Vapor Corrosion Inhibitors for Storage Tanks


API Technical Report 655, First Edition, April 2021

API TR 655 VCIs for Storage Tanks

Purpose of API TR 655

API TR 655 has been published by the American Petroleum Institute (API) to provide information detailing the use of Vapor Corrosion Inhibitors (VCIs) for protection of the soil-side of tank bottoms from corrosion.


VCI Chemistry

VCIs are chemistries which use several different chemical mechanisms to reduce the corrosion rates of metal surfaces in enclosed environments, based on the chemistry composition and delivery method. Click here for more information about VCIs.


Guidance for VCI Use

This new technical report (TR) provides information and guidance on the use of VCIs for corrosion protection of the Soil Side Bottom (SSB) of Aboveground Storage Tanks(ASTs). Application details are provided for tanks which are which are either in or out of service, with a variety of different tank civil foundation designs.


VCI and CP Compatibility

While DOT – PHMSA does not currently permit the use of VCI without without Cathodic Protection (CP) for “break-out” tanks, most non-regulated tanks may use VCI without an active CP system, or for tanks where use of CP is limited or not applicable as defined by API 651. VCIs serve as an alternate corrosion protection system in those scenarios. 


VCIs in Company Specifications

Have you updated your company specifications to include VCIs for Tank Bottom Protection? If you haven’t, please contact us and our team of experts can help!


Purchase API TR 655

If you are interested in purchasing API TR 655, visit the API Publications Store.  It is also available from other standards document providers.


Have You Updated Your Company Specifications to Include VCIs for Tank Bottom Protection?                           

If you haven’t, please allow our team of experts to help.  Click Here to Get in Touch