Bulktransporter 5311 Firstclass Tank Trailer
Bulktransporter 5311 Firstclass Tank Trailer
Bulktransporter 5311 Firstclass Tank Trailer
Bulktransporter 5311 Firstclass Tank Trailer
Bulktransporter 5311 Firstclass Tank Trailer

PHMSA clarifies rules for MC331 tests, MC300-series pressure relief valves

June 20, 2018
PHMSA clarifies rules for MC331 tests, MC300-series pressure relief valves

The Pipeline & Hazardous Materials Safety Administration (PHMSA) issued an official correction in the Federal Register on June 18 addressing two very important cargo tank inspection rules, according to Boyd Stephenson, senior vice-president of government affairs for National Tank Truck Carriers. Inspection requirements addressed include:

• Some MC331 trailers tested or inspected prior to July 18, 2018 are immediately eligible to use the new, 10-year test and inspection period. If a trailer was inspected before the rule took effect, it’s previous 5-year inspection period is automatically extended five years from the original expiration to 10 years; and

• PHMSA also removed the subparagraphs under 180.407(g)(1)(ii).  These subparagraphs were left in erroneously and repeated instructions in 180.407(j). 

• PHMSA went on to include contradictory language about upgraded vents, stating that the rules allowed DOT400 series trailer pressure relief devices to be installed on MC300 series trailers, but, if those devices are installed, they must still meet the existing venting capacity and set pressure requirements for MC300 series trailers.  This is in conflict with the requirements in 180.407(j) according to John Freiler at Truck Trailer Manufacturers Association, which currently is seeking further clarification.

Carriers, testers, and inspectors may take advantage of this regulatory relief immediately.

The correction also changed rules for the use of letters in the emergency response telephone numbers on shipping papers (still not allowed), rules for nitric acid shipment packaging requirements, rules for classifying organic peroxides, and some of the entries in the Hazardous Materials Table. These changes have little effect on tank truck operations, according to Stephenson.