ISO 16625-2013 pdf free download.Cranes and hoists — Selection of wire ropes, drums and sheaves.
For values of Z p , see 5.2. Alternatively, in circumstances when rotation-resistant ropes are used for hoisting and the mass of the sheave block and other lifting attachments and the efficiency of the reeving are not required to be taken into account, the design factor shall be at least 5. In the case of appliances with grabs, where the mass of the load is not always equally distributed between the closing ropes and the holding ropes during the whole of cycle, the value of S to be applied shall be determined as follows.
a) If the hoist mechanism automatically ensures an equal division of the hoisted load between the closing and holding ropes, and any difference between the loads carried by the ropes is limited to a short period at the end of the closing or the beginning of the opening:
1) for closing ropes, S = 66 % of the mass of the loaded grab divided by the number of closing ropes;
2) for holding ropes, S = 66 % of the mass of the loaded grab divided by the number of holding ropes.
b) If the hoist mechanism does not automatically ensure an equal division of load between the closing ropes and the holding ropes during the hoisting motion and, in practice, almost all the load is applied to the closing ropes:
1) for closing ropes, S = total mass of the loaded grab divided by the number of closing ropes;
2) for holding ropes, S = 66 % of the total mass of the loaded grab divided by the number of holding ropes. NOTE For the more common wire rope classes and constructions and, where applicable, rope grade, minimum breaking force factors given in ISO 2408 and ISO 10425 enable the minimum breaking force value to be calculated for a given nominal rope diameter. It should be noted, however, that the minimum breaking force factor used by the rope manufacturer can be greater than that given in the above-mentioned International Standards, resulting in higher minimum breaking force values being specified.
5.4 Diameter In the process of selecting a wire rope to satisfy the minimum breaking force requirement as given in 5.3, the situation can arise where, for practical reasons (e.g. availability, preferred sizes), the minimum breaking force exceeds the required minimum value, leading to a higher design factor than the minimum quoted in 5.2. In such cases, the selected nominal wire rope diameter, d, is to be used when calculating the diameter of sheaves and drums; see 6.2. NOTE The nominal diameter of a given rope type, construction or class, minimum breaking force and, where applicable, grade, is established by the rope manufacturer.
6 Drums and sheaves
6.1 Sheave material The manufacturer shall take account of the type of spooling when selecting the sheave material or sheave groove lining material. Single-layer spooling Where spooling at the drum is single-layer, the choice of sheave material can be critical, as deterioration of the wire rope is most likely to be through bending fatigue — particularly if the fleet angle is not excessive. If all of the sheaves are made of a polymer material or have a polymer groove lining, there is a possibility of internal fatigue damage going largely unnoticed in service unless discard criteria and/or the frequency between inspections is/are significantly modified from that given in ISO 4309 and closely followed. Such an arrangement should generally be avoided; see B.3.1 for recommendation.ISO 16625 pdf download.