Overview
ISO 16625:2013 - "Cranes and hoists - Selection of wire ropes, drums and sheaves" provides practical, safety-driven rules for choosing wire ropes and the drums and sheaves that work with them. The standard defines minimum practical design factors (Zp) for different crane and hoist classifications, rope types and duties, and spooling arrangements, and shows how to use those factors to determine the minimum breaking force of a rope and the minimum pitch circle diameters of drums and sheaves.
Keywords: ISO 16625:2013, wire ropes, drums, sheaves, cranes, hoists, design factor, minimum breaking force, spooling.
Key topics and requirements
- Design factors (Zp): Tables provide minimum design factors according to mechanism classification (M1–M8), rope duty and rope type (standard vs rotation‑resistant). These values are used to size ropes for safety and durability.
- Minimum breaking force: The standard defines the basic formula F_min ≥ S × Zp, where S is the maximum rope tension (accounting for rated load, block mass, reeving efficiency, inclinations, etc.). Specific guidance is given for special cases such as grabs and stationary ropes.
- Drum and sheave sizing: Minimum pitch circle diameters are calculated using selection factors and a rope-type factor (formula: D ≥ h × t × d), where d is nominal rope diameter, h is a selection factor from tables, and t is a rope type factor.
- Sheave material and spooling: Guidance on material selection (steel vs polymer or lined grooves) depending on single‑layer or multi‑layer spooling and fleet angles. Warnings about polymer sheaves masking internal fatigue and the need for adjusted inspection/discard practices.
- Inspection, care and exceptional conditions: Cross‑references to inspection and discard criteria (ISO 4309) and notes on additional rope‑related design aspects (Annex B).
Applications and users
ISO 16625 is intended for:
- Crane and hoist designers and manufacturers selecting rope, drum and sheave geometry.
- Lifting equipment engineers performing safety and durability calculations (breaking force, bending fatigue).
- Maintenance teams and inspectors specifying compatible replacement ropes and groove liners.
- Safety managers and procurement professionals ensuring compliance with international practice.
Practical use cases include sizing hoist ropes for tower cranes, selecting groove diameters for multi‑layer drums, defining minimum rope grades for heavy‑duty installations, and specifying sheave materials to minimize wear.
Related standards
- ISO 2408 - Steel wire ropes for general purposes
- ISO 10425 - Steel wire ropes for petroleum and gas industries
- ISO 4301-1 - Cranes - Classification
- ISO 4309 - Wire ropes - Care, inspection and discard
- ISO 17893 - Steel wire ropes - Vocabulary and classification
ISO 16625 links these requirements into a practical framework for safe, long‑lasting rope and reeving system design.
