Six Facts Needed Before the Overpack Decision

Do not begin with the stretch wrap. Begin with the dangerous goods and the packages that will be placed inside it.

1. Battery chemistry, UN entry and condition
   Confirm whether the shipment contains lithium-ion or lithium-metal cells or batteries, the supplied UN entry, the model, rating or lithium content, and whether the batteries are new, used, damaged, defective, recalled or intended for recycling. Use the separate UN3480 versus UN3481 and UN3090 versus UN3091 guides for configuration orientation; they do not replace trained classification.

2. Shipping configuration
   Identify whether the batteries are shipped alone, packed with equipment or contained in equipment. A product name such as “power bank,” “tool set” or “spare battery” cannot make this decision by itself.

3. Packing instruction and section
   Record the current packing instruction, section, aircraft limitation and any other branch selected by appropriately trained personnel. Do not transfer conditions from one branch to another.

4. Each completed package
   Record the package count, contents, battery quantity, gross mass, dimensions, closures, required marks and labels, and package condition before unitization.

5. The proposed handling unit
   Describe the pallet, crate, master enclosure, wrap, bands and corner protection. State whether the construction is open, transparent, partly obscuring or opaque.

6. Other goods, route and operator
   List other dangerous and non-dangerous goods proposed for the same unit, the origin, transit and destination points, and the intended airline or handling chain.

If one of these facts is missing, an image of a finished pallet is not enough to decide the overpack requirements.

What Is an Overpack in Air Dangerous-Goods Shipping?

In practical terms, an overpack is an enclosure used by one shipper to contain one or more packages and make them easier to handle and stow. A pallet with packages secured by straps or film may be an overpack, but the actual construction and use must be reviewed. The word used by a warehouse or supplier is not conclusive.

The physical levels matter because requirements attach to different objects:

This distinction is especially important when a supplier calls one large outer carton a “master carton.” It may be a package, an overpack or a non-regulatory commercial description. The internal packing arrangement and the applicable instruction must be examined before assigning the level.

Is This Unit a Package, Pallet or Overpack?

Use the following decision sequence as a preparation aid, not as a substitute for trained review:

1. Identify the completed packages

Find the units prepared under the applicable packing instruction. Record their contents, closures, weights, dimensions and required external information. Do not assume that the retail box is the package.

2. Identify the additional enclosure

Determine whether one shipper is adding a pallet, wrap, crate, box, sleeve or other enclosure around one or more completed packages for convenient handling or stowage.

3. Review the completed construction

Record whether the additional layer leaves every required package face visible, partly hides it or fully obscures it. Inspect the finished handling unit, not an empty pallet or an unwrapped staging photograph.

4. Confirm its regulatory treatment

Ask the responsible dangerous-goods party to confirm whether the arrangement is an overpack and which current provisions apply. Escalate any uncertainty involving a single large enclosure, mixed goods, airline loading equipment or a branch-specific exception.

The following examples are orientation only:

• Several marked cartons secured to an open pallet may retain visibility, but the final arrangement still needs an overpack-status and securing review.
• Opaque stretch wrap around several packages may obscure information and trigger an external reproduction decision.
• Several compliant packages placed inside one master enclosure may form an overpack, depending on the actual arrangement and applicable rules.
• One outer carton containing batteries directly under the packing instruction may be the package, even if the warehouse calls it an overpack.

Every Package Must Comply Before It Is Overpacked

Overpacking occurs after the package-level preparation decisions. The additional handling layer does not replace them.

Before unitization, confirm for each package:

• the battery identity, chemistry, UN entry and shipping configuration;
• the applicable packing instruction, section and aircraft limitation;
• terminal protection, separation, cushioning and movement control;
• permitted contents and quantity at package level;
• applicable package construction, closure and capability;
• required package marks and labels; and
• a sound, undamaged condition suitable for transport.

For the complete packaging-system review, use Lithium Battery Packaging for Shipping. For package-level air quantities, use Lithium Battery Air Shipping Quantity Limits.

