Freight answersTransloading
How Is Freight Loaded into a Container for Export?
Short answer
Plan the load before the container arrives: stay within the container's payload and the road limits, spread the weight evenly along the floor with heavy items low and centered, block and brace so nothing can move at sea, use ISPM 15-marked wood packaging, determine the verified gross mass, and seal the doors with a high-security seal whose number goes on the shipping documents.
The packing code
The IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (the CTU Code) is a non-mandatory global code for packing and securing containers for sea and land transport.[1] Its key requirements include: "Do not exceed the permitted payload limits of the unit," "Do distribute heavy cargo appropriately over the floor area" and "Do load with the centre of gravity correctly located in the CTU," with the center of gravity close to half the width and below half the height of the cargo space.[2]
Checklist
- Plan by weight and cube. Check the container's rated payload and the road limits at both ends; U.S. Interstate limits are 80,000 lb gross and 34,000 lb per tandem.[7]
- Spread the weight along the floor, heaviest pallets low and centered, not bunched at the doors or the nose.[2]
- Block and brace gaps with dunnage, load bars or bracing so nothing can shift at sea or on the road.
- Use compliant wood. Pallets, crates and dunnage need ISPM 15 treatment and marking for most destinations; U.S. exporters can buy marked packaging or have it treated at a registered facility.[4] Domestic-only pallets are not marked.[5]
- Determine the VGM by weighing the packed container, or by weighing all contents and adding the tare with a certified method, and give it to the carrier in time for stowage planning.[3]
- Seal and record. Apply a high-security seal meeting ISO 17712 immediately after loading,[6] and record its number on the documents with photos of the loaded doors.
Example
An exporter's 20 pallets arrive at a transload dock in a 53-ft trailer on untreated domestic pallets. The freight is moved onto ISPM 15-marked pallets the shipper supplied, loaded into a 40-ft high cube with the heaviest pallets spread along the floor, braced at the doors, weighed for the VGM and sealed, and the seal number is sent to the forwarder.
Limitations
Destination rules, carrier requirements and hazardous cargo rules add their own steps. This is general guidance, not a load plan.
Related
Related terms
- TransloadingTransloading is moving freight from one type of transport equipment to another on the way to its destination...Glossary
- Verified Gross MassThe verified gross mass (VGM) is the total weight of a packed container, cargo plus packaging plus the...Glossary
- ISPM 15ISPM 15 is the international standard for wood packaging material, such as pallets, crates and dunnage, that...Glossary
- Container SealA container seal is a numbered, tamper-evident device locked through a container's door hardware after...Glossary
- DunnageDunnage is loose material used to support and protect cargo, such as boards, blocks, void fill and inflatable...Glossary
- Blocking and BracingBlocking and bracing is restraining cargo with structures placed against or around it, such as blocks...Glossary
- Shipping ContainerA shipping container is a standardized steel box, most often 20 or 40 feet long and 8 feet wide, built to...Glossary
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Related tools
Related guides
Sources
- International Maritime Organization, “IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (CTU Code),” International code of practice. Accessed September 30, 2026.
- International Labour Organization, IMO and UNECE, “CTU Code: IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (2014), full text,” International code of practice. Published 2014. Accessed September 30, 2026.
- International Maritime Organization, “Verification of the gross mass of a packed container,” International regulation summary. Accessed September 2026.
- USDA Animal and Plant Health Inspection Service, “Export ISPM 15-Compliant Wood Packaging Material From U.S.,” Government guidance. Accessed September 2026.
- U.S. Customs and Border Protection, “Frequently Asked Questions on Wood Packaging Materials,” Government guidance. Accessed September 2026.
- U.S. Customs and Border Protection, “CTPAT Minimum Security Criteria, U.S. Importers (October 2021),” Government program criteria. Published October 2021. Accessed September 30, 2026.
- Legal Information Institute, Cornell Law School, “23 CFR § 658.17, Weight,” Federal regulation. Accessed September 2026.
General operational information, not legal, customs or regulatory advice. Rules and rates change; confirm current requirements with the agency, carrier or contract that governs your shipment.