Considering that every crane in its design phase has been designed to withstand a maximum number of lifting cycles beyond which the seal is no longer guaranteed, very often its structure lasts longer than its parts.
In fact, with the succession of lifting cycles, fatigue phenomena can arise in the structural components, that is, with time they generate small lesions on the material even if not visible to the naked eye, which at each load cycle are amplified, eventually leading to the rupture of the structural component with all the damage and dangers that may result.
In order to avoid this, beyond the tenth year from the placing on the market of the plant it is necessary to resort to the assessment of suitability of the machine and to carry out the residual life calculations, defining according to the design class and the real life cycle, the number of cycles that the installation can still perform safely.
The verification is voluntary but can be prescribed by the supervisory bodies, taking into account that: the manufacturer is no longer responsible for the product after the tenth year (D.Lgs. 206/2005 art. 106 Revocation Paragraph 1) and the owner is obliged to provide his employees with safe equipment and verify that the safety requirements are always met, as per Article 71 of Legislative Decree 81/2008.
Beyond the twentieth year from the placing on the market of the crane, however, it is not enough to perform residual life calculations (such as the ten-year calculation), but it is necessary to perform a supplementary survey, or a structural verification aimed at identifying any defects or anomalies mainly due to structural fatigue phenomena. The additional investigation was imposed by the new Ministerial Decree 11 April 2011, which entered into force on 24 January 2012.
As defined by UNI-ISO 9927-1, the additional survey can be carried out exclusively by the Expert Engineer, or a competent person, practical in the design, construction or maintenance of lifting equipment, be aware of the rules and regulations and must have the necessary equipment to carry out the verification. Well aware of the importance of the plant on the company production cycle and the problems related to the downtime of the machinery, our company provides an Expert Engineer who can carry out all types of checks.