The XYZs of Performance Packaging for Shipping Hazardous Materials

When in doubt, it makes sense to err on the side of safety.

"DADDY, what does that ugly white sign with a '1051 and a tiny six' mean on that big truck?" inquired an 8-year-old as a tanker truck barreled down I-95 within a quarter mile of a Greenwich, Conn., high school. Although her well-educated dad's response would hardly mimic, "Gosh, Sarah, I believe that was a mobile package of hydrogen cyanide, one of the 10 percent most dangerous chemical compounds to human health and ecosystems," it would certainly be accurate.

With the media's focus on highway accidents involving bulk containers, resulting fatalities, and environmental pollution, we tend to forget the vast majority of hazardous materials are shipped in non-bulk containers such as paint cans, bottles, metal drums, pressurized cylinders, and cardboard boxes. Inside are flammable, corrosive, and poisonous liquids; gases; infectious substances; radioactive materials; and explosives, separated only by the containment method, the package. Further, anthrax incidents involving evacuations of city blocks remind us how easily dangerous biological agents might arrive in something as harmless as an envelope.

The purpose of this article is not to frighten, but rather enlighten. With more than a million non-bulk containers moving across North America daily, it's important to note that U.S. and Canadian governments have strict regulations in place for the carriage of dangerous materials via road, rail, sea, and air. This article will present a condensed view of non-bulk "hazmat" packaging requirements, focusing on packing groups and related performance ratings, with references for additional information.

The Regulations
Non-bulk packaging requirements in the United States are found in the Department of Transportation's 49 CFR, Part 173. In general, the Hazardous Materials Regulations (HMR) contained in this part are based on United Nations Recommendations, consistent with international regulations issued by the International Civil Aviation Organization (ICAO Technical Instructions) and International Maritime Organization (IMDG Code). Subpart E contains non-bulk packaging requirements for hazardous materials, other than Class 1 (explosives), and Class 7 (radioactive materials). Canadian regulations (TDGRs), a/k/a "Clear Language," also UN-based, offer reciprocity with 49 CFR when dangerous goods are shipped north of the border, and vice versa.

General Requirements
General standards for packaging can be found in Sections 173.24a and b. Included are specifics on compatibility (between package and contents, different chemicals in same package), closures, outage for liquids, cushioning for inner packaging, and filling limits.

Prior to transporting, one must determine whether a material is hazardous, then classify it (Class 1 thru 9, see Part 173) before proper packaging can be selected. Once the Shipping Description (proper Shipping name, Hazard class, Identification number and the Packing group) has been determined, Columns 8A and 8B on the Hazardous Materials Table (§172.101) will provide the exceptions (8A), as well as non-bulk packaging requirements (8B). Additional quantity and limitation for air transport can be found in Columns 9A and 9B.

Understanding Packaging Groups
With the exception of Class 2 compressed gases, Class 7 radioactive materials, and Division 6.2 infectious materials, there are three packing groups associated with hazardous materials. Packing groups are related to the degree of danger presented by the hazardous materials: PG I indicates great danger; PG II, a medium danger; and PG III, minor danger. Eventually, the packaging standard of the hazardous materials will be based on these packing groups, sometimes called "performance packaging."

For example, if Column 5 (§172.101 Table) includes a "III," it implies the contents (liquid or solid) require a minimum packaging standard (PG III, Z-performance). "I," on the other hand, indicates the maximum quality standard (PG I, X-performance) for most-dangerous contents. While performance level Z applies to PG III only, performance level Y can use PG II or III, and performance level X can use PG I, II, or III packaging groups. When in doubt, it makes sense to err on the side of safety.

Packaging Types
Non-bulk packaging includes various types of UN performance-tested containment (§173.202):

* Single packaging encompasses a variety of drums (e.g., steel, coded 1A1, 1A2), jerricans (e.g., plastic, coded 3H1, 3H2), wooden barrels (coded 2C1), and cylinders (metal, for compressed gas), which usually require no additional containment.
--Composite packaging "means a packaging consisting of an outer packaging and an inner receptacle, so constructed that the inner receptacle and the outer packaging form an integral packaging. Once assembled it remains thereafter an integrated single unit; it is filled, stored, shipped and emptied as such" (§171.8).

