ISO 19694-6:2023

Overview - ISO 19694-6:2023 (Ferroalloys and Silicon Industry)

ISO 19694-6:2023 is an international standard that defines a harmonized methodology for determining greenhouse gas (GHG) emissions from the ferroalloys and silicon industry. Focused on stationary source emissions, the standard uses a mass balance approach to quantify emissions from core metallurgical processes (notably carbothermic reduction in electric arc furnaces), ancillary operations and indirect sources such as purchased electricity. It also defines key performance indicators (KPIs) and reporting principles for plant-level GHG inventories.

Key topics and technical requirements

• Mass balance methodology: Calculate CO2 emissions based on inputs and outputs (reducing agents, ores, products, slag), consistent with IPCC-compatible approaches.
• Direct emissions covered: Smelting/reduction process (carbothermic CO/CO2 formation), decomposition of carbonates in furnaces, and auxiliaries related to smelting (dryers, ladle heating, aggregates).
• Indirect emissions: GHG from purchased electricity and from externally supplied heat are accounted for per ISO 14064-1 principles.
• Process vs combustion emissions: Guidance on distinguishing and quantifying process CO2 from fuel combustion, including fuel quantity determination, calorific values, oxidation factors and biomass considerations.
• Sampling and measurement: Minimum analysis frequencies and sampling approaches to support mass-balance calculations and uncertainty assessment.
• Reporting and KPIs: Recommended reporting periods, unit-based specific emissions denominators, recovery of waste gas/heat KPIs, and handling baselines, acquisitions and disinvestments.
• Uncertainty and quality: Procedures for assessing uncertainties of activity data, material parameters and aggregated mass-balance results.
• Supporting annexes: Tier 1 emission factors, minimum analysis frequencies, and country-specific electricity emission factors.

Practical applications and users

ISO 19694-6 is intended for:

• Plant operators and environmental managers in the ferroalloys and silicon industry who need consistent, auditable GHG inventories.
• Sustainability and compliance teams preparing regulatory reports, voluntary disclosures or carbon management plans.
• Third‑party auditors and consultants performing verification, benchmarking or emissions reduction assessments.
• Policy makers and regulators seeking harmonized methods for industry-level GHG accounting.

Use cases include site-level emissions accounting, performance benchmarking, tracking KPIs over time, designing emission reduction projects (e.g., electrode or reductant substitution, waste heat recovery), and preparing aligned sustainability disclosures.

Related standards

• ISO 14064-1:2018 (GHG accounting principles and organizational boundaries)
• IPCC 2006 Guidelines for National GHG Inventories (methodological compatibility)
• Other parts of the ISO 19694 series addressing energy‑intensive industries

Keywords: ISO 19694-6, ferroalloys, silicon industry, greenhouse gas emissions, GHG, mass balance, stationary source emissions, electric arc furnace, carbothermic reduction, emission factors, KPIs.