For nearly 20 year now, the French ports have been particularly - PDF document

For nearly 20 year now, the French ports have been particularly concerned by their equipment integrity. A bad accident occurred in the port of Le Havre in 1998. The causes of it were analysed and conclusion point out many topics in strong relation with Equipment integrity. Since this dramatic event, many things has been done to improve safety, but unfortunately, some recent incident, or accident, show that attention of terminal operators have to be maintain at a high level. My presentation, today, have the objective : To remind you the different components of an integrity policy, and, To discuss about the use of FMEA to improve the efficiency of your control plan. 1

Before going further in our subject, few words about me and my company. I am Thierry Toubhans, and after 21 years with the port of Le Havre Authority, I have created StratéBord. StratéBord is at the service of its clients to assist them to plan the inventory of their equipment, and manage the project of procurement. We also bring our experience to improve maintenance, operation and control of equipment. 2

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The market pressure is high. As a consequence, the performance request for equipment is strong : Speed, no idle time, maximum adaptability. In the same time : Global operating cost must decrease. Reliability must increase. Working time must increase. Availability must increase. On the other side, many tasks have to be organised. These maintenance and control tasks are necessary, but they require time, regularity, budget. 4

In real life, the priority is often given to operation. In this case, the balance is broken, and the risk for equipment is maximum 5

Finally the question is : How can we satisfy the needs of operation manager, AND still guaranty the equipment integrity. In other words, it means that the technical department have to improve their procedures to do better with less time and less money. 6

After the 1998 accident in Le Havre, our reflections led us to identify the major components of equipment integrity. The first topic which come in mind when we consider integrity is control. Legal control, once or twice a year was already done before the accident, but it was considered not efficient enough. Particularly, regarding the fatigue phenomena, because it is obvious, but previously not taken into account, that the lifetime of a crane is not infinite. It is the reason why, the method of special assessment was created and applied in the French ports since November 2003. Anyway, control is necessary but not sufficient. The quality of maintenance, and particularly the repair procedures are preponderant to obtain the maximum safety. Procurement policy is another component of the integrity. It is easy to understand that these 3 area of action are extremely important. They are, in general, under the responsibility of the technical dpt. A last point is missing at this moment. The operation dpt has also his part of 7

responsibility. The crane drivers practices greatly influence the lifetime. Shocks, blockages, overloads and all sorts of incidents have to be signalled to the engineers because they can generate deformation, cracks, disruptions with dramatics consequences. 7

One of the identified cause of the accident of Le Havre, was a bad repair. The welded joint who broke had been repaired 2 years before. But the welding procedure was not good. To reduce the risk and improve equipment integrity, it is sometimes necessary to modify the original design. 8

The design of each element is part of the knowledge of the constructor. In terms of calculation, the details of design are not always taken into account by calculation codes, like FEM. The fatigue calculation is often done by 1 D elements and only take into account the maximum and minimum stresses and the case of construction. As a consequence, a non optimized design will increase the need of monitoring, as far as the user is aware of weakness of certain parts of his equipment. 9

Quality of manufacturing is part of equipment integrity. A bad weld could be at the origin of early cracks. It also means that integrity doesn’t only concerns old equipment. New ones have also to be integrated in the management of integrity. It is the reason why, the constructors are sometimes requested to deliver an inspection plan with their equipment. 10

As said before, operations have also an important role to play to preserve safety. Bad practices or errors can generate shocks or overload which greatly affect the crane. Drivers practices have to be approved by management and then, respected. In addition, all incidents must be reported to the technical dpt. 11

The control plan is one essential element of integrity. The reflection of the French ports brings the special assessment method which is now largely applied. The control plan issued from this method is based on fatigue appraisal. Nevertheless, some adjustment can be done to move to a risk based inspection. It’s the subject of my next topic. 12

The special assessment method was previously created for aged cranes. Some terminal operators have seen an interest to adapt a part of this approach to the recent equipment. In addition, we think that failure mode an effect analysis (FMEA) can be useful for optimisation of the control plan, and I’d like to show how. 13

At the origin, FMEA has been created to analyse the reliability of devices product in series. To adapt it to our needs, we have replaced the criteria ‘Probability’ by two criteria : Condition and occurrence, and we consider the max value of the 2 criteria. Each criteria is appraised from 1 to 4 A table is used to get an objective appraisal, Criticality is between 1 - 64 14

In the crane structure, some element are redundant, in case of breakage, the crane integrity is not affected, at least in the short term, even if, the reliability can be. 15

Accessibility has also to be taken into account. An easy accessible part can be more often controlled. Thus, a visual check can be sufficient, and it is not necessary to use Non destructive Testing. On the contrary, if a part is difficult to check. The visit will be done at lower frequency. This mean that you must detect little defects. To do so, NDT (Non Destructive Testing) are necessary. 16

A part of FMEA is done at the office. It is based on the drawings of the crane. Anyway, it is important to keep contact with the machine, the appraisal of condition and occurrence necessitate a visit on the crane and examination of maintenance historic. 17

Criticality is calculated, and control plan will be adapted taking into account the global appraisal, and, in some extend the individual criteria. If condition = 4 = It could be necessary to immediately applicate conservative disposition with technical staff of the terminal. If occurrence = 3 or 4 : this mean that this part, or a similar one was repaired many times, It is recommended to analyse the causes and fix the problem. To do it, finite element calculation can be necessary. If severity = 4 = The element will be particularly followed and of course introduced in the control plan. If detection is easy : The frequency of the visit can be increased and the means of detection will stay visual. On the contrary, if it is difficult, the number of visit will be lower and the Non Destructive Testing will be applied. If criticality of an element is >= 16, this element must be treated in the control plan. 18

As you see, this method is simple and pragmatic. It comes in addition to calculation and aditionnal point of view of the crane. 18

In my conclusion I would like to remind few points : 1-Old cranes are concerned as well as new ones, because old cranes suffer from fatigue, but all the cranes are subject to mistake of design, bad fabrication, bad operation practices. 2-The crane integrity is not only a question of control plan. It is also made of good practices in terms of : Procurement, maintenance and operation. I insist on the communication between operation and technical people 3-Special assessment method can be adapted for new equipment. In addition, the use of FMEA is pragmatic, not expensive, and is a good complement to calculation notice. This method helps to make the control plan more adapted and less expensive. 19