What Is UN 3091 Marking? Definition And Purpose

UN 3091 Marking is the UN identification marking for lithium metal batteries packed with or contained in equipment.

The UN 3091 Marking identifies shipments where lithium metal cells or batteries are transported either packed together with equipment, or installed/contained within equipment. It signals to carriers, handlers, and emergency responders that the package contains lithium metal batteries subject to specific handling and transport limitations. The marking is a first-line visual cue used alongside documentation and other label elements required by hazardous materials regulations.

What The Marking Covers

The marking applies to packages that meet the definition for UN 3091: shipments of lithium metal batteries packed with equipment or contained in equipment. This contrasts with UN 3090, which covers lithium metal batteries transported on their own (not packed with or contained in equipment). The marking is used across modal regulations (air, road, sea) where those regulations reference the UN numbers and their associated packing instructions or conditions.

• Scope: Packages containing lithium metal batteries installed in devices (e.g., watches, sensors) or batteries packed with devices (e.g., a battery placed in the same box with a camera) that meet the conditions for UN 3091.
• Exclusions: Cells or batteries shipped by themselves under UN 3090, or other battery chemistries such as lithium-ion which carry UN 3480/3481.

Why The Marking Matters

Regulatory compliance: Carriers and regulators use the marking to confirm the shipment matches the declared UN number and the required packing instructions. Mismarked packages can be refused carriage, result in fines, and create delays at border crossings.

Safety and emergency response: First responders and airline/port personnel rely on the marking to understand fire risk and to apply correct mitigation. Lithium metal batteries present high thermal-runaway and ignition risk if damaged or improperly packed; the UN 3091 marking helps identify that risk class quickly.

How The Marking Differs From Similar Marks

UN numbers differentiate the same hazard based on packaging context. The crucial differences are:

• UN 3090 vs UN 3091: UN 3090 is used for lithium metal cells and batteries by themselves; UN 3091 is specifically for those packed with or contained in equipment.
• UN 3480/3481 (Lithium-ion): These cover rechargeable lithium-ion chemistry — different UN numbers, packing rules, and limits apply.

How To Apply The Marking (General Guidance)

The marking must be durable, legible, and placed on the package such that it is readily visible at the time of offering for transport. While specific size and placement rules vary by mode and regulation, the following operational guidance reflects common requirements:

• Visibility: Place on the largest package surface so it won’t be obscured by other labels or shipping documents.
• Durability: Use labels or direct printing that withstand handling, moisture, and abrasion until delivery.
• Size: Follow modal rules — for air transport, ensure the mark meets ICAO/IATA guidance on size and format; for road/sea, follow 49 CFR and IMDG Code expectations.

Who Is Responsible For The Marking

The shipper (the person or company offering the package for transport) is primarily responsible for correct UN number selection and for affixing the required marking. Carriers, freight forwarders, and consolidators verify compliance during acceptance checks. In practice, the sequence is:

• Shipper: Determines classification (UN 3091 when applicable), packs to the correct packing instruction, completes the paperwork, and applies the marking.
• Carrier/Freight Forwarder: Performs acceptance checks, may refuse non-compliant packages, and ensures documentation accompanies the consignment.

Documentation And Operational Controls

UN 3091-marked packages are typically accompanied by dangerous goods documentation or a shipper's declaration where required by the mode of transport, and by internal controls such as WMS flags, packing checklists, and training records. Common elements include:

• Declaration: Dangerous goods declaration or equivalent statement that lists UN 3091 and the applicable packing instruction.
• Packing Instruction: Reference to the specific packing instruction used (e.g., IATA/ICAO packing instruction for lithium metal batteries packaged with equipment).
• Handling Notes: Internal routing and handling instructions for carriers and warehouse staff to avoid rough handling and to segregate from incompatible goods.

Practical Example

A manufacturer ships digital thermometers with non-rechargeable lithium metal batteries installed. The shipper classifies the consignment as UN 3091, packs each device in protective material inside a corrugated box, applies the UN 3091 marking to the box, completes the required dangerous goods paperwork, and notifies the carrier. At air acceptance, the agent verifies the mark and paperwork match — if they don’t, the consignment is rejected.

Tips For Warehouse And Logistics Teams

• Training: Ensure staff who pack and label batteries understand the difference between UN 3090, UN 3091, UN 3480 and UN 3481.
• Checklists: Use a packing checklist that verifies correct UN number, marking, documentation, and protective measures are in place before tendering.
• WMS Flags: Tag SKUs containing lithium metal batteries so picking, packing, and shipping workflows automatically trigger the correct handling steps.

In short, the UN 3091 Marking identifies lithium metal batteries packed with or contained in equipment and is a regulatory and safety control used across modes to ensure correct handling, documentation, and emergency response.