Stuffing Guide

The efficient loading of cargo in sea freight containers is both an art and a science. It allows the cargo to reach its destination intact in a safe and timely manner. To achieve this, the importance of following best practices for packing, stowing and securing goods inside the container cannot be underestimated.

Dry Cargo


The best practices for loading and unloading dry cargo in general purpose containers comprise the below steps:

Basics

  • Arrange for a safe working environment.
  • Use safe handling equipment and personal protective equipment.
  • Check that the container and any cargo securing equipment are in sound condition.
  • Check that no self-adhesive labels from previous cargo exist (e.g. IMDG placards).
  • Do not smoke, eat or drink during packing, stowing, securing or unpacking.

Planning

  • Choose the most suitable container type to accommodate the cargo.
  • Select the securing methods best adapted to the characteristics of the cargo, the mode of transport and the properties of the container.
  • Do not exceed the maximum payload of the container or the maximum allowed gross mass according to the CSC plate, national road and rail regulations.
  • Consider recipient’s possibilities for unloading cargo from the container.
  • Consider palletization or slip sheets to increase efficiency on handling unit loads.

Packaging Tips

  • Homogeneous Cargo – if the load consist of homogenous cargo (and all the cargo is the same size), the total volume of the container should be utilized.
  • Cartons and Packages – it is important to follow any instructions printed on the cartons, e.g. particular side up for bottles of wine which required corks to remain immersed. A “Bonded Block Stow” ensures greater stability and spreads the weight as evenly as possible.
  • Bagged Cargo – the normal practice is to stow bags in interlocking layers because bagged cargo tends to settle during transit causing pressure on side walls. Bags that are not stowed on pallets may pose the risk of falling out of the container when the doors are opened. To avoid this, a net or brace should be placed against the final row.
  • Drums and Barrels – they should always be upright if possible. If the bung or closure is at one end, then it should be stowed with the bung uppermost. Unless the drums or barrels are specially designed to “nest”, there should be some sort of soft dunnage or ply between each tier of drums. Dunnage should be laid close enough to provide full support to the tier above.
  • Rolls – they should be packed closely together when they are stowed upright. Any empty spaces between the rolls should be filled in by sacks of sawdust, corrugated cardboard or similar soft dunnage. The rolls should be secured using timber, nets or wedges.

Palletization

  • When using pallets, it is preferable to choose one of the two widely accepted sizes: the Standard type (1,000 x 1,200 mm) or the “Europallet” (800 x 1,200 mm). As a rule of thumb, a 20’ long container can take eleven europallets in one deck, or nine to ten standard pallets in one deck. A 40' long container can take 23-24 europallets in one deck, or 20-21 standard pallets in one deck.
  • Pallet-wide containers allow taking advantage of their greater width since they can accommodate more europallets than standard-width containers. The table below provides a quick comparison of the capacity in the number of pallets between regular 40’ and 45’ long containers and their pallet-wide (PW) versions.
40' 40' PW 45' 45' PW
1 m x 1.2 m Standard pallets 21-22 24 24 26
0.8 m x 1.2 m Europallets 25 30 27 33-34

Packing of Goods

  • Observe all handling instructions and symbols on packages such as "this side up".
  • Distribute heavy cargo appropriately over the floor area.
  • Avoid concentrated loads.
  • Load with the center of gravity correctly located in the container.
  • Do not concentrate heavy cargo on small areas of the floor.

The cargo should be lay over as many floor crossmembers as possible so that the weight distribution is as close as possible to the ideal one, based on container maximum payload and length. For example, the limit for a 20’ dry container is about 5 tons per linear meter, based on maximum payload 28 tons and 6 m length.

A quick rule of thumb is:

Cargo distribution over container length 50% 66% 75% 100%
Maximum container payload 66% 75% 80% 100%
  • Do not load with eccentric load distribution.
  • Do not build up irregular layers of packages.
  • Do not stow heavy goods on top of light goods.
  • Do not stow goods with tainting odors together with sensitive goods.
  • Do not pack wet and damp goods.
  • Do not use securing or protecting equipment that is incompatible with the cargo.

Packing of Dangerous Goods

  • Check that all packages are properly marked and labeled.
  • Pack dangerous goods according to applicable dangerous goods regulations.
  • Pack dangerous goods near the container door.
  • Attach required placards, marks and signs on the exterior of the container.
  • Do not pack incompatible goods that should be segregated.
  • Do not pack damaged packages.

