ISO 25457:2023

Overview

ISO 25457:2023 is an international standard developed by the International Organization for Standardization (ISO) for flare systems in the oil and gas industry, including applications for lower carbon energy. The document provides comprehensive requirements and guidance for selecting, designing, specifying, operating, and maintaining flares and related mechanical and combustion equipment used in pressure-relieving and vapor-depressurizing systems. While primarily intended for onshore petroleum, petrochemical, and natural gas facilities, it also covers relevant guidance for offshore applications. This standard updates and supplements API 537 (3rd edition, 2017), ensuring alignment with current industry best practices.

Key Topics

• Flare System Selection and Design: Addresses best practices for choosing and engineering flares for efficient control of process emissions and relief systems.
• Specification Requirements: Defines essential criteria for specifying flare equipment and mechanical details, supporting safe and sustainable operations.
• Operation and Maintenance Guidance: Provides recommendations to ensure reliable flare performance, longevity, and safety in refinery and petrochemical service.
• Specialized Ignition Systems: Details requirements for ballistic/pyrotechnical ignition systems, including components, safety constraints, and use of purge and capture devices.
• Flow Rate Calculation: Updates methodologies for determining volumetric flow rates through flares, supplementing and clarifying the guidance found in API 537.
• Safety and Environmental Protection: Emphasizes operational safety and emission control, supporting lower carbon energy initiatives and regulatory compliance.

Applications

ISO 25457:2023 is widely used in the following areas:

• Refineries and Petrochemical Plants: Ensures effective pressure relief and vapor depressurization, protecting personnel, assets, and the environment.
• Natural Gas Processing Facilities: Guides the design and safe specification of flare stacks and combustion devices for offgas and process emergencies.
• Onshore and Offshore Installations: Offers relevant techniques and requirements for both land-based and offshore oil and gas platforms.
• Lower Carbon Energy Operations: Supports energy transition objectives by providing best practices that facilitate emission reduction and sustainable flare operation.
• Procurement and Engineering Projects: Serves as a critical reference for project engineers, design contractors, and equipment suppliers engaged in the procurement and implementation of flare systems.

Related Standards

For a comprehensive approach to flare system specification and operation, consider referencing these related documents:

• API Standard 537 (3rd edition, 2017 & Addendum 1): Flare Details for Petroleum, Petrochemical, and Natural Gas Industries - the principal US standard, supplemented by ISO 25457:2023.
• ISO 23251 / API Standard 521: Pressure-relieving and Depressuring Systems - addresses broader safety and design aspects of relief systems.
• ISO 4126 Series: Safety devices for protection against excessive pressure, including safety valves integral to flare and vent systems.
• ISO 10418: Standard for offshore production installations, relevant for flare applications in offshore environments.
• IEC Electropedia, ISO Online Browsing Platform: Useful resources for standardization terminology and definitions.

Practical Value

Implementing ISO 25457:2023 supports safer, more reliable, and environmentally sustainable operations across the oil, gas, and petrochemical industries. By providing clear guidance on flare design, selection, and maintenance, the standard helps organizations mitigate risk, ensure regulatory compliance, and advance their lower carbon energy goals. Whether optimizing new installations or upgrading existing flare systems, this standard is an essential resource for achieving industry best practices and operational excellence.