TT Talk - Examining quay cranes critically
It is estimated that 150 quayside container cranes develop a fatigue crack annually, with the potential for a catastrophic failure of a critical structural member. This is revealed in the Port Equipment Manufacturers Association (PEMA) in their latest publication, entitled 'Practical Structural Examination of Container Handling Cranes in Ports and Terminals'.
is an excellent guide to aid understanding of the risks posed by fatigue failure and provide practical guidance to terminal personnel in the detection of cracks through visual examinations of container handling cranes. The paper also draws attention to variations in the relevant International Labour Organization (ILO) regulation and some national standards, as well as confusion as to what constitutes a 'thorough examination'.Who is 'competent'?
The British Standard recommends an interval between thorough examinations of between 1 week and 6 months, while the ILO Convention 152 recommends these should be undertaken at least annually. However, neither provides a detailed explanation of what is involved in a thorough examination apart from a visual inspection by a competent person. The PEMA paper rightly suggests that, while visual examination by non-specialists is better than doing nothing, this should not replace following a proper inspection program by the crane maker or a trained professional which involves, besides a visual inspection, identifying high stress areas and carrying out non-destructive testing (NDT) where appropriate.
TT Club endorses the PEMA paper as an excellent guide for terminal personnel to understand and detect cracks through visual examination of container handling cranes during their regular duties. Further, it agrees that such visual inspections by non-specialists should not replace following a proper inspection program, including NDT as appropriate.
'the PEMA paper is an excellent guide for terminal personnel to understand and detect cracks through visual examination of container handling cranes during their regular duties'The ILO Convention 152 states:
1. Every lifting appliance and every item of loose gear shall be periodically thoroughly examined and certified by a competent person. Such examinations shall take place at least once in every 12 months.
2. A thorough examination means a detailed visual examination by a competent person, supplemented if necessary by other suitable means or measures in order to arrive at a reliable conclusion as to the safety of the appliance or item of loose gear examined.
3. The term competent person means a person possessing the knowledge and experience required for the performance of a specific duty or duties and acceptable as such to the competent authority.What is 'thorough' enough?
Some people interpret the words 'supplemented if necessary by other suitable means or measures' to mean non-destructive testing, since without doing NDT on high stress areas, it is not possible to 'arrive at a reliable conclusion as to the safety of the lifting appliance'.
TT Club believes that this interpretation of the ILO Convention 152 is reasonable. While it is clear that there are varying standards applied both in different jurisdictions and by various engineering departments, the incidence of major structural failures in port equipment around the world would support increased attention to this aspect of preventative care of key assets.
The quayside crane is the most essential piece of equipment on any berth: without it, the whole operation simply grinds to a halt. It is also the biggest single equipment procurement cost for a terminal operator. Overall, in TT Club's claims analysis, quay side crane incidents - including, but not limited to, structural failures - are the most significant insurance claim cost for ports and terminals. Included in this analysis, there are a disturbing number of major structural failures in port equipment during the last ten years. Not only can this type of equipment failure be very costly in terms of repairs and operational downtime, but incidents can involve serious injuries or fatalities.Improving practices?
There are some indications that the trend in relation to crane collapses over the last five years has improved, even as the number of cranes globally have increased substantially. There could be a variety of reasons for this, not least that construction standards have generally been advancing and more new equipment has been deployed. It may also be that there is greater awareness of the inspection standards set out in ILO Convention 152, even where not mandatorily applicable.
'TT Club would argue that this requires a qualified structural engineer, crane design engineer, or equivalent qualified and experienced person, to inspect the crane visually at least annually'
The PEMA paper is a valuable contribution to understanding the principles to be adopted in inspecting equipment that is of crucial importance to every port operation. It remains unfortunate that there are differing interpretations what really constitutes a 'thorough examination' and 'competent person'. TT Club would argue that this requires a qualified structural engineer, crane design engineer, or equivalent qualified and experienced person, to inspect the crane visually at least annually, forming a professional judgement as to whether other measures, such as NDT of high stress areas, are required to ensure the crane is structurally safe.
We hope that you have found the above interesting. If you would like further information, or have any comments, please email us, or take this opportunity to forward to any colleagues who you may feel would be interested.
We look forward to hearing from you.
Risk Management Director, TT Club