Feb 1, 2006 12:00 PM
THE Pipeline and Hazardous Materials Safety Administration (PHMSA) just won't give up on the effort to prohibit retained product piping (also called wetlines) on cargo tank trailers. Agency officials expect to publish a rulemaking sometime in late 2006.
Ben Supko with PHMSA provided a brief update on the latest wetlines regulatory effort during the National Tank Truck Carriers 2005 Cargo Tank Maintenance Seminar held November 7-9 in Louisville, Kentucky. Public comments on the proposed wetlines rulemaking — most of them negative — were sent to the Volpe Institute for further review and will be addressed in a final rule.
Danny Shelton, Federal Motor Carrier Safety Administration (FMCSA), reviewed some of the regulatory changes suggested during the Cargo Tank Technical Information Sessions that were held during 2005. He also discussed factors related to cargo tank rollover and provided an update on overturn protection devices.
With regard to the information sessions, participants said FMCSA needs to identify procedures for revocation of a federal cargo tank registration number and what it takes to be a registrant in good standing. Mobile testing needs to be defined.
Discussing 49 CFR Part 171, information session participants suggested incorporating the Truck Trailer Manufacturers Association Bulletin 113 on thickness testing. The term “design pressure” should be replaced with maximum allowable working pressure (MAWP). All definitions under Part 171 should be moved to Part 171.8.
FMCSA should add the density of compressed gases to the shipping paper requirement in Part 172.203(h). Alternative fill gauges should be allowed on MC331 pressure vessels — 173.242(b)(2). FMCSA needs to clarify the meaning of “unobstructed” and “upward” with regard to the requirement for a protective device to prevent the entrance of debris — 173.315(i).
Regulations should clarify that emergency discharge control equipment must be on the vehicle even if a facility provides hose that has its own emergency discharge control capability — 173.315(n). Bonding and grounding requirements apply to a combustible liquid that has been reclassified from flammable — 177.837(c).
All materials used on the internal surface of the cargo tank wall should be compatible with the commodity transported — 178.337-2(a)(1). Rules should be changed to require that the burst pressure of the relief valve be consistent with the design requirements — 178.337-9(a)(3).
A cargo tank motor vehicle manufacturer (CTMVM) shall ensure that all components including piping, valves, and hoses and fittings comply with Part 178.337-9(b). Tank builders are responsible for the leakage testing of piping, valves, hoses, and fittings on a cargo tank, and the tests must be performed at 80% of the MAWP marked on the ASME (American Society of Mechanical Engineers) data plate.
Shear sections on piping as such are needed to comply with accident damage protection requirements — 178.337-10(a). Participants in the information sessions asked the Department of Transportation (DOT) to clarify the shear section and bending moment requirements.
Participants also asked DOT to change the definition of test pressure integrity to structural integrity — 178.345-1(c). Clarification is needed on the rule stating that voids between double bulkheads must have separate vents and drains — 178.345-1(l)(2). In addition, the rules need to clarify when thermal activation on remote shutdown devices is required by 49 CFR 173.242(b)(2) for medium-hazard liquids and 173.243(b)(2) for high-hazard products.
DOT was urged to remove from the rules any indication that a structural support member must be attached to the cargo tank by means of a pad — 178.345-3(f). Better wording is needed to eliminate confusion regarding the procedures to follow in properly determining the distance of ring stiffeners on vacuum-loaded cargo tanks — 178.345-7(d)(1).
DOT needs to require protection in accordance with Part 178.345-8(b) for controls that operate internal self-closing stop valves that could be damaged in an accident and result in a spill. The department should clarify what is meant by the term “cargo tank motor vehicle at rated payload” — 178.348-8(d)(3) — and clarify that when the rear-end protection device deflects six inches horizontally forward that no part of the bumper can make contact with the cargo tank.
Participants suggested that DOT modify the term “repair” to include the following:
Replacement of up to 50% of the combined shell and head material of a cargo tank.
Maintenance or replacement of piping, valve, hose, or fitting that affect the lading retention capability of the cargo tank motor vehicle.
Non-specification ASME-code cargo tanks transporting hazardous materials should be inspected in accordance with Part 180. In addition, the pass/fail criteria identified in 49 CFR 180.411 should be clarified. DOT needs to make it clear that a cargo tank that has been modified must be pressure-tested to verify the structural integrity of the modified design.
