Bảo dưỡng công nghiệp 7 root cause failure analysis An essential element of Asset Integrity Management and Reliability Centered Maintenance Procedures

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Definition of Root Cause Analysis (RCA)

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Root Cause Analysis (RCA) is a structured

process that uncovers the physical, human,

and latent causes of any undesirable

event in the workplace

Can be:

«Single or multidiscipline cases e«Small or large cases

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Failure Cause —

The physical or chemical

processes, design defects,

quality defects, part

misapplication, or other

processes that are the basic

reason for failure or that initiate

the physical process by which

Some other definitions

Failure Effect — The consequence(s) a failure mode has on the

operation, function, or status of an item

deterioration proceeds to failure

The circumstances during

design, manufacture, or

operation that have led to a

failure

Failure — The termination

of its ability to perform a required function

Failure Mode — The effect

by which a failure is observed on the failed item

Eo

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Root Cause (RCA)

@ Eliminates early life failures

@ Extends equipment lifetime

Q Minimizes maintenance

Slide 4 Edit in Veiw > Header and footer Edit in Vetw > Header and footer MANAGING RISK DINW

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A Root Cause Analysis will disclose:

@ Why the incident, failure or breakdown occurred

@ How future failures can be eliminated by:

changes to procedures changes to operation training of staff

design modifications verification that new or rebuilt equipment is free of defects which may shorten life

- repair and reinstallation is performed to acceptance standards

- identification of any factors adversely affecting service life and

implementation of mitigating actions

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Production Improved availability “up-time”

and increased production

Reactive Periodic Predictive Proactive Era of

maintenance/ Maintenance maintenance

monitoring

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Reactive maintenance

¢ Run the equipment until breakdown

¢ Overhaul and repair

¢ Extensive unplanned downtime and recurrent repair

DNV

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DNV

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Short and long-term benefits of

Proactive Maintenance Strategies

Experience and statistical data

MMS DATABASE

@ Information on equipment design and service conditions

@ Failure statistics 1.e MTBF

@ Description of service failures, approach and methods

for failure investigation

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Methods and analytical tools to identify the causes of failure or breakdown

@ Review background data

@ Loss Causation Model and RCA methods and working process

Detailed analyses of failed parts/components:

@ Analyse service conditions

@ Utilise experience data from data bases or other sources

@ Laboratory investigation

DNV

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The Loss Causation Model

© Det Norske Veritas

The main causes

Investigation techniques

¢ A number of named techniques that are

commonly used within RCA:

¢ The techniques have strength and weaknesses

depending on the situation

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Methods for RCA; Content

¢ Pata Collection

— Interviews

— Paper and technical evidence

¢ Methods for RCA

— STEP

— FMEA

— FTA

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STEP 1: Register Equipment Incidents

Purpose : Register Off-spec Operation / performance, Survey & Condition Monitoring data Start: Trigged by off-spec operation/performance,

Stop: Incident logged in Maximo

Process Off-spec operation /

performance :

and Recommended Maintenance Action

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Resources

STEP 2: Trigger Mechanism for RCA

Start: Registered HSE issues or off-spec operation/ performance incidents

Trigger mechanism for RCA lo sec

IN Incidents above trigger level

performance: with high Z incidents with production

failures

Trios repair cost Off-spec operation vis-a-

Abnormalities ( vis (KPI) KR Recommended

RCA Case

Multiple operating

Do Preliminary r incidents per Tag no./

Cost vs Investment (Replacement) L High risk findings from

survey/CM

Surveys, Audits,

Inspection, Reviews

Plant Reliability Engineer HQ Senior Reliability Engineer MANAGING RISK

Senior Planning Engineer Reliability Engineer (Plant/HQ)

Resources

STEP 3: Appoint the RCA Team

— Leader — appointed by the Plant manager

— Facilitator — reliability engineer

— Discipline(s) or specialists at specific plant

¢ Optional to involve:

— Disciplines from other sister plants

— HQ-Engineering support and technical staff

STEP 4: The Root Cause Analysis

4) RCA method steps

The main RCA report

1 Description of the Incident(s)

An incident is the event that precedes the loss or potential loss This section should include a description of what happened

