Strong Outer Packaging

Written on: January 18, 2016 by SprayTM

One of the most significant advantages of shipping dangerous goods as limited quantities is that expensive United Nations (UN) Performance Oriented Packaging (POP) is not required.
The provisions of the 49 CFR subchapter C Hazardous Materials Regulations (HMR), the International Civil Aviation Organization (ICAO) Technical Instructions for the Transport of Dangerous Goods by Air and the International Maritime Dangerous Goods (IMDG) Code each offer substantial regulatory relief from the use of packaging that has been subjected to very stringent and expensive design qualification testing, including drop, vibration and stacking tests. In lieu of using UN POP, shippers may use strong outer packaging.

Strong Outer Packaging
Strong outer packaging is defined as “…the outermost enclosure that provides protection against the unintentional release of its contents. It is a packaging that is sturdy, durable and constructed so that it will retain its contents under normal conditions of transportation.”

Strong outer packaging must meet the general packaging requirements of 49 CFR part 173, subpart B but need not comply with the specification packaging requirements prescribed in part 178 of the HMR. Strong outer packaging intended for transport by aircraft are also subject to §173.27 of the HMR.

To qualify as a strong outer packaging, the packaging must meet the following requirements:

  • Be designed, constructed, maintained, filled, its contents so limited, and closed, so that under conditions normally incident to transportation, there will be no identifiable release of hazardous materials to the environment;
  • The effectiveness of the package is not substantially reduced;
    It has sufficient impact resistance, strength, and is capable of withstanding minimum and maximum temperatures, changes in humidity and pressure, and shocks, loadings and vibrations, normally encountered during transportation;
  • It is compatible with its lading, particularly with respect to corrosivity, permeability, softening, premature aging and embrittlement;
  • There is no significant chemical or galvanic reaction between the materials and contents of the package; and
  • Any closure is leakproof and secured against loosening.

Packaging used for solids, which may become liquid at temperatures likely to be encountered during transportation, must be capable of containing the hazardous material in the liquid state.

Air Transportation
Packaging hazardous materials for transport by aircraft is usually more restrictive than for ground transport. In addition, many carriers may also require a higher level of packaging safety than required by the U.S Dept. of Transportation (DOT) due to its unique system of moving packages.
Strong outer packaging that is intended for the transport of limited quantities of dangerous goods by air must also conform to the applicable provisions of 49 CFR §173.27. When a limited quantity of hazardous material packaged in a combination of packaging is intended for transportation aboard an aircraft, the inner and outer packaging must conform to the quantity limitations outlined in 49 CFR §173.27(f)(2) Table 3 (shown below).

Other Standards for Strong Outer Packaging
Packaging that meets the requirements of International Safe Transit Association (ISTA) Procedure 3A test requirements may qualify as “strong outer packaging.” ISTA Test Procedure 3A is a general simulation test for individually packaged products shipped through small parcel delivery systems. This test is appropriate for four types of commonly distributed parcels, transported by ground or air, including standard, small, flat and elongated packages.

ISTA Procedure 3A includes an optional test combining Random Vibration Under Low Pressure (which simulates high altitudes). This test procedure tests the container’s ability to hold a seal or closure and the retention of the liquids, powder or gaseous contents without leaking.
Some carriers, such as United Parcel Service of America, Inc. (UPS), require packages containing limited quantities of hazardous materials to have a minimum burst strength of 200 lbs, or qualify as a 32 Edge Crush Test (ECT) certified box. The box must also be of sufficient strength to protect the

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contents while in transit.

Any non-specification package that displays the ISTA seal indicating the package has been tested and certified to ISTA Procedure 3A is not subject to the minimum ECT or burst strength requirements.
Regardless of what standard is used, shippers have a responsibility to ensure that the packaging used for the carriage of dangerous goods in limited quantities are capable of withstanding the forces that are typically encountered in transportation.

For additional information on limited quantity packaging, contact the U.S. Dept. of Transportation Pipeline & Hazardous Materials Administration (PHMSA) website at or ShipMate, Inc. at (310) 370-3600. Spray