A successful containerized cargo shipment depends on four basic fundamentals.
- Matching the cargo to the correct type of container that is best suited for the forthcoming voyage - be it by land or water.
- Ensuring that the container is in good condition prior to loading the cargo and that it is carried and handled correctly throughout the voyage.
- Ensuring that the cargo is loaded correctly into the container and is properly secured against movement during the voyage.
- Ensuring that all the relevant cargo information is communicated to all appropriate parties to ensure that the container and its contents will arrive at the consignee in the expected condition.
This Cargo Care section contains information and guidance on how all parties can work together to best ensure that cargoes are loaded correctly into or onto containers.
This page contains general advice on loading into containers, including some do’s and dont’s, with the associated pages give more specific advice and guidance.
A full container inspection for structural damage requires a competent eye, however for cleanliness and general acceptability, common sense is the watchword. It is very much in the interests of any user whether it be FCL or LCL to carry out a quick internal and external inspection prior to stuffing and also after unstuffing the container. Listed below are some useful hints which can help to minimize cargo damage.
Checklist Before Stuffing
- Holes: No obvious holes or tears in the exterior paneling.
- Doors: No broken or distorted door hinges, locks, or door seal gaskets.
- Tilts: Where containers are fitted with removable roof tilts or side curtains, they should fit correctly, be equipped with tilt wires and have no tears in the fabric.
- Roof Bows: Open tops containers should have all the roof bows (supports) in place. If the roof is of the retractable sort then the roof bows should slide smoothly to the ends of the container.
- Labels: Any labels remaining on the outside of the container which refer to the previous cargo should be removed.
- Clean: No leftovers (sweepings, dust, grease or liquid) of the previous cargo.
- Dry: The interior should be dry and free of any sweat or frost.
- No infestation: There should be no evidence of pests, insects or rodents which might contaminate cargo and lead to delay by Port Health Authorities.
- Taint-free: If delicate goods susceptible to damage by bad odors are to be packed, then the container must be sweet-smelling. This should be checked immediately on opening the doors when any lingering smells will be at their strongest.
- Watertight: This is best checked by entering the container and closing both doors. If any spots of light can be seen then water can gain entry. This also applies to the container floor because water can splash upwards during road haulage.
- Follow instructions: Any recommendations posted inside the container should be noted.
Checklist After Stuffing
When the planned quantity of goods have been stuffed in a container, the following checks should be made.
- Restraint: The goods should be arranged and secured to withstand the normal stresses and strains of the journey. In particular ensure doorway cargo cannot move.
- Customs inspection: If more than one type of article is stuffed in the container it may save time and cost of a search if a sample of each article is positioned near the door.
- Security: When the doors are shut, all securing lugs should be properly engaged forcing the door seals into compression. The company's approved seal should be fitted in the appropriate position on the right hand door and the number noted.
- Contents: Any label on the outside of the container advertising the contents will attract thieves and should be removed.
- Labels: Dangerous Goods Labels, if appropriate, should be affixed in the recommended positions. The labels must be placed in such a way that they do not obscure the number of the container or other distinguishing marks.
Checklist Before Un-stuffing
The following should be checked prior to un-stuffing.
- Security: Seal is intact and has not been tampered with. The number must be compared with the accompanying documents for possible future reference.
- External of the container: Any damage that may have affected the content should be duly noted.
- Labels: Before opening the doors due regard should be taken of any labels such as Dangerous Goods Labels or contents shipped in bulk.
- Doors: The right hand door should be opened cautiously. This is to guard against the risk of improperly secured cargo falling out onto personnel.
Checklist After Un-stuffing
When a container is empty of cargo the container should be checked for damage that might lead to claims. Most tariffs are so worded that it is obligatory for FCL customers to clean out the container after un-stuffing. This includes removal of all packaging and a thorough sweep out.
It is prudent to examine the container for any signs of wet stains, holes in the sides or roof that might have affected the cargo which has just been carried.
Do's and Dont's
- Subject to booking request select the most suitable container type to accommodate the cargo.
- Prepare a pre-stow plan before commencing stuffing so that weight/cubic considerations are covered and point loading limits are observed.
- Do not load by weight above the payload limits of the container.
- Do not load by weight above the road regulations applicable on the transit.
- Distribute the weight of the cargo evenly over the floor of the container. Never stow heavy items in one section and light voluminous items in another.
- Do not stow heavy goods on top of light goods.
- Stow and secure all cargo tightly.
- Observe all the handling instructions on cargo such as "Do Not Drop", "This Side Up"
- Stow goods with sharp corners separate from other softer merchandise. Use dividers and separating material as appropriate.
- Where possible with mixed loads, place packages containing liquid cargo on the bottom tiers with dry on top.
- Use cargo liners for obnoxious cargo such as hides and carbon black.
- Do not use clamps or other loading devices unless the goods can withstand them.
- Do not loads goods in a container with damaged packaging.
- Do not stow wet and damp goods with dry goods.
- Do not use dunnage or packaging which is incompatible with the cargo.
- Do not stow goods with tainting odors close to sensitive merchandise.
- Observe all rules concerning hazardous cargo. Use appropriate labels and placards to identify containers loaded with dangerous goods.
- Stow hazardous cargo near the door where applicable.
- Include all necessary documentation.
- Record the seal number and the container number on all shipping documents.
- Never smoke during loading and unloading.
The International Standards Organization (ISO) has recommended a series of internal and external dimensions for containers together with gross maximum weights which the container may carry.
Not all containers which are used by transport companies are ISO containers and under no circumstances should they be accepted unless with special agreement obtained from the Steamship Line
The main components of a container are described below with accompanying diagram.
- Corner Post: Vertical frame components located at the corners of freight containers and integral with the corner castings and floor structures.
- Corner Castings: Fittings located at the corner of the freight container which provide means for lifting, handling, stacking and securing the container.
- Header and Sill: In way of door entrance with overhead horizontal header frame and similar floor level threshold sill.
