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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 #16-0203 ([AECOM] [Erin Jarman])

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

Interpretation Response Details

Response Publish Date:

Company Name: AECOM

Individual Name: Erin Jarman

Location State: NC Country: US

View the Interpretation Document

Response text:

May 22, 2017

Erin Jarman
Environmental Scientist
1600 Perimeter Drive, Suite 400
Morrisville, NC 27560

Reference No. 16-0203

Dear Ms. Jarman:

This letter is in response to your December 22, 2016, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the use of a cargo heater during the transportation of a Class 3 flammable liquid. You provide a scenario in which there is a closed trailer that has a retractable top and sides, allowing it to become similar to a flatbed truck during loading and unloading but to remain closed in transportation.

We have paraphrased and answered your questions as follows:

Q1. Noting that a closed trailer equipped with a cargo heater contains a Class 3 flammable liquid and does not meet the requirements of § 177.834(l)(2), you ask if the trailer may be transported provided the cargo heater remains off during transportation.

A1. The answer is yes. The requirements of § 177.834(l)(2) only apply to a cargo heater that is turned on or in use while in transportation. This Office further recommends rendering the heater inoperable to avoid opportunity for inadvertent activation.

Q2. You ask if the requirements of § 177.834(l)(2) apply provided the trailer described in the scenario has its top and sides fully retracted to become similar to a flatbed trailer during loading/unloading activities.

A2. See A1. If the cargo heater is not turned on (and inoperable) during loading/unloading and transportation, the requirements of § 177.834(l)(2) do not apply. However, if the cargo heater is turned on (and operable), the requirements of § 177.834(l)(2) apply. The HMR does not distinguish between a closed and flatbed trailer in regards to a motor vehicle equipped with an operable cargo heater.

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

Regulation Sections

Section Subject
177.834 General requirements