FEM 9.755 - Measures for achieving Safe Working Periods for Motorized Serial Hoist Units (S.W.P.)

FEM 9.755-EN

For technical reasons, it is of advantage for a user to adapt serial hoist units as far as possible to the actual loads. For this purpose, serial hoist units are classified into 8 groups of mechanisms in accordance with table 1 resulting from the application of the following regulations (ISO 4301/1, FEM 9.511, FEM 9.661, FEM 9.671).

Many elements involved in the distribution of forces in a serial hoist unit are not visible during the prescribed inspection intervals and cannot be checked. The onset of damage, therefore, cannot be or hardly be recognized. On reaching the theoretical utilization D, at the latest, hazards may occur with increasing probability.

The theoretical utilization D given in table 1 determines, in conjunction with the actual operating conditions, safe working periods (Safe Working Periods; see definitions), for all elements of serial hoist units.

It is therefore the objective of this rule to determine measures for achieving safe working periods over the entire duration of service, although - according to the state of the art - premature failure cannot be ruled out.