* Combination packaging means a combination of packaging, for transport purposes, consisting of one (or more) inner packaging secured in an outer packaging. It does not include a composite packaging.
--Outer packaging refers to the outer packaging component in which an inner package resides (e.g., a 4G fiberboard box that contains four plastic bottles). --Inner packaging (a/k/a "inner pack") means a packaging for which an outer packaging is required to transport it. --Overpacks (a/k/a "salvage packs") are used by a single consignor to enclose one or more complete packages, usually for convenience and/or extra protection. Overpacks must be labeled "Overpack used" and are not required to meet UN specifications (§171.8 and 173.25).

* Variation packages, also known as "V-boxes," are outer packaging (fiberboard, drums, boxes) allowed without testing inner packaging if certain criteria are met [§178.601(g)(2)]. Variation packaging must contain this outside marking (V):

* Exemption packaging is excused from specific packaging HMR requirements [e.g., hazmat label(s)], such as packaging requirements, per a DOT Exemption letter. Packages must be marked with "DOT-E _ _ _ _" and exempted for only a specific period of time.

* Limited quantities require "strong outer packaging" and permit small sizes of inner containers, vary by class, and cannot exceed 66 pounds gross weight (completed carton). For example, flammable liquids (Class 3, PG I) allow inner containers of 0.5 liters or less (§173.150).

Note: Above packaging types were intentionally selected and are not all-inclusive.

Non-bulk Package Testing

Whenever you see hazmat-labeled "cardboard" boxes in a truck, on a dock, or in a delivery person's arms, rest assured that it's not the same type of box seen at your local Wal-Mart. A good portion of hazardous materials are shipped in performance-oriented fiberboard boxes, either as composite or combination packaging. These packages must undergo a series of design-qualification and testing procedures by manufacturers, reflected by a "UN mark." The same is true for steel drums, paint cans, F-cans, and others, with markings on the bottom.

Design qualification testing includes vibration, drop, stacking, Cobb sizing (determines the absorption of water by paper), hydrostatic, leak-proofness, and cooperage test for bung-type wooden barrels (see Subpart M). At our firm, a full-time packaging specialist performs drop testing according to UN protocol. The following depicts a typical procedure for the drop test:

After filling six glass bottles with water, tightening plastic lids, placing in inner packaging and taping the outside, the person knows the completed package, as demonstrated by prototype testing, must be capable of sustaining each of the following drop tests from a height of 1.8 meters (5.9 feet) for PG I materials. They must be dropped "directly onto a solid unyielding surface without breakage or leakage from any inner receptacle and without a substantial reduction in the effectiveness of the package" (§178.603):

* One drop, flat on bottom;
* One drop, flat on top;
* One drop, flat on the long side;
* One drop, flat on the short side; and
* One drop on a corner at the junction of three intersecting edges.

"Drop testing is an important component of DOT testing protocol," says Packaging Specialist Jason Plizga. "If a hazardous liquid like bromine leaks during transport, people can die. Drop tests simulate (well beyond) what a normal package would encounter during shipping, even during mishaps."

In-house package testing is part of a corporate quality control strategy. Others may choose to outsource testing. Either way, if performed by qualified personnel who follow DOT protocol, it warrants the "UN" mark.

Package Selection and Proper Assembly
Here's a brief checklist to help mitigate packaging incidents:

* Always check packaging authorizations (§173.202 and §173.242) for allowed types. Use the Hazardous Materials Table (§172.101), with particular attention to Columns 5, 8a, 8b, for ground shipments. If shipping via air, note Column 9. Via sea, refer to vessel stowage limitations in Column 10.
* Next, make sure packaging is compatible with contents. For example, certain Class 8 solvents will corrode unlined metal cans.
* Be sure packaging is suitable for product's packing group (Column 5). Using a wrong packing type may result in a $1,200 fine (§172.202) and much more during litigation.
* Follow the packaging instructions! Chemical producers and packaging suppliers have spent much time and money to assure clarity and simplicity.

To be sure, proper packaging of hazardous materials can sometimes be a daunting task. The U.S. DOT and Transport Canada intentionally follow strict UN recommendations for global harmonization. More importantly, they have conditioned us to treat dangerous goods with special care--and have provided stringent packaging standards to keep us from harm's way. Perhaps the next time Sarah encounters hydrogen cyanide, she'll be in a high school chemistry class and never will encounter its almond-like odor.

This article appeared in the December 2005 issue of Occupational Health & Safety.

This article originally appeared in the December 2005 issue of Occupational Health & Safety.

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