- Front-End Frame: The structure at the front end of the container (opposite the door end) consisting of top and bottom rails attached to the front corner posts and the corner castings.
- Top Rail: Longitudinal structural members located at the top edge on either side of the freight container.
- Bottom Rail: Longitudinal structural members located at the bottom edge on either side of the freight container.
- Cross-members: A series of transverse beams at approximately 12 inch centers attached to the bottom side rail and an integral part of the floor frame support.
- Floor: The floor may be hard or soft laminated wood, planks or plywood.
- Roof: Roof bows are the undermost structure of the roof and are usually placed at 18 or 24 inch centers. Modern steel GP containers (except open top containers) are not fitted with roof bows but will have corrugated or flat steel sheet roofs welded to the frame members.
- Aluminum containers have aluminum sheathing, bonded with adhesive to the roof bows and riveted to the top rails and headers. GRP containers have fiberglass reinforced plywood panels fastened to the rail and headers. The roof is the part of the container most vulnerable to damage.
- Sides & Front: Modern steel GP containers will have corrugated steel panels. Aluminum containers have aluminum sheathing on the sides and front of the container which are affixed to aluminum stringers which are in turn bolted to the top and bottom rails and also to the front end frame. The stringers may be on the outside or inside of the sheathing. GRP containers do not use stringers for supporting the fiberglass reinforced plywood panels. The side and the front of steel containers are made of corrugated steel sheets eliminating stringers.
- Doors: Doors may be ply-metal (plywood core with steel or aluminum facings), corrugated, or combinations with fiberglass. The hinged doors have plastic or rubber lined door gaskets as seals against water ingress.
- Security seal: Used in conjunction with locking mechanism in order to seal the containers for security purposes. These seals are numbered and often color coded.
Most container fleets can be loosely described in terms of General Purpose (GP) containers or specials.
The GP or general purpose container accounts for the large majority of the fleet and is used for most general cargo commodities. The containers are 20 ft or 40 ft in length with a limited stock of 45 ft.
The standard external height of GP containers is 8 ft 6 inches although high cube containers at 9 ft 6 inches in height are becoming common .
Special containers are provided for specific carriage requirements and examples are listed below.
Type; Sizes (In feet);Characteristics; Typical uses
- Open Tops 20/40; Soft detachable roof tarpaulin or tilt; Machinery requiring top loading and over-height cargo.
- Half Heights 20/40; Soft detachable roof tarpaulin or tilt, half height; High density cargoes such as ingots, heavy steelwork, drums.
- Flatracks 20/ 40; No sidewalls or roof (and ends may be collapsible); For out of gauge cargoes and restricted loading situations.
- Platforms 20/40; Flatbed with corner castings. Limited numbers of high rated equipment; Over-length cargoes and special projects.
- Fantainers 20/40; Extractor fan fitted; Agricultural products requiring ventilation e.g. onions, potatoes. Also used as a normal GP container.
- Highly Ventilated 20; Side vents along top and bottom rails; Hygroscopic cargoes such as coffee, cocoa, tobacco and seeds.
- Top Ventilated 20; Side vents along top rail; Hygroscopic cargoes such as coffee, cocoa, tobacco and seeds.
- Open Sides 20; Side gates and side curtains; Agricultural products requiring ventilation, livestock and side loading.
- Bulk 20; Top loading ports and door discharge shoot; Dry cargoes in bulk e.g. malt , sugar also used as a normal GP container.
- Tank Containers 20; Tank within an ISO frame of various types; Liquid cargoes in bulks including foodstuffs and hazardous.
- Refrigerated Integral Refrigerated Integral; 20/40; 8'6" and 9'6"; Electrically powered self contained refrigeration unit; Refrigerated cargoes throughout the World with connection to terminals and ships electrical power sockets.
- Refrigerated Insulated 20 (8¿ and 8¿6¿); Top & bottom end ports and connects to ships refrigeration system; Reefer cargoes on specialized ships operating in ANZ and SAF Trades.
Every container must have a Container Safety Certificate (CSC) issued by the manufacturer and this must be renewed every 30 months after inspection by a competent inspector. An approved continuous examination program (ACEP) can be agreed as substitute for this procedure and the ACEP number is stamped on the CSC plate.
Common types of container damage are listed below.
- Racking: Is the twisting of the structural shell of the container due to static or dynamic forces and is commonly associated with movements in a seaway. The standard ISO container racking limit is nominally 15 tonnes. To counter these forces, diagonal lashings may be applied in accordance with the vessel's lashing system. In high stacks, the lower container is subject to the greatest racking forces and the lashing systems must be designed to take this into account.
- Toppling: Can occur when containers are subjected to extreme rolling motions aboard ship or standing in a stack, exposed to high winds. Counter measures are twist-locks and lashings.
- Container collapse (corner-post compression) : Results from exceeding allowable loads on the container corner posts and can be avoided by staying within weights limits of the container. Where lashings are applied aboard ship, avoid over tensioning of lashings.
- Local structural failure: Is the separation of structural components of a container such as side-wall separation from top and bottom rails and separation of the corner castings from the side rails.
- Holes in containers: are the most common kinds of damage. Roof damage is often caused by lifting spreaders indenting the roof when locating corner castings and twist-locks and lashing gear being thrown down on top. Holes in container walls can be caused by fork-lift trucks, collision with other containers or lifting devices. Holes in containers can be easily detected by interior inspection with the doors closed and noting any light entering the container. This can also reveal faulty door seal gaskets and is extremely important check to be made.
- Interior Contamination: Container floors become seriously contaminated by cargoes such as wet hides which can cause tainting to future cargoes. Interior paintwork can also be stripped by cargoes such as naphthalene and cloves.
Equipment Interchange Receipt (EIR)
Also referred to as a Trailer Interchange Receipt (T.I.R) and relates to the landside interchange of containers. Where a contracted trucker, barge or rail operator, exchanges equipment as part of the inland journey, an E.I.R. inspection should record each interchange. This may include receipt or delivery of containers from terminals or depots as appropriate and can serve as a valid contract between ourselves the shipping line (or appointed sub contractor) and the hauler.
