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Interpretation Response #10-0046

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

Interpretation Response Details

Response Publish Date: 04-01-2010
Company Name: North Carolina State Highway Patrol    Individual Name: Lt. D. R. Shackelford
Location state: NC    Country: US

View the Interpretation Document

Response text:

April 1, 2010




Lt. D. R. Shackelford
Assistant MCSAP Administrator
North Carolina State Highway Patrol
4702 Mail Service Center
Raleigh, NC 27699-4701

Ref. No. 10-0046

Dear Lt. Shackelford:

This responds to your November 13, 2009 email concerning the requirement of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) to secure packages in a motor vehicle. Specifically, you ask about securing propane cylinders in accordance with § 177.834.

According to your email, the propane cylinders are placed in recessed trays so that the base of each cylinder sits two inches below the horizontal edge of the tray. The trays may be stacked; however, whether stacked or unstacked, no tray or other device is placed on top of the cylinders. You provide pictures illustrating this method of securing the cylinders. Additionally, in a telephone conversation with a member of my staff, you noted that these trays are placed in a closed freight vehicle known a "mickey body" truck. It is your understanding from visual inspections that this method secures the cylinders against shifting, including overturning and ejection from the motor vehicle, under conditions normally incident to transportation and that the likelihood of damage to the cylinder valves is minimal. You ask if this method of securing the cylinders complies with § 177.834(a) or whether a locking ring or other device designed to secure the topmost cylinders is also needed.

Based on the information provided, it is the opinion of this Office that this method of securing the cylinders would achieve compliance with the general requirements of § 177.834(a) as well as the loading requirements specific to transport of Class 2 gases in § 177.840(a)(1). Therefore, so long as there is no shifting or overturning of the cylinders during normal transportation conditions, a locking ring or other method of securing the topmost cylinders is not required.

I hope this information is helpful. If you have further questions, please contact this office.


Charles E. Betts
Chief, Standards Development
Office of Hazardous Materials Standards 

177.834, 177.840(a)(1)

Regulation Sections

Section Subject
§ 177.834 General requirements