![Page 1: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/1.jpg)
Critical Spares Who Needs Them and When?
Australian Gas Turbines Conference
30th October 2013
![Page 2: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/2.jpg)
Agenda
• Definition
• Strategy
• Types of spares
• Factors to consider
• Equipment / spares management
• Determination of criticality
• Spare levels
• Spares Identification
2
![Page 3: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/3.jpg)
Critical Spares Who Needs Them and When?
• To answer the first part is easy
Everyone who operates a system that has to perform when
required will have critical spares
• The second half, now that’s the difficult part!
3
![Page 4: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/4.jpg)
But First - Definition
• All parts of a system can be
critical unless redundancy is built
into the design
• One definition is :
“A part that if not available when
required results in the loss of
production, power generation or
endangers peoples lives or
seriously damages the
environment”
4
![Page 5: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/5.jpg)
Two Extreme Maintenance Strategies
Conservative
Run till it drops
Most
companies fall
somewhere in
between
5
![Page 6: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/6.jpg)
Strategy Affected by
• Contracts in place
• Type of equipment
• Fuels used
• Maintenance Strategy
• Skills availability
• Spares availability
• Geographic location
• Age of plant
Not static – review ever 2 years
6
![Page 7: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/7.jpg)
Types of Maintenance and Repair
• Breakdown
• Routine
• Planned
• Preventative
• Predictive
• Corrective
• Design Out/Elimination Maintenance
• Total Production Maintenance
• Contracted Out Maintenance
• Cannibalisation7
![Page 8: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/8.jpg)
Types of Spare Parts
Commissioning
Spare parts
Initial Spare
parts (1st year)
Operating Spare parts (2 year rolling)
Me
an
Fa
ilure
Ra
te h
(t)
Operating Time
Capital Insurance and Critical
Outage
8
![Page 9: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/9.jpg)
Where do you Start – Original Procurement and
Build
• Due Diligence
• Fleet data
• Operating history
• Number of similar units in fleet
• Availability required
• Storage facilities
9
![Page 10: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/10.jpg)
Other Factors to Consider
• Assessment of the whole system
• Identify redundancy
• Cost of holding spares – 20 to 40 %
of purchase price per year
• Maintenance of the spare part
• Change of operation
10
![Page 11: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/11.jpg)
Equipment /Spares Management
• Implement full Reliability-Centered Maintenance (RCM) to high risk components– Covered in standard SAE JA1011, Evaluation Criteria for RCM
Processes
• Identify all failure modes for each component
• Develop detailed monitoring & inspection test plans specific to each component
• Identifying equipment risk through reliability based inspection is the first step toward this
11
![Page 12: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/12.jpg)
Determination Criticality
• Review history of failed components for the individual
plant and across the fleet
• Review OEM Manuals
• Talk to the Plant Engineers
• Check PID
• Review supply chain
• Component availability
• Risk assessment for mechanical and electrical systems
12
![Page 13: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/13.jpg)
Likelihood Questions
• Age of component?
• Are there damage processes and what is the likelihood?
• Rapid unpredictable failure likely?
• How good is the inspection?
• How good is the maintenance?
• How well is it operated?
13
![Page 14: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/14.jpg)
Consequence Questions
• Extent of damage to other equipment?
• Part availability?
• Length of repair time?
• Safety hazard to personnel?
• Potential loss of production ?
• Cost to repair or replace?
• Potential damage to environment?
