ISO 16745-1-2017 PDF

Full title and description

Sustainability in buildings and civil engineering works — Carbon metric of an existing building during use stage — Part 1: Calculation, reporting and communication. This International Standard specifies requirements and methods for calculating, reporting and communicating a set of carbon metrics (CM1, CM2, CM3) for greenhouse‑gas (GHG) emissions and relevant removals associated with the measured energy use and other relevant emissions of an existing building during its use stage.

Abstract

ISO 16745-1:2017 provides requirements for determining and reporting a carbon metric of an existing building associated with building operation. It defines three carbon metrics (CM1, CM2 and CM3), describes calculation and reporting conventions, states that CM1 and CM2 are not based on full life‑cycle assessment while CM3 may include partial LCA results, and clarifies that the document does not provide modelling methods for operational energy nor a value‑based rating or benchmarking system.

General information

• Status: Published (confirmed in 2022).
• Publication date: 2017-05-17.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 91.040.01 (Building and civil engineering works — sustainability).
• Edition / version: Edition 1 (2017).
• Number of pages: 38.

(General details above taken from the ISO catalogue entry for ISO 16745-1:2017.)

Scope

ISO 16745-1:2017 applies to existing buildings (residential, commercial or building complexes) and specifies methods to calculate, report and communicate carbon metrics for GHG emissions and removals associated with measured operational energy use, measured user‑related energy use, and other relevant GHG flows during the use stage. It follows the general principles in ISO 15392; it is not a modelling standard for operational energy, nor a building‑rating or benchmarking tool, and it does not address regional or national building‑stock assessments.

Key topics and requirements

• Definition and calculation rules for three carbon metrics: CM1, CM2 and CM3 (separate measures to capture different scopes of operational GHG flows).
• Reporting and communication requirements for declared carbon metrics (format, boundaries and accompanying information).
• Clarification that CM1 and CM2 are not quantified using full LCA methodology; CM3 may include partial LCA quantification where appropriate.
• Requirement to follow ISO 15392 general principles for sustainability in buildings where applicable.
• Exclusions and limitations: no operational energy modelling methods provided; not a value‑based performance rating; not intended for national/regional stock assessments.
• Use of measured energy data and user‑related energy inputs as key inputs to metric calculations; transparency in boundaries and assumptions required for reporting.

Typical use and users

This part of ISO 16745 is intended for building owners, facility and asset managers, sustainability and energy consultants, LCA practitioners (when CM3 uses partial LCA), verification bodies, auditors, and policy makers who need a standardized method to calculate and communicate operational carbon metrics for existing buildings. It is used to produce credible, comparable carbon declarations related to building operation and to support internal reporting, disclosure and verification processes.

Related standards

Relevant and related documents include ISO 16745-2:2017 (Verification of the carbon metric calculated in accordance with Part 1), ISO 15392 (general principles for sustainability in buildings and construction works) and ISO 14040 / ISO 14044 (LCA principles and requirements) where LCA methods are applied for CM3. These standards provide principle alignment, verification routes and methodological background for partial LCA use.

Keywords

carbon metric, operational carbon, greenhouse gas (GHG), existing buildings, use stage, CM1, CM2, CM3, reporting, verification, ISO 15392, life cycle assessment (LCA).

FAQ

Q: What is this standard?

A: An ISO standard that specifies how to calculate, report and communicate a carbon metric for GHG emissions and relevant removals from an existing building during its operational (use) stage.

Q: What does it cover?

A: It covers methods and requirements for determining and reporting three carbon metrics (CM1, CM2, CM3) based on measured operational and user‑related energy use and other relevant GHG flows; it sets reporting and communication conventions but does not provide modelling procedures for operational energy or benchmarking criteria.

Q: Who typically uses it?

A: Building owners, facility managers, energy and sustainability consultants, verifiers, LCA practitioners (for CM3), auditors and policy makers who need a consistent, transparent approach to declare operational carbon metrics for existing buildings.

Q: Is it current or superseded?

A: ISO 16745-1:2017 is published and was systematically reviewed and confirmed in 2022, so the 2017 edition remains the current version at the time of confirmation.

Q: Is it part of a series?

A: Yes — it is Part 1 of the ISO 16745 series (Part 1: Calculation, reporting and communication; Part 2: Verification — ISO 16745-2:2017). The series superseded earlier ISO 16745 editions.

Q: What are the key keywords?

A: CM1, CM2, CM3, operational carbon, GHG emissions, existing building, use stage, reporting, verification, LCA (partial for CM3).