INTRODUCTION TO RBI
& API 580
RBI Training Course
Module 01
Scope of the Training
Introduction to RBI
RBI Methodology Theory + with hands on exercises
Likelihood calculation
Consequence calculation
Case Study with the RBI software: refinery unit
Data preparation
Screening analysis
Detailed analysis
Agenda
Module
RBI Training Program. Breaks assumed during the day but not shown. Timing approximate.
Item
1
2
3
4
5
6
7
8
8
9
10
11
12
Introductions - Installations, Introduction to RBI
Lunch
Likelihood theory 1
Likelihood theory 2
Likelihood theory 3
Consequence theory and exercises
Lunch
Project Start up and Data Organization.
Screening Analysis Introduction
Detailed analysis - Data entry
Lunch
Detailed analysis - Data entry
Establishing criteria and using the IP tool
Plant inspection plans
Reporting features / information output
Lunch
Other Features
Start
Day 1
09:00
12:30
13:30
15:00
Day 2
09:00
10:30
12:30
13:30
Day 3
09:00
11:00
12:30
13:30
Day 4
09:00
11:00
12:00
12:30
13:30
End
Objectives
12:30
13:30
15:00
17:00
Thinning: calculation principles and inspection updating
Other limit states
10:30
12:30
13:30
17:00
11:00
12:30
13:30
17:00
11:00
12:00
12:30
13:30
16:00
Other likelihood models
Consequence theory
Inventory groups and Corr circuits
Using the screening tool
Model creation and data entry issues.
Model creation and data entry issues.
Inspection Planning using risk criteria
Creating inspection plans from the RBI guidelines.
Extracting information from software
Other features
INTRODUCTIONS
(Name,
Organisation
type of work,
why interested in RBI,
English )
Presentation Topics - This Session
RBI History – API Standards
General Introduction
The benefits of RBI
What RBI is
How RBI fits within existing plant systems
Implementing RBI
Some case studies
RBI History
Probabilistic risk analysis techniques
Started in the nuclear industry (1970s)
Quantitative risk assessment (QRA) in the Process Industries
Canvey Island and the Rijnmond Report (1980s)
Software tools for QRA
Eg DNV-Technica develops SAFETI and PHAST risk assessment
tools (1980s)
ASME RBI principles overview document in 1991
API develops Risk Based Inspection Methodology (1990’s)
DNV main API sub-contractror
API Base Resource Document 581 (2000)
API RBI software
API RP 580 (2002)
RBI History
DNV develops ORBIT Onshore 1997-now
Some Reasons:
Need for a RBI software for all onshore installations
–
API 581 focuses on refineries
Improved consequence calculations with PHAST link
Enhancements in likelihood calculation
–
ORBIT uses equations for limit state implementation
Need for a robust software architecture & professional
software development and maintenance
ORBIT is consistent with the API 580 RBI standard
ORBIT and API 581 share philosophy/technology
API RBI development by Equity Eng. (2002-now)
API RP 581 Update (2008)
API RP 580 Update (2009)
API Inspection and FFS Standards
Existing
RBI & FFS documents
API
750
API
510
API
570
RBI
API RP 580
API - BRD P 581
RISK BASED
INSPECTION
MPC
FITNESS FOR
SERVICE
FFS
API RP 579
ASME
API
653
Working
Documents
RBI
API RP 581
Research & reference
Documents
New
Documents
Presentation Topics - This Session
RBI History
General Introduction
The benefits of RBI
What RBI is
How RBI fits within existing plant systems
Implementing RBI
Some case studies
A Typical Plant
Storage and
export
Loading facilities
Processing to give
added value.
Typical Operating Objectives
Operate safely and profitably
Maintain high availability and throughput.
Minimize shut downs.
Extending shut down intervals
Prevent/reduce leaks.
Class question?
What are the typical plant objectives here?
Typical Plant Issues
Challenges
Old Plants
Large, complex units
Integrated Feed Systems
Many degradation mechanisms
Raw material price
PROCESS CORROSION
- Continuously degrading integrity
Corrosion Principles
Corrosion rate is measured as weight loss per unit area
and is expressed in mils per year (mpy) or mm/y.
