ISO 50002-3:2025

Overview

ISO 50002-3:2025 - Energy audits - Part 3 provides practical guidance for conducting energy audits of industrial and commercial processes using ISO 50002-1. It is a supplementary document intended to be used alongside the Part 1 general requirements. The standard covers how to define audit scope and boundaries for processes, collect and verify process energy data, plan measurements, perform on-site activities, analyse energy performance and report findings tailored to process environments.

Key topics and requirements

• Scope and boundaries: Guidance on defining process boundaries, inclusion of utilities and outsourced services, and coordination when buildings are also in scope.
• Planning and roles: Clarification of relationships among audit client, auditee and operators where ownership, operation and maintenance can be split.
• Data collection: Recommended types of data to collect (site, utility, production process, energy sources), verification, plausibility checks and handling of missing data. (See Annex A for examples.)
• Measurement plan: How to review existing data, identify measurement needs, develop measurement plans and perform preliminary data analysis to determine significant energy uses (SEUs) and relevant energy performance indicators (EnPIs).
• Site work and analysis: Guidance on site visits, management of fieldwork, energy balance estimation, identification and evaluation of energy performance improvement opportunities.
• Reporting and meetings: Requirements for content of audit reports and conduct of opening/closing meetings.
• Competence: Statements on the competence requirements for the energy auditor.
• Informative annexes: Includes guidance on data collection (Annex A), measurement quality (Annex B) and representative sampling for multi-site organizations (Annex C).

Practical applications and users

Who benefits:

• Energy auditors and consultants conducting process-focused energy audits
• Industrial facility engineers and operations managers (e.g., manufacturing lines, utilities, steam systems, dryers, furnaces)
• Organisations implementing or integrating energy audits into an Energy Management System (EnMS)
• Multi-site organizations seeking representative sampling approaches

Practical uses:

• Structuring process energy audits to identify SEUs and EnPIs
• Preparing measurement plans and data verification procedures specific to process equipment and operational conditions
• Evaluating energy performance improvement opportunities (process optimization, utility interaction, changeover impacts)

Related standards

• ISO 50002-1 - Energy audits: general requirements with guidance for use (normative reference)
• ISO 50002-2 - Guidance for building-related energy audits (use when buildings are included in the audit scope)

Keywords: ISO 50002-3, energy audit, processes, energy performance, energy auditor, EnMS, measurement plan, data collection, SEU, EnPI.