Failure Mode and Effect Analysis - Lecture Notes | ETM 5291, Study notes of Engineering

Download Failure Mode and Effect Analysis - Lecture Notes | ETM 5291 and more Study notes Engineering in PDF only on Docsity! 1 Failure Mode and Effect Analysis Lecture 5-1 Advanced FMEA FMEA in Health Care Other High-Risk Industries References: FMEA in Reducing Medical Errors, Thomas T. Reiley, MD, MHS, ASQ Healthcare Division Newsletter, Winter, 2001 2 FMEA Advanced FMEA Reference: Eubanks, C.F., Kmenta, S., Kosuka, I., “Advanced Failure Mode and Effects Analysis Using Behavior Modeling,” 1997 ASME Design Engineering Technical Conference 97-DETC/DTM-02 2 3 FMEAShortcomings of FMEA Three problems with traditional FMEA, in order of importance, are: 1) FMEA is performed to late and not used to influence design decisions. 2) FMEA does not capture many potential failures. 3) The process for performing FMEA is subjective and tedious. 4 FMEAExamples of Shortcomings Examples of documented shortcomings of FMEA are: • FMEA is applied too late and in such detail that it misses key system-wide, in-service failure modes • Performing FMEA late does not affect important design and process decisions • The analysis is often an afterthought, performed as a “box-checking” exercise • Without a systematic approach, engineers produce a subjective analysis that depends on their experience level • FMEA is tedious and time-consuming 5 9 FMEABasic Concepts • Functional Block Diagram Ice maker Make Ice Cubes Harvest Cubes Create Cubes Create Cube Shape Freeze Water Each behavior is mapped to a specific state transition Behavior: deposit ice cubes in bucket Initial State: no ice cubes in bucket Desired Final State: ice cubes in bucket 10 FMEABehavior Specification deposit ice cubes in bucket no ice cubes in bucket ice cubes in bucket INITIAL STATE BEHAVIOR FINAL STATE (<OBJECT>,<ATTRUBUTE>,<VALUE>) ICE BUCKET, CUBE LEVEL, NOT FULL SWITCH , POSITION , CLOSED COIL , STATUS , ENERGIZED CAM , POSITION , 15 DEG (<OBJECT>,<ATTRUBUTE>,<VALUE>) ICE BUCKET, CUBE LEVEL, FULL S1 S2 Behaviors can be described: Verbally – cause water flow to increase Quantitatively – flow rate increases to .03 m3/sec Mathematically – V = . . . . . 6 11 FMEADecompose Behaviors deposit ice cubes in bucket BEHAVIOR deposit ice cubes in bucketCreate ice cubes 12 FMEAFunction – Structure Mapping Deposit cubes in bucket Verify cube need Create cubes Harvest cubes Verify bucket full Assess ice level Close switch Activate harvest Sense ice level open switch De-activate harvest Fill with water Freeze water Create nom quality Nominal geometry Loosen ice Remove ice Ice maker Ice cube level sensor Ice creation system Harvesting system Feeler arm Arm switch linkage Feeler arm switch Ice mold Mold heating sys Harvesting sys Freezer system Water delivery system FUNCTION STRUCTURE 7 13 FMEAIce Maker State Variables Variable Object Attribute Values V1 ICE BUCKET ICE LEVEL EMPTY, PARTIAL, FULL V2 ICE BUCKET WATER LEVEL NONE, XOME V3 TRAY WATER LEVEL EMPTY, FULL V4 TRAY WATER STATE LIQUID, SOLID V5 ENVIRONMENT TEMPERATURE <=15, >1, >32 deg F V6 WATER VALVE STATUS OPEN, CLOSED V7 WATER SWITCH STATUS OPEN, CLOSED V8 FEELER ARM SWITCH STATUS OPEN, CLOSED V9 TRAY TEMPERATURE <=15, >1, >32 deg F V10 THERMOSTAT STATUS OPEN, CLOSED V11 HEATER STATUS ON, OFF V12 MOTOR STATUS ON, OFF V13 CAM ROTATION ON, OFF V14 EJECTOR ROTATION ON, OFF V15 ICE INTERFACE STATE LIQUID, SOLID V16 ICE MAKER ALIGNMENT NOMINAL, >=2, <-2 V17 REFRIGERATOR ALIGNMENT NOMINAL, >=0, <-4 14 FMEABehavior Model index behavior type mapped to object attribute value object attribute value ice maker ice bucket cube level not full ice bucket cube level full freezer freezer temperature >8 & <15 OF freezer temperature >8 & <15 OF ice maker harvesting status inactive ice bucket cube level not full 1.2 create cubes desired mold mold ice cubes present no mold ice present yes mold mold ice cubes present yes mold ice present no ice bucket ice bucket cube level not full ice maker ice maker harvesting status active desired cube level sensor ice maker BEHAVIOR PRE-CONDITION SPEC POST-CONDITION SPEC 1 deposit cubes in bucket desired harvesting active1.1 harvest cubes1.3 desired ice bucket cube level full verify cube need index behavior type mapped to object attribute value object attribute value 1.2 create cubes desired ice creation system mold ice cubes present no