{"operation":"document","citation":"64 FR 13856","title":"Hazardous Materials: Revision to Regulations Governing Transportation and Unloading of Liquefied Compressed Gases","source_type":"rulemaking","agency":"Research and Special Programs Administration","status":"proposed","official":true,"published_on":"1999-03-22","effective_on":null,"summary":"RSPA is proposing revisions to regulations applicable to the transportation and unloading of liquefied compressed gases. The revisions include new inspection, maintenance, and testing requirements for cargo tank discharge systems, including delivery hose assemblies, and revised attendance requirements applicable to liquefied petroleum gas and anhydrous ammonia to take account of certain unique operating characteristics. The proposed attendance requirements provide a greater level of confidence that a qualified person attending the unloading operation can quickly identify and stop an unintentional release. Further, RSPA is proposing revised requirements for cargo tank emergency discharge control equipment to provide a clear performance standard for passive emergency discharge control equipment that shuts down unloading operations without human intervention. The revised requirements also provide for a remote capability for certain cargo tanks to enable a person attending the unloading operation to shut off the flow of product when away from the motor vehicle during delivery. RSPA is proposing a two-year period for development and testing of emergency discharge control technology. After two years, the proposal would require newly manufactured MC 331 cargo tank motor vehicles to be equipped with emergency discharge control equipment that complies with the proposed performance standards; MC 330, MC 331 and certain nonspecification cargo tank motor vehicles already in service would be retrofitted at their first scheduled pressure test after the two-year period. These proposals are intended to reduce the risk of an unintentional release of a liquefied compressed gas during unloading, assure prompt detection and control of an unintentional release, and make the regulatory requirements easier to understand and comply with.","machine_formats":{"json":"https://regulus.evalyn.ai/document/federal-register-99-6885.json","markdown":"https://regulus.evalyn.ai/document/federal-register-99-6885.md"},"app_url":"https://regulus.evalyn.ai/document/federal-register-99-6885","source_url":"https://www.federalregister.gov/documents/1999/03/22/99-6885/hazardous-materials-revision-to-regulations-governing-transportation-and-unloading-of-liquefied","body":"Federal Register, Volume 64 Issue 54 (Monday, March 22, 1999) [Federal Register Volume 64, Number 54 (Monday, March 22, 1999)] [Proposed Rules] [Pages 13856-13878] From the Federal Register Online via the Government Publishing Office [ www.gpo.gov ] [FR Doc No: 99-6885] [[Page 13855]] _______________________________________________________________________ Part II Department of Transportation _______________________________________________________________________ Research and Special Programs Administration _______________________________________________________________________ 49 CFR Parts 171, 173, 177, 178, 180 Hazardous Materials; Revision to Regulations Governing Transportation and Unloading of Liquefied Compressed Gases; Proposed Rule Federal Register / Vol. 64, No. 54, Monday, March 22, 1999 / Proposed Rules [[Page 13856]] DEPARTMENT OF TRANSPORTATION Research and Special Programs Administration 49 CFR Parts 171, 173, 177, 178, 180 [Docket No. RSPA-97-2718 (HM-225A)] RIN 2137-AD07 Hazardous Materials: Revision to Regulations Governing Transportation and Unloading of Liquefied Compressed Gases AGENCY: Research and Special Programs Administration (RSPA), DOT. ACTION: Notice of proposed rulemaking (NPRM). ----------------------------------------------------------------------- SUMMARY: RSPA is proposing revisions to regulations applicable to the transportation and unloading of liquefied compressed gases. The revisions include new inspection, maintenance, and testing requirements for cargo tank discharge systems, including delivery hose assemblies, and revised attendance requirements applicable to liquefied petroleum gas and anhydrous ammonia to take account of certain unique operating characteristics. The proposed attendance requirements provide a greater level of confidence that a qualified person attending the unloading operation can quickly identify and stop an unintentional release. Further, RSPA is proposing revised requirements for cargo tank emergency discharge control equipment to provide a clear performance standard for passive emergency discharge control equipment that shuts down unloading operations without human intervention. The revised requirements also provide for a remote capability for certain cargo tanks to enable a person attending the unloading operation to shut off the flow of product when away from the motor vehicle during delivery. RSPA is proposing a two-year period for development and testing of emergency discharge control technology. After two years, the proposal would require newly manufactured MC 331 cargo tank motor vehicles to be equipped with emergency discharge control equipment that complies with the proposed performance standards; MC 