Overview
ISO 15117-1:2004 - "Coal flow properties - Part 1: Bin flow" defines standardized laboratory methods for measuring the flow properties of coal primarily to support the design of bins, hoppers and chutes. The standard specifies a bulk density test, a yield locus test (to characterise bulk strength and flowability) and a wall yield locus test (to measure coal-to-wall friction). Although written for coal, the principles and apparatus apply to coke and other semi‑cohesive particulate materials where reliable flow data are required.
Key topics and requirements
- Sampling and sample preparation: Specifies sampling in accordance with ISO 13909-2 and procedures for top size, division and moisture control to ensure representative test material.
- Yield locus determination: Procedures for obtaining instantaneous yield loci and related flow functions (unconfined yield strength versus major consolidating pressure). The standard addresses variants such as time, high‑pressure, temperature and vibration yield loci.
- Wall yield locus / wall friction: Tests and calculations to determine the wall friction angle (φ) between coal and candidate bin wall materials.
- Bulk density and compressibility: Test methods to measure consolidated bulk density and compressibility under specified loading conditions.
- Shear apparatus and test phases: Use of shear cells and defined consolidation/shearing phases to produce reproducible data (preconsolidation, shear consolidation, sample shear).
- Data presentation and reporting: Guidance on how to present yield loci, flow functions and prorating procedures for design use. Annex A discusses bin design philosophy and the relevance of measured properties to flow regimes (mass flow, funnel flow, ratholing).
- Referenced standards: Normative references include ISO 1213-2, ISO 1953, ISO 589, ISO 13909 parts and ASTM D6128.
Practical applications and users
ISO 15117-1 is used to:
- Provide design inputs for bin, hopper and chute design (to avoid ratholing, bridging or erratic discharge).
- Characterize flowability for plant engineering, material handling and storage systems.
- Select or specify wall linings and surface finishes based on wall friction data.
- Support procurement and validation of bulk handling equipment (feeders, reclaim systems).
Typical users: mining and coal preparation engineers, bulk solids handling consultants, mechanical designers, equipment manufacturers, research labs and standards bodies.
Related standards
Keywords: ISO 15117-1, coal flow properties, bin flow, yield locus, wall friction, bulk density, flowability, bin design, shear cell.