Recommended Practice 583

Corrosion Under Insulation and Fireproofing

Covers the design, maintenance, inspection, and mitigation practices to address external corrosion under insulation (CUI) and corrosion under fireproofing (CUF). The document discusses the external corrosion of carbon and low alloy steels under insulation and fireproofing, and external chloride stress corrosion cracking (ECSCC) of austenitic and duplex stainless steels under insulation. The document does not cover atmospheric corrosion or corrosion at uninsulated pipe supports, but does discuss corrosion at insulated pipe supports.

The purpose of this RP is to:

• help owner/users understand the complexity of the many CUI/CUF issues,
• provide owner/users with understanding the advantages and limitations of the various NDE methods used to identify CUI and CUF damage,
• provide owner/users with an approach to risk assessment (i.e. likelihood of failure, and consequence of failure) for CUI and CUF damage, and
• provide owner/users guidance on how to design, install, and maintain insulation systems to avoid CUI and CUF damage.

1st Edition | May 2014

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