330, MC 331 and certain nonspecification cargo tank motor vehicles already in service would be retrofitted at their first scheduled pressure test after the two-year period. These proposals are intended to reduce the risk of an unintentional release of a liquefied compressed gas during unloading, assure prompt detection and control of an unintentional release, and make the regulatory requirements easier to understand and comply with. DATES: Submit comments on or before April 21, 1999. ADDRESSES: Address written comments to the Dockets Management System, U.S. Department of Transportation, Room PL-401, 400 Seventh Street, SW, Washington, DC 20590-0001. Identify the docket number RSPA-97-2718 at the beginning of your comments and submit two copies. If you want to receive confirmation of receipt of your comments, include a self- addressed, stamped postcard. Comments also may be submitted by e-mail to [email protected] . The Dockets Management System is located on the Plaza Level of the Nassif Building at the Department of Transportation at the above address. You can review public dockets there between the hours of 9:00 a.m. and 5:00 p.m., Monday through Friday, except federal holidays. In addition, you can review comments by accessing the docket management system through the DOT home page ( http://dms.dot.gov ). FOR FURTHER INFORMATION CONTACT: Jennifer Karim or Susan Gorsky, Office of Hazardous Materials Standards, Research and Special Programs Administration, (202) 366-8553; or Nancy Machado, Office of the Chief Counsel, Research and Special Programs Administration, (202) 366-4400. SUPPLEMENTARY INFORMATION: List of Topics I. Background II. Negotiated Rulemaking Committee and its Activities III. Statement of the Issues IV. Proposed Revisions A. Prevention B. Identification C. Mitigation D. Implementation Schedule E. Miscellaneous F. Section-by-Section Review V. Regulatory Analyses and Notices I. Background On December 13, 1996 (61 FR 65480), the Research and Special Programs Administration (RSPA, ``we'') and the Federal Highway Administration (FHWA) published advisory guidance on emergency discharge control systems on MC 330, MC 331 and certain nonspecification cargo tanks used to transport liquefied compressed gases. This followed an incident involving the unintentional release of propane from an MC 331 cargo tank motor vehicle during unloading. On February 19, 1997 (RSPA-97-2133 (HM-225), 62 FR 7638), RSPA adopted an interim final rule establishing certain temporary alternative regulations under which cargo tanks could remain in service while RSPA and FHWA evaluated this incident and other situations in which liquefied compressed gases were released unintentionally from cargo tanks during unloading operations. In particular, the interim final rule amended the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) by establishing a new Sec. 171.5, which set forth conditions under which affected cargo tanks, without certification and demonstrated performance of their emergency discharge control systems, could continue in service. On August 18, 1997 (62 FR 44038), RSPA published a final rule and responded to petitions for reconsideration of the interim final rule. The final rule reiterated most of the elements of the interim final rule and extended it as a continuing temporary regulation. Also on August 18, 1997 (62 FR 44059), RSPA published an advance notice of proposed rulemaking (ANPRM) in Docket No. RSPA-97-2718 (HM- 225A). This ANPRM solicited public comment on a series of specific topics. RSPA received more than 150 comments addressing federal agency jurisdiction; active and passive emergency discharge control systems; suggestions for modification of cargo tank discharge systems; hoses, hose assemblies, and hose management; and vehicle attendance requirements. On September 19, 1997 (62 FR 49171), RSPA issued additional advisory guidance in Docket No. RSPA-97-2133 (HM-225), in response to a petition for reconsideration and a request for clarification. On December 10, 1997 (62 FR 65187), RSPA published a second final rule that made changes to the August 18, 1997, final rule, responded to petitions for reconsideration, and made certain corrections and clarifications. On June 4, 1998 (63 FR 30572), RSPA proposed to establish a negotiated rulemaking committee under Docket RSPA-97-2718 (HM-225A) and announced a public meeting to discuss that proposal. The negotiated rulemaking process is defined in 5 U.S.C. 561 et seq. The above-referenced rulemaking documents contain a thorough discussion of the issues that led to issuance of the temporary regulation in Sec. 171.5, and to establishment of a negotiated rulemaking committee to develop recommendations for changes to the applicable regulations. These prior rulemaking publications and the [[Page 13857]] public comments on them (see RSPA-97-2133) are hereby incorporated into this docket by reference. II. Negotiated Rulemaking Committee and its Activities On July 16,1998 (63 FR 38456), RSPA established a negotiated rulemaking committee (the Committee) to develop recommendations for alternative safety standards for preventing and mitigating unintentional releases of liquefied compressed gases during the unloading of cargo tank motor vehicles. In a negotiated rulemaking, representatives