Corrosion Rates can be affected by:
Passivity forming protective surface films (including
corrosion inhibitors, paints and coatings)
Oxygen content
Flow velocity/rates
Temperature
pH effects (Low and High)
Contaminants/intermediates
Some Corrosives Found In The Process Industry
Water
Oxygen
Naphthenic Acid
Polythionic Acid
Chlorides
Carbon Dioxide
Ammonia
Cyanides
Deposits
Hydrogen Chloride
Sulfuric Acid
Hydrogen
Phenols
Dimer and Trimer
acids
Other
Low Temperature Corrosion
Below 500°F (<260°C)
Occurrences
Inorganic compounds such as water, hydrogen sulphide,
hydrogen chloride, sulphuric acid, salts, etc.
Presence of water (even in very small amounts)
Electrolyte in hydrocarbon stream
Hydrocarbons in water streams creating acidic conditions
Solids .. Under deposit
Organic acids
Vapour Streams at water condensation points
Obeys electrochemical laws
Stable films can reduce or prevent corrosion
Low Temperature Corrosion
From Process chemicals
From Process contaminants
Not caused by clean hydrocarbons
Caused by inorganic compounds such as water, hydrogen
sulphide, hydrogen chloride, sulphuric acid, salts, etc.
High Temperature Corrosion
Above 500°F (>260°C)
No water present
Result of a reaction between metal and
process ions (such as oxygen O-, sulphur S,
etc.)
High Temperature Corrosion
Important due to serious consequences
High temperatures usually involve high pressures.
Dependent on the nature of the scale formed
General thinning
Localized thinning (pitting)
Inter-granular attack
Mixed phase flow
Metallurgical changes
Situations Leading To Deterioration
Normal operation, upset, startup /shutdown
conditions
Material/Environment condition interactions
Many combinations of corrosive process streams
and temperature/pressure conditions.
In the absence of corrosion, mechanical and
metallurgical deterioration can occur.
Weather effects ….
Forms Of The Damage
General loss due to general or localized corrosion
Pitting attack
Stress Corrosion Cracking (SCC)
Metallurgical Changes
Mechanical damage
High Temperature Hydrogen Attack (HTHA)
Damage types occur with specific combinations of
materials and environmental/ operating conditions
Stress Corrosion Cracking Detection
SOHIC in soft base metal.
Stress-Oriented Hydrogen
Induced Cracking
In contrast to general
corrosion, SCC is very hard to
detect visually even when it
has progressed to an extreme
condition.
Types of Stress Corrosion Cracking
Chloride stress corrosion cracking (Cl-)
Nitrates
Caustic stress cracking (NaOH)
Polythionic acid stress corrosion cracking
Ammonia stress corrosion cracking (NH4)
Hydrogen effects (in steel)
Sulfide stress corrosion cracking SSC, hydrogen induced
cracking HIC, stress oriented hydrogen induced cracking
SOHIC
Hydrogen cyanide HCN
Others
High Temperature Hydrogen Attack (HTHA)
Carbon and low alloys steels exposed to hydrogen above
430°F (221°C)
Hydrogen Partial pressure above 200 psi (>14 bar)
Dissociation of molecular hydrogen to atomic hydrogen
H2 -> 2 H+
Atomic hydrogen permeation into the steel
Reaction of atomic hydrogen with carbon in steel
Formation of methane at discontinuities
API 941 recommended for new installation
High Temperature Hydrogen Attack
Longitudinal Weld
Magnification: 500x
Etch: 2% Nital
Metallurgical And Environmental Failures
Grain growth
Graphitization
Hardening
Sensitization
Sigma phase
885 F embrittlement
Temper embrittlement
Liquid metal embrittlement
Carburization
Metal dusting
Decarburization
Selective leaching
Mechanical Failures
Incorrect or defective
materials
Mechanical fatigue
Corrosion fatigue
Cavitation damage
Mechanical damage
Overloading
Over pressurization
Brittle fracture
Creep
Stress rupture
Thermal shock
Thermal fatigue
Conclusions
There are many causes of equipment failures in the
process industry.
Many are common and well documented.
Other, less common deterioration mechanisms are not
well documented.
Deterioration is the result of metal and environment/
operating conditions combinations.
These combinations vary somewhat in different process
units.
Detection and characterization of the different forms is a
challenging and critical activity.
Tools exist to assist to assess the severity
of corrosion or determine the appropriate
materials of construction
For Example:
NaOH Chart
These Tools Are Generally Used By
Experienced Corrosion Engineers.