Stowing Loads

  • Allow easy cargo handling with forklifts and other equipment.
  • Restrict total weight to the maximum payload limit.
  • Distribute cargo weight as evenly as possible.
  • Fill void spaces when necessary with dunnage such as timber beams, empty pallets, plastic foam or inflatable bags.
  • Avoid using dunnage on edge.
  • Stow the cargo in a way that forces are distributed over an appropriate area of a unit (e.g. stacking with intermediate boards).
  • Secure each single loaded item independently where necessary.
  • Use non-slip surface material to refrain packages from sliding where appropriate.

Stowing goods against the side walls with dunnage and air bags.

Irregular shaped packages blocked with dunnage bags.

An example of gap filled with a central dunnage bag.

Securing Loads


  • Use blocking or lashing, or a combination of these methods, to prevent the cargo from sliding, bouncing and tipping in any direction.
  • Use hooks or shackles to fasten lashings where applicable.
  • Arrange bracing and shoring that stays intact and keeps cargo in place.
  • Do not secure the cargo with devices overstressing the structure of the container or the cargo.
  • Do not overstress securing devices.
  • Do not over tighten securing devices so that the packaging or goods are damaged.
  • Do not fasten web lashings by means of knots.
  • Protect edges where lashing material passes over with appropriate edge protectors.

Securing against movements lenghtwise with wooden beams.

Proper use of textile lashing.

Proper use of transverse bracing.

Proper use of shoring arrangements.

Examples of lashing against sliding and tipping.

Poor edge protection.

After completion of loading


  • Determine the correct cargo weight of the container.
  • Affix a seal when required.
  • Obtain the verified gross mass (VGM) of the container.
  • Include the container number, the correct gross mass and, when required, the seal number and VGM in the appropriate documents.
  • Provide a packing certificate when required.

Unloading at destination


  • Check that the container identification number and the seal serial number, match the ones on the transport documentation.
  • Check the exterior of the container for signs of leakage or infestation. Examine the container for any signs of wet stains or holes in the sides or roof.
  • Use proper equipment to cut the seal if affixed.
  • Ensure the container is safe to enter. Be aware that the atmosphere in the container may be dangerous – ventilate before entering.
  • Open the container with caution as cargo might fall out.
  • Record every package as it is removed noting any markings and damages.
  • Remove all securing and protection material for reuse, recycling or disposal.
  • Clean the interior of the container to remove all traces of the cargo, especially loose powders, grains and noxious materials and fumigants, unless otherwise agreed with the container operator.
  • Remove all marks, placards and signs regarding the previous consignment from the exterior of the container once it has been cleaned.

  The person who packs and secures cargo into/onto a container may be the last person to look inside the container until it is opened at its final destination. Many people in the transport chain will rely on the skill of such persons. That is why staffing up and preparing in advance to load and unload a container will help avoid mistakes and hazards, save costs, and get the cargo to the destination safely on time.


These guidelines do not cover bulk cargo in bulk containers, or the filling or emptying of tank containers.


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Frozen and Chilled Cargo


  • Think carefully about the factors affecting the ‘shelf life’ of perishables.
  • Set the reefer at the optimal temperature, ventilation and humidity level.
  • Power off the reefer during stuffing to avoid ambient air exchange.
  • For fruits and vegetables, use ventilation with fresh air or absorbing material to reduce the effects of carbon dioxide and ethylene.
  • Frozen cargo needs pre-freeze before stuffing and make sure the fresh air ventilation is closed.
  • Chilled cargo needs pre-cool before stuffing and shippers have to set the unit at carrying temperature and adjust fresh air ventilation required.
  • Stow the cargo evenly to maximize stability and cover the entire floor (e.g. use filler, board or dunnage material) to avoid gaps and improve airflow.
  • Do not stow cargo over the red load line to ensure optimal air flow and temperature distribution.
  • Make sure the airflow is not restricted by cargo or packaging materials. Especially for chilled perishable cargo, there must be ventilation holes at both the top and bottom of each carton to allow free passage of cold air through the entire load.
  • Run the refrigeration unit until the doors are about to be opened for unpacking.
  • Check temperatures of packages from various sections of the load.
  • Record the positions of any damaged cargo to identify the reason of damage.

Maximum cargo height indicated by a red line.

Example of proper airflow circulation in a reefer container.

Recommended conditions for Reefer Cargo

The following table shows the recommended transport conditions and approximate shelf life after harvest (in ambient air) for selected commodities carried in standard refrigerated containers.

