The idea of foldable containers is not so new. In the past several designs have been proposed. The majority of these ideas however never passed the phase of patent granting. Only two concepts have achieved the phase of pilot/testing and market introduction and are currently still available: the Six-In-One container and the Fallpac container.
The Six-in-One (SIO) container is a fully dismountable 20ft dry freight box that once dismantled, can be folded, stacked six high and interlocked to the exact dimensions of a standard 20 ft x 8 ft x 8 ft 6in container. It was launched about sixteen years ago by Six-in-One Container Co (SCC), a Swiss concern with a marketing base in France. Since introduction about 2000 units have been manufactured. A shortcoming of the first series of the SIO was its maximum gross weight of 20 tonnes, while standard boxes have a gross weight of 24 tonnes. In the next generation, the carrying capacity was increased to 24 tonnes, which left only one significant difference with the standard 20 ft container: the higher tare weight, which is about 500-600 kg heavier for the SIO.
The most striking characteristic of the SIO is the absence of hinges, other than the standard door hinge. The SIO incorporates seven separate elements with locking devices. Simple production and reduced manufacturing costs were important motives to choose for this construction based on dismountable parts. Avoiding the use of hinges was believed to be a key factor for success, because of well-known problems with hinges (i.e. corrosion, frost, bending).
In figure 1 the main steps of the (un)folding procedure are shown. To fold a container a three-person team with a forklift is required. SCC claims this process takes approximately 15 minutes. To simplify and speed up the mounting/dismounting process an assembly jig was designed, enabling handling productivity to increase from four to six containers per hour. Initially, SIO containers were only available for sale. In order to market the product more successfully, containers could also be leased from the early 1990s. In addition, the SCC company was willing to organise/operate the assembly and dismounting processes. In this way containers could be delivered erected to the shipping line user, so the customer would notice almost no difference in using a standard box or SIO container.
Although about 2000 SIO containers have been produced – of which the actual number of units still in operation (i.e. being mounted and dismounted) is unknown – one can not speak of a great success. Their market share is far too small compared to conventional container volumes.
To find out the reasons for the lack of market penetration, several experts were interviewed, including representatives of companies that used the SIO. Practical experiences demonstrate that particularly the costs of folding and unfolding the container are a strong barrier. In practice folding and unfolding takes far more time than claimed by the manufacturer. To insert the walls and doors is a time-consuming and difficult process, particularly when parts are slightly damaged.
Vulnerability to damage proves to be a serious concern for potential users, particularly because these kind of containers are often used in areas where containers are usually less carefully handled. In addition, theft of container parts is a serious problem in certain areas (i.e. Third World countries). According to companies, susceptibility to damage and theft make this system vulnerable. Furthermore, companies are of the opinion that the purchase price of the SIO is too high. Compared with the standard box prices, which have dropped enormously over recent years, the SIO is about 3.5 times more expensive. However, one can debate this argument by considering the exploitation costs of the container in relation to the total costs of the container logistics.
Last but not least, problems may arise regarding the integration of the SIO in the existing logistic chain. Most striking are the equipment problems existing container depots might have in handling a bundle of SIO containers, whose handling requires more time and space.
The folding technique of the Fallpac container is quite different from that of the SIO container. The Fallpac is a 20 ft dry freight box which combines dismountable and collapsible features. The roof of the container is dismountable, the remaining elements are foldable. Four folded units can be stacked inside a fifth assembled unit for empty transport (see figure 2). In this way the Fallpac container has also the same dimensions of the 20 ft standard box. The maximum gross weight of the Fallpac container conforms to ISO standards (24 tonnes), but its tare weight is approximately 4000 kg, which is about 1700 kg heavier than the standard 20ft container.
To fold or unfold the container two people and a forklift are required. According to the Swedish manufacturer (Fallpac AB), the box can be folded within 10 minutes. Because the folding technique incorporates folding side doors, the container is suited for side loading as well as end loading. In the original design there was a problem with leakage through the side doors, but this has been solved in the more recent design.
The first Fallpac container dates from the mid eighties. Since then some design changes have been introduced. In addition to the basic design a prototype of a fully-automated version has been launched recently. For the manual version a small test series of containers have been produced and tested with customers, including Swedish Rail. These tests took place many years by now and did not result in succession. Technical problems or serious disadvantages have not been reported, except its high tare weight. Serious problems with the hinges have been reported neither. The successful flat racks might have served as a good example for the folding technique that has been chosen. However, experiences with the Fallpac have been small-scale.
The high tare weight might be an obstinate barrier itself, particular as it comes to transporting and handling a bundle of empty containers. This indicates possible problems of integrating the container in existing logistic processes: this seems not only a problem for the Fallpac, but for the SIO container too. Last but not least, it seems that the very limited application of the Fallpac can be attributed to little marketing and insufficient promotion of the distinct features of the concept.