Changes to API 650, Twelfth Edition - Welded Tanks for Oil Storage

By Vincent A. Carucci

Three addenda were issued for the Eleventh Edition of API 650 in 2008, 2009, and 2011 since it was first published in June 2007. The Twelfth Edition of API 650 was published in March 2013. The following highlights several of the changes that were made and is not all inclusive. Refer to API 650 for complete information. One general comment is that sections that were previously called “Appendix” are now called “Annex.”

Section 2 – Normative References

ASCE Standard 7-10, “Minimum Design Loads for Buildings and Other structures” has been added in addition to ASCE Standard 7-05 of the same title. Both standards are referenced later as alternatives that may be used to determine the appropriate design wind speed to use for tank design.

Section 3 – Terms and Definitions

Section 4 – Materials

Section 5 – Design

Section 7 – Erection

Section 8 – Methods of Examining Joints

Section title changed to above from prior “Methods of Inspecting Joints.” The same word change was made in relevant paragraphs within this section.

Annex AL – Aluminum Storage Tanks

Annex C – External Floating Roofs

Annex D – Inquiries and Suggestions for Change

Annex E – Seismic Design of Storage Tanks

Annex F – Design of Tanks for Small Internal Pressures

Annex G – Structurally-Supported Aluminum Dome Roofs

Annex J – Shop Assembled Storage Tanks

Annex S – Austenitic Stainless Steel Storage Tanks

Annex SC – Stainless and Carbon Steel Mixed Materials Storage Tanks

Annex V – Design of Storage Tanks for External Premiere

Annex X – Duplex Stainless Steel Storage Tanks