Root Cause Analysis (RCA) is a structured process that identifies the underlying causes of undesirable events. It can be used for both single and multidisciplinary cases. The RCA process involves data collection, identifying the immediate causes and basic causes of failures, and determining where lack of control contributed. Common investigation techniques include STEP, FMEA, and fault tree analysis. Laboratory analysis of failed parts is also important for identifying causes like material defects, corrosion, or overloading. Identifying root causes allows corrective actions to be implemented to prevent future recurrence.
CAPA management, corrective and preventive action, Rootcause analysis, RCA, Problem mapping, FMEA, Failure Mode effect and Analysis, Fault Tree analysis, Fishbone : ISHIKAWA, CTQ Tree (Critical to Quality Tree), AFFINITY DIAGRAM, 5 Why’s, Human errors,
CAPA management, corrective and preventive action, Rootcause analysis, RCA, Problem mapping, FMEA, Failure Mode effect and Analysis, Fault Tree analysis, Fishbone : ISHIKAWA, CTQ Tree (Critical to Quality Tree), AFFINITY DIAGRAM, 5 Why’s, Human errors,
ABOUT THE TRAINING PROGRAM :-
Root cause analysis (RCA) is a class of problem solving methods aimed at identifying the root causes of problems or events. The practice of RCA is predicated on the belief that problems are best solved by attempting to address, correct or eliminate root causes, as opposed to merely addressing the immediately obvious symptoms. By directing corrective measures at root causes, it is more probable that problem recurrence will be prevented.
DESIGNED FOR :-
Managers, Engineers, Supervisor and officers engaged in maintenance operation and engineering activities.
OBJECTIVE :-
At the end of the training program, participants will be able
- To gain a basic understanding of the problem solving and decision-making process and the applicable quality tools that support this process.
- To develop specific competencies to use the structured approach to problem solving and decision making and the supporting quality tools.
TRAINING PROGRAM COVERAGE :-
- Basic knowledge about RCA program.
- What are the RCA tools ?
- More about Why- Why analysis ?
- Videos and case studies on RCA
Root Cause Analysis - Tools, Tips and Tricks to Get to the Bottom of Root CauseCraig Thornton
This webinar discusses and investigates how to conduct root cause analysis. Root cause analysis is something that companies really struggle with. There will be plenty of practical advice in the webinar to help with you understand the concepts and the tools.
If you would like to watch the recording of this webinar then copy and paste the below link into your web browser:
http://www.mangolive.com/blog-mango/root-cause-analysis-tools-webinar
Root Cause Analysis (RCA) is a problem-solving technique that aims to identify the underlying or "root" causes of a problem or issue. It involves digging deep into the symptoms of the problem to uncover the underlying factors that led to it. The goal of RCA is to identify the root cause or causes of the problem and address them, rather than just treating the symptoms. By doing so, organizations can prevent the problem from recurring in the future.
RCA can be used in a wide range of fields and industries, including manufacturing, healthcare, aviation, information technology, and many others. The process typically involves gathering data and information, analyzing the data to identify patterns and relationships, and developing a plan to address the root causes of the problem. RCA techniques can include tools like brainstorming, cause-and-effect diagrams, and statistical analysis, among others.
ABOUT THE TRAINING PROGRAM :-
Root cause analysis (RCA) is a class of problem solving methods aimed at identifying the root causes of problems or events. The practice of RCA is predicated on the belief that problems are best solved by attempting to address, correct or eliminate root causes, as opposed to merely addressing the immediately obvious symptoms. By directing corrective measures at root causes, it is more probable that problem recurrence will be prevented.
DESIGNED FOR :-
Managers, Engineers, Supervisor and officers engaged in maintenance operation and engineering activities.
OBJECTIVE :-
At the end of the training program, participants will be able
- To gain a basic understanding of the problem solving and decision-making process and the applicable quality tools that support this process.
- To develop specific competencies to use the structured approach to problem solving and decision making and the supporting quality tools.
TRAINING PROGRAM COVERAGE :-
- Basic knowledge about RCA program.
- What are the RCA tools ?
- More about Why- Why analysis ?
- Videos and case studies on RCA
Root Cause Analysis - Tools, Tips and Tricks to Get to the Bottom of Root CauseCraig Thornton
This webinar discusses and investigates how to conduct root cause analysis. Root cause analysis is something that companies really struggle with. There will be plenty of practical advice in the webinar to help with you understand the concepts and the tools.
