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3.1 Container design

3.1.1 Container design and types

3.1.1.1 Part 1

3.1.1.2 Part 2

3.1.1.3 Part 3

3.1.2 CSC & structural and testing regulations

3.1.3 Cargo securing equipment

A container user should be aware of the most important structural differences betweencontainers, so that he/she is in a position to make appropriate preparations for packingand cargo securing and correctly to assess container loading capacity.Problem-free dispatch has been assisted by the standardization of transport units, suchas containers, while the standardization of certain components and some dimensionspermits the use of standard handling equipment and means of transport.

We will describe fundamental components and designs first of all with reference tostandard box containers. More detailed information is given under the heading "Containertypes".

Basic container frame

The load-carrying element of all box containers is a steel framework, consisting of fourcorner posts and two bottom side rails, two top side rails, two bottom cross members, afront top end rail and a door header.

Bottom cross members serve as supports for the container floor.

Additional bottom cross members are fitted between the bottom side rails, to serve assupports for the floor covering.

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Side walls End walls

Roof panel

The side and end walls and the roof are the components of a standard box containerwhich are capable of bearing the least load. To a certain degree, this naturally alsodepends on the construction materials used for them.

The following three Figures illustrate the essential components of standard boxcontainers. Not included by name are, for example, the door bar handles, the locking

components required for sealing, etc. Where necessary, descriptions of and commentsabout these components are provided at other points in the Handbook.

Essential components of a container

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They differ both in dimension and in the shape of the corner fittings or "corner castings".Most ASA containers, i.e. containers like those used by Sealand constructed according to"American Standards Association" standards, have since been adapted to match ISOdimensions. To simplify handling, special universal spreaderswere used, which couldhandle both types without difficulty.

ISO corner castings - horizontaland vertical mirror images

ISOstandard 1161 specifies different shapes for top and bottom and mirror images forright and left.

The eight corner castings of a container or a corresponding CTUhave to be particularlystrong, since they work with the corner posts and the other basic components of thecontainer frame to absorb the forces which lock units or lashingsexert on containers

when they are stacked on top of one another, during handling and during transport.

Securing on board

Cargo handling

Securing on achassis

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DIN/ISO standards specify certain minimumrequirements for the loading capacity and stackabilityof containers; while higher levels of performance may beprovided for individual properties, lower levels may not.It must be possible to stack six ISO containers packedto the maximum weight vertically on top of one another.Maximum offset is set as follows: widthwise - 24.4 mm(1"), lengthwise - 38 mm (1!").

The actual values of moderncontainers are generally higher.Many are designed to bestacked eight or nine high. Themaximum stacking loadmust bemarked on the CSC plate. (More

details are given in the relevantsection of the Handbook).

According to safety regulations, stacked containers must where necessary be securedagainst toppling and shifting.On larger container ships, the containers are stowed nine to twelve high in the hold. Insuch cases, the containers loaded must either be only partly full or designed to havegreater stackability. The latter is generally the case with modern containers, but it ispossible to use fold-out flapsin the cell guides, which subdivide the stacks.

Indicating stacking heightson a container

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the containers currently in use, a rough estimate would suggest that 85% are made ofsteel sheet.

Aluminum container skin

Aluminum containers are built either with a pure aluminum skin or with a plywood innerlining; they may also either be riveted or with a smooth or lightly riveted finish.In plywood containers, the outer walls are made of plywood coated with glass fiber-reinforced plastic (GRP). Plywood is a popular material for "coffee containers".

Container doors are often also made of plymetal,which consists of a plywood core with sheetmetal adhered to it on both sides.

Materials information on containers

It is clear from these examples that containers are not generally made from a singlematerial but various material combinations, here including steel, aluminum and plywood.The information even covers the type of preservatives used.

Wood treatment

information

Special impregnation against insect or other pests is required for certain regions ofservice. Most container floors or wooden parts undergo preventive treatment.

