News / Warning to buyers on shipping container safety – it all hinges on the detail

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Caveat emptor (buyer beware) is the warning from the TT Club to those in the industry who are having containers built..

The buyer is fundamentally seeking conformance to a series of requirements, although the focus may be on the detail of the product to be built, rather than defining the measure of quality. The same consideration can be applied to the maintenance of containers.

Vigilant container depots, where most maintenance checks are carried out, will register both major and minor damage and wear and tear to a container. When approval is sought from the owner’s local office or agent for repairs to be undertaken, the most suspect work-items and easiest deletions inevitably are resolving minor dents or stiff door hinges. All in the interests of cost savings – operational economies.

While understandable, these may be false economies. Just as a lower standard of newbuild specification can often quickly create problems of container failure, so can ignoring the little points of damage or deterioration that occur during a container’s working life, and minor malfunctions can sometimes lead to more serious incidents.

One example where poorly constructed or maintained containers have caused problems is with the humble door hinges.

General cargo containers are fitted with a pair of swinging doors at the rear end, through which the cargo passes when being packed or unpacked. They are designed to be secured shut with two locking devices on each door and swing approximately 270 degrees to be tied back against the side of the container. The specification for the components used in the assembly of door hinges include readily available materials generally of suitable grades of stainless steel for the blade, lugs and pins, together with bushes that are designed to be maintenance free.

In one case, the user of a particular series of containers complained that after a short period of time there had been a serious accident involving at least one door from the series where all four of the hinge pins had sheered. When opening the door, it had broken away, injuring the operator. It transpired that over time the doors had been getting harder and harder to open and close.

Anecdotally, in this scenario, it is not unusual that forklift trucks are used to pull stiff doors open or force them shut, which clearly exacerbates any underlying problem.

Metallurgic analysis following this incident found that the material used for the hinge pins was not stainless steel and had consequently corroded to such a state that the pins seized within the hinge blade. Unfortunately hinge pins are difficult to see after they have been welded into the j-bar on the container end frame and post-assembly inspection is almost impossible. At the time of acceptance of the container, and before the pins started to corrode, the doors would have operated satisfactorily thus hiding the non-compliance.

As an isolated incident it might be viewed as a simple mistake. However, over the last couple of years door hinge failure has recurred at an uncomfortable level. The essential nature of these hinges, combined with a manufacturing process that largely obviates the need for lubrication, should result in a very low failure tolerance. Apart from in-service damage, the problems should be few and the doors should continue to operate with relative ease.

In terms of manufacturing, the use of the appropriate material specifications and exact alignment of the components should be managed within a quality control process. Where incidents of this nature occur, the spotlight is inevitably turned on quality at the manufacturing stage.

Given the rugged environment in which containers are deployed and their decentralised dispersion, independent assurance at the time of manufacture of “right first time” may be the best way to ensure the asset performs as expected as well as managing the manufacturing risk. While door hinges should be maintenance free, obviously the rugged environment they operate in may give rise damage.

So at what point should the container carrier, or his agent, accept the word of the repair yard which says that the hinges are stiff and need attention? Whatever the amount of the 18m or so global units are under the control of any given owner or operator, there needs to be relevant systems in place to sift through the estimated work-items and make appropriate decisions. Over-zealous cost control is at risk of transferring the problem from one repair budget to another – assuming that a given unit passes through a repair depot, rather than ‘triangulating’ directly from a consignee to the next shipper.

Of course, every packer should now seek to adhere to the CTU Code and reject a container where the doors do not work properly and with ease.

The reality is that the control an owner or operator has over the use and condition of units is delegated to a significant degree. The importance of container integrity is clear. So many stakeholders in the supply chain rely on the equipment performing as expected – and for the driver reaching from the ground to a unit loaded on a chassis, the dynamic forces are extremely dangerous should a failure occur. Quality of manufacture and maintenance should be viewed as entirely appropriate when set in the context of an injury or fatality – the price of doing it right against the value of life.

This is the first of a series of monthly guest posts from TT Club’s risk management director Peregrine Storrs-Fox in which he discusses some of the emerging safety and compliance issues in today’s global supply chains