Between January and May 1991, the National Transportation Safety Board investigated seven highway accidents in which bulk liquid cargo tanks, Department of Transportation (DOT) specification MC 306 or MC 312, overturned and released hazardous materials through damaged closures or fittings on top of the tanks. In three of the accidents, structural failure of the rollover protection devices for the top fittings resulted in impact damage to the fittings and the release of the cargo; in four of the accidents, the design and configuration of the devices were not adequate to protect and shield the top fittings from external objects or from plowing into the ground. As a result of these accidents, the safety board conducted a special investigation on cargo tank rollover protection. The safety issues discussed in this report are the adequacy of DOT regulations regarding the design and performance of rollover protection devices installed on bulk liquid cargo tanks; the effectiveness of oversight pertaining to the design and construction of the cargo tanks; and the adequacy of accident reporting to and data collected by the DOT. Recommendations concerning these issues were made to the research and special programs administration and to the Federal Highway Administration. Adopted: February 4, 1992. Notation: 5651.
Samenvatting