of interests affected by a regulation meet to discuss the safety issues and to identify potential solutions. The group attempts to reach consensus on a proposed solution and prepares a recommendation for a notice of proposed rulemaking to be made by the agency. This process is intended to give parties the opportunity to find creative solutions, improve the information data base for decisions, produce more acceptable rules, enhance compliance, and reduce the likelihood of court challenges. For this rulemaking, in addition to the Department of Transportation (DOT), the Committee consists of persons who represent the interests affected by this rulemaking, including businesses that transport and deliver liquefied petroleum gases, anhydrous ammonia and other liquefied compressed gases; manufacturers and operators of cargo tanks and vehicle components; and state and local public safety and emergency response agencies. Particular care was taken to identify any unique interests that were determined to be significantly affected by the proposed rule and ensure that they were fully represented on the Committee. The members of the Committee are: 1. Department of Transportation--Edward Mazzullo, Research and Special Programs Administration 2. National Propane Gas Association--Charles Revere, Revere Gas and Appliance 3. The Fertilizer Institute--Charles Rosas, Farmland Industries 4. National Tank Truck Carriers--Clifford Harvison 5. Compressed Gas Association--Ronald McGrath 6. National Fire Protection Association--Theodore Lemoff 7. Propane Distribution (Small)--Mike Gorham, Northwest Gas, and Lin Johnson, Lin's Propane 8. Propane Distribution (Large)--Russell Rupp, Suburban Propane, and Ken Faulhaber, Ferrellgas 9. Anhydrous Ammonia/Dual Use Anhydrous Ammonia-Propane (Small)-- Charles Whittington, Grammar Industries 10. Anhydrous Ammonia/Dual Use Anhydrous Ammonia-Propane (Large)--Jean Trobec and Cliff Shoettmer, Growmark; and Jim York and Tom Stene, National Private Truck Council 11. State Safety Enforcement Agencies--Steve Hermann, Cooperative Hazardous Materials Enforcement Development (COHMED), and Eric Adair, Commercial Vehicle Safety Alliance (CVSA) 12. State Safety Regulatory Agencies--Vicki O'Neill, Bureau of Liquefied Petroleum Gas Inspections/Florida Department of Agriculture and Consumer Services, and Ronny Coleman, California State Fire Marshal 13. State/Local Emergency Response Agencies and Fire Services--Ronald Dykes, International Association of Fire Chiefs 14. Cargo Tank Manufacturers (Transports)--Mike Pitts, Mississippi Tank 15. Cargo Tank Manufacturers (Bobtails)--David Auxier, Bulk Tank and Transport 16. Technology--Jim Griffin, Fisher Controls The Committee was chaired by Philip J. Harter, Esq., a trained facilitator. The role of the facilitator was to apply proven consensus building techniques to the negotiations. The facilitator was not involved with the substantive development of the standard. Rather, his role was to: (1) chair the meetings of the committee in an impartial manner; (2) impartially assist the members of the committee in conducting discussions and negotiations; (3) act as disclosure officer for committee records under the Freedom of information Act (FOIA); and (4) keep minutes of all committee meetings in accordance with the Federal Advisory Committee Act (FACA) requirements. In some instances, work groups were formed around particular issues, and certain members were identified as spokespersons for these groups. Interested parties who were not selected to membership on the Committee were provided an opportunity to contribute to the negotiated rulemaking effort in the following ways: They were provided with the minutes of Committee meetings and could submit written comments to the Committee as appropriate. They could attend the Committee meetings, which were open to the public, caucus with the Committee member representing their interest on the Committee, and were provided opportunities to address the Committee as time permitted. They could participate in the workgroups established by the Committee. These informal workgroups were used to assist in addressing various technical matters (e.g., developing standards for an emergency discharge control system or verifying certain engineering procedures, or commenting on particular matters before the Committee) to facilitate Committee deliberations. They also assisted in drafting regulatory text. The workgroups were made up of Committee members and other parties who had expertise or a particular interest in the technical matter(s) being discussed. The Committee met in plenary and working sessions on six occasions. Among the materials considered by the Committee in developing the proposals in this NPRM are the prior rulemaking actions in RSPA-97- 2133, public comments filed in response to those actions, information provided by regulatory and enforcement officials, and incident data. The Committee agrees that the costs imposed by the proposed rule will be off-set by the benefits. The Committee had no role in preparing DOT's ``Preliminary Regulatory Evaluation'' or ``Environmental Assessment'' and did not consider them in its deliberations. III. Statement of the Issues The goal of all parties to this negotiated rulemaking was to enhance safety in transportation through