According to the ISO 4301/1/FEM 9.511 series, lifting equipment is classified and dimensioned into groups depending on the operating conditions (driving mechanism classification). The group a hoist is classified in, is determined by the class of operating time and the load spectrum. The class of operating time indicates the average daily operating time. The load spectrum indicates to what extend a hoist or parts thereof are subject to maximum stress or to smaller loads only. Four load spectra are distinguished: L1 (light), L2 (medium), L3 (heavy) and L4 (very heavy). By applying the classes of operating times and the load spectra, the hoists are classified into eight groups. This results in the theoretical operating time.

By comparing the theoretical operating time with the actual operating time (operating conditions and times) the used rate of the theoretical operating time can be calculated. When the theoretical operating time has been reached, the hoists must be put out of operation or a general overhaul must be performed according to manufacturers requirements so that the hoists can be operated furthermore.

A useful tool for determining the actual operating time is now available on the website of J.D. Neuhaus.

Neuhaus places an online calculator for determing the remaining theoretical use at your disposal.