Include all aspects related to the incidents, like outage time, cost of repair, people involved, tools in use, operational status, weather conditions etc

4 Lack of Control Lack of Control means insufficient oversight of the activities from design to planning and operation Control is achieved through standards and procedures for operation, maintenance and acquisition, and follow-up of these If an oil spill has occurred because of wrong installation of a sealing, the Lack of Control could be related to inadequate procedures for

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Potential Consequence (1-5) Assets: Production Loss:

CO 2 Working Environment nt CO 11 Operation of equipment outside design

OO 6 Mobilization of equipment CJ 14 Process Control

O 8 Deterioration / Corrosion

Sub Category Sub Category:

basic Cause

(0 2 Inadequate Com petence

OO 3 Motivation

L1] 4 Physical and psychological load during work

Personal Factors(B}

Sub Category

Causes related to the work (8B)

(0 11 Design Failure (or lack of design)

OO 12 Purchasing C1 13 Maintenance C1 14 Ageing / Obsolescence

Sub Category:

Lack of Control (C):

(CO 2 inadequate system standards

OD 4 inadequate Maintenance Procedures

OO 6 inadequate Design Procedures

BASIC WAUSES CO Fiersonal Factors

RCA reporting system

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RCA TEMPLATE 5 Gastent A | Substandard condition: = B_ | Personal F actors

CI Pending Defect setae Sbaication or use of the equipment for B11:Laekc£ : TITLE: Root Cause Reporting Form RCA=: = suá tose Al.2: Defect material used in tool and equipment ro s B1.2: Lack of information

Incident Date: 5 ic tr A1.3: Equipment failure during operation Bl ec B1.3: Lack of training for new employee

ngdent Uate ystem/Component/T ag AD asked ve care teves process B1.4: Lack of training related to modification/change in process

Say = conditions A2 Working A2.2: Too little space to do work B1.5: Misunderstanding environment | A 3: Fire and explosion risk in the area B2.1: Lack of basic training Loss: Description of the Incident AD 4 Bad 2 t household Inadequate 2.2: Long period between each time the lnow ledge is

l6 = B2 used required

E a3 [Extemal | 43.1: Failure causad by bad weather conditions B23: Lack of instroction/ Misting instniction

2 aoe a Point (pressure, temperature, B3.1: Lack of feedback (positive negative) for conducted work

B A4 |CSnwol [A42:1aekcfinsromentsien B3 | Motivation [B3.2:Lack of Sadback related toquality when thatis required

— a A4.3: Lack of logic in the ins tument function B3.3: Lack of follow-up during work execution

ae Ce ae A4.4: Defect controller devices B3.4: General frustration of working conditions

Group: Problem Code: ee | T1 TH HH HỖ PPERRDDADES Physical and | B4.1:Stress due to psychological pressure

Failure Class: Cause Code Change of = B4 vcho-

r x š logical load si ce 3 Risk Assessment Matix RAM = ST As eae A6.1: Change in operation conditions not verified dosing work B4.2: High physical demand

Potential Consequence (1-5) ý ” CN ATL Modification of Go

> ah: e not ver aams'

A7 TEEN t | the system (Causes related to the work

AS ay reams can hs naa B10.1:Unel snication lines

Sub-Standard Condition (A): Sub-Standard Acts (A): Ghana, —— B102: Unclear guidance for responsibility

B || G 1 DetectE quipment & Tools CO 10 Maintenance Hy aT a as B103: Unclear goals for execnted work

a O 2 Working Environment O 11 Operation of equipment outside design ——— : =o ee

= [1 3 External //eather boundaries Al0 | Maintenance 10.2: Welding and hot wodk without proper — B104: Lack of instructions, procedures, reference documentation

3 O 5 Production Profile 1 13 Violation of procedures Al0.3: Defect initiated by maintenance or inspection fwork: B105: Lak of identification /foos on possible loses damages

= bản Elis SHERCMnninim men Operation of |A11.1: Operation outside rated capacity B10.7- Unqualified personnel used for the work

- AI a a All.2: Operated outside pressure limits B10.8: Lack of overall goals for the work

