Fort Vale — Hazardous Materials Safety Interpretation

Page 1: of Transportation U.S.Department 400 Seventh Street, S.W. Special Programs Research and Washington, D.C. 20590 Administration OCT 1 4 1998 Mr. Don Kilgore Sales Manager Ref. No: 98-0116 Fort Vale 8560 Katy Freeway, Suite 160 Houston, Texas 77024 Dear Mr. Kilgore: This is in response to your letter dated June 1, 1998, requesting clarification on reclosing pressure relief valves on MC 307 cargo tanks under § 180.405 (h) of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). A "properly functioning" reclosing pressure relief valve is one that functions according to the specification in the HIMR. There is a difference between repair, refurbishment and replacement. Internal parts such as o-rings or valve seats may be replaced. If external threads are galled or stripped to an extent that the pressure relief valve can no longer meet the performance requirements in the original specification (e.g., MC 307), the valve must be replaced. Until August 31, 1998, a replaced valve could be in conformance either with the requirements for the pressure relief valve at the time the specification became superceded (see § 178.342), or with the requirements for the pressure relief valve for the DOT 407 cargo tank motor vehicle (see § 178.347). After August 31, 1998, replacement valves must meet the requirements in § 180.405 (h)(2). A frangible and/or fusible cap may be used in conjunction with the reclosing pressure relief valve after August 31, 1998, as long as the original air flow requirements for the specification are met. In response to your question on calculating air flow, the pressure relief device system must limit the internal pressure of the cargo tank to 130% of the MAWP as per the original specification requirements. The pressure relief device must be rated at a pressure no less than 130% of the MAWP and no more than the test pressure of the cargo tank. I hope this satisfies your request. Delmer F. Billings Chief, Standards Development Office of Hazardous Materials Standards#

Page 206/01/98 08:44 5 713 464 8137 P. 81 FORT VALE Fax: (713) 464-0137 Phone: (713) 464-9474 8560 Kaly Freeway, Suite 160 Houston, l'exas 77024 FAXMESSAGE To: U.S. DEPARTMENT OF TRANSPORTATION Date: June 1, 1998 Fax No: 1-202-366-3753 Ref: From: Don Kilgore No. of pgs.: 2 Attn: Edward Mazzullo Dear Edward, cargo tanks. I hava heard several different opinions as to application of the regulations. I am reguesting The regulations will change, after August of this year, for reclosing Pressurc Relief Vents on MC307 clarification. They arc as follows. Section D, Subpart E, 180.405 (h) Pressure Relief Systems. Properly functioning reclosing pressure relief valves... fructerie does that continue replacement? lf he thread on the body are galed restripe bring. What is the definition of a " accord to spec! that cause for placement? Is there a difforonco belween repair, réfurbish and roplacement? As one of the major suppliers of these valves, what repair or replacoment of reseating to a leak-light condition after a pressure surge, and the volume of lading relcased (h)(2) Afier August 31, 1998, replacement of any reclosing pressure relief valve must be capable set forth in 178.345-10(h)(3) of this subchapter. may not exceed one liter. Specific performance requirements for these pressure relief valves are I Does this mean that a frangible and/or fusible cap cannot be used in conjunction with the reclosing pressure reliof valve after August 31, or is it the intent of the law 1o insure that MC307K listed rollover conditions? Cargo Tanks are equipped with reclosing pressure relief valve that provide a reduced spillage in spellow Vete meer or KraKkpetite 6119/221#

Page 306/81/98 08:45 S 713 464 8137 P.BZ EDWARD MAZZULLO Junc 1, 1998 Page 2 (h) (3) As provided in paragraph (c)(2) of this section, the owner of a cargo tank may elect 1o replacement devices construcled to the requirements of 178.345-10 of this subchapter must mudify reclosing pressure relief devices to more recent cargo tank specifications. However, tank was designed und constructed. provide the maximum venting capacity required by the original specification to which the cargo #3 internal pressure of the cargo tank to 130% of MAWP as per the original design criteria of the How does this related to the formula by which we calculate airflow? Should the vent limit the MC307 or should the airflow of the vent be calculated at 150% of MAWP as would apply to a DOT407 cargo tank? Your attention and response 1o thosc issues is greatly appreciated. Sincerely, Don Kilgore Ikro flame Don Kilgore Sales Manager DK:kr --:. - -.. ..=#

Page 4Until August 31, 1998, a replaced valve could be in conformance either with the requirements for the pressure relief valve at the time the specification became superceded (§ 178.342), or with the requirements for the pressure relief valve for the DOT 407 cargo tank motor vehicle (§ 178.347). 0123178 Charlie-sentence abore Is suggested "replacement" for the 4th sentence in the 2ad F. fank#