Vessel Cell Numbering
Container slot positions aboard ship are expressed by three co-ordinates indicating :
Bay -- Row -- Tier
- Bays: Are numbered lengthwise from bow to stern with odd numbers for 20' containers and even numbers for 40' containers. The even number between two 20' containers is used to define 40' bays.
- Rows: Are numbered from centerline to portside with even numbers and from centerline to starboard with odd numbers. The container row stowed on the centerline is marked 00.
- Tiers: In under-deck stows, containers are numbered vertically downwards with even numbers from top to bottom. The bottom row will be 02, except where as a result of the hull contour, the bottom of an adjacent row is at a higher level. In case of two half heights the bottom ones are to be numbered by an odd number. On deck stowage is indicated by code key 8 followed by an even number sequence.
If the load consists of homogeneous cargo (all the cargo has the same sizes) the complete volume of the container should be utilized. Different kinds of packaging methods exist such as cartons, boxes, bags, drums and barrels, rolls, liners for liquid bulk and small wooden crates. The container may have vacant cubic on completion of stuffing due to weight restrictions or otherwise and sensible securing is necessary on grounds of safety and cargo care.
When uniform cargo is stowed into a container and free space is unavoidable, the cargo must be stowed in such a way that there is a gap in the middle of the stow as per diagram.
The gap, which can be fore and aft or athwart, must be chocked with wood or lashed with rope and if the cargo is fragile, nets or dunnage bags can be used.
Cartons & Packages
Important to follow any instructions printed on the cartons, e.g. particular side up for bottles of wine which require corks to remain immersed. To ensure stability in the stow and spread the weight as evenly as possible the "Bonded Block Stow" should be used.
Bagged cargo tends to settle during transit causing pressure on side walls. Normal practice is to stow bags in interlocking stows. Bag on bag or building air chimneys within the stow may be necessary where extra ventilation is required. To avoid the risk of bags falling out of the container when the doors are opened, a brace or net is placed against the final row. Bags which are stowed and secured on pallets do not cause this problem and the cargo can be handled much faster.
Drums & Barrels
Drums and barrels in containers should always be stowed upright if possible. If the bung or closure is at one end, then it should be stowed with the bung uppermost. Barrels of earthenware etc should always be stowed upright.
Unless the drums or barrels are specially designed to "nest", there should be some form of soft dunnage or ply between each tier of drums. Dunnage should be laid sufficiently close to provide full support to the tier above
Rolling hoops, when pressed out of the side walls of the drums are particularly susceptible to rupture through chafe. In some instances it may be necessary to lay dunnage between individual drums to prevent rolling hoops from chafing one another. A second option is that each alternate row of drums may be lifted a few inches by carefully laid dunnage, allowing the rolling hoops to ride clear and reducing the effective diameter of each drum.
Ensure proper securing in way of the doorway with a fence, net or lashing.
When rolls are stowed upright they should be packed closely together. Any empty spaces between the rolls should be filled in by sacks of sawdust, corrugated cardboard or similar soft dunnage. Secure the rolls by means of timber, nets or wedges.
When the rolls are stowed horizontally, the rolls which are nearest to the door should be secured by wedges or other similar devices as per diagram. Support the rolls evenly along their length on a flat surface particularly with cargo such as carpets.
Rolls of paper require paper clamps for careful handling.
Wine, latex, printing ink and other non-hazardous liquids are often transported in strong synthetic "Flexi-Bags" in 20' GP containers. The bags must be braced at the door end of the container with a strong timber (or other material) bulkhead. Also make sure that the harness straps on the bags are secured tightly to the anchorage rings in the container. It is not only necessary to secure the load but also to make sure the pressure on the walls is not too high (if so the pressure must be distributed with planks or plates).
Bulk bags are used for a wide range of granular substances including malt, cocoa and coffee.
Specialist containers are available for shipping clothing garments. They are carried either on hanger rails or suspended from strings and significant traffic moves from the Far East, India, Sri Lanka and South Africa to Europe. Separate procedures issued by ICM cover all aspects of container preparation which are crucial for a successful out-turn. Failure to observe procedures can result in considerable claims for dry cleaning of garments which have dropped to the container floor.
Cars and similar light vehicles are commonly shipped in containers. Webbing or Spanish Windlass lashings are used as cross lashings. In the case of non-operating reefers this is via lashing eyes clipped into the T section flooring.
See AUTOMOBILES rules regarding petrol under the IMDG Code. Special car racks can also be fitted into containers to allow more cars to be carried.
All documentation must be completed.
Container must be properly placarded with an IMO danger label affixed to each of the outside walls of the container (front, door and the two sides).
IMO stowage segregation MUST be complied with at all times.
Safety & Securing
This section picks up important issues of safety that have been experienced with containerised cargo and to the related subject of cargo securing.
There have been considerable incidents over the years of containers being loaded above their stipulated payload. In many cases the manifests declare cargo within payload limits when it is over. This is often exposed by the suspicions of a container handler or even an accident, resulting in a weigh-bridge check.
Overloading is something which no Steamship Line cannot entertain and in accepting cargo the following should be obtained or checked :
- The number of pieces, size, weight and cubic of any commodity must be obtained.
- The payload and cubic of the container selected/requested must be compared with the cargo particulars to establish whether a weight or cubic restriction applies. (A higher rated container may be appropriate).
- Where a weight restriction applies the point loading of the cargo must also be checked in order that the tons per square meter loading limit is not breached. Cargoes such as metal ingots come into this category and timber is often required to spread the weight.
Road and Rail Limits
Apart from not overloading the container, the gross weight of the container (cargo plus container tare) must not breach the road or rail limits appropriate on all legs of the transit journey. This information can be obtained in DRS records or from the appropriate trade. The importance of observing these limits cannot be overstressed particularly where liability occurs in the case of an accident.