They can also be implemented in
software as corrosion evaluation
supplements
Determining Equipment Integrity
Requires information about the level of degradation:
Monitoring (Fluid corrosivity) and
Inspection (Wall condition)
“MONITORING” POSSIBILITIES
Monitoring
Fluid Composition/Quality
Pressure, Temperature, pH
Contaminants when relevant
Fluid corrosivity
Corrosion probes (e.g. Weight loss, electrical
resistance, linear polarization)
Function of protective systems e.g. inhibitor injection
Inspection: Pressure boundary condition checks, e.g.
Visual examination
Thickness measurements
Other checks
Non Destructive Examination
- Inspection
Selecting Inspection method. Factors to consider
Type of defect
General metal loss
Localized metal loss
Pitting
Cracks
Metallurgical changes
Location of defect
On the outside wall of an item
The inside wall
Within the body of the wall
Associated with a weld
Selecting Inspection method. Factors to consider:
Material of construction
Magnetic
Non magnetic
Operating at high temperatures
Insulated
Equipment geometry:
May be hard to access
May require extensive activity e.g. scaffolding,
entry preparations, to perform the inspection
Many considerations when determining how to
inspect.
Also, need to justify the need for inspection.
NDE Methods
American Society for Nondestructive Testing (ASNT)
Acoustic Emission Testing (AE)
Volumetric
Eddy Current Testing (ET)
Surface/ Volumetric
Infrared/Thermal Testing (IR)
Surface
Leak Testing (LT)
Magnetic Particle Testing (MPT)
Surface
Neutron Radiographic Testing (NR)
Volumetric
Penetrant Testing (PT)
Surface
Radiographic Testing (RT)
Volumetric
Ultrasonic Testing (UT)
Volumetric
Visual Testing (VT)
Surface
Magnetic Flux Leakage (MFL)
Penetrant Testing
Penetrant solution is applied to
the surface of a pre-cleaned
component. The liquid is pulled
into surface-breaking defects by
capillary action.
Excess penetrant material is
carefully cleaned from the surface.
A developer is applied to pull the
trapped penetrant back to the
surface
The penetrant spreads out and
forms an indication. The indication
is much easier to see than the
actual defect.
Magnetic Particle Testing
A magnetic field is established in a
component made from ferromagnetic
material.
The magnetic lines of force or flux
travel through the material, and exit
and reenter the material at the poles.
Defects such as cracks or voids are
filled with air that cannot support as
much flux, and force some of the flux
outside of the part.
Magnetic particles distributed over
the component will be attracted to
areas of flux leakage and produce a
visible indication.
Radiography Testing
X-rays are used to produce images
of objects using film or other detector
that is sensitive to radiation.
The test object is placed between the
radiation source and the detector.
The thickness and the density of the
material that X-rays must penetrate
affect the amount of radiation
reaching the detector.
This variation in radiation produces
an image on the detector that shows
the internal features of the test object.
Ultrasonic Testing
High frequency sound waves are sent into a material by use of a
transducer. The sound waves travel through the material and are
received by the same transducer or a second transducer. The
amount of energy transmitted or received, and the time the energy
is received are analyzed to determine the presence and locations of
flaws. Changes in material thickness, and changes in material
properties can also be measured.
Ultrasonic Principles
Angle Beam
(Shear Wave)
Straight Beam
(Longitudinal Wave)
Ultrasonic Presentations
TOP VIEW
(C-SCAN)
A-SCAN
END VIEW
(B-SCAN)
SIDE VIEW
(D-SCAN)
Risk Based Inspection
Presentation Topics
General Introduction
The benefits of RBI
What RBI is
How RBI fits within existing plant systems
Implementing RBI
Some case studies
The Value of RBI
What is the first duty of Business?
“The first duty of business is to survive, and the guiding
principle of business economics is not the
maximisation of profit - it is the avoidance of loss.”
Peter Drucker
The Key Benefits of an RBI Study
Identify the high risk items
Understand the risk drivers and develop mitigation plans
Focussed inspection plans which:
Increase safety and reduce risk
Help to improve reliability
Often results in cost benefits due to:
Reduced turnaround time and/or
A reduction in the number of items to be inspected
The associated “maintenance” costs e.g access
arrangements
Normally an overall reduction in risk and cost savings
from the inspection activity.
Presentation Topics
General Introduction
The benefits of RBI
What RBI is
How RBI fits within existing plant systems
Implementing RBI
Some case studies
What Is RBI?
A method/process for prioritizing equipment for
inspection based on risk.
