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Failure Mode and Effect Analysis

Lecture 5-1Advanced FMEA

FMEA in Health CareOther High-Risk Industries

References:FMEA in Reducing Medical Errors, Thomas T. Reiley, MD, MHS, ASQ Healthcare Division Newsletter, Winter, 2001

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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

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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.

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FMEAExamples of ShortcomingsExamples 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

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FMEASystems Aspect of FMEA

A standard FMEA is likely to miss some failure modes because it may not account for issues related to an items interface with the rest of the system.

Rule of Thumb:Always seek to optimize the next hight

level systemHelps you avoid the problem of suboptimizing

the design to a subsystem level

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FMEAAdvanced FMEA

AFMEA applies to the early stages of design and captures failure modes normally missed with conventional FMEA.

AFMEA uses behavior modeling to link desired behaviors with components, environment and supporting systems

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FMEAApproach

Guided by the function structurerelationship, one can build a behavior model describing the state changes of variables expected during normal operation.

The model qualitatively simulates normal operation and analyzes the effects of failures in terms of the resulting system state.

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FMEAAdvantages of Behavior Modeling

Behaviors do not rely entirely on physical structure

Behaviors can reflect customers desired requirements

Provides a systematic framework for generating failure modes

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FMEABasic Concepts

Functional Block DiagramIce 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

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FMEABehavior Specification

deposit ice cubes in bucket

no ice cubes in bucket ice cubes in bucket

INITIAL STATEBEHAVIOR

FINAL STATE

(,,)ICE BUCKET, CUBE LEVEL, NOT FULL

SWITCH , POSITION , CLOSEDCOIL , STATUS , ENERGIZED

CAM , POSITION , 15 DEG

(,,)ICE BUCKET, CUBE LEVEL, FULL

S1 S2

Behaviors can be described:Verbally cause water flow to increaseQuantitatively flow rate increases to .03 m3/secMathematically V = . . . . .

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FMEADecompose Behaviors

deposit ice cubes in bucket

BEHAVIOR

deposit ice cubes in bucketCreate ice cubes

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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 deliverysystem

FUNCTION STRUCTURE

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FMEAIce Maker State VariablesVariable Object Attribute Values

V1 ICE BUCKET ICE LEVEL EMPTY, PARTIAL, FULLV2 ICE BUCKET WATER LEVEL NONE, XOMEV3 TRAY WATER LEVEL EMPTY, FULLV4 TRAY WATER STATE LIQUID, SOLIDV5 ENVIRONMENT TEMPERATURE 1, >32 deg FV6 WATER VALVE STATUS OPEN, CLOSEDV7 WATER SWITCH STATUS OPEN, CLOSEDV8 FEELER ARM SWITCH STATUS OPEN, CLOSEDV9 TRAY TEMPERATURE 1, >32 deg FV10 THERMOSTAT STATUS OPEN, CLOSEDV11 HEATER STATUS ON, OFFV12 MOTOR STATUS ON, OFFV13 CAM ROTATION ON, OFFV14 EJECTOR ROTATION ON, OFFV15 ICE INTERFACE STATE LIQUID, SOLIDV16 ICE MAKER ALIGNMENT NOMINAL, >=2, =0, 8 & 8 &

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FMEAIdentifying Failure Modes

Failure = condition where achieved final state does not match desired final state

3 types of failure modes: non-behaviors undesired behaviors misbehaviors

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FMEANon-behaviors

Select a behavior for investigation Consider it not to occur Simulate how the system responds Compare list of resulting final state

variable values with list of desired values to indicate which system or component failed

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FMEAComparison

FAILURE MODE FMEA AFMEAthermostat failure yes yeswater switch failure yes yesfeeler arm damaged yes yespower cord disconnected yes yeshigh/low water pressure no yesbucket misplacement no yesrefrigerator misalignment no yesiced gears no yeshigh freezer temperature no yes

Comparison of failure modes captured by FMEA and AFMEA

Users of AFMEA claim it captures a richer set of potential failure modes than traditional FMEA. Many failure modes can be captured which do not necessarily relate to components., but to interaction with system components.

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FMEA

FMEA in Health Care

Reference:FMEA in Reducing Medical Errors, Thomas T. Reiley, MD, MHS, ASQ Healthcare Division Newsletter, Winter, 2001

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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)

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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

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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

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FMEAPotential Failure ModesWrong drug/IV Allergy to drugWrong drug for patients

diseaseIncorrect administration

techniqueWrong diluent Wrong doseExcessive doseInsufficient doseWrong concentration

Too-rapid IV flow rateOmitted drug Wrong patientWrong time Wrong routeWrong procedure Wrong test procedureViolation of orders Wrong label directionsWrong preparation

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FMEAPotential CausesHuman knowledgeChaotic work environmentUnauthorized floor stocksUsing floor stock medicationsNot following policies Verbal ordersHuman performance Lack of personnelIV solutions that are not premixedUnnecessary use of medicationsLack of dose verification processMath errors Typographical mistakesPoor handwriting

AcronymsCoined namesMultidose vialsDefective packaging Similar packagingLack of dose limits Similar drug namesBorrowing medications from a

multiple-dose cartDangerous abbreviations (OD & QD

for once daily; U for unit)Lack of interdisciplinary team review

of medication errorsUnnecessary use of IVs, catheters,

and nasogastric tubesLack of dosage check for high-risk

drugs and pediatric patientsmedications

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FMEAExample

Errors recorded during one quarter:

0 10 20 30 40 50 60

otherNot transcribed

calculation of dose in errorIV infiltration

drug labelling errorstaff education issue

Equipment/tubing issueoral communication error

Medication not givenOrder overlooked, forgotten

Transcription errorPharmacy misread order

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FMEASeverity

Severity of Effectsnoncritical illness does not improve 3noncritical illness worsens 6noncritical illness becomes critical 9noncritical illness becomes fatal 10

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FMEA

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FMEA

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FMEA

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FMEA

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FMEA

http://www.datakel.com.au/FMEAlinks.htm

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FMEA

Other High-Risk Industries

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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

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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

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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.

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FMEANASA The goal of the Failure Modes and Effects Analysis (FMEA) is to

anticipate, identify and avoid failures in the operation of a new system while the system is still on the drawing board. The recent occurrence of failures in some new systems in operation has had disastrous effects on many lives. These events prompted the author to evaluate the documented problems and to seek improvements in FMEA procedures and their application. The result was surprising. While a great number of procedures exist, not one single FMEA procedure could be found as an all encompassing document. Each FMEA procedure was different. It is believed that the recent disasters could have possibly been avoided if a good FMEA procedure had been applied during development. A simple, complete FMEA procedure is proposed.

NASA Scientific and Technical Information (STI) Program Feb.2000http://www.sti.nasa.gov/new/fmea33.html##28

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FMEASupply Chain

Many organizations are training their key suppliers in FMEA techniques

Focus is on Process FMEA at the supplier site Potential issues with ramp to vaolume

production Prevention of disruption in the supply chain Disaster prevention and contingency

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FMEAMining Industry

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FMEALimitations of FMEA

Although the FMEA methodology is highly effective in analyzing various system failure modes, this technique has four limitations:

Examination of human error is limited. Focus is on single-event initiators of

problems. Examination of external influences is

limited. Results are dependent on the mode of

operation.