The incidence of cargo moving inside a container during transit is considerable. It is usually because the cargo has not been secured properly or the packaging is defective. In particular we have recorded several cases where road vehicles have turned over due to cargo moving when negotiating a bend. The key issue is to secure cargo effectively to prevent the initial movement, because once loose the game is lost.
Securing & Reference to the International Maritime Organization (IMO)
Though containerized cargo is well protected, it is still subject to the constant movement and stress of transport. In heavy seas, the cargo is exposed to compressive forces due to pitching and rolling. These forces may increase the normal strain on lashings, struts and other securing devices as much as 100%. Effective securing of the load throughout the entire transport process is of absolute importance.
Reference books of note for detailed information include :
IMO Code of Safe Practice for Cargo Stowage and Securing. Vessel Cargo Securing Manuals - available onboard all merchant vessels and approved by the vessels Flag State Maritime Authority. Thomas' Stowage (ISBN 0 85174 625 X)
Contained in the IMO code above is a simple "Rule of Thumb to apply to securing loads aboard ship. (Refer to the code for more detailed information).
The total of the MSL values of the securing devices on each side of a unit of cargo (port as well as starboard) should equal the weight of the unit.
MSL or Maximum Securing Load is to securing devices as safe working load (SWL) is to lifting tackle. It is a term used to define the load capacity for a securing device.
Lashing and securing is a matter of know-how and experience and is normally performed either by terminal staff or specialized riggers. Essential information required when considering any piece of sizeable cargo is :
Mass in metric tons Principle dimensions (drawing if possible) Location of centre of gravity Bedding area and particular bedding precautions. Sometimes referred to as the "Footprint".
Lifting points or slinging positions Lifting gear if any accompanying the cargo, complete with test certificates Securing arrangements aboard ship Landside transport arrangements
When considering the shipboard stowage location of cargo items, acceleration forces should be borne in mind:
Lower accelerations forces occur in the mid-ship sections, lowest cell position under-deck and as close to the centerline as possible
Higher accelerations forces occur at ship's extremities, high on deck and in the outrigger slots by the ship's side.
When the lashing material is not specified (size of wire etc.) by the forwarder the lashing company will lash the cargo according to their own rules and experiences.
Not all cargo necessarily needs to be lashed. The best way of stowing cargo is often to stow one piece of cargo tight against the other cargo so they can support each other.
A basic securing lashing may comprise the pieces listed below and its strength is that of the weakest link.
Wire of suitable strength. (MSL). Wire measured in diameter, parts, strands. Wire /bulldog clips to tie the wire. (Must be fitted correctly). Turnbuckles/ bottle-screws to tension the lashing Shackles to fasten the ends.
A securing lashing will always break at the weakest point or at the part with the lowest breaking strength so make sure you know the breaking strength of all lashing materials used. Protect the lashing material from additional weakening factors such as sharp edges, bending of bottle screws and shackles.
Where bottle-screws or turnbuckles are introduced the rating of this equipment must be equal to the maximum weight each lashing is expected to bear.
Securing in Containers
The cargo in containers needs to be stowed in such a way that the cargo can not move. The container itself is designed to permit tight, secure stowage of cargo.
These facilities include:
- Floor of wood or plywood which permit blocks, stays and wedges to be anchored with nails or screws.
- Internal walls, for the support of light cargo only.
- Corner posts which are suitable for bracing to with timbers and lashing from via lugs .
- Lashing lugs are located along top and bottom rails of the container at regular intervals.
An example of a typical 20 ft GP's lashing facilities are:
- Sidewalls - Base - 5 lashing points rated at 2000kg Safe Working Load (SWL).
- Sidewalls - Top - 5 lashing points rated at 500kg SWL.
- Front end - Base - 1 lashing point rated at 500kg SWL.
- Rear end - Door area - 5 lashing points rated at 500kg SWL.
The walls, doors and roof of the container are merely a protective shell which can not withstand concentrated stress. If the walls or ceiling are used for lashing purposes, make sure the stress on the walls or ceiling is evenly distributed.
Most types of cargo can be secured using the following materials :
- Timber beams, struts, chocks, planks for shoring, bracing and relieving pressure.
- Adjustable wooden battens, rods or strap belts for securing the load in sections, facilitating mechanical discharge.
- Plywood and dunnage to separate several layers of cargo or to segregate different types of cargo into separate sections.
- Foam-rubber cushions and air bags to reduce vibration and prevent the load from shifting.
- Second hand tires or bags with paper-waste or sawdust to fill empty spaces, soften the impact and prevent shifting.
- Nets to secure fragile goods.
- Rope (hemp, manila, sisal etc.), wire, steel bands and terylene straps for lashing.
- Nylon span sets
- Bolt clips into T section flooring in Insulated containers
- Bulkhead bars
Securing Calculations Aboard Ship
As per the previous diagram forces acting in a seaway are :
Rotational:- Rolling Pitching Sheering/Yawing
Linear movements:- Swaying Surging Heaving
Calculations to secure against the above forces follow a prescribed discipline and it is important to refer to this procedure when performing calculations. The recognized calculations are contained in "IMO Code of Safe Practice for Cargo Stowage and Securing".
Condensation Issues for Containers
For a given atmospheric pressure, air holds more water vapor at higher than lower temperatures.
The maximum amount of water vapor contained in a cubic meter of saturated air decreases with a decrease in temperature. At 40degC it can contain 51 grams, at 20degC 17 grams and at 0degC only 5 grams.
Is the temperature at which a sample of saturated air will condense. Warm air has more capacity to support water vapor within it than cold air.
Expressed in percentage terms is the ratio of water vapor present in a given sample against the saturated level. If the Relative Humidity (RH) is said to be 100% then the air sample is saturated
Occurs when moisture laden air releases its water vapor on to the surrounding surfaces in the form of water droplets. For condensation to occur the following conditions need to be present:
- Temperature gradient (Between air inside and outside the container)
- A source of water vapor (moisture).
- Pathway for it to move.
Occurs when the skin of the container is cooled to a temperature below that of the dew point of the air enclosed within the container.