mold ice cubes present yes water delivery system mold water level none mold water level full mold mold ice cubes present no 1.2.2 freeze water desired freezer system water state liquid water state solid mold freezer temperature <32 OF mold ice cubes present yes mold water level full BEHAVIOR PRE-CONDITION SPEC POST-CONDITION SPEC 1.2.1 fill mold with water desired Decomposition of behavior “create cubes” 10 19 FMEAMedical Situation • 2.5 billion prescriptions dispensed from pharmacies • 3.5 billion drug administrations delivered in a hospital setting • Medications errors in hospitalized patients is about 2% • Increased average hospital stay 4.6 days • Increased average cost of hospitalization $4,700 per admission (2.8 million per year for a 700 bed teaching hospital) 20 FMEAMedical Errors • Adverse human events – injuries caused by medical management rather than by underlying disease or patient condition • Medical errors – adverse human events may or may not result from an error 11 21 FMEAHuman Error • The problem of medical systems, like all human systems, is that humans err. • Human error becomes an accident when the preventive, error-proofing processes within the system are inadequate (latent system faults) • Impact on the system is often delayed 22 FMEAPotential Failure Modes Wrong drug/IV Allergy to drug Wrong drug for patient’s disease Incorrect administration technique Wrong diluent Wrong dose Excessive dose Insufficient dose Wrong concentration Too-rapid IV flow rate Omitted drug Wrong patient Wrong time Wrong route Wrong procedure Wrong test procedure Violation of orders Wrong label directions Wrong preparation 12 23 FMEAPotential Causes Human knowledge Chaotic work environment Unauthorized floor stocks Using floor stock medications Not following policies Verbal orders Human performance Lack of personnel IV solutions that are not premixed Unnecessary use of medications Lack of dose verification process Math errors Typographical mistakes Poor handwriting Acronyms Coined names Multidose vials Defective packaging Similar packaging Lack of dose limits Similar drug names Borrowing medications from a multiple-dose cart Dangerous abbreviations (OD & QD for once daily; U for unit) Lack of interdisciplinary team review of medication errors Unnecessary use of IVs, catheters, and nasogastric tubes Lack of dosage check for high-risk drugs and pediatric patients’ medications 24 FMEAExample • Errors recorded during one quarter: 0 10 20 30 40 50 60 other Not transcribed calculation of dose in error IV infiltration drug labelling error staff education issue Equipment/tubing issue oral communication error Medication not given Order overlooked, forgotten Transcription error Pharmacy misread order Figure 4. Probability Rating ‘MEA Frequent - Likely to occur immediately of within a short period (may happen severel times in one year) ‘Occasional - Probably will occur (may happen several times in 1 to 2 years) Uncommon « Possible to accur (may happen sometime in 2 to 5 years) Remote - Unlikely to occur (may happen sometime in 5 to 30 years) Figure 5. Hazard Scoring Matrix Frequent Probability 29 Hypothetical Failure Mode and Eifects Analysis i ye BEA hee tas bake fn Reiee any pwc tao need Sorter He Beatacua ae ‘te tae Tn: 0 St savien | Flas “i eae ee ailfibip ag mtr Lad cal 3 = bias Fi Sar «sag ade {pd nr Samo ode TAFT TUBA Po iio 12 hey /www.datakel.com.au/FMEAlinks.htm 15 16 31 FMEA Other High-Risk Industries 32 FMEAHeavy Industry • Alcoa reported 1.83/100 employees missing at least 1 day per year due to on-the-job injuries • Industry average 5/100 • Rate lowered to 0.14/100 through: – Employee incentives to report unsafe conditions – FMEA – Root cause analysis of each incident 17 33 FMEAConstruction • FMEA used to anticipate potential problems in construction. Potential problem analysis used to analyze project plans and develop contingent actions. • Shipbuilders (primarily US Navy) use FMEA to improve safety for workers 34 FMEAPackaging Industry • Key environmental decisions are made during the design of a new or modified package. The requirements of our proprietary Package Development Protocol© include a Failure Mode and Effects Analysis (FMEA) to make certain the issues of package integrity are addressed, from manufacture to retail customer. This ensures the contents stay in the package until opened by the customer. R. A. Miller & Co.