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Fault-tree analysis is a deductive technique that focuses on a particular failure mode, and provides a method for determining and weight causes of that failure.
It uses logical operators, principally the OR and AND gates.
Failure Mode
Operators
Failure Causes
Basic Events
with knowledge Reliability
From KAPUR K.C. PECHT M. Reliability Engineering. Wiley. P.126
Calculate total cost of maintenance task, including:
- Cost of task.
- Cost of failure in task.
- Cost of materials.
- Cost of labor-hour.
...
Reassessment of reliability
ALARP Process
Review maintenance program and apply mitigation measures to reduce risk to tolerable region
Define Failure Modes
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Make a business case to check risk reduction vs cost maintenance program and mitigation measures.
Optimise the cost of maintenance program
Acceptable region
ISO 14224:2016 Annex B provides criterias and list of accepted failures modes
Based in NS Z-013 Ed 3. Risk and emergency preparadness assessment. A.5 As low as reasonably practicable (ALARP) evaluations
To include a criteria to assess criticality of failures modes.
Just study the failures modes with criticality enough.
Example of criticality matrix from ISO 17776:2000 Annex A.
ISO 14224:2016 Petroleum, petrochemical and natural gas industries - Collection and exchange of reliability and maintenance data for equipment
Reassessment of Consequences
2. Apply a taxonomic classification of equipment
1. Define a clear boundary description
3. Data should include equipment unit data, failure data and maintenance data.
ISO 14224:2016
8.2. Taxonomy
ISO 14224:2016.
8.1. Boundary description
ISO 14224:2016
9.3.2. Logical structure
Figure 3 - Taxonomy classification with taxonomic levels
Figure 2 - Example of boundary diagram
Figure 5 - Logical data structure (example)
- Insurances
- Extended Warranties
- Maintenance Services
- Lease Contracts
Event-tree analysis is an inductive logic method for identifying the various sequences that can generate from a single initiating event.
Spare Parts System:
1. Needs of spare parts.
2. Location of spare parts.
3. Flow of spare parts.
4. Optimum stock of spare parts (by HPP).
5. Optimum order of spare parts.
6. Guarantees management.
7. Obsolencence management.
Consequences ($)
Failure Mode
From STAPELBERG R.F. Handbook of Reliability, Availability, Maintainability and Safety in Engineering Design. Springer. P.562.
Sequences of effects
Work Order flow management.
Work Order prioritization.
AlterEvo Ltd.
www.alterevo.es
ROI
IRR
NPV
PayBack