This results in water droplets forming on the interior roof and side panels, then dripping down on the cargo causing mould and water damage. Cargoes that spontaneously heat from within can increase the problem.
An example is:-
A cargo loaded in the tropical belt in warm conditions with high Relative Humidity, is transported to cold winter conditions in Europe. The temperature outside the container gradually cools down in transit until it experiences cold conditions in Europe. The steel container allows the chill to conduct from the outside of the panel through to the inside. The situation inside the container is now one of cool side panels and warm moist air in the header space above the cargo and within the stow. The temperature of the side panels is therefore below the dew point of the air inside the container and condensation occurs. Condensation will continue until the dew point of the interior air falls to that of the outside air. Different solutions are discussed further in this procedure however the simple solution is to ventilate the container by passing air through it and replacing the warm moist air with similar air to outside the container.
Occurs when the surface of the cargo is cooler than the dew point of the air enclosed within the container. Droplets of water then form on the surface of the cargo. An example is:- A cargo of canned goods is loaded in cold winter conditions in Europe and transported to the tropical belt. The container will gradually heat up during transit to the warmer moist climate however the cargo temperature will lag behind, slowly heating up and replacing the cold from loading.
If ventilation was allowed to take place the warm moist air from outside the container would condense on the cold cargo. In this case it is better to avoid ventilation during transit and allow the cargo temperature to gradually increase thereby restoring equilibrium between the cargo temperature and the outside air.
Radiation of Heat at Terminals and On Board Ship
Where possible cargoes sensitive to condensation must be protected from the extremes of radiant heat and extreme cold as under:
- Whilst container is in the terminal stack: shaded stow required.
- Aboard ship: under-deck stow or protected deck stow required.
- Long road/rail transit.
An example is:-
A non insulated container sitting on the terminal in Assab with a load of bagged coffee is subjected to the radiant heat of the sun. The air inside the container will become heated and absorb moisture from the coffee thus establishing high humidity conditions. Night cooling can cause the temperature of the container skin to fall below the dew point of the humid conditions within the container thus causing condensation.
The need to avoid radiant heat is emphasized in this example and late packing of coffee prior to export would also help. In addition long periods exposed at transshipment terminals such as Djibouti, in the summer, should be avoided.
At the other end of the journey it is important that early delivery is carried out for sensitive/hygroscopic cargoes arriving at terminals with near zero temperatures. In such cases the cargo can experience what we call the "cold shock" of first night ashore. When acceptable to the shipper it is often prudent to crack a door open to ventilate the container.
Are those which are permeable to water and which retain moisture under certain conditions.
Timber, coffee, cocoa and most materials of organic origin are hygroscopic. Coffee for example can have a moisture content of 12% and container sweat is therefore an issue.
- The importance of good packaging cannot be over-stressed in achieving good out-turns. It is also a key cost issue for our customers and therefore achieving an optimum packaging policy commensurate with good product delivery is an important element of cost control.
- Each commodity must be individually assessed to determine the most suitable packaging. Several examples of packaging are listed below.
- BAGGED CARGO : The physical composition of the cargo in terms of moisture content and sensitivity to contamination will determine the bags used which include:
- Paper (single or multi-ply) which may be sewn or glued.
- Plastic (which may be airtight).
- Woven polypropylene (May also have an inner sealed bag made of polythene).
- Jute, hessian (Traditional materials) and the type most likely to be re-used.
- The danger of taint from residual cargo must be considered.
- Open mesh sack of plastic fiber for maximum ventilation.
- BALES & BUNDLES : Outer cladding usually of hessian or similar material with an inner plastic packaging. Some baled cargo such as straw or hay are not covered.
- CASES, CRATES, CARTONS : Cases and crates are usually made of timber which may be plywood or heavier timber. Pallets or timber skids may also be part of packaging to facilitate lifting and ventilation. Excess moisture in the timber can cause damage to cargo! e.g. Canned cargo becoming rusty. Cartons of flimsy cardboard material and high moisture content are liable to suffer crushing and consequent damage to the cargo! The importance of good quality multi-wall fiberboard is stressed which may be wax impregnated to resist moisture. In stowing cartons the use of the recognized "bonded block stow" technique is necessary to ensure proper weight transmission within the stow of cartons.
Rusty cans with peeling labels are the nightmare scenario for supermarkets! De-humidifiers are used in warehouses to create controlled conditions for goods and packaging prior to export. In very special cases de-humidifiers have been used in containers prior to loading to ensure a dry container is presented for loading.
The moisture content in the floors of containers is an important aspect of condensation control and maximum permissible amounts may be specified by customers, e.g. 15-18 % moisture.
Desiccants & Absorbent Materials
A basic desiccant is one which will absorb 27% (of its dry weight) of moisture when placed in an atmosphere of 50% Relative Humidity at 25 degrees C.
Desiccants can be very effective when used with certain cargoes (Steel reels, cars, cartonware). In the case of hygroscopic cargoes they may only be part of the solution because of the high moisture content present within the cargo (e.g. Coffee 12%). At the other end of the spectrum, in certain situations desiccants can extract too much moisture from the cargo and where the cargo is sold by weight this results in claims.
Silica-gel is probably the most familiar to us and others include activated alumina and activated clay. Brand names using desiccants include Dry Bag, Absormatic, Moisture-Grip and Grafo Therm.
Dry Bag: A Danish desiccant made up of roasted moler clay mixed with calcium chloride. Bags of kg are normally used in containers and the numbers utilized will be determined by the commodity.
Dry-Bag is successfully used with cars, machinery, milk powder and many other cargoes.
Absormatic: Uses water retaining poles in conjunction with a desiccant and are placed into the corrugation of the container side panels in order not to waste cubic space for cargo. Effective but vulnerable to forklift damage which can release moisture into the container.
Moisture-Grip: A product developed in Japan and is an absorbent polymer sheet taped to the container ceiling of the container. Sometimes used with cargoes of tobacco.