œ

Sub Category Sub Category: cai : A11.3: Operation outside temperature Rrrwts B109: Lack of experience Sedback

aries

A121: Operation with defect equip B1l1.1: Missing/not complete design requi and specifi

j Wrong use of | A12.2: Equipment'tools used for a purpose not Design Pate i

Personal Fadors(B} Causes related to the work (B) 33 |xapmer [designed fr sii|SIesœ [BU 2: Taek of operations

` À12.3: Equtpment tools overioadaở during operation = B11 3: Lack of start-up procedures

Š L1 2 Inadequate Com petence L1 11 Design Failure (or lack of design) process

2 O 3 Motivation OO 12 Purchasing Violation of =e B12.1: Lack of needs analysis and specification of

3 O01 4 Physical and psychological load during work E134: Maintenance Al3 | procedure nem svsternyequipmentrequirernent

EÏ 14 Ageing / Obsolescence Al4.3: Procedures for maintenance B122: Inadequate specifi to vendor

Sub Celene: Sub Categury: Ấn 1: cs _ ation control % ane

A14 Process šicbdký quak~ ta B12) Purchaimz |B124: Inadequate storage of equipment

À14.2:-—tmtHatzd automattcally by svstem B12 Š: Inadequate transport of equipment Lack of Control (C): Ineffective! : _ J

5 OO 2 Inadequate system standards 0 5 Inadequate Operational Procedures protection : ° °

ö CO 3 Inadequate compliance with routines OO 6 Inadequate Design Procedures B13] MM Bl3.1: Lack/not sufficient

5 = - B132: haẻsquate glanninz c£rmatntenance

Methods for RCA

STEP; Sequential Time Event Plotting

FMEA; Failure Mode Effect Analysis

FTA; Fault Tree

¢ + common sense, engineering/operational

experlence

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STEP; Sequentially Time Event Plotting

FMEA ; Failure Mode and Effect Analysis

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Component

Broken axel Fatigue None Pump Impeller Corrosion | Loss of Pressure

P /Wear Pressure Indicator

El Motor Winding None

Soft-starter Fail to Unknown None

Fault Tree

Top

Identifies causes for an Intermediate

causes and effects

Which one to use?

¢ STEP:

— For complex events with many actors

— When time sequence is important

Detailed analyzes of failed

parts/components

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Typical examples of systems/equipment

that can be analyzed:

@ Electrical generators @ Fire and gas-detectors

@ Heat exchangers @ Sensors and measuring devices

@ Subsea equipment @ Components of gasturbines

@ Control systems @ Cranes and lifting equipment

@ Pumps @ Well and down hole drilling

equipment

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@ Systematic removal of failure sources

@ Prevent repetitive problems

@ Minimise maintenance down-time

@ Extend equipment life

DNV

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RCFA evaluates factors affecting

service performance such as:

@ Materials/corrosion/envIronment

@ Changes in operational conditions

@ Stresses and strains

@ Presence of defects and their origin, nature and consequences

@ Incorrect repair introducing new defects

@ Poor quality manufacture leading to sub-

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Examples of problems disclosed

by the laboratory investigation

as part of the RCFA:

GEARS

e Incorrect material Vibration

Incorrect surface

¢ Incorrect design treatment

¢ Incorrect assembly ¢ Geometric imperfections

© Corrosion ¢ Incorrect operation

Fatigue or overloading

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¢ Lubricating problems

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Examples of problems disclosed

by the laboratory investigation

as part of the RCFA:

Incorrect torque or

overloading

DNV

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Examples of problems disclosed

by the laboratory investigation

as part of the RCFA:

| BALL-/ROLLER BEARING

¢ Poor design ¢ Overload

¢ Manufacturing defects Inadequate lubrication

¢ Poor alignment and ¢ Vibration

¢ Electrical discharge © Corrosion

(arcing)

Ed

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Root Cause Failure Analysis Disclosed Failure of:

| MAIN BEARING

| ¢ Heavily worn raceway, cracking of

| casehardened surface, plastic deformation of

¢ Four gas leaks on TLP

platform equipment in HP &

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Examples of problems disclosed by

the laboratory investigation as part

of the RCFA:

| DRIVE SHAFTS

¢ Incorrect material quality @ Surface defects

¢ Incorrect design @ Corrosion

¢ Poor quality manufacture @ Incorrect balance and