PHMSA clarifies inspection requirements for cargo tank trailer upper coupler plates

The Pipeline and Hazardous Materials Safety Administration recently issued a letter of clarification for the cargo tank rules relating to inspection requirements for a tank trailer upper coupler.

The writer described a lined cargo tank transporting lading that is corrosive to the tank but—due to the lining—does not come in contact with the tank itself. The writer asked if the areas covered by the upper coupler must be tested every two years in accordance with Section 180.407(d)(2)(ix), even though the tank is lined.

PHMSA replied yes, that Section 180.407(d)(2)(ix) required that when transporting lading corrosive to the tank, the areas on the cargo tank covered by the upper coupler (fifthwheel) must be inspected every two years for corroded and abraded areas, dents, distortions, defects in welds, and any other condition that might render the tank unsafe for transportation service.

The lading described in the letter is corrosive. Therefore, even though the lading does not physically come in contact with the tank, the HMR requires that the inspection be completed every two years.

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