UPDATE to Use of Current ASME Code (HM-261)

7/1/16 – On 4/29/16, the DOT has published a rule (view it here) that finally abandons the requirement that tanks be designed to the 1998 Edition of the ASME Code. The published rule was somewhat unclear whether it is truly the DOT’s intent to continue limiting allowable stress to UTS/4. Based on letters from various commenters, the DOT sent out letters of interpretation clarifying that it IS, in fact, their intent that the UTS/4 allowable requirement still applies. The letter sent to NJP Engineering may be viewed here. This means this rule makes little difference in the end design, as this is essentially the same allowable stress as the 1998 ASME rules allowed. But it will, at least, eventually allow users to finally stop maintaining their 18-year-old Code books! On a related note, the 49 CFR still requires repair shops to work to the 1992 Edition of the NBIC.