Where a packing branch requires 3 m stack capability or 1.2 m drop capability, the relevant package must meet that requirement. A strong pallet, crate or stretch-wrapped overpack does not transfer its strength to the package inside. See the separate guides to the 3 m stack requirement and 1.2 m drop requirement.

When Must Marks and Labels Remain Visible or Be Reproduced?

First determine which marks and labels each package requires. Task 63 does not replace that package-level decision. The guide to Lithium Battery Marks and Labels for Shipping owns the selection and presentation of the individual regulated items.

Then apply the overpack visibility review:

1. Photograph all relevant package faces before unitization.
2. List the required regulated information already present on each package.
3. Complete the pallet, wrap, crate or other enclosure.
4. Inspect the finished unit from every relevant side.
5. Record which package information remains visible and legible.
6. Where information is not visible, determine what the current rule requires to be reproduced outside.
7. Determine whether the word OVERPACK is required for the actual arrangement.
8. Photograph the finished unit and compare it with the package inventory and shipping records.

Do not use the word OVERPACK as a generic warehouse label. It has a regulatory purpose, and its presence does not compensate for missing required marks or labels.

Transparent film also requires judgment. It may preserve a line of sight, but glare, folds, condensation, overlapping packages, straps or multiple layers can make information unreadable. Verify the actual finished unit under ordinary handling conditions instead of assuming that “clear” always means “visible.”

Opaque film or covers are not automatically prohibited by this article. They simply make the visibility and reproduction decision unavoidable. The current rule, the actual package information and the intended operator must decide the correct result.

Package Limits and Overpack Totals Are Different Levels

Many lithium-battery air limits are stated per package. Other provisions may control the number of packages in a consignment, the use of an overpack or the aircraft on which the goods may travel. These levels must not be combined into one informal “total battery weight” rule.

For example, placing three individually compliant packages into one overpack does not turn them into one package for the purpose of a per-package limit. Conversely, the fact that each package is within its own limit does not automatically decide every consignment, overpack, segregation or operator condition.

There is no useful universal overpack-quantity calculator for all lithium-battery air shipments. The responsible party must first identify the actual UN entry, configuration, packing instruction, section, quantity basis and current variations.

Secure Packages Without Hiding or Damaging Them

An overpack should remain a safe handling unit throughout normal transport and transfer. The package condition after unitization matters as much as the condition before wrapping.

Check that:

• packages cannot shift into a damaging position;
• straps and bands do not crush cartons or cut into package surfaces;
• corner protection does not cover required information unless the applicable information is correctly reproduced;
• closures remain effective and are not disturbed by the unitization process;
• intended package orientation is preserved;
• heavy packages cannot damage lighter packages;
• protrusions, pallet boards or nails do not puncture packages;
• wrap does not conceal leakage, deformation or damage; and
• the final dimensions and gross mass remain suitable for the planned handling chain.

The overpack should not be described as “tested” or “certified” merely because it is stable in a warehouse photograph. Physical stability, regulatory package capability, correct hazard communication and airline acceptance are different questions.

Check Compatibility and Segregation Before Combining Packages

Do not assume that all compliant packages may be placed together in one overpack. Inventory every package and identify any other dangerous goods proposed for the same handling unit.

The review should capture:

• every dangerous-good UN entry and hazard class or division supplied by the responsible party;
• every applicable subsidiary risk and handling label;
• the number and position of each package;
• relevant package orientation;
• materials or goods that could react dangerously if released;
• current compatibility and segregation provisions; and
• more restrictive State, operator, airport or handling requirements.

A generic segregation chart copied from another mode of transport is not enough. Air requirements must be checked against the current air regulations and the actual goods. Mixed-dangerous-goods overpacks should be escalated to appropriately trained personnel and the intended operator before booking.

Reconcile the Overpack With Shipping Documents

The physical unit and the paperwork should describe the same shipment. A clean visual presentation cannot compensate for inconsistent package counts, weights or UN entries.