14
![Page 15: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/15.jpg)
Total Risk
• Total Risk is defined as the likelihood versus
consequence
• The risk profile can then be generated as a plot of the
risk for each piece of equipment or area
15
![Page 16: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/16.jpg)
Distribution of Risk for a Frame Unit
16
![Page 17: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/17.jpg)
Distribution of Risk for an Aero-derivative Unit
17
![Page 18: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/18.jpg)
Likelihood versus Consequences
• Frame Unit - GE Frame 9
• Aero-derivative Unit - GE
LMS100
18
![Page 19: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/19.jpg)
Maintenance / Critical Spares – Reliability – Failure
Rates
• Assume a constant failure rate
• With a constant failure rate the reliability is based on the exponential
distribution –
� � � exp��
• Failure rate (λ) reciprocal is the mean time between failure (MTBF)
� �� �1
�
• The survival probability time is given by using
tr � 1/� x ln(1/R(tr))
19
![Page 20: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/20.jpg)
Maintenance Spares – Levels
• To determine maximum stock level required is given by
= λ +K√λ
λ = average consumption/failure rate per year
K = a factor depending on service level required
• Minimum stock is given by
= K√λ
• Should be reviewed - approximately every 2 years
20
![Page 21: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/21.jpg)
Example Effect of Various MTBF on Spares
Service Level/
Reliability
75% 90% 95% 99%
K Factor 0.7 1.3 1.7 2.3
MTBF λ +K√� λ +K√� λ +K√� λ +K√�
0.75 month 19 22 23 26
1.5 months 12 13 15 16
2 months 8 10 11 12
3 months 6 7 8 9
1 year 2 3 3 4
10 years 1 1 1 1
100 years 1 1 1 1
21
![Page 22: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/22.jpg)
Spare Parts Identification
• Depending on the model, year of manufacture and any
service bulletins applicable the correct part number may
have changed. The OEM spare parts manual details how
the system is structured
• The OEM manual structure is normally based on flange
to flange
TURB9EA2##/BA05A/0512 – 112E1407G016
Gas Turbine
Type/Model
Unit Number
Section Number Subsection Number
Article Number
22
![Page 23: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/23.jpg)
Outside the Gas Turbine/ Balance of Plant
• The identification system relays on tag numbers which
are referred to on the process line diagrams
• Reference then has to be made to the manufacturers
operating manual for each component
23
![Page 24: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/24.jpg)
Outage Spares –
• Planned Maintenance - regular inspection of the
combustion and hot gas path parts of the gas
turbine
24
Frame Hours Starts
CI 12000 450
HGP 24000 900-1200
Major
Inspection
48000 2400
Aero Derivative Hours
Inspection and Blade
wash
2000 -4000
Annual Inspection 8000
Hot Section Overhaul 25000
Full Overhaul 50000
![Page 25: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/25.jpg)
Typical A/B Inspection Consumable Packages
Qty Description Part # Delivery (weeks)
24 Hexagon Socket Head
bolt
HTMA200312P0013 16
1 Packet Welding
Electrode
HZN 403494P0250 6
1 Welding Wire HTCZ401077P0003 9
2 Packet of shims GMD5246056R001 12
2 Gasket GMD0924574P0001 16
• 28 line items
• 131 components
25
![Page 26: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/26.jpg)
C Inspection Consumable Package
• Broken down into six parts :
– C inspection package
– C inspection bolting package
– C inspection compressor spares
– C inspection consumables
– C inspection MTS consumables
– Noble parts assembly material
• Total number of line items 708
• Longest lead time 34 weeks
26
![Page 27: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/27.jpg)
Critical Spares and Integrity Management
Equipment Integrity
Management
ActivitiesProcurement
Operation
Engineering
Inspection
Maintenance
ProcessesPolicies
Standards
Record practices
Procedures
Control
Disciplines Involved Everybody
OrganisationTraining
Competencies
Structure
People
Succession
27
![Page 28: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/28.jpg)
Main Benefit of Critical Spares Review
Cost of
unplanned
outage or
failure
Cost of
undertaking
review and
holding
necessary
parts
28
![Page 29: Stephen Rowbotham, Quest Integrity: Critical spares: Who needs them and why?](https://reader034.vdocuments.mx/reader034/viewer/2022042700/55615a46d8b42a654b8b4658/html5/thumbnails/29.jpg)
Any Questions?
Remember look after your spares!
29