Interpretation Response #08-0140 ([Burdette & Associates, Inc.] [Michael Burdette, P.E.])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Burdette & Associates, Inc.
Individual Name: Michael Burdette, P.E.
Location State: LA Country: US
View the Interpretation Document
Response text:
February 20, 2009
Michael Burdette, P.E.
Burdette & Associates, Inc.
P.O. Box 264
Milton, LA 70558
Ref. No. 08-0140
Dear Mr. Burdette:
This responds to your e-mail request for clarification of the requirements for IM and UN portable tanks under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). I apologize for the delay in responding and any inconvenience it may have caused. Your questions are paraphrased and answered as follows:
Q1. A portable tank currently authorized for use (IM 101/102) that does not meet the definition of a "container" in 49 CFR 450.3(a)(2)(iv) is in need of welded repair to a portion of its framework. The portable tank"s owner prefers to weld the immediate area of the framework needing repair while the designated approval agency recommends the damaged frame member be replaced. Is it permissible to repair (weld) the immediate damaged frame area or must the frame member surrounding the damaged frame be replaced?
A1. In accordance with § 180.605 (j), repairs to portable tanks must be made in accordance with requirements in the specification for the tank"s original design and construction. Thus, all repairs must employ materials and workmanship at least equal in quality to the original construction while maintaining all elements of the original design. The HMR permit the owner of a portable tank the discretion to determine the type of repair that is most appropriate given the condition of the portable tank, subject to the approval of a Designated Approval Agency where indicated.
If an aggrieved owner disagrees with the decision of a Designated Approval Agency and chooses to go to another Agency, he should provide the new Agency with a written statement including the name of the previous Agency that rejected the repair and the reason for the rejection. Alternatively, the aggrieved owner may petition this Office in accordance with the procedures specified in § 178.273(d).
Q2. Is it permissible to rebuild, with modifications, the framework of a portable tank that is no longer authorized for construction to its original specification (e.g., IM 101/102)? All of the portable tank supports, frameworks, lifting and tie-down attachments would be replaced. The purchaser of the portable tank would not have access to the original drawings or documentation supporting the original construction, but would generate documentation to support its "new" construction under the original specification. It is the understanding of the original designated approval agency that such modification to a portable tank could only be made if it were certified to a UN portable tank specification and not a former specification no longer authorized for construction.
A2. It is not permissible to rebuild the framework of a portable tank that is no longer authorized for construction. Under the scenario you describe, the portable tanks are considered to be newly constructed. Thus, they must be constructed in conformance with authorized UN portable tank specifications and certified by a Designated Approval Agency as specified in §178.273. It is the responsibility of the Designated Approval Agency to determine if sufficient drawings and documentation exists to approve the portable tanks; however, the Agency may take issue if the original welding procedures and material test certificates (MTRs) are not available.
Q3. If an IM 101 or IM 102 portable tank were constructed with adequate thickness to contain a higher maximum allowable working pressure (MAWP) capability than was originally marked on the specification plate, is it permissible to re-mark the specification plate with a higher pressure? Is this action considered a modification of the portable tank?
A3. An increase in a tank"s MAWP is considered a modification and requires the approval of a Designated Approval Agency in accordance with §178.273(e). We caution any party contemplating such a modification that shell/head thickness alone does not determine a tank"s MAWP. You must consider all aspects of the portable tank"s design, including nozzle thickness and reinforcement, openings and their fittings or closures, piping, and the like. The Designated Approval Agency is responsible for reviewing all elements of the design that are affected by an increase in MAWP and corresponding increase in test pressure. In addition, a supplemental metal identification plate and new approval and test certificate, indicating modifications made to the tank, must be prepared as specified in § 178.273(e)(iv).
Q4. Most UN portable tanks have a minimum design temperature of -40 °C (-40 °F), which requires the use of normalized steel for the tank"s shell. What temperature standards apply to portable tank supports, frameworks, lifting and tie-down attachments? Are there any charpy impact requirements for joules or foot-pounds at a specific temperature? Must they be constructed to the same integrity standards as the portable tank shell?
A4. The design and material properties of an attachment or support of a portable tank must be constructed to withstand at a minimum the loadings and temperatures specified in §178.274(b) and (h). The integrity of a portable tank and its supports, frameworks, and lifting (lugs) or tie down attachments must be such as not to compromise the lading retention capability of its shell. The manufacturer and designer, as appropriate, are expected to give due consideration to this design capability while in consultation with the Designated Approval Agency. The service in which the portable tank will be utilized (i.e. Offshore, Arctic, or both Offshore and Arctic), must also be considered in its approval. While an attachment or support is technically outside the scope of the pressure boundary and the pressure vessel code applied to it, it would be prudent to follow the requirements of UG-20(f) of Section VIII, Division 1, of the ASME Code. If all the conditions of UG-20(f) are met, material impact criteria required by UG-84 is not required. Impact testing is normally required for a material when the combination of its thickness and minimum design metal temperature is below the appropriate curve in Figure UCS-66 of the ASME Code.
I trust this satisfies your inquiry. Please contact us if we can be of further assistance.
Sincerely,
Edward T. Mazzullo
Director, Office of Hazardous
Materials Standards
180.605(j) 178.273(d)