improvements in the regulations governing the unloading of liquefied compressed gases from MC 330, MC 331, and certain nonspecification cargo tanks. Concerns with emergency discharge control on certain of these cargo tanks were identified in 1996. RSPA issued the temporary regulation in Sec. 171.5 of the HMR to address these concerns as related to the unloading of liquefied compressed gases because information and data gathered during the rulemaking process indicated that the problems were not limited to specific materials or specific cargo tank configurations. The Committee focused its discussions, analyses, and recommendations on liquefied petroleum gases (LPG) and anhydrous ammonia. These are the liquefied compressed gases that are most commonly transported in cargo tanks; as a result, LPG and anhydrous ammonia are the materials most frequently involved in unintentional releases during unloading. However, the [[Page 13858]] Department intends to address safety issues related to unloading of all liquefied compressed gases in a single proposed rule to the extent feasible and practicable. Accordingly, we propose to adopt the Committee's recommendations for all liquefied compressed gases that present risks similar to or more serious than those presented by LPG and anhydrous ammonia. The issues identified by the Committee apply equally to compressed gases with poison inhalation hazards, refrigerant gases, and compressed gases that present risks similar to those of LPG and anhydrous ammonia. The safety benefits that will be realized from this proposed rule justify a broad rulemaking approach. As one of its first activities, the Committee examined incident reports of unintentional releases of LPG, anhydrous ammonia, and sulfur dioxide during unloading operations. The data included incidents reported to RSPA as required by Secs. 171.15 and 171.16 of the HMR and other incidents not required to be reported to RSPA that were identified through reports from DOT field office staff, industry representatives, and newspapers. The Committee identified 70 incidents that occurred from 1990 to 1998 and analyzed them to determine how the current regulations applicable to unloading could be improved. More than 54 percent of the incidents resulted in unintentional releases from hoses and hose fittings. Another 37 percent involved releases that originated from equipment on the cargo tank motor vehicle itself, including pump seals, swivel joints, pump flanges, and piping and related fittings such as gauges, filters, and flex connectors. Many of these incidents appeared to result from problems with maintenance, installation, or mechanical damage rather than design flaws. Based on this information, the Committee concluded that improved inspection and maintenance programs for delivery hose assemblies and other discharge system components would prevent many incidents and, thus, would improve the safety of cargo tank unloading operations. However, the Committee also concluded that additional safety enhancements are possible. Thus, the Committee agreed to consider alternative approaches for identifying the occurrence of unintentional releases and reducing their severity by determining which methods or combination of methods provide the most cost-effective means for controlling unintentional releases during cargo tank unloading operations. The Committee heard presentations from manufacturers of a variety of systems designed to shut down cargo tank unloading operations automatically (without the need for human intervention) or by means of off-truck remote shut-off devices. Based on its discussion and findings, the Committee recommended a program combining measures to prevent unintentional releases during unloading operations with measures that will assure quick identification of releases and effective mitigation. Therefore, we are proposing revisions in these areas: Prevention--new inspection, maintenance, and testing requirements for discharge systems, including delivery hose assemblies, on cargo tanks transporting liquefied compressed gases. Identification--revised attendance requirements for monitoring unloading operations of LPG and anhydrous ammonia to take account of certain unique operating characteristics while assuring that the person attending the unloading operation can quickly determine if an unintentional release occurs. Mitigation--revised requirements for emergency discharge control equipment on certain cargo tanks in liquefied compressed gas service to provide a clearer performance standard for equipment that shuts down unloading operations without human intervention and to provide for an off-truck remote capability for certain cargo tanks to enable a qualified person attending the unloading operation to shut off the flow of product from wherever he may need to be during the delivery. The new requirements vary according to the degree of risk involved with the transportation of specific liquefied compressed gases. IV. Proposed Revisions A. Prevention The Committee recommends and we are proposing the following measures to prevent unintentional releases during unloading of liquefied compressed gases: A hose management program, including post-delivery safety checks of hoses and hose assemblies. A new inspection and maintenance program for on-truck