Shelton said that CTTIS participants wanted the language in 180.407(b)(5) to be changed from probable cause to reasonable belief. The rules should clearly state that a registered inspector shall be required to demonstrate knowledge and expertise during a compliance review performed by FMCSA special agents.
DOT needs to clarify the date when inspections are required to be performed. Cargo tank inspections should be based on product-specific requirements and type of service rather than the current system. Dents on the cargo tank shell in the void area between bulkheads should be evaluated using the same criteria as dents on other parts of the cargo tank shell.
During the inspection of the cargo tank shell and heads, all appurtenances attached to those areas must be inspected — 180.407(d)(2)(i). Clarification is needed to ensure that an appurtenance that does not provide structural support to the cargo tank should still be consistent with the definition of appurtenance.
The rules should permit the area of the tank shell above the upper coupler to be inspected without mandating that the upper coupler be removed — 180.407(d)(2)(ix).
The distance for annual testing of remote shutoffs should be 300 feet. The operator who performs the daily check of hoses and fittings on MC330/331 pressure vessels should have function-specific training for that task — 180.416(c).
Establish tolerance guidelines for reclosing pressure-relief devices. The rules should be clarified to state that a lining inspection is only required when the cargo tank is lined to protect the vessel from the product being transported.
DOT rules should mandate removal from service of cargo tanks that no longer conform to the minimum thickness and cannot meet specification requirements for reduced-weight-per-gallon products. The rules should be clarified to state that repairs to piping, valves, hoses, and fittings that do not require welding on the tank wall still must be tested for leaks.
DOT was asked to modify cargo tank retest markings and only allow the most recent test and inspection marking. In addition, the CT number of the facility that performed the inspection should be displayed on the cargo tank in association with the test and inspection marking — 180.415(a).
ASME Section XII
While DOT currently handles the development of new cargo tank rules from within, steps are already underway to turn over much of the process to ASME. Nick Paulick, Brenner Tank LLC, provided an update of the progress made with the ASME Section XII program.
As of now, the Section XII committee is in place with representatives from the cargo tank manufacturing sector, cargo tank inspectors, and DOT. The Section XII scope covers only the cargo tank (which ASME terms a pressure vessel). Excluded components include external accident damage protection, cargo tank use, and regulatory enforcement.
The main body of Section XII has been written and approved. The first modal appendix covers cryogenic portable tanks, which was needed to replace existing DOT/United Nations regulations that had expired.
Section XII was released in the 2004 edition of the ASME Code, and the addenda issued in 2005 contains the main body. “It does not contain a modal appendix for cargo tanks,” Paulick said. “This means Section XII is not applicable to our industry at this time.”
However, the Cargo Tank Modal Appendix is nearly complete and might go into the 2006 Addenda that will be published this summer. DOT would then initiate a rulemaking to adopt Section XII requirements, and a final rule could be published as early as October 2007. Tank manufacturers and repair shops would have three years to change over from the “U” stamp to the new “T” stamp.
“This is an optimistic timetable, though,” Paulick said. “Most likely, we won't see a rulemaking on Section XII until 2008, and compliance wouldn't become mandatory until around 2011. There is still a lot of work to be done.”
In the Section XII work done to date, DOT's transparency requirement has prevented any significant changes to cargo tank construction. This hasn't always sat well with ASME, according to Paulick. It has created some “interesting and difficult issues for ASME.”
Most changes will be in wording and phrasing. The primary impact probably will be in the way paperwork and design work are performed and documented. Final design and overall cost of tank trailers should not be affected, according to Paulick.
The most visible changes should be:
The title “registered inspector” will be changed to “certified individual.”
Tank trailers no longer will be known as ASME or non-ASME. They will be called Class 1 or Class 3.
New NBIC rules will cover repairs, alterations, and maintenance.
Cargo tank builders do have some concerns about Section XII. At the top of the list, design allowables will be increased due to adoption of current ASME allowables.
Next is concern about longitudinal compressive stress calculations. As the requirements currently are written by ASME, nearly all DOT407 trailers on the road today would be out of compliance. Either ASME needs to adopt less conservative rules, or DOT will have to set its own dynamic factor requirements.
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