ISO 20915:2018

Overview

ISO 20915:2018 - Life cycle inventory calculation methodology for steel products - provides a standardized methodology for preparing life cycle inventory (LCI) studies specific to steel. The standard focuses on the factory-gate (cradle-to-gate) stages of steel production and explicitly incorporates steel’s capacity for closed‑loop recycling. ISO 20915:2018 defines how to set the functional unit, determine system boundaries, treat scrap and co‑products, and report LCI results. The standard conforms to ISO 14040 and ISO 14044 principles; application of LCI results to life cycle impact assessment (LCIA) is outside its scope.

Key topics and requirements

• Functional unit and function definition: Guidance on selecting the functional unit appropriate for steel products LCI to ensure comparability and consistency.
• System boundaries: Requirements for defining system boundaries that capture raw material sourcing, production at the steelworks, and scrap recycling processes.
• Scrap evaluation and recycling: Methodology to account for ferrous scrap inputs, scrap treatment, and calculation of burdens and credits associated with recycling to reflect closed‑loop recycling.
• Co‑product handling and allocation: Procedures for allocating inputs and outputs among primary products and co‑products, including system expansion options.
• Data quality and data collection: Criteria for temporal, geographical and technological coverage, data sources, and cut‑off rules.
• Cradle‑to‑gate LCI calculation: Steps for performing LCI calculations with and without allocation for scrap input.
• Reporting and critical review: Prescribed reporting elements and requirements for critical review to ensure transparency and reproducibility.
• Supporting annexes: Informative annexes provide worked examples (LCI calculations, recycling rate calculations, electricity/steam treatments) and comparisons among standards.

Applications and practical value

ISO 20915:2018 is practical for:

• Steel producers preparing consistent LCIs for product lines or EPD inputs.
• LCA practitioners performing product LCA where steel is a major material.
• Sustainability and supply‑chain managers assessing environmental performance and recycling benefits.
• Product designers and OEMs optimizing material choices and design‑for‑recycling strategies.
• Policy makers and certifiers seeking standardized LCI inputs for regulation or procurement.

Use cases include LCI development for Environmental Product Declarations (EPDs), comparative LCA of material options, supplier reporting, and internal sustainability accounting where accurate representation of scrap recycling is essential.

Related standards

• ISO 14040:2006 - Environmental management - Life cycle assessment - Principles and framework
• ISO 14044:2006 - Environmental management - Life cycle assessment - Requirements and guidelines

Keywords: ISO 20915:2018, life cycle inventory, LCI, steel products, closed‑loop recycling, scrap evaluation, functional unit, system boundaries, co‑products, reporting.