Til innholdet

Design for subsea structures

Shaping your structures together with our engineers, you may expect in-depth understanding of subsea operations and their design consequences.

Our team of engineers colloborate to provide cathodic protection engineering to ensure full corrosion control throughout the entire life of the structure.

Scope of work

Design work undertaken by Cathwell would typically include the following:

  • Review of the corrosion protection philosophy and structure exposure.
  • Calculate the cathodic protection requirement.
  • Propose anode types and positions.
  • Document the work.
  • Indicate material price (and if requested, offer for the supply of anodes).

You may also read about

What is corrosion?

Engineer undertaking design on computers
Front-end engineering and design (FEED) will benefit from early project involvement

Any documentation submitted by Cathwell will demonstrate the adequacy of the design, and will be sufficiently well organised and detailed to allow for third party verification, if requested.

Cathodic protection material (sacrificial anodes) can be offered by Cathwell in line with the result of the engineering work, if requested. See the full range of sacrificial anodes for offshore application.

Design codes

Cathodic protection of subsea structures are designed based on established codes, but also a good share of experience. If not otherwise requested, one of the following specificiations will generally be used for facilitating the execution of conceptual and detailed cathodic protection design, as well as for specification of manufacture of aluminium or zinc based galvanic anodes:

DNV-RP-B401: Recommended practice for design, manufacture and installation of sacrificial anodes, primarily intended for CP of permanently installed offshore structures associated with the production of oil and gas.

NORSOK M-503: Cathodic protection requirements for cathodic protection design of submerged installations, pipelines, internally in vessels and tanks, and sea water containing compartments.

You may also read

Different forms of corrosion

Design input request

  • To undertake detail design of cathodic protection of subsea structures, the following input would generally be requested:
  • Drawings of the structure(s) to be cathodically protected, preferably in dwg format.
  • Information about steel structures adjacent to the “main scope structure(s)”.
  • Type and extent of surface treatment and coating standard/category applied.
  • Information about possible mechanical exposure that may lead to accelerated coating breakdown.
  • Requested design lifetime of the cathodic protection.
  • Cathodic protection specification to be applied, if any (e.g. NORSOK M-503 or DNV-RP-B401).

You may direct your input and request here.

Cathodic protection explained

Principles of cathodic protection. How to stop corrosion

Learn more

Aluminium vs. zinc anodes

Which to use; aluminium or zinc anodes in salt water environments?

Learn more

Galvanic series

Galvanic series determines the electro potential and nobility of metals and metal alloys.

Learn more
See more articles