Determination of the
remaining lifespan by
calculating the S.W.P.
No machine has an infinite lifespan. Hoist manufacturers are therefore required to state the theoretical lifespan (Safe Working Period) in each manual. After this period of use expires, hoists must be fully inspected.
The FEM class classification
Each hoist is calculated for a specific application and designed for a certain number of lifting cycles and lifting hours. The number of hours is expressed by the FEM class classification, a classification used by the FEM (the European Materials Handling Federation). The FEM class classification is mainly based on the expected average load combined with the expected average daily usage time. For example, a hoist with FEM class classification FEM 3m can lift a nominal load 3200 hours but once the 3200-hour limit is reached, the hoist must be replaced or undergo a general overhaul.
So the remaining theoretical potential of the hoist will be exhausted the longer you work with it. To ensure that the safety of the hoist is maintained and that no non-visible component exceeds its theoretical lifespan during maintenance, the S.W.P. calculation should be performed and recorded at least once a year.
THE S.W.P. calculation
The calculation of the remaining lifespan (S.W.P. calculation) is done in 3 steps:
– Data collection: all available data are collected. This is done either together with the customer, based on the data provided to us (loads lifted, average lifting cycles …), or by reading the data from the hoist if it is equipped with a load totaliser. Both can also be combined if the hoist is equipped with an hour meter.
– Calculation: the calculation can be done using specialised software. This software also serves as a database for recording the characteristics of the hoist and data from previous calculations.
– Report: once the calculation is complete, the customer receives a report with all the technical data, the load data of the installation, the calculation and the result. The report also indicates how many years the lifting system can continue to operate (on condition that the load remains the same).
Has the installation reached or exceeded its lifespan? Then it must be taken out of service immediately to avoid the risk of incidents. The installation can be taken out of service, replaced with a new installation or a company can be appointed to subject it to a general overhaul.
