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Is a new lease of life for old equipment safe?

October 21, 2015: Legal framework that regulates expert reviews of lifting equipment requires immediate improvement, or it will be quite difficult to ensure safety of such equipment. 

Remaining operational life

Many engineering equipment is used at railway station and railway sheds to ensure lifting process. Over the last years, the Russian Railways has started to renovate operated equipment. However, old equipment is still used despite the fact that operational lifetime is over. In some cases such situation is permissible, if we deal with cranes, for instance. In general, operational lifetime of all equipment shall be determined by the producer. When the design lifetime is over, operation of equipment depends on the remaining life that shall be determined by the expertise. The legislation foresees initial, repeated and unscheduled inspection of cranes when operational life is over. Initial inspection shall be conducted after expiration of the lifetime specified in the nameplate. Repeated inspection shall be conducted till the deadline determined by the expert agency that inspected the equipment for the first time. However, the practice shows that such inspection is assigned twice a year. Unscheduled inspection shall be conducted by necessity (e.g.: Federal Service of Environmental, Technological and Nuclear Supervision may demand to inspect equipment when dangerous defects have been identified or after an emergency situation). Cranes produced abroad shall definitely pass through expertise regardless of production date to identify compliance of equipment with the Russian Federation technical regulatory documents and norms, prepare operational documents in accordance with the requirements of Federal Service of Environmental, Technological and Nuclear Supervision and obtain permissions for imported equipment operation in Russia.

Evaluation criteria

Traditionally, experts were guided by documents of Federal Service of Environmental, Technological and Nuclear Supervision during inspections. Such guidelines specified safety and operational criteria of steel constructions that determine the possibility of further operation of cranes; listed possible damages and defects; explained what to focus on when the expert commission was going to enhance the operational lifetime. The owner of a crane determines how to maintain mechanisms, electric equipment and control devices. The main thing is compliance with regulatory documents. Experts shall report about feasible remaining lifetime of Lifting equipment that shall not be violated. Cranes can be damaged and have defects in the operable condition that do not affect safety and main operational parameters (e.g.: slight corrosion, deformation of the crane details and deterioration of some details that doesn’t exceed established norms). Criteria of cranes limit condition are appearance of fatigue and other types of cracks, changes in the properties of used material, etc. Remaining operational life shall be evaluated by comparison of actual load bearing characteristics and criteria that correspond to limiting conditions. Initial data for such evaluation shall be nameplate and actual operational data. Regulatory documentation recommends using calculate methods or experimental-calculate methods for evaluation of the remaining operational lifetime, as they can forecast several scenarios of limiting conditions, identify longevity of the crane details and determine the level of internal damage accumulation. According to the regulatory documents, some conclusions were possible to make after visual inspection and technical diagnostics of the cranes (e.g.: cracks, metal deformation and deterioration). Lifetime of cranes used to be enhanced in accordance with special conditions, for instance, reduction of carrying capacities or reinforcement of metal constructions.

In expectation of new methodologies

The fact is that expert shall use exact descriptions of hazardous defects and practical methodologies for defect identification to make an expert conclusion (e.g.: whether deflection of the longitudinal beam or cracks in the bearing structure shall be considered dangerous or a permissible case). Regulatory documentation allowed experts to use all methods of non-destructive control (ultrasonic, radiographic and magnetic-particle). However, the documentation didn’t specify the cases when these or those methods shall be applied to the areas of identified damages. First of all, it is required to identify damaged areas and to know the most typical areas where hazardous deformation may appear. Main regulations are based on inspection results carried out 15-20 years ago – this is the problem. However, the regulations were supplemented by documentation elaborated by the scientific and technical council of Federal Service of Environmental, Technological and Nuclear Supervision and recommendations of Research and Development Institute for Crane Engineering and other related institutes. Elaborated documentation was used in parallel to the regulatory one and this situation made the work of experts rather complicated. The entire system required improvements, especially when significant changes in the Russian legislation occurred. There was a tendency of expertise rules unification in all industrial sectors that changed approaches to the expertise of equipment. Federal Service of Environmental, Technological and Nuclear Supervision cancelled regulatory documents that should be replaced by new technical regulations and supplementary documents. However, such regulations have not been introduced for lifting equipment and experts have to solve the problem applying general technical standards, for instance, to assess dangerous deflection of the crane boom. The Custom Union specifies regulations related to several types of equipment. However, they are too general and lack technical parameters of inspections and indicators of permissible limit of defects. Expertise of imported equipment has become more complicated, as experts generally shall use non-destructive control results, condition of load-carrying structure and standards that are applied for expert calculations in other countries. Now, there are practically no documents that clearly determine how many times the expertise shall be conducted. Earlier, there was a rule that an overhaul is required for the operational lifetime enhancement when two inspections have been carried out. Nowadays, the frequency of inspections is not limited. Federal Service of Environmental, Technological and Nuclear Supervision doesn’t provide conclusions to the experts after forthcoming inspections and the customer who initiated the inspection doesn’t inform experts about the recommendations issued by the inspectors. All these make the work of expert rather complicated. In other words, equipment is repaired after assessment of technical conditions. Consequently, owners of equipment may formally follow the rules. Federal Service of Environmental, Technological and Nuclear Supervisionу shall facilitate improvement of regulatory documentation related to diagnostic procedures and ensure sharing of experience between different expert agencies to make expertise more effective and apply non-destructive control equipment. 

Authors: Alexander Tomashevskiy, Manager of Engineering Equipment Expertise Dept.; Rostislav Levkovich, Evgeny Lomakin, Kirill Gurkovskiy – Experts of Engineering Equipment Expertise Dept. (GCE Group)

Source: RZD Partner magazine

 
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