DATA collected during a two-year-long cargo tank rollover study is on its way to the Department of Transportation (DOT), according to Doug Pape with Batelle Laboratories. Regulatory action is a distinct possibility.
Researchers at Batelle looked at the ability of four key factors — trailer design, highway design, vehicle control technology, and driver training — to prevent cargo tank rollovers. Pape discussed some aspects of these factors during the 2006 Cargo Tank Maintenance Seminar October 16-18 in Nashville, Tennessee.
Drivers stand out as possibly the single biggest factor in rollovers, according to Pape. The Batelle study suggests that drivers probably were key contributors in three out of four rollover accidents reviewed by the researchers.
Training may be the biggest preventive measure, but current programs miss the mark. Researchers found that there are no accepted standards for driver training effectiveness and no training that is specifically for cargo tank vehicles. Batelle researchers found little follow-up by truck driving schools once the student successfully passes the commercial driver license test.
Pape said the study shows that driver training warrants a closer look, with a specific focus on anti-rollover training programs. Researchers also need to gather more detail on dispatcher training, rollover accident reductions and cost saving from training, and turnover rates for tank truck drivers.
Reviewing tanker overturn data county by county across the United States, researchers found a number of areas where the design of roads and highways may be contributing to rollovers. This data will be forwarded to the Federal Highway Administration and could lead to highway design improvements.
Equipment design also plays a role. For instance, lowering the center of gravity improves tank trailer stability and reduces the potential for rollover. “This could be done with smaller wheels and tires, which would reduce the height at the rear of the trailer,” Pape said. “Stability also can be enhanced with 102-inch-track axles and wide, single tires.”
A number of vehicle technology factors were studied, including the electronic stability systems that have entered the market over the past several years. Stability technology is available for both tractors and trailers. Pape said the devices appear to be very effective and are becoming relatively inexpensive for new vehicles.
In addition to studying rollovers and how to prevent them, DOT agencies are looking at ways to make cargo tanks more robust and better able to survive an overturn event. Danny Shelton with the Federal Motor Carrier Safety Administration (FMCSA) discussed a study now underway for rollover protection devices on cargo tanks.
The study includes an analysis of the forces that can act upon rollover protection devices during an overturn accident. Factors being evaluated include ground contact positions for the devices, forces encountered by the devices, and roll speeds.
Shelton went on to review some of the points that are likely to be addressed in HM-213C, a possible rulemaking that is under consideration at FMCSA. If a rulemaking were initiated, it would incorporate a variety of issues that were not covered by other cargo tank rules. Many of the points under consideration were raised during public outreach meetings conducted by FMCSA over the past couple of years.
Among the factors under consideration: The agency is looking at a number of changes to the data plate, specification plate, and nameplate on cargo tanks built to DOT code. For instance, the following statement would be added to the nameplate: Cargo tank constructed in accordance with the applicable DOT/MC specification.
New requirements for cargo tank fabrication drawings might call for a piping drawing that identifies the location, make, model, and size of each valve and the arrangement of all piping on the vehicle. Additional documentation could include pressure test reports for the piping, valves, and fittings; hose certification; and certification of emergency discharge control systems.
Shelton pointed out that FMCSA is giving consideration to a rule clarification stating that emergency discharge control equipment must be on a cargo tank vehicle even if the shipping and receiving facilities provide product hose with emergency shutdown capability.
FMCSA would like to develop a formal definition for mobile cargo tank testing and inspection services. The agency would like to require that non-specification ASME-code tanks transporting hazardous materials be inspected in accordance with Part 180.407(a).
FMCSA would like to add language to the rules stating that a registered inspector shall be required to demonstrate knowledge and expertise during a compliance review performed by FMCSA special agents as defined in Appendix B of 49 CFR 180.407(c).
The agency would like to clarify rules that apply to remounting cargo tanks on a different chassis. The agency also wants to clarify section 180.413(e) to require that the facility performing the remounting verify the original methods and means of attachment of the tank to the chassis and accident damage protection devices and their respective means of attachment to the cargo tank motor vehicle.
Even as DOT officials work on cargo tank refinements in HM-213C, they are putting the finishing touches on HM-214, which will bring the most radical changes in cargo tank design, construction, and repair that the tank truck industry has seen in its nearly 100-year history. Due to be published sometime in the next two years, this rulemaking will designate the American Society of Mechanical Engineers (ASME) as the primary source for cargo tank design, testing, and inspection requirements. ASME will publish those requirements under Section XII of the Boiler and Pressure Vessel Code.
Stan Staniszewski Jr from DOT's Office of Hazardous Materials Safety provided an update on the Section XII program. “We've been talking about this change for eight years,” he said. “We're moving forward, but there is still a lot of work to do. This is all part of an effort to clean up the regulations that pertain to cargo tank design and maintenance. We believe this will make it faster to develop new cargo tank rules and rule updates.”
Staniszewski added that DOT would maintain its oversight of the cargo tank regulatory program even though ASME is being given responsibility for developing new design, manufacturing, and maintenance requirements. “We will continue to publish rule changes in the Federal Register, and the industry will have an opportunity to comment,” he said.
Section XII will cover virtually all cargo tanks ranging from full vacuum to 3,000-psi capacity. Along with builders of code tanks, it will affect approximately 3,500 transport tank builders that are currently exempt from the ASME code tank requirements.
ASME will replace the current U and R stamps with T and TR stamps. The registered inspector program will see significant changes. For instance, ASME wants to require third-party inspectors. Staniszewski said DOT would not change the current system of recognizing a registered inspector. Between 8,000 and 10,000 registered inspectors currently work in the industry.
Much work still must be done on Section XII. Only the cryogenic portable tank section has been completed. The Cargo Tank Modal Appendix will be voted on soon by ASME's main committee.