Overview
ISO 16625:2025 - "Cranes and hoists - Selection of wire ropes, drums and sheaves" provides a structured proof-of-competence framework and selection criteria for steel wire ropes used in cranes (as defined in ISO 4306-1). The standard covers how rope-drive geometry and drum / sheave geometry influence rope stresses and life expectancy. It replaces the 2013 edition and introduces a cycle-based approach and a new mathematical method for assessing fatigue strength (S–N curves and a characteristic reference point).
Key topics and technical requirements
- Scope and terminology: Definitions for running ropes and stationary ropes, design life, work cycles and rope bending diameter.
- Proof of competence: Methodologies for demonstrating adequate performance, separated into:
- Static strength proofs (including limit design rope forces).
- Fatigue strength proofs using a new reference point and S–N curves that account for different D/d ratios (drum/sheave bending diameter over rope diameter).
- Multilayer spooling specific proofs for ropes that coil in multiple layers on drums.
- Geometry effects: Incorporation of rope-drive geometry, drum and sheave groove radii, fleet angles, and reeving arrangements into force and fatigue calculations.
- Rope types and terminations: Guidance on rope selection, rope terminations (ferrules, socketing, swage terminals) and how termination type affects allowable forces.
- Operational and inspection criteria: Discard criteria, estimated number of relevant bending cycles, and assumed number of hoist ropes over the design life.
- Symbols and parameters: Comprehensive symbol set (design forces, limit forces, factors for lubrication, diameter influence, etc.) used in proofs.
Applications and users
ISO 16625:2025 is intended for practical use by:
- Crane and hoist designers - to select ropes, drums and sheaves and to verify static and fatigue competence.
- Manufacturers and rope suppliers - for specification and testing of wire ropes and terminations.
- Safety engineers and inspectors - to assess discard criteria, inspection intervals and maintenance planning.
- Consultants and certifying bodies - performing conformity assessments and design reviews.
Typical applications include hoist rope specification, verifying multilayer drum arrangements, calculating design rope forces under different reeving and fleet-angle conditions, and using S–N based fatigue proofs to predict rope life in cycles.
Related standards
ISO 16625:2025 is intended to be used alongside relevant standards such as:
Keywords: ISO 16625:2025, wire ropes, cranes, hoists, drums, sheaves, rope selection, proof of competence, fatigue strength, static strength, multilayer spooling, D/d ratio, S–N curve.