It determines the risk associated with the
operation of specific items of equipment and
identifies the key factors driving the risk.
A tool which demonstrates the value (or not) of
performing specific inspection activities.
It is a decision making management tool applied
to the issue of Inspection Planning.
Equipment Types
•Pressure Vessels—All pressure containing
components.
•Process Piping—Pipe and piping components.
•Storage Tanks—Atmospheric and pressurized.
•Rotating Equipment—Pressure containing
components.
•Boilers and Heaters—Pressurized components.
•Heat exchangers (shells, floating heads, channels,
and bundles).
•Pressure-relief devices.
Risk Based Inspection
Strategic Process
Increasing reliability (revenue)
Lowering cost
Lowering risk
Integrated Methodology
Risk factors
Likelihood
Consequence
Supports effective decision making
What Constitutes an Undesirable Event In RBI?
Failure is defined as a leak of the
equipment contents to the atmosphere;
“breach of containment” or LOPC
Heat exchanger failures are channel or
shell leaks.
Pump failures are due to seal leaks and
adjacent piping fatigue cracking.
RBI - Detailed Analysis
Components in the calculation of the risk
=
Risk
Likelihood of Failure
MF x Fp x Fm x Fu
Abbreviations:
:
Damage
DF:
Factor
GFF: Generic Failure
Frequency
x GFF x
DF
Damage Area.
Age
Equip. Repair
Damage
Type/Rate
Fi : Process, Mechanical
& Universal Factor
Fdomino:Domino Eff.Factor
MF: Management Factor
X
Consequence
of Failure
Fdomino x CoF
Other repairs
Injury
Business Int.
Inspection
Effectiveness
RBI_Key_Concepts.vsd
Common Damage Mechanisms in RBI
Damage
Mechanisms
Internal
Thinning
• HCl
Stress
Corrosion
Cracking
External
Damage
• Caustic
General
• HT Sulfide . • Amine
CUI
& Nap. Acid • SSC
• HT H 2S/H 2 • HIC/SOHIC Cl SCC
• H2SO 4
• Carbonate
• HF
• PTA
• Sour Water
• ClSCC
• Amine
• HSC-HF
• HT
Oxidation
• HIC/SOHIC-HF
Brittle
Fracture
Piping
Fatigue
HTHA
Lining
PRVs
CALCULATING THE FAILURE FREQUENCY
MANUAL ACTIVITY
Damage factor Calculation
Estimate the likely
damage state /
severity
Determine the Likelihood of being in one
of the different possible damage states:
Consider data source
Assess the
inspection history
(Effectiveness)
Inspection Effectiveness
Failures only occur when
the rate of degradation is
higher than expected.
Damage states
1
No worse than predicted
X%
2
Up to 2x worse than predicted
Y%
3
Up to 4x worse than predicted
Z%
Calculate the failure frequency for each
state using the relevant limit state
equation
Calculate the weighted failure frequency
for the item based on the Likelihood of
being in the different states.
Steps in Bayes_LoF
Undesirable Consequences in RBI
HEAT from flames destroys equipment, injures people
PRESSURE WAVE from explosions knocks down
structures and people, causes flying objects
TOXIC cloud, for some duration, causes toxic
exposure injuries
ENVIRONMENTAL DAMAGE due to spill (currently
only included in AST RBI software)
Consequence Calculation
Process
Information
Physical
Properties
Equipment
Information
Calculate Release Rate or Release
Mass
Assessment of Incident
Outcome
Damage Areas
Safety
Costs
Business
Interruption Costs
Equipment Damage
Costs
Amount of Effort - RBI vs QRA
Likelihood
Consequence
QRA*
RBI**
* Quantitative Risk Assessment
** Risk Based Inspection
Input Data For A Quantitative RBI Assessment
The main input data collected
Item
Design Data
Operating Data
OD Tnom Matl Ins Press Temp Fluid Temp. Press Fluid
A
Damage mechanisms
Mechanism
Severity/rate
Thinning,
SCC,
Furnace,
HTHA,..
Inspection data
Done?
Result?
What do we
expect to find
and what at
what severity?
What has been
looked for and
what has been
found
B
C
Identify
all items
For some damage
mechanisms, e.g. SCC,
brittle fracture, fatigue,
other data may be
needed e.g. PWHT,
Charpy test temp.
Is it
operating as
intended?
RBI Results?
Calculation of the risk with a lookahead:
Item Type From To Damage
no.