If you would like to watch the recording of this webinar then copy and paste the below link into your web browser:
http://www.mangolive.com/blog-mango/root-cause-analysis-tools-webinar
Root Cause Analysis (RCA) is a problem-solving technique that aims to identify the underlying or "root" causes of a problem or issue. It involves digging deep into the symptoms of the problem to uncover the underlying factors that led to it. The goal of RCA is to identify the root cause or causes of the problem and address them, rather than just treating the symptoms. By doing so, organizations can prevent the problem from recurring in the future.
RCA can be used in a wide range of fields and industries, including manufacturing, healthcare, aviation, information technology, and many others. The process typically involves gathering data and information, analyzing the data to identify patterns and relationships, and developing a plan to address the root causes of the problem. RCA techniques can include tools like brainstorming, cause-and-effect diagrams, and statistical analysis, among others.
PFMEA, Risk Reduction and Effectiveness – Advance (AIAG FMEA #4 Edition)
Is your FMEA performing for you?
This is advance level of PFMEA, Have basic understanding fo Core IATF Tools before refering to this presentation.
Introduction of FMEA; Definition, Activities, important terms, factors, RPN; Process of FMEA; Steps of FMEA
Types of FMEA; FMEA Application; FMEA Related Tools:
Root Cause Analysis, Pareto Chart, Cause Effect Diagram
Not having the ability to identify and rapidly respond to an abnormality means risking potential line shutdown, re-work, or maybe even a recall. Learn the steps needed to formalize and implement a proactive abnormality management program - including methods to error-proof your operations.
Asset Integrity Management for purpose-built FPSOs and subsea system facilitiesAdvisian
Abe Nezamian discusses various aspects of ageing related to FPSOs (floating facilities for production, storage and offtake) and outlines the required procedures for maintaining structural integrity.
Reliability Centered Maintenance for minimizing integrity failure by Bhavesh Shukla at APAC 2015 Process Safety Management Conference 9th March 2015 Singapore.
On the nature of FMECA... An introductionMartGerrand
Here's a presentation on Failure Modes, Effects and Criticality Analysis (FMECA) I did a few years ago, so the references may be truly historical. It's for educational use only - not for resale - so just enjoy!
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In the face of escalating global tensions, particularly those emanating from geopolitical disputes with nations like hashtag#Russia and hashtag#China, hashtag#Germany has witnessed a significant uptick in targeted cyber operations. Our analysis indicates a marked increase in hashtag#cyberattack sophistication aimed at critical infrastructure and key industrial sectors. These attacks range from ransomware campaigns to hashtag#AdvancedPersistentThreats (hashtag#APTs), threatening national security and business integrity.
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Our comprehensive report delves into these challenges, using a blend of open-source and proprietary data collection techniques. By monitoring activity on critical networks and analyzing attack patterns, our team provides a detailed overview of the threats facing German entities.
This report aims to equip stakeholders across public and private sectors with the knowledge to enhance their defensive strategies, reduce exposure to cyber risks, and reinforce Germany's resilience against cyber threats.
1. Root Cause Analysis
Root Cause Analysis
(RCA)
(RCA)
An essential element of Asset Integrity
Management and Reliability Centered
Maintenance Procedures
Dr Jens P. Tronskar
2. Definition of Root Cause Analysis (RCA)
Definition of Root Cause Analysis (RCA)
Root Cause Analysis (RCA) is a structured
Root Cause Analysis (RCA) is a structured
process that uncovers the physical, human,
process that uncovers the physical, human,
and latent causes of any undesirable
and latent causes of any undesirable
event in the workplace.
event in the workplace.
Can be;
Can be;
•
•Single or multidiscipline cases
Single or multidiscipline cases
•
•Small or large cases
Small or large cases
3. Some other definitions
Failure Mode – The effect
by which a failure is
observed on the failed item
Failure – The termination
of its ability to perform a
required function
Failure Effect – The
consequence(s) a
failure mode has on the
operation, function, or
status of an item.
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
deterioration proceeds to failure.
• The circumstances during
design, manufacture, or
operation that have led to a
failure.
