Interpretation Response #22-0088
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: DOT Training Solutions
Individual Name: Rex Railsback
Location State: KS Country: US
View the Interpretation Document
Response text:
March 28, 2023
Mr. Rex Railsback
Safety Consultant
DOT Training Solutions
P.O. Box 253111
Overland Park, KS 66225
Reference No. 22-0088
Dear Mr. Railsback:
This letter is in response to your July 29, 2022, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the testing of insulated Department of Transportation (DOT) specification MC 331 cargo tanks. Specifically, you ask whether previous Letter of Interpretation (LOI) No. 04-0221—issued on October 1, 2004—is still valid, and request information as to how insulated MC 330 and MC 331 cargo tanks could be exempt from compliance with the periodic test and inspection requirements found in Note 4 to § 180.407(c) or § 180.407(d)(1).
LOI No. 04-0221 discusses inspection requirements for MC 330, MC 331, and MC 338 cargo tanks in carbon dioxide, refrigerated liquid service. After reviewing LOI 04-0221, it is the opinion of this Office that the letter is still accurate and considered current.
In addition, nothing in § 180.407 exempts MC 330 or 331 cargo tanks from the requirements of § 180.407(c) Note 4 or § 180.407(d)(1). The compliance dates specified in § 180.407(c) require insulated MC 330 and 331 cargo tanks to undergo an internal visual inspection once every five years. Section 180.407(d) states that insulated cargo tanks that cannot be entirely externally inspected due to the insulation must be internally inspected in the areas where external inspection is precluded. Further, if the inside of the cargo tank is lined, coated, or designed to prevent access for an internal inspection, then the cargo tank must be hydrostatically tested.
In summary, while internal inspections are required every five years, either an internal inspection or a hydrostatic test must be conducted annually if insulation precludes a full external inspection.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division