Compare the completed overpack with:

• the package inventory and package identifiers;
• battery models, chemistry, UN entries and configurations;
• net battery quantity or other applicable quantity basis for every package;
• package and overpack gross weights and dimensions;
• package-level information visible through the completed enclosure;
• marks, labels and wording reproduced on the outside when applicable;
• the commercial invoice and packing list;
• the dangerous-goods declaration or other transport record when applicable;
• the booking description and aircraft limitation; and
• dated photographs before and after overpacking.

Use the Lithium Battery Shipping Documents Checklist for the wider technical, commercial, dangerous-goods, transport and customs record set.

Keep one traceable review record for the actual completed unit. A photograph from a previous shipment is not sufficient if the battery model, package, package count, arrangement, wrap, marks, route or operator has changed.

State and Operator Variations Can Change Acceptance

The international air framework does not remove route-specific conditions. Origin, transit and destination States may publish variations. Airlines may also impose conditions that are more restrictive than the regulatory baseline.

The FAA dangerous-goods shipping guidance describes the shipper's responsibility for correct classification, packaging, marking and labelling and notes that carriers can impose additional restrictions or prohibitions. This is an important responsibility principle, but U.S. guidance does not replace the rules applicable to a different jurisdiction or route.

Before offering the shipment, recheck:

• the effective ICAO Technical Instructions and updates;
• the effective IATA Dangerous Goods Regulations or other controlled source used by the responsible party;
• State variations for origin, transit and destination;
• operator variations and current carrier policy;
• terminal, airport and handling restrictions;
• Cargo Aircraft Only conditions where applicable; and
• booking and advance-approval requirements.

A shipment accepted last month is not automatic proof of acceptance today. Record the rule edition, variation check and operator response used for the current shipment.

Common Lithium Battery Overpack Errors

Calling one non-compliant master carton an overpack

If the carton directly performs the package function under the applicable instruction, it cannot avoid package requirements by being renamed an overpack.

Assuming every pallet is automatically an overpack

A pallet is a physical handling platform. The completed arrangement and use must be examined before deciding its dangerous-goods status.

Wrapping before recording the package information

Once opaque or reflective film is applied, package identifiers and regulated information may be impossible to verify. Photograph and inventory the packages first.

Hiding required information under film or straps

The final unit must be reviewed after all wrap, bands and protective materials are applied.

Adding OVERPACK but not reproducing obscured information

The word does not replace the marks or labels that the applicable provision requires outside.

Reproducing the wrong package information

An overpack review begins with correct package-level information. Copying an incorrect UN entry, mark or label creates a consistent-looking but still incorrect handling unit.

Using the overpack total to bypass a package limit

Per-package limits stay with each package. Overpack capacity does not enlarge them.

Treating overpack strength as package capability

A stable pallet does not prove that the applicable package satisfies its own stack, drop or other capability requirement.

Combining goods without a segregation review

Individually compliant packages may still be unsuitable for combination in the same overpack.

Allowing packages to shift, crush or lose orientation

Unitization must not damage packages or defeat their intended preparation.

Leaving counts and weights inconsistent with the records

The package inventory, overpack total, packing list, declaration when applicable and booking data should reconcile.

Treating prior acceptance as permanent approval

Regulations, variations, carrier policy, route and the physical shipment can change.

Pre-Enquiry Overpack Review Checklist

Before requesting an air-freight acceptance or quotation, confirm that:

• battery chemistry, UN entry, configuration and condition are supplied;
• the applicable packing instruction, section and aircraft limitation are identified by the responsible party;
• every package is correctly prepared and undamaged before unitization;
• package-level quantities and capability requirements are checked separately;
• required package marks and labels are recorded before overpacking;
• the pallet, enclosure, wrap and securing plan are described;
• overpack status is confirmed or escalated;
• packages are secured without damage, crushing or harmful movement;
• visibility, reproduction and OVERPACK wording decisions are documented;
• compatibility and segregation are checked for all contents;
• counts, quantities, weights, dimensions, records and photographs agree; and
• current State/operator variations and carrier acceptance remain to be checked.

This checklist is an information-gathering tool. It is not an IATA, ICAO, FAA or government form, and completing it does not approve the shipment.