4. Edit in Veiw > Header and footer Edit in Veiw > Header and footer
Slide 4
Root Cause (RCA)
Root Cause (RCA)
Indispensible component of proactive and
reliability centred maintenance
Uses advanced investigative techniques
Apply correctives
Eliminates early life failures
Extends equipment lifetime
Minimizes maintenance
5. Traditional maintenance strategies
Traditional maintenance strategies
tend to neglect something important:
tend to neglect something important:
Identification and correction of the
underlying problem.
6. A Root Cause Analysis will disclose:
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
7. Improved availability “up
Improved availability “up-
-time”
time”
and increased production
and increased production
Reactive Periodic Predictive
maintenance/
(conndition
monitoring
Proactive
Maintenance
Strategies RCFA
Era of
maintenance
strategies
Todays’ level
Production
9. Periodic maintenance
Periodic maintenance
Scheduled calendar or interval-based
maintenance
Expensive components exchanged even
without signs of wear or degradation
Unexpected failures with incorrect schedules
and component change-out
10. Predictive maintenance by
Predictive maintenance by
condition monitoring
condition monitoring
Apply technologies to measure the condition of
machines
Predict when corrective action should be
performed before extensive damage to the
machinery occurs
11. Short and long
Short and long-
-term benefits of
term benefits of
Proactive Maintenance Strategies
Proactive Maintenance Strategies
involving RCFA:
involving RCFA:
Optimization of service conditions:
Optimization of service conditions:
Increased production
Reduced downtime
Reduced cost of maintenance
Increased safety
12. Experience and statistical data
Experience and statistical data
MMS DATABASE
Information on equipment design and service conditions
Failure statistics i.e. MTBF
Description of service failures, approach and methods
for failure investigation
Consequences of failure:
Downtime/pollution and spillage/secondary damages
Causes of failures
Recommendations and remedial actions
13. Methods and analytical tools to identify
Methods and analytical tools to identify
the causes of failure or breakdown
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
16. Interviewing Considerations
• Where to interview
• Who to interview
• Condition of people
at the scene
• How to handle
multiple witnesses
• How to handle after
the incident
• How to work with
teams
17. Investigation techniques
• A number of named techniques that are
commonly used within RCA:
– Step-method
– FMEA
– Bow-tie
– Event Tree
– Failure Tree
– Interview
– Fish Bone
– Why-Why
• The techniques have strength and weaknesses
depending on the situation.
18. Methods for RCA; Content
• Data Collection
– Interviews
– Paper and technical evidence
• Methods for RCA
– STEP
– FMEA
– FTA
19. STEP 1: Register Equipment Incidents
Assess cause
of failure
Issue Run-Log or
Work Request in
Maximo
Purpose : Register Off-spec. Operation /
performance, Survey & Condition Monitoring data
Start: Trigged by off-spec. operation/performance,
Survey & Condition Monitoring data
Stop: Incident logged in Maximo
Perform
short-term
Corrective action
Register Equipment Incidents
Failure report
in Maximo
Operation
log
Input to
Process
Expected
output from
Process
Process control
Resources
Maintenance
department
Off-spec operation /
performance :
• Equipment failure
• Trips
• Abnormalities
Off-spec operation/
performance logged
in Maximo:
* Equipment failures
* Trips
* Abnormalities
Operation
department
History of Condition
Monitoring, Surveys,
and Recommended
Maintenance Action
in Maximo
1
Survey/Inspections/
Audits/Reviews and
Condition Monitoring
by Maintenance
Maximo
20. STEP 2: Trigger Mechanism for RCA
Purpose: Evaluate need for RCA
Start: Registered HSE issues or off-spec operation/
performance incidents
Stop: Start RCA
Prepare
monthly report
per site
Prepare
quarterly report
for HQ
Input to
process
Expected
output
from
process
Process control
Resources
Recommended
RCA Case
No Action
Single incidents
with high
production loss or
repair cost
Incidents above trigger level
Surveys, Audits,
Inspection, Reviews
and Condition
monitoring by
Maintenance
Off-spec operation/
performance:
Equipment
failures
Trips
Abnormalities
Single operation
incidents with production
loss/repair cost > X
Off-spec operation vis-à-
vis (KPI)
Multiple operating
incidents per Tag no./
Equipment type
High risk findings from
survey/CM
Incidents below trigger level,
and mitigation not cost
effective
Plant Reliability Engineer/
Senior Planning Engineer
HQ Senior
Reliability Engineer
Reliability Engineer
(Plant/HQ)
RAM
Do Preliminary
LCC; Actual Loss/
Cost vs Investment
(Replacement)
21. STEP 3: Appoint the RCA Team
• Minor RCAs:
– Run within a department, using the procedure
• Larger RCAs:
– 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
– Vendor
– Failure laboratories
– Other 3rd parties
– Specialist
23. 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.
