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In Service Inspections Avoiding Disasters!
David Lake
RBI’s are Important
• Cost effective method of preventing failure?
• Method of meeting statutory obligations
• Duty of Care
• Prevention of DISASTER?
• ALL stages of RBI planning and implementation must be done WELL by PEOPLE!
Explosion de gas en Reynosa, Tamaulipas
Disasters are infrequent BUT!
• Varanus Island WA • Corrosion -was it visible –under coating –
Inspected?
• Estimated to cost the WA economy $billions
• +
• Alcoa sues Apache Energy over gas pipeline blast ........... Consequences...
The RBI Process
1. Analysis
• Process / product initiated risk
• Equipment risk
• Environmental condition induced risk
• People / Human error
Then assess the likelihood – severity --- etc to categorise the risk into high/medium/ low
The RBI Process
2. Inspection and test plan
Cost versus Risk “Appetite” now key elements
• Process parameter monitoring
• Visual inspection
• NDT is most often used where the potential risk has been assessed as medium or high
• Results are “plugged” into the model
• Iterative process
How much can you Inspect?
• Coverage vs. Cost
• How do we inspect cost effectively where we cant see?
• Permanent quick recording / reporting important to measure “change” accurately
RBI NDT Inspections
• Only undertaken where assessed risk is med/high ?
• Most likely a statistical sampling process is used, therefore results MUST BE RIGHT!
• NDT equipment is very capable and available
Cost vs. Value? Global Inspections –
Visual (VT cert?)
Asset Management
Global Inspections – Acoustic Emission
Sensors
Located AE
AE Signal A
mplit
ude
Threshold
Duration
Rise time Decay time
Event Counts = 7
Time
AE Testing – Tank Set Up
Sensors
Tank floor results
Global inspection techniques
• Thermography
• Long wave Ultrasonics
CUI • Pulsed eddy current
• Radiography
• MFL
• And others
Risk?
• The equipment is NOT “automatic”
• Even the simple UT thickness check can give erroneous results in the wrong hands
• The NDT technician is critical, to getting reliable accurate results
Scanning
• A-Scan
• S-Scan
• C-Scan
• B-Scan
• D-Scan
• Advanced Views (polar/merged/etc)
Phased Array Ultrasonics “quick?”
Consequences
• No defect indications? Where they exist
• False sense of security – miss one miss all?
• Failure potential remains BUT.......
• Indications found where they don’t exist $$$
• Sizing wrong or rate of change ......
What certification is best?
• ISO9712 + NATA? (ISO 17025)
• AINDT trained/certified to Australian standards
• PCN (/CSWIP) and other ISO 9712 compliant schemes
Advanced skills
Difficult
The Future
• The Risk In Risk Management, will be the PEOPLE!
• Select best methods
• Get the greatest coverage for your $
• Get accurate information for a statistical analysis approach
Thankyou for Listening
Questions?