Overview

The foundational LCA standard: principles, framework and the four phases of life cycle assessment; amended by Amendment 1:2020

ISO 14040:2006 describes the principles and framework for life cycle assessment (LCA). It is the entry point to the LCA standards and is always used together with ISO 14044, which contains the detailed requirements. The second edition, published in 2006, replaced ISO 14040:1997 as part of the consolidation of the earlier ISO 14040–14043 series, and has since been amended by ISO 14040:2006/Amd 1:2020. It is maintained by ISO/TC 207/SC 5.

ISO 14040 is explicit about its limits: it describes the principles and framework but does not describe the LCA technique in detail, nor specify methodologies for the individual phases. Practitioners who need requirements — on functional units, allocation, data quality, impact assessment or critical review — must use ISO 14044.

LCA is defined as the compilation and evaluation of the inputs, outputs and potential environmental impacts of a product system throughout its life cycle. The framework consists of four phases: goal and scope definition, life cycle inventory analysis (LCI), life cycle impact assessment (LCIA) and interpretation. A defining feature is that the phases are iterative: findings in the inventory or impact assessment routinely send the practitioner back to revise scope, system boundary or data requirements.

The principles that govern an LCA include the life cycle perspective (covering the whole chain from raw material acquisition through production, use and end-of-life treatment), an environmental focus, a relative approach organised around a functional unit, an iterative approach, transparency, comprehensiveness across environmental aspects, and priority of scientific approach in decision-making. The relative approach matters: LCA results are always expressed relative to a functional unit, so they answer "per unit of function delivered", not "per factory" or "per year".

ISO 14040 also sets out what LCA can and cannot do. LCIA results are relative expressions of potential environmental impacts; they do not predict actual impacts at specific locations or times, nor exceedance of thresholds or safety margins. It notes that value choices and subjective elements are present in LCA — in system boundary setting, allocation and impact category selection — and that these must be made transparent. It also flags that there is no single method for conducting LCA and that organizations have flexibility within the framework.

The standard establishes the reporting and critical review concepts that ISO 14044 then specifies, including the heightened requirements that apply to comparative assertions intended to be disclosed to the public.

ISO 14040 and 14044 are the methodological basis for a large family of downstream standards and programmes: ISO 14025 (environmental product declarations), ISO 14067 (carbon footprint of products), ISO 14046 (water footprint), ISO 14026 (footprint communication), EN 15804 for construction products, and the Product Environmental Footprint methods used in EU policy. LCA is not itself certifiable: studies are subject to critical review, and declarations built on them are verified under programme rules.

Purpose

To establish the principles, framework and terminology of life cycle assessment, defining the four phases of an LCA study and the ground rules that make results transparent, comparable and technically defensible.

Key Benefits

• Defines the internationally accepted framework and terminology for life cycle assessment
• Establishes the four-phase LCA structure used by every downstream footprint and declaration standard
• Introduces the functional unit, ensuring results are comparable per unit of function delivered
• Requires a full life cycle perspective, exposing burden shifting between life cycle stages
• Sets transparency expectations for assumptions, value choices and limitations
• Clarifies that LCIA results are potential, relative impacts rather than predicted local effects
• Provides the methodological basis for EPDs, product carbon footprints and water footprints
• Supports eco-design, product comparison and supply chain decision-making
• Recognised by regulators, customers and reporting frameworks worldwide
• Applicable to products and services in any sector

Key Requirements

• Note: ISO 14040 sets principles and framework — detailed requirements for conducting an LCA are in ISO 14044
• Apply the four phases: goal and scope definition, inventory analysis, impact assessment and interpretation
• Treat the phases as iterative, revisiting earlier decisions as data and results emerge
• Define the goal, including the intended application, reasons for the study and intended audience
• Define the scope, including the product system, system boundary and functional unit
• Express results relative to the functional unit rather than in absolute organizational terms
• Adopt a life cycle perspective covering raw material acquisition through production, use and end-of-life
• Ensure transparency about methods, data, assumptions, value choices and limitations
• Recognise that LCIA results are relative expressions of potential environmental impacts
• Report results and, where applicable, subject the study to critical review
• Apply the additional requirements of ISO 14044 for comparative assertions intended for public disclosure
• Use ISO 14044 for detailed methodological requirements on allocation, data quality and impact assessment

Who Needs This Standard?

LCA practitioners and consultants, product designers and eco-design teams, sustainability and environmental managers, EPD authors and programme operators, procurement teams evaluating environmental claims, and researchers and students learning LCA methodology.

Related Standards