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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #23-0079

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Hazmat Safety Consulting, LLC

Individual Name: Ryan Paquet

Location State: VA Country: US

View the Interpretation Document

Response text:

January 18, 2024

Ryan Paquet
Hazmat Safety Consulting, LLC
1765 Duke Street
Alexandria, VA  22314

Reference No. 23-0079

Dear Mr. Paquet:

This letter is in response to your August 17, 2023, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to special provision (SP) B81 approval. Specifically, you seek clarification regarding the use of venting and pressure relief devices (PRDs) for tank cars and cargo tanks.

We have paraphrased and answered your questions as follows:

Q1. You ask whether a tank car manufacturer or tank car shipper is responsible for applying for and receiving approval from the PHMSA Associate Administrator for Hazardous Material Safety, as required by § 172.102(c)(3), SP B81.

A1. While a tank car manufacturer or a tank car shipper may apply for an SP B81 approval, ultimately, it is the shipper's responsibility to ensure that a hazardous material offered for transportation is in an authorized packaging or container that has been manufactured, assembled, and marked in accordance with the HMR. Thus, it is the opinion of this Office that the primary responsible party for ensuring a valid SP B81 approval is obtained prior to offering the tank car for transportation is the shipper of the tank car. See § 173.22(a)(2)(i) through (v).

Q2. You ask whether a PRD approved in accordance with SP B81 would be specific to a designed system or can the same approved PRD be used for either a tank car or cargo tank.

A2. It is the opinion of this Office that venting and PRDs approved in accordance with SP B81 would be specific to a designed system for a tank car or cargo tank and not transferrable for use on other tank cars or cargo tanks. Moreover, an approved PRD for a specific system designated in the approval application could not be installed on a different tank car or cargo tank that is not part of the application without prior approval from PHMSA's Associate Administrator of the Office of Hazardous Material Safety.

Q3. You ask whether there is a list of PRDs approved under SP B81 and—if so—can those approved PRDs be integrated into future designs without requesting approval from PHMSA's Associate Administrator of the Office of Hazardous Material Safety.

A3. The answer is no. There is no approved list of PRDs and vents authorized under SP B81, as each approved PRD and vent authorized for use is based on the specifics in an approval application submitted to PHMSA.

Q4.    You ask whether PHMSA agrees there is no requirement for a Competent Authority Approval (CAA) when shipping "UN2015, Hydrogen peroxide, stabilized or Hydrogen peroxide aqueous solutions, stabilized with more than 60 percent hydrogen peroxide, 5.1, PG I" internationally by vessel in accordance with the International Maritime Dangerous Goods (IMDG) Code. Specifically, if a United Nations (UN) portable tank complies with portable tank instruction "T9" of section of the IMDG Code—which requires "normal" PRD requirements—then there is no associated CAA necessary.

A4. There is not a requirement to obtain a CAA provided the shipment of "UN2015" satisfies the requirements of the IMDG Code. A UN portable tank in compliance with the requirements for "T9" and any additional requirements of Part 171 Subpart C—as applicable—would not be required to obtain a SP B81 approval for venting and pressure relief devices in accordance with § 172.102(c)(3) as generally "B" code requirements do not apply to UN portable tanks or IBCs.

I hope this information is helpful. Please contact us if we can be of further assistance.


Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

173.22(a)(2)(i) through (v), 172.102(c)(3)

Regulation Sections

Section Subject
172.102 Special provisions
173.22 Shipper's responsibility