Mechanism
1 Pipe
2 Vessel
3 Fin Fan
What (Risk priority)
Inspection Plan
GFF DF LoF CoF Risk Insp. Insp. New
Type Date DF
Thinning
CUI
Erosion
3000
100
0.5
Why (Damage mech. &
factor)
Where / How (Item - Effectiveness - Material - Mechanism)
When (Basis Inspection
planning targets.)
The Presentation Of Risk
Likelihood
Category
5
Medium-High Risk
4
High Risk
Med. High Risk
3
2
1
Medium Risk
Low Risk
A
B
C
D
Consequence Category
E
Likelihood of Failure
How Will This Picture Change With Time?
A
B
C
A
B
C
D
E
Consequence of Failure
Likelihood of failure
will increase over
time because of timedependent material
degradation
Likelihood of Failure
Risk Increase Over Time
A
B
C
D
E
Consequence of Failure
Likelihood of Failure
What is the effect of Inspection ?
A
B
C
D
E
Consequence of Failure
Steps Leading To The Inspection Plan
Risk Criteria
High Risk
Risk cannot be justified
save in extraordinary
circumstances
Unacceptable region
Tolerable only if risk reduction is
impracticable or if it cost is grossly
disproportionate to the improvement
gained
The ALARP or Tolerability
region
(Risk is undertaken only if
a benefit is desired)
Tolerable if cost of reduction would
exceed the improvement
Broadly acceptable region
(No need for detailed working to
demonstrate ALARP)
Necessary to maintain assurance
that risk remains at this level
Negligible risk
Traditional Vs. Risk-Based Inspection Planning
Traditional
RBI
Inspection based on
experience (usually by
previous leaks and
breakdowns)
Inspection based on
experience and systematic
(risk) review
Inspection effort driven by
“Likelihood of failure”
Inspection effort driven by
“risk”, i.e. Likelihood of failure
and consequences of failure
Reactive “fire fighting”, running
behind the ball
Pro-active planning and
execution of inspections
Use of appropriate /
Inappropriate NDT techniques
Systematic identification of
appropriate NDT techniques
Inspection Program Options for Influencing Risk
Change inspection frequencies (when)
Change inspection scope / thoroughness (what)
Change inspection tools / techniques (how)
RBI - Applications
Risk-prioritized Turnaround planning
High safety/reliability impact = more attention (in order to
lower risk
Less impact safety/reliability = less attention (in order to
lower costs)
Result:
Lower equipment life cycle costs
Fewer incidents / outages
Fewer unnecessary inspections
Higher reliability
May also assess the impact of delaying a turnaround/
shut down
RBI - Applications
Special focus studies e.g.:
Corrosion under insulation.
Positive material identification.
Hydrogen sulfide etc.
What if studies e.g.
Assess the impact of process changes.
Assess the impact of a different feed.
Can RBI Help To Prevent All Releases?
Where Inspection Can Help
About half of the
containment
losses in a
typical
petrochemical
process plant
can be
influenced by
inspection
activities
Mechanical
Failure
43%
11%
Natural Hazard
5%
Operational
Error
21%
Process
Upset
1% Sabotage/Arson
Unknown
14%
Design Error
5%
Source: Large Property Damage Losses in the HC-Chemical Industries - A thirty year review, 17th edition, J&H Marsh& McLennan.
Managing Risk - Considerations
THE SYSTEM FACTORS
"HARDWARE"
"SOFTWARE"
PEOPLE
Risk Exposures (Potential Losses)
Experienced Losses - Cause and Costs
Percentage
Avg. $ loss
% and MM$
100
50
0
Mech.
Fail.
Operator
Process Natural
Unknown
error
upsets hazards
Design Sabotage
errors
/arson
Percentage
43
21
14
11
5
5
1
Avg. $ loss
72.1
87.4
68.9
81
55.7
82.5
37.1
Source: Large Property Damage Losses in the HC-Chemical Industries - A thirty year review, 17th edition, J&H Marsh& McLennan.
The Equipment Involved
Losses vs Equipment Type
% of losses
Avg. $ loss
% and MM$
100
50
0
Piping Tanks
React Tower Pump Drum Heat Unkno
Vesse Heater
Misc.
ors
s s/Com s
exch. wn
ls
s
% of losses
33
15
10
8
8
7
5
5
5
2
2
Avg. $ loss
76.9
61.9 151.8
86.9
68.1
38.9
69.6
60.6
34.6
82.4
16.3
Presentation Topics
General Introduction
The benefits of RBI
What RBI is
How RBI fits within existing plant systems
Implementing RBI
Some case studies
Managing Integrity
Plant
Integrity
Normally fixed.