Commodity Temperature
(ºC)
Fresh-air ventilation
(cbm/h)
Humidity relative
(%)
Approximate shelf life after harvest
Apples –1 ~ +4 10 ~ 60 90 ~ 95 1 ~ 7 mo
Apricots –0.5 ~ 0 15 ~ 60 90 ~ 95 1 ~ 4 wk
Artichokes 0 ~ +2 0 ~ 15 90 ~ 95 2 ~ 3 wk
Asparagus 0 ~ +2 15 ~ 25 90 ~ 98 2 ~ 3 wk
Avocados +4 ~ +13 30 ~ 60 85 ~ 95 2 ~ 3 wk
Bakery products +10 ~ +18 0 (closed) 60 ~ 95 depends on commodity
Bakery products (frozen) –18 or colder 0 (closed) 3 ~ 18 mo
Bananas +13 ~ +14.4 25 ~ 60 90 ~ 95 18 ~ 22 days
Beans, green, snap +4 ~ +7.5 20 ~ 30 95 ~ 98 7 ~ 10 days
Blueberries –1 ~ 0 0 ~ 10 90 ~ 95 10 ~ 14 days
Broccoli 0 ~ +1 20 ~ 60 90 ~ 98 10 ~ 14 days
Butter 0 ~ +8 0 (closed) 2 ~ 6 wk
Butter (frozen) –18 or colder 0 (closed) 8 ~ 12 mo
Cabbage, Chinese 0 ~ +2 20 ~ 60 90 ~ 98 2 ~ 3 mo
Cabbage, early 0 ~ +2 20 ~ 60 90 ~ 98 3 ~ 6 wk
Cabbage, late 0 ~ +2 20 ~ 60 90 ~ 98 5 ~ 6 mo
Carrots 0 ~ +2 10 ~ 20 90 ~ 98 1 ~ 9 mo
Cassava, yuca, manioc 0 ~ +5 10 ~ 20 85 ~ 90 1 ~ 2 mo
Cauliflower 0 ~ +1 20 ~ 60 90 ~ 98 2 ~ 4 wk
Cheese 0 ~ +18 0 (closed) depends on variety
Cherries –1 ~ 0 0 ~ 15 90 ~ 95 2 ~ 3 wk
Chocolate +8 ~ +18 0 (closed) 65 ~ 85 5 ~ 15 mo
Cocoa butter +15 ~ +25 0 (closed) 12 ~ 24 mo
Coconuts, dehusked 0 ~ +2 0 ~ 25 75 ~ 85 1 ~ 2 mo
Codfish, dried, salted +1 ~ +3 0 (closed) 65 ~ 70 12 mo
Corn –0.5 ~ +1 10 ~ 15 90 ~ 98 5 ~ 8 days
Cucumbers +10 ~ +13 15 ~ 25 90 ~ 95 10 ~ 14 days
Dates 0 ~ +2 0 ~ 5 65 ~ 85 6 ~ 12 mo
Eggplants, aubergine +8 ~ +12 10 ~ 15 90 ~ 95 1 ~ 2 wk
Eggs, dried, whole solids +4 ~ +10 0 (closed) 1 ~ 2 years
Eggs, with shell –1 ~ +3 0 (closed) 5 ~ 6 mo
Figs -0.5 ~ 0 0 ~ 5 85 ~ 90 7 ~ 10 days
Fish (frozen) -18 or colder 0 (closed) 4 ~ 12 mo
French fries, potato wedges (frozen) -18 or colder 0 (closed) 12 ~ 24 mo
Fruit (frozen) -18 or colder 0 (closed) depends on commodity
Garlic –3 ~ +1 0 ~ 15 60 ~ 70 6 ~ 7 mo
Ginger +12 ~ +14 10 ~ 15 65 ~ 75 2 ~ 3 mo
Grapefruit +10 ~ +15 15 ~ 50 85 ~ 90 1 ~ 2 mo
Grapes –1 ~ 0 10 ~ 15 85 ~ 95 1 ~ 5 mo
Honey, strained +10 ~ +20 0 (closed) 1 ~ 2 years
Ice cream, dairy desserts (frozen) –26 or colder 0 (closed) 4 ~ 6 mo
Juice, concentrate, fruit (frozen) –18 or colder 0 (closed) 1 year