The immediate causes of an incident are the circumstances that immediately preceded the contact and can usually be seen or
sensed. For example if the incident is an oil spill, the immediate cause could be a broken sealing. The Immediate Causes
often are the same as the failure codes registered in Maximo.
Basic Causes are the real causes behind the immediate causes: the reasons why the substandard acts and conditions
occurred, the factors that, when identified, permit meaningful management control. In case of an oil spill caused by a broken
sealing, the Basic Causes could be that the sealing used was of wrong type, it had a design failure or it might be installed
wrong.
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
checking after maintenance.
1 Description of the Incident(s)
2 Immediate Cause(s)
3 Basic Cause(s)
4 Lack of Control
The main RCA report
26. Methods for RCA
• STEP; Sequential Time Event Plotting
• FMEA; Failure Mode Effect Analysis
• FTA; Fault Tree
• + common sense, engineering/operational
experience
27. STEP; Sequentially Time Event Plotting
Actors
Event 1
Event 4
Event 3
Event 2
Time line
Event 5
Actor 1
Actor 2
Actor 3
Actor 4
Actor 5
Event 7
Event 6
Accident
1 2
Deviation 1 Deviation 2
1. Identify actors
2. Identify events
3. Link 1&2
4. Mark Substandard
acts/deviations
…all links are AND gates
28. FMEA; Failure Mode and Effect Analysis
Loss/Consequence:
Pump not started
No detection
of failure and
larger damage
Wrong signal
to control unit
Loss of
Pressure
Consequence
System/
Component
None
Fatigue
Broken axel
None
Fail to operate
Sensor
Alarm
Signal
None
In off position
Switch
Fail to operate
High Temp.
Protection
None
Unknown
Fail to
Operate
Soft-starter
None
Winding
El. Motor
Pressure
Indicator
Corrosion
/Wear
Impeller
Pump
Comment
Likelihood
(low – possible- high)
Detection
Failure
Cause
Failure Mode
Function/
Object
29. Fault Tree
• Identifies causes for an
assumed failure (top event)
• A logical structure linking
causes and effects
• Deductive method
• Suitable for potential risks
• Suitable for failure events
What is a Fault Tree?
Top
event
Component 1 And
Gate
Component 2 Component 3
E3 E4
E1
A
E2
OR
AND
Basic
Event
Intermediate
Event
30. Which one to use?
• STEP:
– For complex events with many actors
– When time sequence is important
• FMEA:
– Getting overview of all potential failure
– Easy to use
• FTA:
– Identifies structure between many
different failure causes
– Non-homogenous case (different
disciplines)
31. Detailed analyzes of failed
Detailed analyzes of failed
parts/components
parts/components
32. Typical examples of systems/equipment
Typical examples of systems/equipment
that can be analyzed:
that can be analyzed:
Electrical generators
Heat exchangers
Subsea equipment
Valves
Control systems
Pumps
Fire and gas-detectors
Sensors and measuring devices
Components of gasturbines
Compressors
Cranes and lifting equipment
Well and down hole drilling
equipment
33. Proactive maintenance through
Proactive maintenance through
Root Cause Failure Analysis
Root Cause Failure Analysis
(RCFA)
(RCFA)
Maintenance strategy based on systematic and
detailed knowledge of the causes of failure and
breakdown
Systematic removal of failure sources
Prevent repetitive problems
Minimise maintenance down-time
Extend equipment life
34. RCFA evaluates factors affecting
RCFA evaluates factors affecting
service performance such as:
service performance such as:
Materials/corrosion/environment
Changes in operational conditions
Stresses and strains
Presence of defects and their origin,
nature and consequences
Design
Welding procedures and material
weldability
35. The most common causes of
The most common causes of
service failures or breakdown:
service failures or breakdown:
Incorrect operation
Poorly performed or inadequate
maintenance
Incorrect installation and bad