Cannot be
neglected!
Management System
RBI project
procedures.
Data Integrity is
essential!
Data
Trained staff are
needed.
Plant Design
Operating &
Maintenance
Procedures
Data
analysis
Trained and Competent Staff
Model For An MI System
System
Documentation
Actions
(Do what you say)
(Say what you do)
TOP LEVEL
SYSTEM
DOCUMENTS
GENERAL
PROCEDURES:
(Document the actions)
ESTABLISH
SYSTEM
FILING SYSTEM:
PLANNING
RBI
INSPECT
WORK
INSTRUCTIONS
STANDARDS
Documentation/
Records
ASSESS THE
RESULTS
UPDATE/REVISE PLANS:
Asset Register
Design data
MI equipment
Inspection data
Operational data
Deficiency data
Inspection Plans
Repair information
Defect Assessments
Inspection due dates
The Integrated Plan
INSPECTION PLANNING
Codes and
Standards, RP's,
RAGAGEP
General "Good
House keeping
findings
Corporate Policy
Monitoring info.
Local Legislation
Inspection Planning activity
RBI analysis/
priotitization
Corporate Philosophy
Data analysis
The Inspection
Plan
i. Inspect
ii. Onsite assessment
iii. Detailed FfS if
needed
Anomalies
DM's
Database
Design
Construction
Operation
Inspection
06_Inspection Planning RBI role.vsd
Update database
Presentation Topics
General Introduction
The benefits of RBI
What RBI is
How RBI fits within existing plant systems
Implementing RBI
Some case studies
Typical RBI implementation
Define scope of RBI Study
Set up RBI team and train
Collect Data
Identify inventory groups (For consequences)
Identify Corrosion circuits
Perform Screening Analysis
Select high risk equipment items for Detailed Analysis
Perform detailed RBI analysis
Consequence data-Likelihood data
Run risk assessment & Review the results
Develop action criteria
Discuss Orbit proposed inspection guidelines and run final
Translate into an actual inspection plan with schedule
Implement plan-perform inspections
Update the model with latest inspections
Risk Target and Inspection Planning
Risk / Damage Factor (DF)
Risk / DF
Inspection
Target
Fairly Effective
Highly Effective
Predicted Risk
Increase
Time to next
inspection
Now
1st
Turnaround
Time
2nd
Turnaround
Implementation Timeline (Tight Deadlines)
Equipment Data Collection
Risk Analysis and Prioritization
Inspection Program Improvements
Weeks
Effort
2
4
6
8
Evergreen
Level of Effort
Critical Success Factors
Defined objectives and planning
A robust working process to assure
efficiency and quality
A good knowledge of the RBI theory
Trained competent staff
A good understanding of the tools to be used.
“Evergreening” the process.
Types of Analysis
A qualitative unit analysis (API 581 for Plant Units)
Which unit or platform should be the first based on risk
A system screening analysis
Which piping systems need to be included
A qualitative circuit based analysis
A qualitative equipment analysis
A semi-quantitative circuit based analysis
A semi-quantitative equipment based analysis
A fully quantitative equipment based analysis.
THE STEPWISE APPROACH
Will be of most benefit to
a large facility just
starting on the journey.
This course introduces
the semi-quantitative
approach but focuses on
the quantitative.
FfS/ CBA
of a few.
Quantitative analysis of
high risk items
Semi-quantitative analysis of the
included equipment
System Screening
- Determine which systems to be included
These steps may be
formal or informal.
Facility Screening
- Determine where to start the study
Vision for the RBI Services.vsd
Qualitative vs Quantitative - COST COMPARISON
Proportion of the time spent on activity:
Method
Est. total
hours
Activity
Accum.
Hours
"Value"
na
40
150
na
100
155
620
40
140
700
100
Hours on
Data Coll. Analysis Insp. plan insp plan
Initial Analysis
10%
40%
50%
155
Qual.
310
Quant
500
60%
Qual.
310
10%
Quant
200
15%
10%
30%
Second time around:
40%
50%
15%
70%
For repeat analyses the quantitative approach is far
more efficient.
