Overview
ISO 21398:2019 - Hard coal and coke - Guidance to the inspection of mechanical sampling systems - provides recommended practices for inspecting mechanical sampling systems used for hard coal and coke. Designed to support conformance with ISO/TC 27 standards, this guidance covers general considerations (precision, mineral variability and bias), establishment of inspection systems, audit and operational procedures, and quality-control elements such as sampling ratios and record keeping.
Keywords: ISO 21398, mechanical sampling systems, hard coal, coke, sampling inspection guidance, precision, bias, audit, ISO/TC 27
Key Topics and Requirements
- Precision and bias: Recommends precision testing for each coal/coke type and bias verification after commissioning or major modifications (references ISO 13909 series for test methods).
- Operation of sampling systems: Guidance on start-up procedures (purging foreign materials, hydraulic warm-up), conditioning cuts for multi-feed systems, and ensuring cutter integrity.
- Establishment of inspection systems: Steps to develop sampling checklists and operator records using design criteria, equipment manuals, historic records and personnel input (Clause 6).
- Audits and inspections: Defines external audits (independent review, recommended at least annually), internal audits (routine, non‑operator reviews) and operational inspections (shift-to-shift checks by operators).
- Quality control metrics: Guidance on sampling ratio, coefficient of variation, extraction ratio, and maintaining sampling records and operator inspection reports (Clauses 7–8).
- Supporting annexes: Informative annexes include control-chart monitoring, example checklists, operator inspection report formats and inspection summaries to aid implementation.
Practical Applications and Users
ISO 21398 is intended for organizations involved in the handling, trade and quality control of coal and coke. Typical users:
- Plant operators and shift supervisors conducting operational inspections and maintaining sampling records
- QA/QC managers implementing sampling inspection systems and control charts
- Auditors and independent inspectors performing external and internal audits
- Designers, suppliers and commissioning engineers validating sampling plant performance
- Port and terminal operators managing multi-user sampling facilities
Typical use cases:
- Commissioning and acceptance testing of new sampling plants
- Routine inspection programs to detect bias or deterioration of sampling performance
- Preparing for or complying with contractual quality assurance requirements
- Developing operator checklists and reporting templates based on annex examples
Related Standards
- ISO 13909 (all parts) - Mechanical sampling of hard coal and coke (normative reference). Specific parts mentioned include ISO 13909-2, -5, -7 and -8 for sampling schemes, bias tests and precision methods.
- ISO/TC 27 - Technical committee for solid mineral fuels, which oversees related standards.
ISO 21398:2019 is practical guidance for ensuring reliable, auditable mechanical sampling and supports consistent quality control across coal and coke supply chains.