workmanship
Incorrect repair introducing new defects
Poor quality manufacture leading to sub-
standard components
Poor design
36. Examples of problems disclosed
Examples of problems disclosed
by the laboratory investigation
by the laboratory investigation
as part of the RCFA:
as part of the RCFA:
GEARS
• Incorrect material
• Incorrect heat treatment
• Incorrect design
• Incorrect assembly
• Corrosion
• Lubricating problems
• Vibration
• Incorrect surface
treatment
• Geometric imperfections
• Incorrect operation
• Fatigue or overloading
37. Examples of problems disclosed
Examples of problems disclosed
by the laboratory investigation
by the laboratory investigation
as part of the RCFA:
as part of the RCFA:
BOLTS
• Indoor material
• Poor design
• Manufacturing defects
• Incorrect assembly
• Corrosion
• Vibration
• Poor or incorrect surface
treatment
• Geometric imperfections
• Incorrect application
• Incorrect torque or
overloading
38. Examples of problems disclosed
Examples of problems disclosed
by the laboratory investigation
by the laboratory investigation
as part of the RCFA:
as part of the RCFA:
BALL-/ROLLER BEARING
• Poor design
• Manufacturing defects
• Poor alignment and
balance
• Seal failure
• Electrical discharge
(arcing)
• Overload
• Inadequate lubrication
• Vibration
• Contamination
• Fretting
• Corrosion
39. Root Cause Failure Analysis
Root Cause Failure Analysis
Disclosed Failure of:
Disclosed Failure of:
MAIN BEARING
• Heavily worn raceway, cracking of
casehardened surface, plastic deformation of
sealing groove
• The main cause of failure was overloading of
the bearing.
Actions/recommendation:
• Reanalysis by FEM and redesign
40. Root Cause Failure Analysis Disclosed
Root Cause Failure Analysis Disclosed
Failure of:
Failure of:
O-RING
• Four gas leaks on TLP
platform equipment in HP &
IP service
• Caused by explosive
decompression (ED) of O-
Ring
• Actions/recommendation:
Change to another O-Ring
type with other elastomer
41. Examples of problems disclosed by
Examples of problems disclosed by
the laboratory investigation as part
the laboratory investigation as part
of the RCFA:
of the RCFA:
DRIVE SHAFTS
• Incorrect material quality
• Incorrect design
• Poor quality manufacture
• Geometric imperfections
• Incorrect operation
Surface defects
Corrosion
Incorrect balance and
alignment
Incorrect assembly
Fatigue or overloading
42. ROOT CAUSE FAILURE ANALYSIS
ROOT CAUSE FAILURE ANALYSIS
DISCLOSED:
DISCLOSED:
Bearing Breakdown
Bearing Breakdown
• Axial overloading
• Thrust washers fitted in both bearing housings
• Incorrect assembly
Actions/recommendation:
Remove thrust washers from one bearing
housings
43. ROOT CAUSE FAILURE ANALYSIS
ROOT CAUSE FAILURE ANALYSIS
DISCLOSED:
DISCLOSED:
Gear Breakdown
Gear Breakdown
• Broken gear tooth. Fatigue initiated from
quench cracks.
• Fabrication induced defects (Basis for
discussion of liability and subsequent claims
against manufacturer)
Actions/recommendation:
Fitting of new gears where heat treatment and
case hardening procedure had been verified
to be correct
44. ROOT CAUSE FAILURE ANALYSIS
ROOT CAUSE FAILURE ANALYSIS
DISCLOSED:
DISCLOSED:
Damaged pinion and gear wheel
Damaged pinion and gear wheel
Severe surface deformation on one side of teeth
No surface hardening
Incorrect lubrication
Actions/recommendations:
Renew gear wheel and pinion with components
that have been verified to have correct surface
hardening. Change lubricant and revise
lubrication procedure.
45. Typical components
Typical components
that can be
that can be analysed
analysed
Gears
Bearings
Bolted connections
Shafts
Impellers
Pistons/cylinders
Motor rotors/stators
Pressurized components and
pressure vessels
Steel wire ropes
Hydraulic components
Welded joints
48. STEP Method
• Capturing of the sequential events leading up to an
accident.
