Cargo tanks and hazardous materials transportation will remain focal points for federal regulators in 2000. Design issues being studied include new requirements for enhanced protection for tank rollovers and frontal impacts.
An update on federal initiatives was provided during the 1999 Cargo Tank Maintenance Seminar October 25 to 27 in Chicago, Illinois. The seminar was sponsored by National Tank Truck Carriers and the Truck Trailer Manufacturers Association.
The update began with a review of HM-225A, which focuses on the transportation and unloading of liquefied compressed gases, such as propane. "The final rule was developed through a negotiated rulemaking," said Ron Kirkpatrick, Research and Special Programs Administration (RSPA). "It was a challenging process, but it all came together in the end. We will probably do more negotiated rulemaking in the future."
Bruce Swiecicki, National Propane Gas Association, added that industry achieved some important successes in negotiating the final rule. Most importantly, RSPA dropped a proposed requirement for two workers to be present during propane deliveries.
Equipment tests and inspections are key elements of HM-225A. The first requirements took effect on July 1, 1999. Prior to unloading after the system has been pressurized and reaches equilibrium, the operator much check the discharge system to assure that it is of sound quality, without obvious defects, and that the connections are secure. After unloading, the operator must visually examine the hose and hose assemblyfor defects.
Daily Tests The remote shutoff must be tested daily, and must function at a distance of 150 feet. Monthly inspections are required for every delivery hose, and the cargo tank's piping must be thoroughly checked. The internal self-closing stop valve must be inspected for leakage.
Cargo tanks up to 3,500 gallons transporting LP-gas or anhydrous ammonia must have an attendant within 150 feet of the tank and 25 feet of the delivery hose during unloading. The attendant must be able to visually check the cargo tank and the receiving tank at least once every five minutes. For larger cargo tanks, the attendant is to have an unobstructed view to the maximum extent practicable.
When the receiver provides the delivery hose, the attendant must visually examine the hose and fittings for defects prior to unloading. He must remain within arm's reach of the mechanical means of valve closure except for short periods when it is necessary to activate controls or monitor the receiving container.
New requirements were added on January 1. Written procedures for controlling discharge in an emergency must be carried on the vehicle. On July 1, 2000, delivery hose assemblies and piping will have to be checked by a registered inspector while the system is at the required pressure for leakage tests.
New equipment was mandated by the rule. By the first pressure test after July 1, 2001, passive shutdown equipment must be installed on all existing MC331 tanks. Those under 3,500 gallons must have remote control shutdown equipment by that date. Operators of larger tanks have until July 1, 2003, to install the remote shutdowns.
Head Protection MC331 tanks also are getting attention from bureaucrats, who are studying accident protection for front heads. The study was initiated as a result of several catastrophic accidents involving MC331 tanks.
A key objective of the study is to evaluate the cost-effectiveness of improved head shielding. The study also is looking at the use of finite element analysis in studying head stresses in a frontal impact, various head shapes, and head shielding through the use of foam insulation.
The University of Michigan's Transportation Research Institute (UMTRI) is involved in a government study to analyze the force acting on vehicle overturn protection devices during various cargo tank rollover scenarios. Changes in rollover device design may emerge from this study.
The UMTRI study suggested that the design of rollover devices should be able to provide protection when an impact onto a flat surface normal to the surface of the cargo tank occurs at velocities of at least 12 feet per second, and further that this occurs at angular orientations of the tank with respect to the impact surface. The study added that it would be desirable to overturn devices to handle impacts of as much as 24 feet per second.
Inspection Problems RSPA and other DOT agencies continue to review the way cargo tanks are tested and inspected. RSPA's Phil Olson pointed out that Environmental Protection Agency's Method 27 leakage test is getting a second look from DOT.
"We had contemplated rejecting Method 27 for use in the cargo tank leakage tests required by DOT, because we felt Method 27 was not precise enough," he said. "However, EPA has changed the test requirements. Method 27 now limits the water column drop to one inch. We will probably limit Method 27 to cargo tanks in gasoline service."
Joe DeLorenzo, Federal Highway Administration (FHWA), called on tank fleet maintenance managers to be ever more diligent in their inspection, testing, and repair operations. "When we perform roadside inspections, we're finding that half of the cargo tank rigs have two or more hazmat violations," he said.
Topping the list are errors in shipping papers and placards and tank markings. Specification problems come next. About 3% of the tanks inspected have leaks. "We believe that is too many leaking tanks," DeLorenzo said. "We will continue to target these areas."
Venting violations turned up in about 21% of the roadside inspections of cargo tanks that were conducted in the Ohio area, according to Ted Turner, FHWA. Insp ectors still find just fusible caps, instead of self-closing pressure-relief vents, on some code tanks. Many vents are set for the wrong pressure.
"Vents either are not being tested, or they are being tested under the wrong standard," Turner said. "Vents aren't being cleaned, and mechanics aren't checking to ensure that vents reseat correctly."
Beyond the cargo tank, repair shops need to put greater emphasis on safe work practices, DeLorenzo said. Steps need to be taken to reduce injuries and incidents related to cargo tank repairs. Nine to 10 people a year are killed in tank repair accidents.
Canadian Rules Cargo tank regulations in Canada very closely mirror those of the United States, and Kevin Green, Transport Canada, provided an update on the latest changes in the Canadian rules. The 400-series tanks and the HM-183 tests and inspections have been incorporated into the Canadian rules. "We expect the final rule to be published in the Canada Gazette (similar to the Federal Register in the United States) in spring 2000," Green said. "A six-month phase-in is likely."