Abstract
There have been many instances of Corrosion Under Insulation (CUI) in the Gulf of Mexico (GoM) and worldwide. On most sites, CUI tends to be a medium to long-term phenomenon with the risk of CUI increasing significantly after a 5 to 10 year service, but can occur well before this. A lack of appreciation of the impact on the type of insulation used, the proper application and maintenance /repair, combined with regular testing firewater deluge systems, water leaking from poor connections in adjacent pipework, severity of the prevailing weather conditions, or simply due to the general environment like offshore, can often lead to CUI failures earlier than could otherwise have been envisioned. In order to reduce the likelihood of CUI under traditional typical types of insulation, proper insulative coatings can be used instead where applicable.
The objective of this study was to evaluate five insulative coating systems applied to several test panels to determine which system(s) are most suitable for GoM offshore applications. These systems were applied according to manufacturers’ procedures, on similar panels, applied by the same applicator, on the same day. The systems were evaluated by a third party independent laboratory to determine their performance. The lab evaluation program included the following tests on various selected insulating coatings; temperature reduction tests, corrosion mitigation tests, impact and adhesion test, moisture permeability, ease of application, ability to inspect metal substrate under coating and thermal cycle cracking resistance tests. The testing procedures and test results are discussed in this paper.
Introduction
Offshore Oil & Gas Production facilities in the Gulf of Mexico have hot pipes and vessels which need thermal insulation and corrosion protection. The traditional method is to apply protective coatings on steels, overwrapped with a thick layer of insulation material, (e.g. mineral wool, fiberglass, etc.) and then sealed with metal jacketing. However, severe corrosion under insulation (CUI) issues have been discovered after some year service. The CUI has become a widespread industry concern. One of the issues is not able to inspect the corrosion easily without removing the metal jacketing and insulation materials. Recently, a new class of insulative coating system became available as an alternative to the traditional thermal insulation system. The new insulative coating system uses a primer and overcoat with the waterborne acrylic coating filled with hollow glass microspheres or Silica Aerogel?.