Kiwifruit –0.5 ~ +5 20 ~ 40 90 ~ 95 2 ~ 3 mo
Lemons +10 ~ +14 15 ~ 25 85 ~ 95 1 ~ 3 mo
Lettuce 0 ~ +1 20 ~ 50 90 ~ 98 2 ~ 3 wk
Limes +8 ~ +12 15 ~ 25 85 ~ 90 2 ~ 5 wk
Lychees +2 ~ +6 10 ~ 15 90 ~ 95 3 ~ 5 wk
Mandarins, clementines, tangerines +4 ~ +8 15 ~ 25 90 ~ 95 3 ~ 8 wk
Mangoes +8 ~ +14 25 ~ 30 85 ~ 95 2 ~ 4 wk
Margarine 0 ~ +8 0 (closed) 4 ~ 5 mo
Meat –2 ~ –1 0 (closed) 1 ~ 8 wk
Meat (frozen) –18 or colder 0 (closed) 6 ~ 18 mo
Melons, cantaloupe, charentais +2 ~ +5 25 ~ 30 90 ~ 95 1 ~ 2 wk
Melons, galia, orange flesh +7 ~ +8 25 ~ 30 90 ~ 95 2 ~ 3 wk
Melons, water, honeydew +9 ~ +12 25 ~ 30 85 ~ 95 2 ~ 3 wk
Milk, dried +7 ~ +21 0 (closed) 6 ~ 9 mo
Milk, pasteurized 0 ~ +1 0 (closed) 2 ~ 4 mo
Mushrooms 0 ~ +1 0 ~ 10 90 ~ 98 5 ~ 7 days
Onions, bulbs 0 ~ +8 10 ~ 40 65 ~ 75 2 ~ 9 mo
Oranges +2 ~ +10 15 ~ 25 85 ~ 90 1 ~ 3 mo
Papayas +7 ~ +13 25 ~ 30 85 ~ 90 1 ~ 3 wk
Peaches, nectarines –0.5 ~ 0 15 ~ 25 90 ~ 95 2 ~ 5 wk
Pears –1.5 ~ 0 15 ~ 25 90 ~ 95 1 ~ 8 mo
Peas, snow, sugar snap 0 ~ +1 15 ~ 25 90 ~ 98 1 ~ 2 wk
Peppers, bell, sweet, chili +7 ~ +10 10 ~ 15 90 ~ 95 2 ~ 3 wk
Persimmon, kaki –1 ~ +1 15 ~ 25 85 ~ 95 1 ~ 3 mo
Physalis, cape gooseberries +10 ~ +16 0 ~ 15 65 ~ 85 3 ~ 6 wk
Pineapples +7 ~ +13 15 ~ 25 85 ~ 90 2 ~ 3 wk
Plums -0.5 ~ 0 15 ~ 25 90 ~ 95 2 ~ 5 wk
Pomegranates +5 ~ +9 10 ~ 25 90 ~ 95 2 ~ 3 mo
Potatoes, for processing +10 ~ +15 10 ~ 50 85 ~ 95 2 ~ 12 mo
Potatoes, seed +4 ~ +8 10 ~ 25 65 ~ 90 2 ~ 6 mo
Potatoes, sweet +12 ~ +16 0 ~ 30 80 ~ 95 4 ~ 6 mo
Potatoes, table +5 ~ +10 10 ~ 50 85 ~ 95 2 ~ 12 mo
Poultry (frozen) -18 or colder 0 (closed) - 6 ~ 16 mo
Radish 0 ~ +5 0 ~ 15 90 ~ 95 1 ~ 4 wk
Seafood, shrimps, mussels, octopus, squid (frozen) -18 or colder 0 (closed) - 6 ~ 12 mo
Squash, summer, soft rind +5 ~ +10 0 ~ 10 90 ~ 95 10 ~ 14 days
Squash, winter, hard rind, pumpkins +10 ~ +13 0 ~ 60 60 ~ 85 5 ~ 8 wk
Strawberries -0.5 ~ 0 10 ~ 15 90 ~ 95 3 ~ 8 days
Taro, malanga +7 ~ +13 10 ~ 15 85 ~ 90 2 ~ 5 mo
Tomatoes +7 ~ +15 15 ~ 30 65 ~ 90 1 ~ 4 wk
Turnips 0 ~ +4 0 ~ 10 90 ~ 95 4 ~ 5 mo
Vegetables (frozen) -18 or colder 0 (closed) - depends on commodity
Wine +12 ~ +15 0 (closed) - 1 ~ several years
Yams +16 ~ +20 0 ~ 10 65 ~ 85 2 ~ 5 mo

