Experience that Delivers

ICorr CED Day

Subsea Thermal Insulation – The Need For Training

1Experience that Delivers

Presentation Overview

• Introduction

• Corrosion under insulation

• Flow assurance

• Insulation– Dry– Wet

• International Registered Marine Insulation Inspection course

2Experience that Delivers

Introduction

• Corrosion under insulation has been a problem for many years• The energy crisis in 1970 meant insulation was used more widely• Deeper hotter more complex field meant insulation was required to produce

in more demanding environments• The understanding of hydrate and wax control meant the use of insulation

for flow assurance particularly subsea (marine)• All these have led to more problems with insulations

– Corrosion under insulation– Insulation and coating failure– CP shielding issues

• What have we done to combat this and in particular training

3Experience that Delivers

Examples of problems

Damage to cladding – poor application (absence of mastic

sealant at joints)

Poor inspections (open cladding terminations allowing free water

ingress

Poor maintenance / neglect

4Experience that Delivers

Corrosion Under insulation CUI (1)

• CUI is a medium to long-term problem– Lag before problems occur - after 5 to 10 year “holiday period”– Routine inspection and maintenance sometimes not fit for purpose– Resulting failures can have serious H, S & E implications

• Thermal insulation refurbishment projects high cost , subsea involves expensive intervention

5Experience that Delivers

Corrosion Under insulation (2)

• CUI is difficult to detect

• Onshore problems there is a need to remove insulation

• Subsea difficult inspection and repair by Diver– Removal could create more problems than it solves

• Deepwater only accessible by ROV– Very expensive intervention

• For marine insulation it is important to apply properly– There is need for effective inspection during application in plant and in the

field

6Experience that Delivers

Field Joint Attack

• Corrosion occurs due to ingress of water

• Due to poor application joint seal

• High temp application make it worse

• Carbon steel corrosion threat

• Concentration of Chlorides

• CRA possibility of pitting attack

• Often no anti corrosion coat applied

• High risk of corrosion

7Experience that Delivers

Why is it so aggressive?

• Normally associated with ingress of water

• Some insulating material can contain measurable amounts of aggressive ions (eg Cl-)

• Highly polluted industrial environments can result in water pH of 4 to 5

• Coastal locations will usually result in significant Cl- content

• Local microclimates can also represent a high risk, eg:•Cooling towers•Emissions of acidic vapours•Frequent testing of water deluge systems•Enthusiastic water jetting activities

8Experience that Delivers

Carbon and Low Alloys Steel Issues

• Manifest as localised wastage at areas in contact with water• All insulated equipment operating between –5oC and 200oC at risk

•Highest corrosion rates found between 60oC and 120oC•1.5 mm/y typical corrosion rate; but 3 mm/y has been reported

• For operating temperatures below ambient the differential vapour pressure across the insulation draws water towards steel substrate

•Corrosion rate at sub zero temperatures low, but if ingress occurs•Severe corrosion can occur• During transition to ambient temperature or at protrusions through insulation

• Subsea insulation used to keep temperature high – High corrosion at holidays

• Suitable Anti corrosion coating should be used under insulation

9Experience that Delivers

Flow assurance issues

• Marine Insulation used for flow assurance– Hydrate formation– Wax formation

• Failure of the system can lead to very high costs– Loss of production– Subsea intervention

10Experience that Delivers

• Insulation problems are commonly “self inflicted”– Due to general lack of awareness – routine plant maintenance and operational activities by many site personnel need to be defined

• Responsibilities for the integrity of the thermal insulation system need to be clearly assigned– A full risk assessment for inspection and maintenance schedule

– Routine inspections of insulated plant and equipment should be carried out

– A strict quality control regime should be enforced during all insulation maintenance  and inspection activities

Why does it occur?

