The new 2011 Edition of AWWA D100 has just be released for public distribution and is available from Document Center Inc. AWWA D100, titled “AWWA Standard for Welded Carbon Steel Tanks for Water Storage,” provides minimum requirements for the design, construction, inspection and testing of new welded carbon steel tanks for the storage of water at atmospheric pressure. The new revision replaces the previous 2005 Edition with the 2007 Errata.
This standard is based on the allowable-stress design method, with the exception of reinforced concrete foundations. Additionally, all tanks storing potable water are expected to have roofs. Tanks storing nonpotable water may be constructed without roofs.
This edition of the standard includes numerous corrections, updates, and new material to clarify some of the existing requirements.
1. Section 1 was revised to show the latest edition of references.
2. Section 3 was revised to match the wind exposure definitions of ASCE 7-05. The requirement that dome roofs constructed of aluminum shall comply with ANSI/AWWA D108 was added. The stress evaluation procedure of ASME SECTION VIII, DIV. 2 was added as an acceptable method for evaluating local shell or pedestal stress for anchor chair designs that are based on a detailed analysis.
3. Section 10 was revised to include an erection tolerance multiplier for elements of ground-supported flat-bottom tanks that are designed in accordance with Sec. 3.4.4 and subject to small compressive stresses.
4. Section 11 was revised to make leak testing of the bottom-to-shell joint mandatory for all ground-supported flat-bottom tanks.
5. Section 13 was revised to not require a site response analysis for short-period structure located on liquefiable soils. The site-specific procedure of FEMA 450 was deleted, and the site-specific procedures of ASCE 7-05 were referenced. The scaling requirement for the alternate procedures was clarified.
6. Section 14 was revised to clarify the DMT-thickness requirement for Category 1 and Category 2 materials when impacts are provided.
7. Section 15, covering dome roofs constructed of aluminum, was deleted and replaced with a reference to ANSI/AWWA D108.
ANSI/AWWA D100-11 does not cover all details of design and construction because of the large variety of sizes and shapes of tanks. Details that are not addressed shall be designed and constructed to be adequate and as safe as those that would otherwise be provided under this standard. And this standard does not cover concrete–steel composite tank construction.
This standard, and all AWWA standards, are available from Document Center Inc. at our website, www.document-center.com. Or contact us by phone (650-591-7600), fax (650-591-7617) or email (info@document-center.com). We’re happy to assist you with your standards requirements and questions.