ISO/IEC 80079-20-2:2016

Overview

ISO/IEC 80079-20-2:2016 - Explosive atmospheres - Part 20-2: Material characteristics - Combustible dusts test methods is a dual-logo ISO/IEC standard that defines laboratory test methods to identify and characterise combustible dust and combustible dust layers. The results support classification of hazardous areas and the proper selection and installation of electrical and mechanical equipment for environments where combustible dusts may be present. The standard applies under standard atmospheric conditions (temperature −20 °C to 60 °C, pressure 80–110 kPa and air with normal oxygen content ≈21 % v/v) and excludes recognized explosives, propellants and pyrophoric materials.

Key topics and requirements

• Scope and exclusions: Defines what materials and situations are covered (combustible dusts) and what are excluded (explosives, propellants, oxygen-independent fuels, pyrophoric substances).
• Sample handling: Requirements for receipt, characterisation, preparation and conditioning of dust samples prior to testing.
• Test conditions: Specifies the atmospheric and equipment conditions for reproducible results.
• Identification tests: Visual inspection and particle size distribution to determine whether a material can form a combustible dust or combustible flying.
• Ignition/reactivity test methods:
  • Modified Hartmann tube (vertical tube) for ignition sensitivity.
  • 20‑litre sphere dispersion tests for dust cloud ignition (with informative Annex E).
  • Godbert‑Greenwald (GG) and BAM ovens for minimum ignition temperature (MIT) of dust clouds (Annex B, F).
  • MIT of dust layers using heated surface tests.
  • Minimum Ignition Energy (MIE)/Minimum Ignition Energy of dust/air mixtures with high-voltage spark systems (examples in Annex C).
  • Powder resistivity measurement methods relevant to electrostatic ignition hazards.
• Reporting: Prescribed test report content and recording of results for use in risk assessments.
• Normative/Informative annexes: Apparatus designs and example data (e.g., Annex D - modified Hartmann tube, Annex H - 1 m vessel).

Applications and who should use it

• Process safety and explosion protection engineers performing dust hazard analyses and area classification.
• Testing laboratories that perform combustible dust characterisation and certification.
• Equipment manufacturers selecting or certifying electrical/mechanical equipment for dusty environments.
• Plant designers, safety managers, insurers and regulators requiring objective data for mitigation measures and compliance.
• Use cases include chemical, food, metallurgy, pharmaceuticals, wood processing and other industries where dust formation and accumulation present explosion risks.

Related standards

• Part of the ISO/IEC 80079 series on explosive atmospheres. This edition combines and replaces earlier IEC 61241-2 series documents (1993–1994). For full compliance and installation guidance, consult other parts of the 80079 series and national regulations.

For authoritative test procedures and instrument designs, obtain the full ISO/IEC 80079-20-2:2016 publication from an authorized distributor.