components of a cargo tank's discharge system. A visual check of the discharge system and its components prior to each unloading. Hose Management Program The Committee conducted an in-depth analysis of the incident data for liquefied compressed gas spills during unloading. The data indicate that failure of hoses and piping components is the cause of the majority of unloading incidents. In addition, the data show that relatively minor leaks can result in major consequences if a liquefied flammable gas is ignited. For these reasons, the Committee decided that any rule it recommended should contain provisions focused on preventing incidents. Supporting this position is research conducted by Pennsylvania State University's Transportation Institute (PSUTI) under contract with The Fertilizer Institute. PSUTI analyzed the risks involved in deliveries of anhydrous ammonia and the most cost effective way of mitigating those risks. The PSUTI study identified a hose management program as the most cost-effective method of mitigating risks associated with unloading anhydrous ammonia. The majority of the incidents examined by the Committee involved leaks from hoses or failures of hose couplings. An incident in Sanford, North Carolina, in September of 1996 provides an example. In that case, the hose couplings of a newly assembled delivery hose assembly disconnected from the hose when subjected to delivery pressures. Less severe hose failures are more frequent and generally occur as a result of cuts and gouges to hoses that have experienced rough handling, such as being dragged across uneven ground or over rough structures during deliveries. For the reasons outlined above, we are proposing a hose management program for liquid hoses carried on cargo tanks that transport liquefied compressed gases. Although the accident data and analysis focused on unloading operations involving LPG and anhydrous ammonia, the preventive measures we are proposing are equally applicable to unloading operations for all liquefied compressed gases. The proposed program includes tests of new and repaired hose assemblies; safety checks of hoses after each unloading; monthly and annual hose assembly inspections; and specific rejection criteria. The hose management program would apply to delivery hose assemblies on cargo tank motor vehicles used to transport liquefied compressed gases. For purposes of this rule, a ``delivery hose assembly'' is defined as a liquid delivery hose and its attached couplings. During Committee deliberations, certain Committee members described instances in the field when it is necessary to attach ``adapters'' to the end of a delivery hose assembly to unload product from the [[Page 13859]] cargo tank into the receiving container. Because these adapters are not regularly attached to the liquid delivery hose and its couplings, they are not considered part of the delivery hose assembly for purposes of the hose management program. The hose management program would require an operator to remove and replace damaged hose sections and to correct any defects discovered in hoses or hose assemblies. The operator would be required to pressure test a repaired hose at a minimum of 120 percent of the maximum working pressure of the hose before placing it back in service. A pressure test would not be required if the operator corrected defects such as replacing or tightening loose or missing bolts or fastenings on bolted hose assembly couplings provided no slipping of the coupling has occurred. The annual hose inspection would be conducted by a Registered Inspector as part of the leakage test procedures already required by the HMR, making updating of registration unnecessary. For hoses not permanently attached to the cargo tank motor vehicle, the annual hose test would not necessarily have to be done by the same Registered Inspector or at the same time as the leakage test for the cargo tank motor vehicle. Discharge System Inspection and Maintenance Another area of emphasis identified by the Committee with respect to prevention of incidents during unloading was targeted at leaks from piping systems--defined by the Committee to include any component other than the delivery hose assembly that contains product during unloading. Again, the incident data indicate that leaks from piping components during unloading are a cause of a significant proportion of the reported incidents. The Committee heard presentations from two pump manufacturers about how pumps function and how they should be maintained. The Committee also investigated meters and other piping components. Because of the incident data and the constant wear on piping components, the Committee recommends and we are proposing to institute a program of inspections and tests for piping systems in cargo tanks that transport liquefied compressed gases. The inspection and testing program is similar to the program recommended for hoses. Piping system inspections and tests would include monthly checks of internal self- closing stop valves for closure, testing of linkages designed to close internal self-closing stop valves during emergencies, visual inspections of all piping system components, and rejection criteria for piping system components. Pre-Delivery Safety Check As an additional means to prevent unintentional releases