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must correspond to 0.6 times theuniformly applied payload, i.e. 60% ofthe payloador 0.6 g. Higher or lower

values should again be marked on thecontainers. More details are given in

Section 3.1.2 CSC & structural andtesting regulations".

Side wall loading capacity

Since the values for end and side walls are valid only for large-area loads, any pointloading of the walls should be avoided. Because the weight-carrying capacity of manygeneral purpose containers is not fully utilized, loading is kept below the maximum valuesin the case of compact and even packing. However, if the rate of utilization is high and/oruneven, countermeasures must be taken.

In the case of container roof panels,an evenly distributed 200 kg load maybe applied to a surface area of600 x 300 mm, so meaning that twopeople may stand next to one anotheron the container roof. Under nocircumstances may container roofpanels be covered with cargo.

Some containers are fitted with forklift pockets for handling with ground conveyors.Appropriate regulations relating to the required dimensions may be found in appendix Cof ISO 1496/1. The pockets are cavities formed crosswise in the floor structure and allowinsertion of the forks from the side; the forks must be pushed fully into the pockets. Forkswhich are too short must under no circumstances be used for lifting, since they maycause damage to the floor.

Unmarked forkliftpockets on a boxcontainer.

The forklift pockets generally only allow handling of empty containers. Packed containersmust not be picked up in this way unless specifically permitted. This is not the case here;hence, the container may only be picked up with forks when empty.

Forklift pockets ona flatrackmarked

EMPTY

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Forklift pockets on a flatrack not marked EMPTY

Both containers may only be picked up when empty.

For the most part, no marking is provided or no explicit instruction is given to pick uponly empty containers, missing. To rule out errors, marking should be made arequirement.

Marking variant: the arrows bear the mark "Tare".

The containers shown here merely bear the marking "Tare" at the inner forklift pockets.

The outer pairs of pockets lack markings or symbols. It is obvious here that thearrangement of these pockets also allows handling of the full container by forklift truck,but one can never be sure. This example shows that there is a need for marking to bemandatory.

Forklift pockets ona "tilt" container

With this container, it is even less certain how the forklift pockets are to be used.Standardized regulations and compliance therewith in practice could help in the avoidanceof many losses resulting from the incorrect use of these components.

Straddle carrierrecess

Some containers have a recess along the longitudinal sides which allows the containers tobe picked up using straddle carrierload suspension devices for transport within cargohandling facilities. Straddle carriers are specially built (low) van carriers with which loadsmay be lifted but not stacked.

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Handling a swap-bodywith grappler ingrappler pockets

Grappler pocket in a semitrailer Grappler pocket in a swap-body

Grappler pockets are slots or recesses in the bottom side rails of containers or otherCTUs, especially inland containers and swap-bodies. Grapplers slot into them duringcargo handling. Such grapplers may also be used with gantry cranes, if no spreadersareused. Grappler pockets also allow direct pick-up of the containers with the tongs of a vancarrier.

Detailed images of grapplers

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Gooseneck tunnel

Many containers have recesses in the bottom of the front end This centrally located recessis known as a gooseneck tunnel. A large number of CTUs, especially flatrackshave themat both ends. The tunnel does not have any effect on loading space, the inside of thecontainer floor or the flatrack loading area being flat. This recess serves in centering thecontainer on a gooseneck chassis.

Container with goosenecktunnel on a normal

container chassis

Container with gooseneck tunnelon a gooseneck chassis

Containers with goosenecks can be carried on both normal chassis and gooseneckchassis. Containers without goosenecks can only be carried on normal chassis. Depending

on the construction of the chassis, a lower road vehicle overall height may be achievedwith gooseneck chassis. In this way, many articulated truckscan see their height reducedby approx. 150 mm.

40' flatrackwithgooseneck tunnel

20' flatracks withoutgooseneck tunnel

In accordance with the standards, gooseneck tunnels are only provided for 40' containers.

GDV 2007 | Container Handbook | German version

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