RegulusPipeline research62 FR 49171
Passage 1[Federal Register Volume 62, Number 182 (Friday, September 19, 1997)] [Rules and Regulations] [Pages 49171-49172] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 97-24974] ======================================================================= ----------------------------------------------------------------------- Research and Special Programs Administration [Docket No. RSPA-97-2133 (HM-225)] RIN 2137-AC97 Hazardous Materials: Cargo Tank Motor Vehicles in Liquefied Compressed Gas Service; Advisory Guidance for Leak Testing Discharge Systems AGENCY: Research and Special Programs Administration (RSPA), DOT. ----------------------------------------------------------------------- SUMMARY: On August 18, 1997, RSPA published in the Federal Register a final rule adopting certain safety standards applicable to cargo tank motor vehicles used in liquefied compressed gas service. This advisory guidance identifies a potential safety problem when leak testing a cargo tank motor vehicle's discharge system and clarifies a pressure test requirement for new or repaired transfer hoses. It is responsive to a petition for reconsideration and a request for clarification. FOR FURTHER INFORMATION CONTACT: Ronald Kirkpatrick, Office of Hazardous Materials Technology, RSPA, Department of Transportation, 400 Seventh Street, SW., Washington, DC 20590-0001, telephone (202) 366- 4545, or Nancy Machado, Office of the Chief Counsel, RSPA, Department of Transportation, 400 Seventh Street, SW., Washington, DC 20590-0001, telephone (202) 366-4400.#
Passage 2SUPPLEMENTARY INFORMATION: On August 18, 1997, RSPA published a final rule in the Federal Register (62 FR 44038) that adopts temporary requirements for cargo tank motor vehicles in certain liquefied compressed gas service. It requires a specific marking on affected cargo tank motor vehicles and requires motor carriers to comply with additional operational controls intended to compensate for the inability of passive emergency discharge control systems to function as required by the Hazardous Materials Regulations. The interim operational controls specified in the rule are intended to assure an acceptable level of safety while the industry and government continue to work to develop a system that effectively stops the discharge of hazardous materials from a cargo tank if there is a failure of a transfer hose or piping. Following publication of the August 18, 1997 final rule, The Fertilizer Institute (TFI) filed a petition for reconsideration seeking, in part, a revision to a requirement in Sec. 171.5(a)(1)(i) which specifies that an operator must subject the transfer hose to full transfer pressure before commencing the first transfer of each day. TFI's petition stated, in pertinent part:#
Passage 3In the final rule, RSPA adopts a requirement concerning the pressure testing of the transfer hose prior to the first transfer each day. Specifically, RSPA requires that ``prior to commencing the first transfer of each day, the transfer hose shall be subjected to full transfer pressure.'' 49 CFR 171.5(a)(1)(i). No further guidance concerning this requirement is found in the regulations or the preamble to the final rule. TFI is concerned that RSPA or Federal Highway Administration (FHWA) inspectors may interpret this requirement to mandate pressurizing the hose, after opening the vapor valves on the cargo tank and customer tank, and engaging the power take-off (PTO) without opening the product valve on the customer's tank. Under such an interpretation, this requirement is unreasonable and not in the public interest. To explain why such a requirement is unreasonable and not in the public interest, it is necessary to describe a typical anhydrous ammonia unloading operation. To unload a cargo tank containing ammonia, the operator first connects the vapor line from the cargo tank to the customer's tank and opens the valve at each end of the line. Next, the operator connects the product transfer hose to the cargo tank and customer's tank. After making this connection, the operator opens the internal valve on the cargo tank to flood the pump and, after the pump is flooded, opens the discharge valve on the pump to charge the transfer hose. At this point in the delivery process, the transfer hose is charged with the product pressure. Next, if there are no signs of leakage, then the operator opens the product valve on the customer's tank. Finally, the operator engages the PTO to commence product transfer. If Sec. 171.5(a)(1)(i) is interpreted to require engagement of the PTO and pumping against a closed product valve at the customer's storage tank, TFI asserts that such a requirement is unreasonable. This requirement is unreasonable because pumping against a closed valve could cause the vanes in the transfer pump to break. Also, the PTO, which is rotating at 650 revolutions per minute, could be damaged and break. Because of the likely potential for damage to the pump and PTO, it is unreasonable for RSPA to require an ammonia cargo tank operator to pump against a closed product valve to ensure the integrity of the transfer hose. In addition to being unreasonable, such a#
Passage 4requirement is not in the public interest because failure of the pump or PTO may result in injury to the cargo tank operator and public in proximity to the unloading operation. If the vanes in the pump break, it is possible that the integrity of the pump casing may be compromised, resulting in flying debris. Also, a PTO which breaks, while rotating at 650 revolutions per minute, may cause injury, including death, to those within proximity of the cargo tank. TFI understands RSPA's concern with ensuring the integrity of the transfer hose prior to commencing product transfer. As RSPA is aware, TFI has consistently been a proponent through this rulemaking of measures designed to ensure the integrity of the transfer hose and couplers. TFI believes that RSPA's goal of ensuring that a hose is sound prior to commencing transfer may be accomplished through the daily visual inspection of the discharge system, including the transfer hose and couplers, and charging of the transfer hose with product at the pressure within the closed system. This is especially true when RSPA considers the safety implications of engaging the PTO with the customer's storage tank product valve closed. For these reasons, TFI requests that RSPA modify the language in 49 CFR 171.5(a)(1)(i) to read: In addition, prior to commencing the first transfer of each day, the transfer hose shall be subjected to product pressure without mechanical influence (e.g., engaging the power take-off).#
Passage 5The provisions of Sec. 171.5(a)(1)(i) are intended to ensure that a cargo tank's discharge system, including transfer hose and couplings, is subjected to pressure prior to beginning transfer of product from a cargo tank motor vehicle to a receiving tank. It is not intended that any components of the discharge system should be subjected to pressures greater than full transfer pressure as part of this leak test. RSPA believes that the problem described by TFI is common to larger cargo tank motor vehicles, known as transports, which may not have separate back-to-tank bypass valves; smaller cargo tank motor vehicles, known as bobtails, generally do have separate back-to-tank bypass valves, and during delivery the transfer hose is charged with pump discharge pressure all the way to the hose end valve, which tests the integrity of the transfer system at each delivery. RSPA agrees with TFI's concern that some cargo tank pumping systems are not capable of pumping against a closed product valve without being damaged. Therefore, operators may determine the leakproofness of a delivery system, before beginning transfer of product from a cargo tank motor vehicle to a receiving system, by flooding the pump and charging the transfer hose with product pressure before the receiving system is opened. RSPA will publish a response to TFI's petition for rule change and petition to extend the termination date of the final rule in the near future. Section 171.5(a)(1)(ii) requires, in part, that prior to commencing transfer using a new or repaired transfer hose or a modified hose assembly for the first time, the hose assembly must be subjected to a pressure test performed at no less than 120 percent of the design pressure or maximum allowable working pressure (MAWP) marked on the cargo tank motor vehicle, or the pressure a hose is expected to be subjected to during product transfer, whichever is greater. In response to a recent telephone inquiry, RSPA noted that this requirement is based on the MAWP marked on a cargo tank motor vehicle, not the maximum working pressure marked on a transfer hose. Issued in Washington, DC on September 16, 1997. Alan I. Roberts, Associate Administrator for Hazardous Materials Safety. [FR Doc. 97-24974 Filed 9-18-97; 8:45 am] BILLING CODE 4910-60-P#
This material provides agency context. It does not replace binding regulatory text, and its legal effect depends on the underlying authority and facts.