11Experience that Delivers

Mitigations - Specifications

• Prescriptive to ensure that only quality materials and should be followed

• Specifications to cover Client’s expectations wrt materials and design details• For new build, the spec. should be made available to process equipment designer in time to influence design/layouts• Contractor should provide certificate of conformance for materials used• Non conformances should be approved• Effective inspection

•CUI has been reported under the entire range of commonly used thermal insulating materials

12Experience that Delivers

Dry Insulation

• Dry insulation has been used for many years• Used to keep fluid hot or cold• Reduce power requirement• Economics• Systems were mainly based on rock wool within a casing• More recently coating type insulation products have been developed

13Experience that Delivers

Types of dry insulation

14Experience that Delivers

Dry Insulation

• Application over anti corrosion coating• Application as per specification• Materials should conform to specifications• Non conformances should be approved• If required the insulation should be covered and sealed effectively• Ensure no ingress of water• Monitoring program suitable methods

– Thermography– Water detection

• Inspection program – stripping and visual inspection• High risk areas - Risk based inspection

15Experience that Delivers

• Initial pipeline coating for offshore FBE

Marine (wet) Insulation

16Experience that Delivers

• Next step was to encapsulate foam in Neoprene• Problem  were degassing of foam during curing of neoprene

History

• First insulation was neoprene / EPDM– 1980’s

– Problems EPDM was conductive so negative effects on CP

– Poor insulation properties

17Experience that Delivers

• Further improvement – Syntactic PU 

• Encapsulated in PU (polyurethane) 

Next advances

18Experience that Delivers

• POLYPROPYLENE (PP)

•PP Insulation:• Similar properties but • Cost effective insulation

Next giant step

19Experience that Delivers

Subsea Production System (SPS)

• Typical manifold

20Experience that Delivers

PUPhenolic Epoxy

Syntactic Silicone

SPS Insulation Systems

21Experience that Delivers

• Difficult to inspect

• Limited time for FJC inspection during pipe lay

• High cost of repair

• Need to inspect correctly when applied

• Failures are seen and are costly

• Industry lack of insulation marine inspection training

Wet (marine) Insulation

22Experience that Delivers

Marine Insulation -The Future

• Different system understanding of various system limited

• Knowledge held by a few individuals

• Dissemination of information important

• Deeper the water the more important application and inspection becomes

• IRMII ‘industry first’ course on Subsea Insulation 

23Experience that Delivers

Marine Insulation Inspection Course

Course Details

International Registered 

Marine Insulation Inspector(IRMII)

Accredited by the International Institute of Marine Surveying

www.wgim/irmii

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24Experience that Delivers

• The course is being written by industry known experts in insulation / Coatings

• 100 years + experience

• Peer reviewed by steering committee comprising

– Other experts from industry and academia

• Course and Examination approved via the International Institute of Marine Surveying

Course Development

25Experience that Delivers

Details of course

• 5 day course (Pipeline sand separate SPS Courses)– 4 ½ days taught

– ½ day examination (including oral)

• Independent examination– Registration via Institute of Marine Surveying

• 5 year re‐certification course will be available

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26Experience that Delivers

Course Content & Outline

1. Refresher on basic corrosion and coatings.

2. Alternatives to wet insulation. Day 1

3. Purpose to wet or dry insulation. Day 1

4. Wet or dry insulation areas. Day 1

5. Insulation types. Day 2

6. Application methods. Day 3

7. Application at mill or site. Day 4

8. Process Inspection and testing. Day 4 & 5

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27Experience that Delivers

• Corrosion under insulation is a big issue

• It can be controlled– Need anti corrosion coating under insulation

• However inspection and monitoring important– Specifications should be followed

– Procedures should be followed

• Dry insulation inspection can be carried out– Involves removal of insulation required

– Costly but can be done

• Monitoring can be carried out– Correct methods should be deployed

Summary

28Experience that Delivers

Summary

• Marine insulation more difficult to inspect maintain repair during operations

• Operation inspection and monitoring almost impossible 

• Repairs very expensive

• Inspection during application critical

• New course developed for inspector accreditation

• First course has been  ‐ held more in the future

• Info www.wgim/irmii