Victor Singer  VSinger01@aol.com
As sent in a email to Senator David McBride on 3/23/03
At the DNREC Aboveground Storage Tank Technical Advisory Committee (ASTTAC) March 20 meeting, hard copies of Secretary Hughes' March 17 response to your e-mail of February 15 were distributed to all who cared to pick up a copy. Also, hard copies of my February 4 essay entitled "Thoughts on a Brittle Fracture Requirement for New Above-Ground Metal Storage Tanks" were distributed in like fashion. But neither your February 15 e-mail nor its antecedents were distributed. They are appended below.
In his letter, Secretary Hughes said that DNREC's Tank Management Branch is researching the "Leak-Before-Burst" (LBB) issue that I raised in my "Thoughts on a Brittle Fracture Requirement" essay. In particular, he said that preliminary contacts with the American Petroleum Institute (API) subcommittee responsible for API Standard 653 have disclosed that "the current standard specifically does not include the mathematical calculations suggested by Mr. Singer because . . . there are more sophisticated formulas in the more recently developed methods."
Upon my request at the March 20 ASTTAC meeting to see the records of DNREC's communications with API in this regard, I was given a copy of a February 20 letter from Jill Hall to Roland Goodman of API, which was NOT distributed to ASTTAC. It includes the following key text:
". . . A member of the general public has raised questions concerning brittle fracture failure of aboveground storage tanks. It is our understanding that the requirements of API 653 were formulated to ensure that the materials allowed by this standard in the construction of aboveground storage tanks are of adequate toughness to avoid brittle fracture failure. We would like to request a confirmation from API that this standard or others adequately address the issue of brittle fracture failure according to the research conducted by API. . ."
Note that the February 20 letter doesn't mention my name, and doesn't cite my "Thoughts on a Brittle Fracture Requirement" essay, in which I proposed requirements only for NEW tanks - - tanks that haven't yet been built. In support of my proposed LBB provision, I showed that the requirements of API Standard 650 - - a design standard for NEW tanks - - can lead to tank designs without LBB capability.
[As an example, at the API 650-prescribed minimum impact energy requirements, ASTM A-633D steel is permissible under API 650 for use at a 28 ksi allowable stress level in a tank with a wall thickness up to 1.5 inch at a service temperature as low as minus 10 degF. Under these conditions, API 650 doesn't even require that impact energy specimens be tested. Yet I showed in my "Thoughts on a Brittle Fracture Requirement" essay that below a 20 degF service temperature, ASTM A-633D steel tank wall thicknesses above 1.11 inch would not provide LBB capability at the 28 ksi allowable stress level and the minimum impact energy levels that API 650 would permit. Further, I showed that a more stringent US Department of Defense criterion in "Fracture Control Requirements for DoD Shuttle Payloads," which demands LBB capability all the way to the yield stress level, would prohibit use of ASTM 633D steel at 20 degF in thicknesses larger than 0.235 inch.]
By citing only API Standard 653 - - a standard for alteration and modification of existing tanks - - and by NOT providing API with a copy of my "Thoughts on a Brittle Fracture Requirement" essay, DNREC's February 20 letter suggested to API that I'm seeking to disqualify EXISTING tanks, which of course is absurd.
Somehow, Secretary Hughes neglected to tell you that DNREC assured an unfavorable response from API by changing the scope of my proposal.
And somehow Secretary Hughes chose to request that unfavorable response from API, which could hardly be expected to brand its own standard as inadequate, especially without a copy of such a showing. It shouldn't take a rocket scientist to seek out an unbiased expert, such as the U of D faculty member who teaches a graduate level course in Fracture Mechanics, and ask for her opinion. (No, I haven't ever met her, or spoken with her, or communicated with her.)
And somehow Secretary Hughes neglected to tell you that the "more sophisticated formulas" in API Standard 650 - - that I referred to - - have nothing to do with brittle fracture.
Secretary Hughes needs to be reminded that there are TWO public policy issues here, and several sub-issues, which I state according to my own views of what is appropriate:
- In Delaware, all NEW tanks for hazardous liquids should be designed to have Leak-Before-Burst capability at the lowest service temperature and the highest
allowable operating stress level.
- Such a requirement should be explicitly stated in Delaware's regulation for Aboveground Storage Tanks containing hazardous liquids, unless
explicit statements to that effect are shown in reference standards therein included.
- For liquids more hazardous than petroleum, more stringent requirements should apply, as for instance UL Standard No.2285, "Protected Above
Ground Tanks for Flammable and Combustible Liquids."
- A computational methodology for assuring LBB capability should be explicitly stated in the regulation unless a methodology of like effect can be included
by citation of a reference standard.
- The computational methodology should be simplistic enough to assure error on the side of safety even when applied by practitioners without
thorough understanding of the relevant technology.
- More complex approaches should be permissible for those with the
requisite facility with the subject matter.
Secretary Hughes should be urged to READ and TRY TO UNDERSTAND what I proposed. If it would help, I would be happy to give a blackboard-and-chalk presentation - - or more properly in this day and age, a whiteboard-and-marker presentation - - on the relevant technical issues and background. I've often given such presentations to technically proficient and non-proficient groups over the past thirty years - - most recently, on March 13 this year, and before that in San Antonio last August. I can assure you that the underlying concepts are readily understood by folks without mental blocks, and that the underlying complex mathematics are avoidable.
The technology of fracture is a new science, developed over the 2nd half of the 20th century. Those who are sensitive about lesser proficiency in that technology than they might like, are reluctant to display that sensitivity. Formidable mathematical treatments are further discouragements. Yet except for the purists, it can be enough that certain mathematical expressions describe how structural materials fracture. After all, when Newton described how the apple falls from the tree, he didn't need to concern himself with why it falls.
Should Secretary Hughes take advantage of the presentation offer, and perhaps stage it at or after an ASTTAC meeting, it would overcome both the mental block and the reluctance. If YOU suggest it, it will have more weight than my suggestion.