Grafo Therm: A porous paint application applied to the container ceiling which absorbs moisture within the container. This product has been championed as the solution to condensation in coffee shipments. Where major temperature gradients are present, as with coffee entering a cold winter climate, this may not have the capacity to absorb all the condensation. Requires maintenance and may absorb dirt and contamination.
Insulation blankets are normally used to clad the inside of a GP container with temporary insulation. They are used mainly to combat cold being conducted through steel GP containers to cargoes such as red wine and liqueurs.
They are listed in this section to make the point that insulation can reduce extreme temperature gradients between inside and outside the container.
In cases of extreme "Container Sweat" the need to bring equilibrium between air inside and outside a steel container is paramount. Good ventilation serves this purpose by evacuating the warm moist air from the container and replacing it with ambient air from outside.
Vent-Containers having vent ducts along the side panels at top and bottom rails achieve this by convection effect. Warm moist air is expelled via the upper ducts and replaced with colder ambient air via the lower ducts. Plywood insulation on the interior of side panels is fitted only on part of the owned fleet and is preferable. High leasing costs are an issue with this equipment.
Fantainers are used successfully to carry onions and potatoes throughout the world. An extraction fan draws ambient air through the cargo to maintain equilibrium with the temperature outside the container. Control of ancillary equipment such as control boards and leads reduces the appeal of this method. The use of Fantainers for use with other cargoes is currently being evaluated.
GP Containers: A large number of owned containers have four small passive vents in way of top corner castings with each providing air paths with at least 5 sq cm total cross sectional area).
The above provides a small amount of ventilation and it is important for sufficient free space to be left in the header space for it to be effective. The majority of dry cargoes can be successfully carried in GP containers.
Taping off the passive vents in GP containers is also necessary when carrying hygroscopic cargoes as under and also for cargoes liable to spontaneous combustion :
The use of desiccants combined with lining the container with kraft paper or fiberboard are additional options according to the risk. (Details are available under coffee stowage). This amounts to parceling the cargo effectively to avoid contact with the steel container and placing desiccant bags on top of the stow to absorb moisture in the header space.
Infestation & Fumigation
Causes of Infestation
Cargoes can become infested and damaged by the following common forms of pest or vermin.
- Rats consume approximately their own weight in food per week. The damage that rats can do to a cargo of foodstuffs is compounded by the fact that the presence of rats will almost certainly mean that the cargo has to be condemned. This is due to the fact that rats are carriers of virulent diseases. Control of rats aboard ship is done by fumigation and a periodic renewal of a "De Rat" Certificate. In the case of containerized cargo, care should be taken to inspect the cargo during packing for signs of rats having penetrated the cargo.
- Beetles, moths and mites are known to cause damage to a wide range of commodities. Each insect grows from an egg produced by an adult female. The egg of the beetle and moth hatches into a caterpillar which actively feeds on cargo. This is the greatest cause of damage from infestation. Caterpillars moult several times during their life cycle before entering a pupil stage which releases the moth to restart the cycle. Mites are hatched from eggs producing an insect which goes through a series of development stages before reaching adulthood.
- Lice are often found in bales of rags. A reliable sanitary certificate normally accompanies the cargo.
- White Ants are found in certain tropical woods and often in flat dunnage.
- Cockroaches are found in various cargoes including hollow bamboo and old cord wood.
- Sirex Wood-Wasp is found in timber dunnage and is particularly outlawed in Australia.
- Maggots are found in animal hoofs, horns, bones and skins.
- Tropical Warehouse Moth is found in cocoa beans and coffee.
- Weevils are common in bran rice.
- Copra Beetle is found in coconuts and cereals.
- Black Mould Parasite is found with onions.
- Sitophilus Zeamais is common in maize.
- Tribolium Castaneum is found in wheat flour
Infestation is obvious when insects are visible on bags or bulk, but it may be that insects are feeding inside the foodstuff itself. This can happen for example with wheat grains and coffee beans. Tropical countries are associated with the origins of particular insects, however cross contamination with other infested cargoes is a common cause.
There are four types of damage resulting from insect or mite infestation:
- Boring and nibbling mixed with webbing and excreta.
- Loss in weight and heating. It is important to note that heating can be caused in dry materials solely by the activity of insects.
- Water damage. Essentially a surface phenomenon confined to the top few inches of the cargo resulting from "hot spots" and insect activity.
- Depreciation of value. A good example of this is Tribolium beetles within desiccated coconuts which cannot be removed by a commercially practicable process.
Fumigation is the recognised means of combating infestation by the application of fumes to disinfect or purify. There are several substances used for this purpose which are listed below. Further sections are provided on the disciplined procedure necessary for applying fumigants as well as the relationship to the IMDG code for hazardous cargo.
Types of Fumigants
- Methyl Bromide (Bromomethane):
Methyl Bromide, at normal temperature, is a colorless gas 3.27 times heavier than air. The pure gas has a faintly sweet smell but it normally has a marker added for warning which causes watering of the eyes.
There is widespread international concern over Methyl Bromide because of its properties as a category one ozone depletant under the Montreal Protocol of 1992. Not withstanding its abilities as a fumigant there is a mounting consensus that a more suitable substance must be found by the end of the century. Methyl Bromide is highly toxic to mammals and is the most widely used fumigant for timber, agricultural products, empty containers, foodstuffs, seeds and plants. In particular Australian quarantine clearance by AQIS requires this method which includes fumigation against :
- Weeds and organisms within soil and compost,
- Insects and mites,
- Infestation in fresh fruit,
- Within nursery stocks of plants.
Effect on foodstuffs: After fumigation the bulk of methyl bromide is removed by aeration although there may be small residues. There can on occasion be a chemical reaction with certain food products if some absorption takes place.
Methyl Bromide is absorbed by oils, fats and finely ground materials. It can also react with materials containing sulfur to cause discoloration or odor. The following materials are among those which should NOT normally be fumigated by Methyl Bromide.
