1. AB CD Lloyd’s Register EMEA Risk Based Approach to Managing Corrosion Under Insulation Mike Adams Technical Delivery Manager

2. AB CD Lloyd’s Register EMEA Risk Based Approach to Managing CUI An Integrity Management Strategy needs to establish three things- When to Inspect Where and how to inspect Mitigating actions. This presentation outlines a risk based approach, being developed within Lloyds Register Integrity Services.

3. AB CD Lloyd’s Register EMEA The CUI Chain Breakdown of Weather Shield Water Ingress Coating Breakdown Corrosion Failure

4. AB CD Lloyd’s Register EMEA Factors Influencing CUI: Environment. There is a good correlation between the exposure of a component and CUI. Factors to be considered include:- Nature of the water. (Sea/Rain/Firewater) Exposure to the elements. Deluge testing. Condensation. Environment is a major factor. Breakdown of Weather Shield Water Ingress Coating Breakdown Corrosion Failure

5. AB CD Lloyd’s Register EMEA Factors Influencing CUI: Insulation System. Although much work has been done on improving insulation systems and weather shields this has limited effect on reducing the CUI threat. Reasons for this include:- Specification of low cost systems. Inadequate installation. In service Damage. Exposure to deluge. Consequently the insulation system in offshore installations is not considered a major factor. Breakdown of Weather Shield Water Ingress Coating Breakdown Corrosion Failure

6. AB CD Lloyd’s Register EMEA Factors Influencing CUI: Coating The integrity of the coating system is considered to be the most important factor in preventing CUI. In all cases a coating system should be applied that is capable of withstanding immersion at the normal operating temperature of the component. Inadequate coating systems, or inadequate application lie at the root of many CUI failures. Breakdown of Weather Shield Water Ingress Coating Breakdown Corrosion Failure

7. AB CD Lloyd’s Register EMEA Factors Influencing CUI : Temperature Temperature is the third major factor. High temperatures degrade coatings and increase consequent corrosion rates. Subsidiary factors are:- –Heat Leaks –Thermal Cycling –Heat Tracing There are considered to be safe ranges, less than -5C or greater than 240C, within which CUI is not considered a threat. Breakdown of Weather Shield Water Ingress Coating Breakdown Corrosion Failure

8. AB CD Lloyd’s Register EMEA Other Factors Influencing CUI Component Size Small bore pipe has thinner wall and is therefore more likely to fail if CUI goes undetected. Internal Corrosion CUI must never be considered in isolation from internal corrosion. Breakdown of Weather Shield Water Ingress Coating Breakdown Corrosion Failure

9. AB CD Lloyd’s Register EMEA Risk Based Approach Probability of failure. Effect on Probability Score DecreasesNo EffectIncreases Temperature º C (taking into account heat sinks) 240 Score -3-4 to 30 Score 130-120 Score 2 Cyclic or intermittent Operation Into lower threat range Score 0Into higher threat range. Score 2 Heat Tracing None Score 0Yes Score 2 Environment Dry Score -1Sheltered or t<ambient Score 0Deluge or spray Score 1 Component Size Greater than 6” Score 04 to 6” Score 1Less than 4” Score 2 Insulation System Integrity (Coating plus Insulation) High Score -1Low Score 2 Total of Scores

10. AB CD Lloyd’s Register EMEA Risk Based Approach: Risk Factor Assessment of Hazard would be carried out in accordance with normal practice and then applied to threat to obtain risk HazardThreat HighMediumLow High Medium HighMedium LowMediumLow The score is then converted to a high, medium or low threat Total Score 0 to 1 2 to 3>3 LowMediumHigh

11. AB CD Lloyd’s Register EMEA Risk Based Approach: Interval It is intended to base the interval upon coating life and consequent corrosion rate. However more work is required to establish realistic values for these. High:- General Visual Examination (GVI) Annually Non Intrusive Inspection (NII) and selected insulation removal every 3 years Refurbish on onset of CUI Medium:- GVI Every 3 Years NII plus selected insulation removal every 6 Years Refurbish on onset of CUI Low:- GVI Every 3 years. NII plus selected insulation removal on signs of insulation damage or water ingress then reassess risk.

12. AB CD Lloyd’s Register EMEA Risk Based Approach: Inspection Extent. CUI is a predictable form of attack, therefore a focussed approach can be used to derive a practical workscope. Initial screening for damaged insulation and or water ingress GVI possibly supported by Thermography 100% Check all wet areas because isolated coating break down is not predictable. Non intrusive Methods can be used where corrosion rates are likely to be low. Insulation must be removed where corrosion rates are likely to be high because NII will not detect the initial stages of coating breakdown. Be prepared to increase the extent if CUI is detected.

13. AB CD Lloyd’s Register EMEA Risk Based Approach: Managing Campaigns. The previous approach assumes regular activity: In the case of a retrospective campaign:- Establish a register of insulated components. Carry out an initial visual examination to confirm insulation status. Use the risk assessment to prioritise work but bear in mind that access requirements may be the main driver.

14. AB CD Lloyd’s Register EMEA Risk Based Approach: Mitigation Challenge Need for Insulation Challenge Need for Heat Tracing Treat Coatings as seriously as you would welds. Minimise treat of water ingress. Minimise Water retention: Eliminate traps, use closed cell insulation and provide drain points.