• Can be a simple timeline
• Investigation of larger incidents/accidents where the
time sequence is important
• Handles complex events with:
– several actors
– several events in parallel
– a longer time horizon
• Should include both equipment, control and human
actions
(Sequentially Time Event Plotting)
49. STEP; Sequentially Time Event Plotting
Actors
Event 1
Event 4
Event 3
Event 2
Time line
Event 5
Actor 1
Actor 2
Actor 3
Actor 4
Actor 5
Event 7
Event 6
Accident
1 2
Deviation 1 Deviation 2
1. Identify actors
2. Identify events
3. Link 1&2
4. Mark Substandard
acts/deviations
…all links are AND gates
50. Example of a simple STEP diagram
Time
Actors
Missed annular
inspection of
valve sealing
Sealing
becomes dry
and brittle
Inadequate
tightening
Oil leakage
January May June
Engineer
Sealing
Valve
1
Operator
Manually
Moving the
valve
Case:
Manual valve
oil leakage
Deviation 1
51. FMEA
Failure Mode and Effect Analysis
FMECA
Failure Mode and Effect Criticality
Analysis
52. FMEA (Cause-Consequence)
• Overview of failure mode and effect for a
complex machinery/operation
• Getting an overview of all potential failure
causes and effects at an initial stage of an
investigation
• Requires detailed knowledge of the problem in
question
• Easy to use for both events and for potential
losses where risk is included
• Not good at handling time series
(Failure Mode and Effects Analysis)
53. Technique/Working Process
Analysis Goal
System definition
•System boundaries
•Operational state
•Limitations, assumptions
System description
•Documentation
•Division into sub-systems
(e.g. functional decomposition)
Analysis planning
•Find expert team
•Plan expert sessions
(when, what, who?)
•Make documentation available
Expert sessions
•Guided brain-
storming to collect
information
•Fill in forms
Likely
Causes
Exclusion
Final
Causes
Evidence Finding
•Inspections
•Failure Analysis
•Interview
55. Offshore Gas production
Statistics from 320 incidents/ “RCA” cases
Personal related
26 %
Lack of
management of
work
15 %
Design
33 %
Preventive
Maintenance
8 %
Other
18 %
Total Losses;
Ca. 100 mill$/yr
56. Immediate causes
Immediate Causes - Substandard Acts
0
5
10
15
20
25
A14.1: Operator initiated
failure
A10.1: Error during
maintenance/repair
A13.1: Violation of operation procedures
A13.4: Failure during praparation for maitenance
A13.3: Violation of working
prcedures
A11.1: Operator overlooking
control signals
A10.3: Equipment damaged
during
constgructiun
Too slow
operator reaction
Error during testing
W
ork without workperm
it
Immediate Causes - Substandard Conditions
0
20
40
60
80
100
120
140
160
180
A1.3: Failure during
service
A1.4: Failure during
startup
A1.5: Failure during
mainteannce
N
57. Basic Causes
Basic Causes - work related
0
10
20
30
40
50
60
70
Bad
design
Insifficient PM
Insufficient planning
o...
Insufficient Q
A
after...
Insuficient CM
O
perational response
Q
A
of work
Planning
of m
aintenance
Q
A
at delivery
Change
in
SW
/design
...
Procedure/work
descri...
No
of
events
Basic Causes - Personal Factors
0
5
10
15
20
25
Lack
of experience
Lack
of job
related
...
Lack
of info/draw
ings
Stressfull work
situa...
Lack
of support
Job
related
training
Lack
of knowledge
62. Root Cause Failure Analysis
BRITTLE FRACTURE IN CHANNEL
TO TUBESHEET WELD
• Low temperature due to process upset
• caused brittle fracture initiation from root
• of weld containing lack of fusion defect
• Actions/recommendations:
Actions/recommendations:
• Reconstruct using low temperature steel
• grade, carry out proper UT. Modify operation
• procedure and controls to prevent
• future process upsets.
Damage mechanism:
Damage mechanism:
Brittle fracture
Brittle fracture
DISCLOSED:
67. Findings
• Explosion caused by trip of turbine and leak
from WHRU gas coil to header weld
• Following gas leak, auto-ignition of air/gas
mixture occurred. The auto-ignition temperature
was equal to the surface temperature of the
equipment based on instrument readings
• Weld failure due to creep/fatigue and time
dependent embrittlement of weld HAZ
• Damage was caused by air/gas mixture
explosion equivalent to 68 kg TNT