- Butter, lard, fats, avocado, soybean flour, flours and baking powders,
- Bone meal, charcoal and cinder blocks,
- Furs, felts, horsehair, pillows, rugs and papers,
- Iodized salt,
- Leather goods and photographic chemicals (excluding film).
- Photographic prints,
- Rubber goods,
- Woolen goods
Health Warning : Exposure to Methyl Bromide has in the past resulted in a number of deaths. A particular danger is that signs of poisoning may be delayed for several hours following exposure to the gas. There is no significant antidote and the human body can absorb it by inhalation and via the skin.
Headache, dizziness, eye irritation, coughing, nausea, abdominal pains and numbness of the feet are early indications of poisoning.
Methyl Bromide is usually administered from approved cylinders or cans. It is important to stress the use of the correct protective clothing during fumigation.
Guideline quantities : For ANZ destinations - 5.0 lbs per 1000 cft or 80 gms/cbm For USA destinations - 4.5 lbs per 1000 cft or 72 gms/cbm For other destinations- 3.0 lbs per 1000 cft or 48 gms/cbm
Phosphine used for fumigation purposes is usually produced by the reaction of atmospheric moisture with slow release formulations containing aluminum or magnesium phosphide.
Phosphine is highly toxic although it requires a relatively high temperature and long exposure period to be effective. Under normal conditions Phosphine is a gas and is colorless and odorless. A fishy or garlic-like smell may be evident due to impurities.
A significant fire/explosion risk associated with phosphine is reduced by using metal phosphides specially prepared for fumigation purposes. Care must be taken during use to isolate any electrical connection (switches can be covered in paraffin wax) and any sources of ignition must be removed.
Phosphine is used for fumigating a wide band of insects and pests. It has a low degree of absorption by foodstuffs and penetrates well into the stored product.
Australian AQIS recognize its advantages over Methyl Bromide on milled and oily commodities such as flour, soybean flour, fishmeal, nuts and oilseeds. It is however not favored for use on timber due to concerns over its ability to penetrate the material.
Health Warning : Very poisonous and very similar symptoms to those of Methyl Bromide if exposed to it. A notable effect is chest tightness and difficulty in breathing.
Phosphine preparations for fumigation are dispensed as :
- Powder sachets
- Degesch plates impregnated with metal phosphide formulations and sealed prior to use
- Bag blankets or belts
- Mixed in cylinders with CO2 with 3% phosphine.
- Tablets or pellets,
Guidelines on tablets : 3 tablets per CBM. The advised temperature for Phosphine NOT to be used below 10 deg C.
- Sulphuryl Fluoride: Sulphuryl Fluoride (Vikane) is used extensively in the USA to control insect pests in timber. It should not be used on living plants and foodstuffs. It does have an advantage over Methyl Bromide in that it does not have any harmful effects on photographic supplies, metals, electronic components, paper, leather, rubbers, plastics and wallpapers.
- Ethylene Oxide: Approval for use in foodstuffs was withdrawn by Australian authorities (AQIS) in 1988 due to concern over toxicity of residues formed in some foods. The properties of Ethylene Oxide as an insecticide and effectiveness in devitalizing seeds make it specific to special needs such as fumigating rice straw matting. A major drawback is the explosive qualities of Ethylene Oxide requiring it to be normally applied under vacuum.
- Ethylene Dibromide (EDB): Used for years as a treatment for fruit fly in fresh fruit and vegetables and agricultural needs this form of fumigation has gradually been replaced.
Reference to the IMDG Code
Reference is made to the IMO/ILO guidelines for packing cargo in freight containers or vehicles and recommendations on the safe use of pesticides in ships.
Only a cargo transport unit that can be closed in such a way that the escape of gas is reduced to a minimum, should be used for the carriage of fumigated cargo.
A closed cargo transport unit under fumigation should not be allowed on board until sufficient time has elapsed to allow the attainment of a reasonably uniform gas concentration throughout the cargo. Because of variations due to types and amounts of fumigants and commodities and temperature levels, the period which should elapse between fumigant application and loading should be determined by the competent authority. Twenty four hours is normally adequate for this purpose.
The master should be informed prior to loading of a cargo transport unit under fumigation. These should be identified with a warning sign affixed to the access doors incorporating the identity of the fumigant and the date and time of fumigation. The transport documents for a closed cargo transport unit should show the date of fumigation and the type and amount of fumigant used.
Equipment for detecting the fumigant gas or gases should be carried on the ship, with the instructions for its use. Fumigants should not be applied to the contents of a cargo transport unit once it has been loaded aboard a ship.
The provisions of this code should NOT apply to a closed cargo transport unit which has been ventilated after fumigation to ensure that no harmful concentrations of gas remain. Such a unit should also have the warning signs removed.
Health & Safety
Due to the very serious hazards, both health and fire, associated with fumigation, only competent specialist people should be employed to undertake this operation. When opening a container which has undergone fumigation, care must be taken to guard against residual levels of the fumigant. This will depend on the time since fumigation and the amounts applied. The container must be properly ventilated and suitable equipment used (Draeger Sets) to measure for residual gas prior to un-stuffing.
How to Apply Fumigants
As a general rule there must be a minimum of two person conducting any fumigation.
Secure fumigation sit: Fumigation should be conducted at an approved and isolated area specially designated for this purpose. Notification of planned fumigation should always be provided to relevant parties so that the danger to staff is flagged in advance.
Protective Equipment: Special protective suits are required which have respiratory protective equipment (RPE). This equipment must be maintained properly and tested at regular intervals.
Inspect container prior to stuffing to ensure that there are no holes in the container's side panels, roof, floor or doors.
Seal any ventilation ducts on the OUTSIDE of the container using grip tape or suitable equivalent.
Alternative methods of sealing cargo for fumigation include sealing the container or cargo under gas-proof sheets (Not commonly used).
Ventilated containers must be sealed along their top and lower side vents on the outside.
Fantainers can be sealed on the underside intake vent either with tape or by placing the container on a cushion blanket.
On completion of stuffing and observing the relevant safety procedures referred to previously, the fumigant is applied inside the container, with a door cracked open, and doors then quickly closed.
