Decisions on crane refurbishment are rarely made overnight: regular inspections indicate when the time is right. Those who pay attention to the results can take a planned approach. Those who, on the other hand, wait until the malfunction, which tends to carry out refurbishments under duress and at a higher cost.
The stages of the investigation lead to a decision
International standards for cranes designed for a service life of ISO 9927-1 standard It stipulates a multi-level inspection system: in addition to daily checks by the machine operator, a regular inspection is carried out at intervals of no more than three months, a periodic major inspection at intervals of no more than one year, and a so-called enhanced, extended inspection at intervals of no more than ten years.
The latter is the most thorough. It reveals whether the condition of the structure, the drive mechanisms, the brakes and the cable system still meets the requirements for safe operation, or whether more substantial work is required.
The more The more complex the examination, the greater the level of expertise required. The daily inspection may be carried out by the machine operator; the main inspection by an experienced technician or crane inspector; and the in-depth inspection by a lifting equipment expert.
The logic behind the „safe period of use”
In the case of these cranes and hoists, the industry operates on the basis of the concept known as the ‘Safe Working Period’, which the ISO 12482 standard refers to as the ‘design service life’. The total service life of a crane, when used for its intended purpose, consists of one or more such periods, typically lasting ten years. The remaining duration of a given period can be calculated on the basis of actual load data (operating hours, number of cycles, load spectrum).
When a service period is drawing to a close, a targeted condition assessment – known as a ‘Special Assessment’ – determines whether the crane can continue to be operated safely for a further service period, or whether a major overhaul is required.
It is important to emphasise that the need for and timing of major repairs are always determined by the results of a specialist inspection, rather than by a predetermined calendar date.
What does „major overhaul” actually mean?
Major repairs in practice the replacement of certain components or the refurbishment of existing components means.
If replacement is not economically justified, continued safe operation can be ensured by increasing the frequency of inspections. This option is important because a complete refurbishment or replacement is not always the right answer: as long as the equipment can be operated economically, closer monitoring is sometimes sufficient. All this is closely linked to what is discussed in the section on the service life of cranes in our previous article As we have already mentioned: the end of the technical and economic service life do not necessarily coincide, and the findings of the study help to underpin this very decision.
In the next instalment of our series, we will show what specific signs, visible to the naked eye, indicate in day-to-day practice that A crane is in need of refurbishment.