from cargo tank delivery hose assemblies and piping, the Committee recommends and we are proposing that the person unloading liquefied compressed gases from a cargo tank visually check those components of the discharge system that are readily observed during the normal course of unloading. This check would be done before each delivery after the pressure in the discharge system reaches equilibrium with the pressure in the cargo tank. This check should assure that all connections are secure and that each component of the discharge system, including delivery hose assemblies and piping, is of sound quality and free of defects detectable through visual observation and audio awareness. B. Identification The Committee recommends and we are proposing new attendance provisions applicable to unloading of LPG and anhydrous ammonia. The attendance provisions in Sec. 177.834(i), which we are proposing to revise for clarity and consistency, will apply to all other cargo tank loading and unloading operations. We are proposing the following changes: A definition for ``metered delivery service.'' Revised regulations for monitoring the unloading operations of LPG and anhydrous ammonia in metered delivery service. Revised regulations for monitoring the unloading operations of liquefied compressed gases. Definition for ``Metered Delivery Service'' The Committee recommends that the attendance requirements in the HMR take account of the differences in design and configuration of cargo tank motor vehicles delivering LPG and anhydrous ammonia. Unloading of LPG and anhydrous ammonia from large-capacity cargo tanks through large-diameter delivery hoses involves the transfer of thousands of gallons of product into large storage containers at a rate of 200-400 gallons per minute. Typically, the vehicle is unloaded through a short delivery hose (less than 25 feet). [NOTE: As an aid to the reader, units of measure in this preamble are expressed in U.S. standard or customary units. In the regulatory text, consistent with the requirements of Sec. 171.10 of the HMR, they are expressed using the International System of Units (``SI'' or metric) as the regulatory standard, followed in parentheses by the U.S. standard unit.] Cargo tank motor vehicles that unload LPG or anhydrous ammonia through small- diameter delivery hoses differ in design and operation. These vehicles are used almost exclusively for deliveries in which small volumes of product are transferred to small storage containers at metered flow rates much lower than those used in other unloading operations. The average delivery for these vehicles involves the transfer of fewer than 170 gallons of product at a rate of 40-60 gallons per minute through a delivery hose that commonly ranges from 100 to 150 feet in length. To account for these differences, we are proposing to define a new term--``metered delivery service.'' The proposed definition for ``metered delivery service'' is an unloading operation conducted at a metered flow rate of 100 gallons per minute or less through an attached delivery hose with a nominal inside diameter of 1.25 inches or less. Monitoring Unloading Operations for Metered Delivery Service By far the most common unloading scenario for cargo tank motor vehicles in metered delivery service is the delivery of propane for heating and cooking by households and small businesses, and for light industrial applications. In these settings, the vehicle is typically positioned in the customer's driveway, farm lane, or parking area, and the customer's storage container is located to the side or rear of the facility. The storage container may be located more than 25 feet from the nearest point of vehicle access, and can be up to 150 feet away in extreme cases. Fences, buildings, vegetation, or other obstructions may make it impossible to maintain an unobstructed view of the cargo tank from the position of the storage container. The delivery hose on a cargo tank motor vehicle in metered delivery service remains attached and full of product during transit. It is equipped with a hose end valve that the attendant opens and closes to start and stop the flow of product into a customer container in the course of each delivery. As a result, an attendant located at the receiving container has a ready means to shut off the flow of gas in the event of a leak at the connection to the receiving container. An attendant located at the vehicle end of the system could respond to such a leak by closing the vehicle's internal self-closing stop valve, but [[Page 13860]] product in the downstream piping and hose could still continue to escape until the hose empties. Attendance at the position of the receiving container has the advantage of facilitating more effective mitigation of releases at the connection to the receiving container through use of the hose end valve. Attendance at the receiving container also addresses safety concerns about overfilling. The primary tool used to ensure against overfilling is a fixed maximum liquid level gauge mounted on customer containers. Propane industry safety procedures emphasize the need for close attendance of receiving containers to ensure that this gauge is monitored as necessary to prevent overfilling. While these considerations favor attendance at receiving containers, attendance