# AECOM — Hazardous Materials Safety Interpretation - **operation:** document - **citation:** 16-0203 - **title:** AECOM — Hazardous Materials Safety Interpretation - **source type:** guidance - **agency:** Pipeline and Hazardous Materials Safety Administration - **status:** guidance - **official:** true - **published on:** 2017-05-22 - **effective on:** Not available - **summary:** 16-0203 response to AECOM concerning 177.834. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-16-0203.json - **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-16-0203.md - **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-16-0203 - **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2017/160203.pdf **body:** <<>> of Transportation U.S. Department 1200 New Jersey Avenue, SE Materials Safety Pipeline and Hazardous Washington, DC 20590 Administration Erin Jarman Environmental Scientist MAY 2 2 2017 AECOM 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(1)(2), you ask if the trailer may be transported provided the cargo heater remains off during transportation. Al. The answer is yes. The requirements of § 177.834(1)(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(1)(2) apply provided the trailer described in the loading/unloading activities. scenario has its top and sides fully retracted to become similar to a flatbed trailer during 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(1)(2) apply. The vehicle equipped with an operable cargo heater. HMR does not distinguish between a closed and flatbed trailer in regards to a motor I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely. Dirk Der Kinderen Chief, Standards Development Branch Standards and Rulemaking Division <<>> Luccoro 5177,834(1) AECOM General AECOM 16-0803 Requiemen Morrisville, NC 27560 1600 Perimeter Drive, Suite 400 919 461 1100 919 461 1415 fax December 22, 2016 www.aecom.com Mr. Charles Betts, Division Director Standards and Rulemaking (PHH-10) U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration East Building, 2nd Floor 1200 New Jersey Ave., SE Washington, DC 20590 Dear Mr. Betts: I am writing to request a written Department of Transportation (DOT) interpretation concerning the use of cargo heaters in a motor vehicle with a closed trailer when transporting Class 3 flammable liquids. The particular closed trailer in question has retractable top and sides, where it basically becomes a flatbed truck during loading and unloading activities, but remains closed in transport. As set out in 49 CFR 177.834(I), there is a requirement whereby a motor vehicle equipped with a combustion cargo heater may be used to transport Class 3 (flammable liquid) materials only when certain conditions are met. The cargo heater meets all required criteria in 49 CFR 177.834(I). Question 1: If the above-described motor vehicle with a closed trailer does not meet all of the requirements set out in 49 CFR 177.834(I), but the cargo heater is never turned on during transportation, would the cargo heater be allowed to remain in the closed trailer during transportation? [For example, electrical apparatus retrofitted into the trailer is not certified non-sparking or explosion proof as required by 49 CFR 177.834(I)(2)(i)(A)(1), but the electrical equipment is never turned on in transportation.] Question 2: If the trailer with retractable top and sides is positioned such that the top and sides are fully retracted and the cargo heater is not turned on, and the trailer essentially becomes a flatbed truck during loading/unloading activities, would the requirements of 49 CFR 177.834(l) apply, as trailer is fully open and not functioning as a closed trailer? I appreciate your assistance with these questions. Sincerely, Erin N. Jarmar Erin N. Jarman Environmental Scientist AECOM - **truncated:** false - **body characters:** 4260