USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

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

Interpretation Response #21-0001

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

Interpretation Response Details

Response Publish Date:

Company Name: Oilmen’s Truck Tanks

Individual Name: Robert Strong

Location State: SC Country: US

View the Interpretation Document

Response text:

May 17, 2021

Robert Strong
Design Certifying Engineer
Oilmen's Truck Tanks
140 Cedar Springs Rd
Spartanburg, SC  29304

Reference No. 21-0001

Dear Mr. Strong:

This letter is in response to your December 31, 2020, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the motor vehicle transportation of packages containing diesel fuel and gasoline connected via piping. Specifically, you describe two scenarios, and ask whether the described package arrangements meet the requirements of the HMR. Additionally, you ask a question regarding the HMR's hazard communication requirements for each scenario.

Scenario #1: You describe a package arrangement consisting of multiple refueling tanks, each tank with a capacity of 119 gallons. The tanks are connected via piping with ball valves capable of isolating each tank.  The material intended for transportation in this scenario is diesel fuel. Although not explicitly described, for the purposes of this response, it is assumed that the diesel fuel in question has a flash point at or above 38 °C (100 °F), and, therefore, is eligible for the combustible liquid exception found in § 173.150(f).

Scenario #2: You describe a package arrangement consisting of multiple 119-gallon metal refueling tanks manufactured in accordance with Department of Transportation DOT special permit (DOT-SP) 14227. The tanks are connected via piping with ball valves capable of isolating each tank. The material intended for transportation in this scenario is gasoline.

We have paraphrased and answered your questions as follows:

Q1. You ask whether the package arrangement described in Scenario #1 meets the requirements of the HMR.

A1. The answer is yes, if the ball valves separating the individual tanks are in a closed position while in transportation. If there are no stop valves on each individual outlet preventing the flow of lading between tanks, and free flow between tanks is allowed during transportation, then the tanks would be considered a single bulk package and the requirements of § 173.150(f)(3) would apply, including marking and placarding. A hazardous material classed as a combustible liquid in a non-bulk package (capacity less than or equal to 119 gallons) is not subject to the requirements of the HMR (see § 173.150(f)(2)).

Q2. You ask whether the packaging arrangement described in Scenario #2 meets the requirements of the HMR.

A2. The answer is no.  DOT-SP 14227 prohibits manifolded packages; see section 7.c.(3) in the enclosed copy. Please note that packages connected by piping or tubing are considered "manifolded" for the purpose of DOT SP-14227, regardless of whether the valves are in the open or closed position.

Q3. For both scenarios, you ask whether placards are required on all four sides of each of the individual tanks, or all four sides of the transport vehicle.

A3. For Scenario #1 - No hazard communication is required, either on the tanks or the transport vehicle, if the valves are closed because non-bulk packages (119 gallons or less) containing a combustible liquid are not subject to the HMR requirements, including hazard communication for highway transportation. However, if any free flow exists between tanks during transportation, the individual tanks attached to the motor vehicle are considered a single bulk packaging (e.g., portable tank, IBC, or cargo tank, depending on how the packaging is constructed and used in transportation) and must comply with all applicable requirements including placarding requirements for a particular bulk package and the transport vehicle.

For Scenario #2 - The hazard communication requirements for DOT-SP 14227 packages are included in paragraph 7.c.(5) of the special permit, specifically that each tank must be marked and placarded in accordance with the requirements for Intermediate Bulk Containers (IBCs). However, the manifolded packages do not comply with the requirements of DOT-SP 14227, and, therefore, are not in compliance with the HMR (see § 171.2(g)).

Please note, the requirements for a commercial driver's license (CDL) (See 49 CFR Part 383) are under the purview of the Federal Motor Carrier Safety Administration (FMCSA). FMCSA is the lead Federal government agency responsible for regulating and providing safety oversight of commercial motor vehicles.

You may wish to contact FMCSA should you require clarification of any requirements relevant to CDLs.

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

171.2(g), 173.150(f), 173.150(f)(2), 173.150(f)(3)

Regulation Sections

Section Subject
171.2 General requirements
173.150 Exceptions for Class 3 (flammable and combustible liquids)