at the vehicle end of the unloading system can effectively ensure prompt mitigation of releases from hose assemblies, piping, pump seals, or other components of the unloading system through closure of the internal self-closing stop valve. A requirement for attendance at one end of the unloading system to the exclusion of the other would thus be inappropriate. Therefore, the Committee agreed that the attendant should monitor both ends of the delivery system. Because of concerns about potential cost and other factors, the Committee agreed that using two persons to monitor unloading operations is not a viable option. The Committee recommends and we are proposing that the qualified person attending the unloading operation remain within 150 feet of the cargo tank and within 25 feet of the delivery hose throughout the unloading operation. In addition, the qualified person must observe the cargo tank, the receiving container, and the delivery hose at least once every five minutes during unloading operations that take more than five minutes to complete. For purposes of this requirement, the qualified person would not be required to be in position to view the entire length of the delivery hose. This proposed requirement should assure that leaks are detected before a substantial release occurs. Many of the releases that occur during metered delivery operations occur in close proximity to the attendant and are thus detected immediately. In any event, substantial releases would usually be evident to the attendant at any point along the delivery hose, whether or not such releases occur close to the attendant or within the attendant's field of view. Indeed, industry experience has been that substantial leaks during unloading are typically detected first by sound rather than by sight, regardless of the position of the attendant relative to the cargo tank or the source of the leak. Large ruptures and similar mechanical failures are accompanied by loud pops or bangs, followed by the hiss of escaping gas, both of which should be audible at a significant distance in most environments. Even small releases can cause changes in pump sound or vibration, or oscillation in the delivery hose that are detectable by an experienced qualified person located within 25 feet of the delivery hose. Monitoring Unloading Operations for Other Than Metered Delivery Service For a cargo tank in other than metered delivery service, as well as for all cargo tanks in LPG and anhydrous ammonia service, a manual emergency discharge control system is located on or within the cargo tank itself. Any releases that occur during unloading are detectable from the position of the cargo tank because of the short delivery hose used; therefore, safety considerations favor attendance from that position. Thus, for unloading of anhydrous ammonia and LPG in other than metered delivery service, and for other liquefied compressed gases in all types of service, we propose that the qualified person attending the unloading operation must be positioned within 25 feet of the cargo tank during unloading. The qualified person must maintain an unobstructed view of the cargo tank and the delivery hose to the maximum extent possible during unloading, except during short periods when it is necessary to activate controls or monitor the receiving tank. For purposes of this ``unobstructed view'' requirement, the qualified person would not be required to be in position to view the entire length of the delivery hose. Monitoring Unloading Operations for Dual Service Vehicles Where cargo tank motor vehicles in anhydrous ammonia or LPG service are equipped to unload with both small diameter delivery hoses (1.25 inch nominal inside diameter or less) and larger diameter delivery hoses, the proposed requirements for attending unloading operations for metered delivery service would apply when such vehicles are being used to transfer product at a metered flow rate of 100 gallons per minute or less through the small diameter hose. The attendance requirements applicable to unloading operations for other than metered delivery service would apply at all other times. Taken together, the Committee believes that the proposed attendance requirements will provide the flexibility necessary to accommodate the need to ensure that both ends of the unloading system can be monitored effectively and, in combination with new inspection and emergency discharge control requirements also being proposed, will provide greater safety benefits on a cost-effective basis. C. Mitigation The Committee considered alternatives to the current regulatory requirements for emergency discharge control with a view towards assessing their effectiveness and the need for modifications. The Committee recommends, and we are proposing, the following revisions to the current requirements for equipment designed to minimize the consequences of an unintentional release of a liquefied compressed gas: Modification of the performance standard for a passive means to shut down unloading--that is, one that operates without human intervention. Modification of the current requirements for emergency discharge control equipment on cargo tanks transporting liquefied compressed gases to account for varying degrees of risk presented by specific materials. New