Can you believe it! I have finally received a proof copy of Addendum 1 to the 11th Edition of API-650! Yes, Addendum 1 will be finally released in the next 4 to 6 weeks. I will be working my way through this addendum to see what changes have been made. It looks like Appendix E has been corrected. Also, duplex stainless, aluminum, and mixed material appendices have been added. There is a change in Appendix V on how loadings are calculated combined for wind and vacuum. It appears there are some minimum thicknesses that are changing slightly. There is also a change in the determination of the maximum spacing of rafters (both inner and outer). The calculations for anchor bolts has changed as well. Appendix F has revised formulas for calculating the internal pressure. Appendix S has specific requirements for the use of "seamed" stainless steel.
This is just a quick overview of what I see in my first glance through the addendum. I will be posting more on the specific changes as I begin a more complete reading of the addendum. Be sure to come back for more information.