Specification Plate Requirements for Cargo Tank Meeting Two Design Specifications
Pipeline and Hazardous Materials Safety Administration · Jan 15, 2015 · Reference No. 14-0232
Interprets: 49 CFR § 178.345-14(e), 49 CFR § 178.345-15(b), 49 CFR § 178.345-15(c)(2)
Reggie’s quick take
A company that makes new cargo tanks asked whether it may put a variable specification plate on a tank built to both DOT 407 and DOT 412 design specifications. The agency said yes. Before the plate is marked, the manufacturer's responsible official and a Registered Inspector must sign a certificate confirming the tank, its certificate of construction, and its plates meet both specifications (§ 178.345-15(c)(2)). The manufacturer must also provide a certificate of compliance for each design type the tank is built to meet.
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This is in response to your November 17, 2014 e-mail and November 20, 2014 telephone conversation with a member of my staff requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the specification plate requirements for cargo tanks. You state your company manufactures new cargo tanks that meet both the DOT 407 and DOT 412 design specifications. You ask if the HMR permit such cargo tanks to receive a variable specification plate that meets two different specification design requirements. We have paraphrased your questions and answered them in the order you provided.
Q1. Does the HMR allow a variable specification plate to be placed on a newly constructed cargo tank that was originally rated for the maximum allowable working pressure (MAWP) and constructed to meet both the DOT 407 and 412 design specifications (e.g., DOT 407/412)? I have enclosed an example of a DOT 407/412 variable specification plate my company might use.
A1. The answer is yes. Newly constructed cargo tanks that meet two design specifications must have a certificate signed by the responsible official of the manufacturer and a Registered Inspector certifying that the cargo tank, its certificate of construction, and specification plates meet both specification requirements prior to marking (see § 178.345-15(c)(2)).
Q2. When a cargo tank is originally manufactured to meet two design specification requirements, do the HMR require that the cargo tank must be marked with the "variable specification" plate prescribed in § 178.345-14(e), and must comply with the certificate of compliance (COC) requirements in § 178.345-15(c)(2)?
A2. The HMR require the manufacturer of a specification cargo tank to mark the cargo tank with a nameplate and specification plate that comply with § 178.345-15(b) for specification or American Society of Mechanical Engineers cargo tanks, and § 178.345-15(c) for variable specification cargo tanks. Further, the HMR require the manufacturer provide a COC for each cargo tank's design type listed in § 178.345-15(b) that the cargo tank is constructed to meet (see §§ 178.345-14(a) and 178.345-15(c)(2)).
I hope this satisfies your request.
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.