ISO 21931-2:2019

Overview

ISO 21931-2:2019 - "Sustainability in buildings and civil engineering works - Framework for methods of assessment of the environmental, social and economic performance of construction works - Part 2: Civil engineering works" - provides a common framework to improve the quality and comparability of methods used to assess the environmental, social and economic performance of civil engineering works using a life cycle approach. It applies to both new and existing civil engineering works and their area of influence, and is intended to harmonize regional and national assessment methods without prescribing performance benchmarks.

Key topics and technical requirements

The standard defines the framework and core elements that assessment methods should document and follow, including:

• Purpose and scope: clear statement of objectives and the object of assessment (whole works, part, or combinations).
• System boundary: specifying life cycle stages and the geographic/functional area of influence.
• Assumptions and scenarios: declaring uses, operating modes and time horizons that affect results.
• Assessment categories: identification of environmental, social and economic indicators relevant to civil engineering works.
• Life cycle perspective: inclusion of construction, operation, maintenance, end-of-life and external works where relevant.
• Quantification methods: rules for data quality, traceability, transparency and avoiding double‑counting.
• Functional equivalent: defining technical and functional characteristics to enable fair comparisons.
• Aggregation and weighting: guidance on combining indicators while noting the standard does not set weights or benchmarks.
• Reporting and evaluation: requirements for assessment documentation and presentation to support comparability and verification.

Note: Risk assessment of environmental, social and economic risks is excluded, although its results can be considered in assessments. The standard does not set performance levels or valuation methods.

Practical applications and users

ISO 21931-2:2019 is intended to be used by:

• Civil engineers, infrastructure designers and asset owners to structure sustainability assessments.
• Assessment and certification bodies developing national or scheme-specific methods.
• Policymakers, procurers and regulators seeking consistent assessment frameworks for infrastructure projects.
• Contractors, consultants and life cycle assessment (LCA) practitioners preparing sustainability reports or benchmarking studies.

Practical uses include informing design choices, guiding procurement and operation strategies, benchmarking sustainability performance across projects, and aligning national/regional assessment schemes with internationally recognized principles.

Related standards

This part is intended to be used alongside other ISO sustainability documents, notably:

• ISO 15392 (General principles)
• ISO 21931-1 (Part 1: Buildings)
• ISO/TS 21929-2 (Indicators for civil engineering works)
• ISO 21930 (Environmental product declarations)
• Related ISO 21931 series documents for holistic sustainability assessment of construction works

Keywords: ISO 21931-2:2019, sustainability assessment, civil engineering works, life cycle approach, environmental social economic performance, assessment framework.