requirements for design and certification of emergency discharge control equipment. A new requirement that all internal self-closing stop valves on MC 330 and MC 331 cargo tanks and nonspecification cargo tanks authorized by Sec. 173.315(k) with water capacities less than or equal to 3,500 gallons be equipped with a fusible element. Fusible elements are currently required on cargo tanks with capacities greater than 3,500 water gallons. A requirement for unloading operating procedures to be maintained on cargo tank motor vehicles. Modification of the Performance Standard for Passive Means To Shut Down Unloading A ``passive'' means to shut down unloading when a leak is detected is one that operates automatically, that is, without human intervention. The current regulation at Sec. 178.337-11(a)(1)(i) of the HMR requires that ``each internal self-closing stop valve or excess flow valve must automatically close if any of its attachments are sheared off or if any attached hoses or piping are separated.'' It was reported to the Committee that Sec. 178.337-11(a)(1)(i) has been a source of confusion since it was amended in 1989. This section might be read as requiring an excess flow valve or an internal self-closing [[Page 13861]] stop valve with an integral excess flow valve or feature to close automatically at any time if any attachments were sheared off or attached hoses or piping were separated regardless of the rate of flow of product through the valve. An excess flow valve is only required to close if its flow rating as established by the original manufacturer is exceeded. The Committee recommends and we are proposing clarifying the current regulations to accurately reflect an excess flow valve's performance capabilities. The clarification appears in proposed Sec. 178.337-8(a)(4)(iv). None of the unloading incidents examined by the Committee involve complete separations of piping. Indeed, incidents involving piping and other discharge system components on the cargo tank itself usually involve relatively small leaks or releases. Because complete separations of piping during cargo tank unloading operations are unlikely to occur, the Committee concluded that RSPA should modify the current performance standard for passive shut-down. We are therefore proposing that, when required by regulation, a passive means to shut off the flow of product will be defined as one that is designed to shut off the flow of product without the need for human intervention in the event of an unintentional release caused by a complete hose separation. With respect to shearing off of piping, the requirement for automatic shut-down in the event of a complete pipe separation would be modified to apply only to shearing off of piping directly attached to an excess flow valve or an internal self-closing stop valve with an integral excess flow valve or feature. The proposed modification would require the valve to close automatically when any piping mounted directly on the valve is sheared off at a point before the first valve, pump, or fitting downstream from the excess flow valve or feature if the flow of product reaches the rated flow of gas or liquid specified by the original valve manufacturer. The current requirement for installation of additional downstream excess flow valves if branching or other restrictions reduce the flow rating to less than that of the excess flow valve at the cargo tank has been eliminated. Modification of Requirements for Emergency Discharge Control Equipment The Committee considered two types of emergency discharge control equipment: (1) passive means to shut down unloading, and (2) off-truck remote shut-off equipment that can be activated by a person attending an unloading operation at a distance from the cargo tank. The Committee also discussed different cargo tank motor vehicle configurations and capacities with a view towards determining the most appropriate equipment for each configuration and operating situation. a. Passive shut-down. For cargo tanks transporting LPG and anhydrous ammonia in other than metered delivery service, the Committee agreed that a requirement for a means to shut off the flow of product without human intervention in the event of a complete liquid hose separation is justified because of higher flow rates during unloading and the relatively low projected cost of technology currently being developed. The Committee therefore recommends that each MC 330 and MC 331 cargo tank intended for transportation of LPG or anhydrous ammonia in other than metered delivery service must be equipped with a passive means to shut down unloading that is designed to shut off the flow of product in the event of unintentional releases resulting from complete liquid hose separations only. The Committee discussed at length the timeframe within which the passive means should operate. The Committee agreed that the regulation should require shut down of unloading within a specified timeframe. Most of the technology currently being developed is designed to shut off the flow of product within 10 seconds. However, the Committee was concerned that none of this technology has been operationally tested with liquefied compressed gases. The Committee was also concerned that the characteristics of specific mater","truncated":true,"body_characters":157203}