threshold Shift! DO NOT play with this! Reduce Noise Level (Engineering Measures) Consult Noise Consultant or Ear Specialist!
  29. 29. Counter Measures Some Examples (Also Consult Doctors orSpecialist! Hearing Problem Must not beTaken Lightly) E.g. The Sum of Hearing Threshold LevelsShows an Increase of 30 dB Compared toPreceding Level. Very Serious Shift!(Case Study : Less than 10 yrs employment, 1st cluster 20 dB andbelow. 2nd cluster 30 dB and below.: More than 10yrs employment, cluster 30 dB andbelow) International Standard Organisation (ISO)
  30. 30. Real Examples Vibration AnalysisPumps or Compressors Pump fails Compressor showing highvibration (fitters showingconcern of the compressorvibration)FrequencyAmplitudef 2f 3fAfter correction
  31. 31. Counter Measures Condition Monitoring Program- Compressors and Pumps Characteristics Principle Of Vibration Is Caused By Rotation of Shaftand Components Connected to the Shaft Inside TheCompressors Or Pumps, A Sinusoidal BehaviourAmplitude YTimeDirectionXDirectionVibration in Xand YDirectionShaftRotationDirectionf = 1/Tf = frequencyT
  32. 32. Counter Measures Identify Equipment to Measure, Critical Pumpsor Compressors (e.g. Screw Compressor) Collection of Data at Specified Points, e.g. X-Directionor Y-Direction Storage of Data Analyse and Compare Spectrum Corrective and Rectification Actions, Take YourTime to Decide Spot the Rise DO NOT Exceed the Limit
  33. 33. Counter Measures Engage a Vibration ConsultantCollection SpotFrequencyAmplitudef 2f 3fAnalyseDataCollectDataCorrectiveActionAxial CompressorInvoicePump Blade1 Qty.Received ByExecutive
  34. 34. Counter Measures Compressor was overhaul, monitored andshows low vibration. Pump Performance before and aftershows the peak has reduced. To Avoid Failures Which Will CauseProcess Interruption. If NO Breakdown,Smooth Operation
  35. 35. Real Examples Reducing Machine Set Up Time AnImprovement in Production Output- Trending The Set Up Time was Recorded, From Start Time toFinish Time
  36. 36. Real ExamplesSETUP TIME141210864201 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17