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Interpretation Response #12-0249 ([Praxair Distribution, Inc.] [Mr. David B. Sonnermann])

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

Interpretation Response Details

Response Publish Date:

Company Name: Praxair Distribution, Inc.

Individual Name: Mr. David B. Sonnermann

Location State: CT Country: US

View the Interpretation Document

Response text:

May 22, 2013


Mr. David B. Sonnemann
Manager, Transport Regulations and Fleet Safety
Praxair Distribution Inc.
39 Old Ridgebury Road
Danbury, CT  06810-5113

Reference No.: 12-0249

Dear Mr. Sonnemann:

This is in response to your November 06, 2012 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). You ask several questions concerning the definition of an overpack and marking and labeling requirements for cylinders in overpacks.  Your questions are paraphrased and answered below:

Q1) You request clarification as to whether the packaging configuration in the photo provided (Figure 1) is a unit load device.  Figure 1 consists of a deck plate and one or more railings to which cylinders are secured through the use of strapping.   You believe this configuration is not an overpack because (1) it is not an enclosure, (2) it meets the definition of a freight container in § 171.8 except for having a volume less than 64 cubic feet and (3) it is intended primarily for containment of packages in unit form.    

A1) The answer to your question is no.  The packaging configuration in your photo (Figure 1) does not meet the definition of a freight container or a unit load device.  However, this packaging configuration does meet the defining criteria for an overpack.  
As defined in § 171.8, a unit load device is “any type of freight container, aircraft container, aircraft pallet with a net, or aircraft pallet with a net over an igloo.”  And a freight container means “a reusable container having a volume of 64 cubic feet or more, designed and constructed to permit being lifted with its contents intact and intended primarily for containment of [smaller] packages (in unit form) during transportation.”  Since the packaging configuration in your photo (Figure 1) does not meet the definition of a freight container, or any of the other package types described in the definition of unit load device, this packaging configuration cannot be categorized as a unit load device.
In contrast, the definition for overpack in § 171.8, provides several examples of overpacks.  One such example is “one or more packages placed or stacked onto a load board such as a pallet and secured by strapping, shrink wrapping, stretch wrapping or other suitable means.”   This definition corresponds with the packaging configuration described in your letter.   

Q2) You request clarification on the requirement to display the “OVERPACK” mark when an overpack contains multiple packages with different specifications.  

A2) Section 173.25(a)(4) requires a shipper to mark the word “OVERPACK” on an overpack when specification packagings are required if the specification markings on the inside packages are not visible.  Unlike the marking and labeling requirements in § 173.25(a)(2), this provision does not exempt the overpack from being marked “OVERPACK” when a marking representative of each inner package is visible; rather, the marking on every inner package must be visible.  However, since specification markings are unlikely to be visible on the innermost packagings within an overpack and there is no basis to distinguish the requirements in § 173.25(a)(2) and (a)(4), it is reasonable for the “OVERPACK” mark to be required, unless specification markings representative of each type included in the overpack are visible, as stated in Letter of Interpretation 10-0149.  Therefore, PHMSA anticipates addressing this requirement in a future rulemaking.

Q3) You request acknowledgement that the labels shown in your photo (Figure 2) are visible as required by § 173.25(a)(2).

A3) The only visible label in Figure 2 is a neck ring label described in CGA Pamphlet C-7, Appendix A.  As provided by § 172.400a, a cylinder containing a Division 2.1, 2.2 or 2.3 material that is not overpacked is authorized to be marked in accordance with CGA Pamphlet C-7, Appendix A without further DOT labeling.  However, since the cylinders in Figure 2 are overpacked that exception does not apply and a hazard warning label must be applied to each cylinder.  

Additionally, the overpack must display appropriate marks and labels for each hazardous material contained in the overpack unless marks and labels representative of each hazardous material in the overpack are visible, as required in § 173.25(a)(2).  The portions of the cylinders shown in Figure 2 (i.e. the upper portions) do not display any visible markings or labels, so markings and labels are required on the overpack.  However, if unobscured markings and labels, representing each hazardous material in the overpack, are visible on the lower portions of the cylinders that are not depicted, that is acceptable.  (See 49 C.F.R. Part 172, subparts D and E.)

Q4) You request acknowledgement that a protective mesh attachment shown in your photo (Figure 3) is allowable for the purpose of safeguarding labels against abrasion and damage during transport.  You state that the labels are not obscured by markings or attachments when using the protective mesh.

A4) The mesh attachment pictured in the photo (Figure 3) you submitted does not appear to be consistent with § 172.406(f). The requirements for label visibility in § 172.406(f) specify that labels “must be clearly visible and may not be obscured by markings or attachments.”  The intent of this requirement is to ensure that hazard communication labels clearly illustrate the hazards presented within the package, and that the view of the required label is not obstructed by any additional markings or packaging accessories that may reduce the

effectiveness of the required hazard communication. As pictured, the mesh attachment in the photo you provided reduces the effectiveness of the label to convey the hazards represented within the package by partially obscuring the text on the markings and labels, making them difficult to decipher.

I trust this satisfies your inquiry.  Please contact us if we can be of further assistance.


Delmer Billings
Senior Regulatory Advisor
Standards and Rulemaking Division

171.8, 173.25, 172.406

Regulation Sections

Section Subject
171.8 Definitions and abbreviations
172.406 Placement of labels
173.25 Authorized packagings and overpacks