The benefits multiply with time
ADVANTAGES OF THE QUANTITATIVE APPROACH
Not simply opinion based-easily reproducible
Accuracy-Time model
The results of qualitative and semi quantitative studies are
frozen in time. In reality the risk will change as the
equipment ages and as new data is available from
inspection. The quantitative method incorporates this.
What if studies, e.g.:
New campaigns in swing plants
If the study had been done qualitatively or semi
quantitatively, the effort would be much higher
i.e. It is more efficient and powerful to use an analytical
approach
Presentation Topics
General Introduction
The benefits of RBI
What RBI is
How RBI fits within existing plant systems
Implementing RBI
Some case studies
Issue:
EXAMPLE STUDY 1
Should we change our feed to a cheaper
but more corrosive alternative?
What does this mean for our risks and
inspection requirements?
Example Study 1
Maximum Tolerable Risk
Corrosive Conditions
Risk
Tolerable Risk
Unacceptable Risk
Standard
Operating
Conditions
Changed Inspection
Frequency
Inspection Interval
Financial Risk after Inspection
($ per year per equipment item)
Example Study 1
Financial Risk Exposure
$65,000
$55,000
$45,000
$46,846
$35,000
$25,000
$34,793
$26,421
$15,000
0.1%
0.5%
Corrosive in the feed
0.8%
Example Study 1
Cost of Inspection
Cost of Inspection
$350,000
$300,000
$250,000
$200,000
$150,000
$100,000
$50,000
$0
0.1%
0.5%
% Corrosive in Process Feed
0.8%
Example Study 1
The study gave the facility the information on:
The increased risk exposure
The increased cost of inspection
They compared this with the cost benefits of the cheaper
feed and made their decision.
Example Study 2
Current Inspection Costs
Current Maintenance Costs
Total Current Costs
RBI Inspection Costs
RBI Maintenance Costs
RBI Total
Total Savings
$1,400,000
$1,200,000
$1,000,000
$800,000
$600,000
$400,000
$200,000
$0
Unit 30
-$200,000
-$400,000
Unit 33
Unit 34
Unit 48
Unit 51
Example Study 2
Results for all Units
COST BENEFIT ANALYSIS
$3,000,000
$2,500,000
$2,000,000
$1,500,000
$1,000,000
$500,000
Current
RBI
Savings
$0
I
ion
t
c
e
nsp
in
Ma
ce
n
a
ten
ta
o
T
l
Example Study 3
Cost effective decision making
for an older refinery with a
limited inspection history.
Using The Financial Risk Values
Total Risk vs. Risk Rank
Refinery Process Unit, Top 10% Risk Items
$1,400,000
$1,200,000
Risk,$/yr
$1,000,000
Total Risk =
$11,500,000/year
$800,000
$600,000
$400,000
$200,000
$0
0
10
20
30
Risk Rank
40
50
Assess The Cost Benefits Of Inspection
Total R is k vs . R is k R ank
R e fine ry Proce s s Unit, Top 10% R is k Ite ms ,
Same Ite ms , Each with 1 M ore Ins pe ction
$ 1 ,2 0 0 ,0 0 0
$ 1 ,0 0 0 ,0 0 0
Total Risk = $4,100,000/yr,
Risk, $/yr
$ 8 0 0 ,0 0 0
Savings = $7,400,000/yr
$ 6 0 0 ,0 0 0
Cost = $250,000 (mostly piping,
approximately $5,000 avg. insp. cost)
$ 4 0 0 ,0 0 0
$ 2 0 0 ,0 0 0
$0
0
10
20
30
Ris k Rank
40
50
The Risk of the Lowest 10% Items
Total Risk vs. Risk Rank
Refinery Process Unit, Bottom 10% Risk Items
$1,600
$1,400
Total Risk = $12,000/yr
Risk, $/yr
$1,200
$1,000
$800
$600
$400
$200
$0
0
10
20
30
Risk Rank
40
50
The Inspection Benefits Here
To ta l R is k v s . R is k R ank
R e fine ry Proce s s Unit, B otto m 10% R is k Ite ms ,
S ame Ite ms , Each with 1 M ore Ins pe ction
$ 1 ,2 0 0
$ 1 ,0 0 0
Total Risk = $4,300/yr,
Risk, $/yr
$800
Savings = $7,700/yr
$600
Cost = $250,000 (mostly piping,
approximately $5,000 avg. insp. cost)
$400
$200
$0
0
10
20
30
Ris k R ank
40
50
END