Bulk Cargo


Many recommendations for stowing dry cargo also apply for loading non-packaged dry bulk solids or liquid bulk cargoes in general purpose containers.

Solid Bulk Cargo

  • Use cardboard or plastic lining to protect cargo against container dirt and smell.
  • Ensure the cardboards are folded at front end/door end/two sides to prevent floorboard from contaminating.
  • Ensure scrap and similar waste material are sufficiently dry to avoid leakage or oil spill.
  • Apply a bulkhead at the door to prevent cargo falling out when a door is opened.

Dry bulk in lined box containers

  • Avoid corrosion inside the container.
  • Side walls, roof and floor should have no damage, such as sharp edges, rough weld repairs or debris, to prevent damage to the liner.
  • Discharge and tipping with one of the two container doors closed are considered a safer method than with two open doors.
  • The tipping chassis should be designed/equipped with rear landing legs.

Lining a 40' long container with chipboard panels.

Container with liner bag accomodating a sensitive bulk cargo.

Container with wall liners and door barrier loaded with scrap.

Liquid Bulk

  • Use ISO tank containers, or Flexitanks inside closed containers, for liquid bulk. Carrying dangerous goods in Flexitanks is strictly prohibited.
  • Cargo should always be checked for compatibility with the Tank/Flexitank material.
  • Reduce container payload when used for carrying a loaded Flexitank.
  • Secure tightly the Flexitank harness straps to the anchorage rings in the container.
  • Flexitanks must be braced at the door end of the container with a strong steel (or other material) bulkhead.
  • The bottom valves of the flexitanks, when existing, must be enclosed and secured by the bulkhead panel, to protect against shifting and bending during transport, which can tear the tank.
  • While unloading a Flexitank, the right-hand container door should be opened carefully for getting access to the top or bottom connection tube of the Flexitank. The left-hand door should be kept closed until the Flexitank is substantially empty. The use of spill protection devices like collecting bag or drip tray is recommended.

Container fitted with Flexitank.

Flexitank warning label.

Forms of Stress


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Packing, stowing and securing which appear safe when the container is static might not withstand the unfavorable conditions that land, sea, and air transport offer. This is because cargo in a container is always subject to several forms of mechanical and climatic stress. Freight forwarding has become a complex industry with many logistics parties often handling the same container from origin until destination.

This increases stress on the handling, storage and transport cycles. For example, handling by port operations often exerts vertical acceleration that will increase stack pressure on cargoes in the containers. While at sea, container ships experience swaying, rolling or pitching due to rough weather - it causes movements of cargo and a combination of forces that lead to sliding, shocks and cargo damage. Moreover, road transport creates horizontal pressures on the cargoes due to acceleration or deceleration of the vehicle. Correct packing stowing and securing of cargoes minimize stresses on the containers during the entire intermodal run. It prevents not only cargo damage but also protects the ships’ crews, the container itself and the parties who handle it.

Condensation is also a major cause of concern for shippers. It may materialize damage in the form of corrosion, mildew, rot, fermentation, breakdown of cardboard packaging, leakage, staining, or undesired chemical reactions. It occurs in longer transport routes when there is a large variation of temperatures between the origin and destination locations. In fact, during their voyages, ships often pass through several different climate zones.

For example, a shipment from Southeast Asia, where the ambient temperature and relative humidity are high, can carry a significant amount of water inside the container, in the form of water vapor and as moisture trapped in the packaging. After arriving in Northern Europe, a region with low ambient temperature and relative humidity, water will condense and drip down onto cartons. The consequences are the collapse of stacked cartons, the spill of contents and destruction of goods. The use of shrink-wraps or protective film in packing helps cargo be waterproof to avoid condensation damage.

During product development, manufacturers often place much emphasis on packaging as the way to build up a favorable image to consumers. They do not take into account the whole supply chain with complex cycles of storage and transportation. Since cargo damage often occurs during transport, good packaging design is essential to help protect cargo along the way, not just to promote it.

Air Cargo


Air freight uses a range of ULD (unit load devices) to meet shippers’ needs. ULD include containers for most general cargo, baggage, and mail, but also pallets are flat platforms (plastic, aluminum or wooden) on which shipment pieces are stacked.


  • Use dunnage to avoid empty spaces in packages and reduce stacking strength.
  • Use cushioning material to reduce shock and vibration forces.
  • Place the heavy items as the bottom layers.
  • Build upwards, in inter-locking layers.
  • Pallets should be built properly for stability.
  • Overpack while palletizing to reduce damage, pilferage and allow ease handling.
  • Stretch wrap to keep all pieces of a shipment together.
  • Do not wrap only cartons or load - the stretch wrap should first be applied around the pallet and continued around the load and upward.
  • Place polythene sheets with care to give maximum protection to your palletized container load.
  • It is recommended to cover each pallet with a net to secure loose pieces.

This information is for general reference only and is not intended to replace any existing regulations or guidelines.

Adapted from multiple sources, including the IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (CTU Code), International Maritime Solid Bulk Cargoes (IMSBC) Code, and UPS Air Freight Packaging Pointers. The carriage of bulk cargo is already well regulated by the MARPOL and SOLAS international conventions.


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