The amount and type of fumigant will be determined by the temperature, commodity, cargo cubic and country of destination. (See guidelines under Methyl Bromide and Phosphine).
A competent contractor will have a chart to readily determine the amount required. If it is the intention to ship the cargo under fumigation then the cargo must be treated as IMO Haz Class 9 and booked through the existing company procedures for hazardous cargo. The relevant packing declaration must accompany the cargo and the container appropriately labeled.
At least 24 hours must elapse after fumigation prior to the container being shipped. The reason for this is to allow the fumigant to properly permeate the cargo. In cases where the cargo requires ventilation during the voyage e.g. Coffee, the vents must be unsealed prior to shipment. In this case the container should be rendered non hazardous by opening the doors to fully vent the container prior to shipment.
A gas free certificate should be issued by the company conducting fumigation operations which then exempts the cargo from hazardous regulations. If shipping gas free then time scales must be carefully considered up to the arrival of the ship designated to lift the cargo. Sufficient time must be given to allowing the fumigant to act as well as making the container gas free afterwards. Fumigation can also be carried out on arrival at the destination port and will be subject to the port health requirements of that country.
Out of Gauge & Heavy Lifts
Out of Gauge (OOG)
Out of gauge cargo, that is cargo which is slightly higher or wider than will fit standard containers, can still be carried in open top, open-side or flat-rack containers. The latter type has higher payload ratings which is often important. When such cargo is shipped on a flatrack it is essential that accurate positioning is achieved and particularly for cargo destined for under-deck stowage. Under-deck cargo must clear the cell protrusions and cargo in adjacent cells.
Vessel Operations require this cargo to be booked for shipment under an OOG request and will allocate the number of slots required to accommodate.
OOG Under-deck within the cell guides:
Cargo which is too large to be containerized, either by weight or measurement, can be shipped as un-containerized cargo. This is performed either on a bed of flat-racks or by preparing a timber bed which is normally stowed on deck.
Heavy Lifts Above Container Payloads
The following is essential information for considering heavy lift pieces:
- Mass in metric tons.
- Principle dimensions (drawing required).
- Location of centre of gravity both athwartships and fore and aft.
- Bedding area and particular bedding precautions. Sometimes referred to as the "Footprint".
- Lifting points or slinging positions.
- Lifting gear if any accompanying the cargo, complete with test certificates.
- Securing arrangements aboard ship.
- Landside transport arrangements.
- Landside lifting arrangements e.g. gantry crane, floating crane, ship's gear.
The hallmark of good heavy lift work is careful planning and good communications between commercial and operational teams. Further issues to consider include :
- Delivery and receiving arrangements.
- Police escorts if applicable.
- Weight spreading measures on the loading beds/containers.
- Riggers and lashing equipment.
- Timetable/ critical path how this will fit in with normal operations.
- Ship stability and stress.
Heavy Lifts within Container Payloads
Large cases and crates:
Large and heavy units which take up only a part of the container space, should be place in the middle of the container. This is to ensure even weight distribution. The container space on either side of the cargo can be used for securing the cargo. Struts or chocks should never be used directly against the walls of the container as they are not strong enough to withstand pin point pressure (Stiletto effect) and planks should be used to distribute the weight evenly.
When shipping heavy goods particular care must be taken to distribute the weight of the load evenly over the floor of the container. Objects with a small base should be placed on bearers or skids to help spread the weight sufficiently over the length.
The centre of gravity of the load in a container must be kept as low as possible. Unevenly loaded containers often do not fit in the cell guides of a vessel and must be carried on deck.
If the weight of an individual package is more than three tons the weight should be printed in a prominent position on the package itself. The centre of gravity of large or heavy loads should be indicated, and lifting points well marked so to prevent damage during loading or unloading with lifting devices.
As a general rule, the heavier the cargo, the more carefully it has to be secured. Additional bracing structures are frequently needed to reinforce the walls of the container. It is also often necessary to use friction devices that absorb stress by allowing limited movement.
Heavy Unit Loads:
These goods should be stowed tightly in strong, well-built crates to prevent them from shifting. Due to the weight of the goods and the payload of the container, it may be possible to load only a single row of units. The units should be placed in the middle of the container. For securing these kinds of cargo the sidewalls must be reinforced with sizeable timber and the unit must be braced against these planks and bars with diagonal struts.
Heavy pipes, beams or girders should be stowed on transverse struts, placed across the floor of the container or flat rack. These kinds of goods have the tendency to slide lengthwise causing extreme stress on the container-endwalls. To prevent this packing should be used between each layer of the cargo. The types of packing which should be used are rubber strips, timber batons, soft boards, hessian, pieces of rope, etc.
Pressure on the sidewalls should also be relieved by strapping the load together at several places with strong steel bands or similar devices. The steel bands must be placed on the floor before the commencement of loading. Flats used to transport lengthy cargo should be equipped with side support bars to prevent lateral rolling. Tie the bars together above the loads to keep them from splaying. Where no side supports are available, secure the load from rolling by fixing end wedges on the transverse spacers. In both cases, strap securely with steel bands wire or span sets.
Particular care must be taken to prevent movement when transporting in open top containers, strap the rolls together in pairs and secure each pair with large timber blocks nailed to the floor. Reinforce the container ends with crossbars positioned at height of the centre of the rolls. Fill in empty spaces with timber. Very large and heavy rolls should be placed horizontally on a sledge that can either be anchored to skids from sliding or allowed to slide by means of friction devices. Lash the roll to the sledge with steel bands or strong wire and turnbuckles. Rolls shipped on flat racks should be stowed in heavy duty timber cradles and strapped together in pairs. Secure each roll individually to the flat by lashing through its centre hole.
Heavy & Large Vehicles:
Trucks, farm machinery, bulldozers and other heavy or large vehicles can be shipped on flat-racks or as break bulk straight onto a hatch lid or deck. If loading by the latter method the point loading of the deck should be checked.