ISO 23552-1:2026

Overview

ISO 23552-1:2026 is an internationally recognized standard developed by the International Organization for Standardization (ISO) for control and protective devices for gaseous and liquid fuels. Specifically, Part 1 of this standard focuses on electronic fuel/air ratio control (FARC) systems, including the associated sensors and mechanical actuators. These systems are essential for burners and appliances using gaseous or liquid fuels, ensuring that fuel and air are mixed in optimal proportions for safe, efficient, and environmentally sound combustion.

The standard outlines comprehensive safety, design, construction, performance, and testing requirements for electronic FARC systems. It aims to guarantee inherent safety, proper operation, and reliable supervision of fuel/air ratios in a wide range of heating and process equipment.

Key Topics

• System Types:

  • ERC (Electronic Fuel/Air Ratio Control Systems): Full closed-loop systems that automatically adjust both fuel and air to achieve a set ratio.
  • ERT (Electronic Fuel/Air Ratio Trim Systems): Closed-loop systems that fine-tune the air/fuel ratio, complementing primary controls.
  • ERS (Electronic Fuel/Air Ratio Supervision Systems): Supervision-only systems that monitor the air/fuel ratio and provide alerts or shutdown signals if unsafe conditions are detected.

• Scope of Components:
  The standard covers complete systems and individual components such as:

  • Sensors (for measuring air and fuel flow, flue gases, etc.)
  • Mechanical actuators (e.g., variable speed fans for air, valves for fuel)
  • Motors and blowers

• Safety Requirements:

  • Inherent safety for FARC systems and their declared operating values and sequences
  • Strict requirements for performance, durability, and functional reliability
  • Protection against internal faults to ensure functional safety

• Testing and Evaluation:

  • Detailed procedures for evaluating compliance through type testing
  • Supplemental requirements to align with other relevant burner or appliance standards
  • Emphasis on electromagnetic compatibility (EMC) and resistance to environmental factors

• Documentation and Marking:

  • Clear marking, installation, and operation instructions for integrators and end users
  • Requirements for manufacturer’s declarations, especially for repeatability and sensor reliability

Applications

Electronic fuel/air ratio control systems designed and validated per ISO 23552-1:2026 have widespread applications in:

• Industrial and Commercial Burners:
  Ensuring precise fuel/air mixture for maximum efficiency and reduced emissions in boilers, furnaces, and process heaters.

• Heating Appliances:
  Applied in residential and commercial heating systems burning natural gas, LPG, or oil, contributing to safe and efficient operation.

• Process and Manufacturing Equipment:
  Used wherever the combustion process requires close monitoring and adjustment of fuel and air to optimize product quality and minimize environmental impact.

• Appliance Safety Integration:
  FARC systems form a critical part of appliance safety chains, providing supervision and closed-loop controls to mitigate combustion risks.

Related Standards

For full compliance and practical implementation, ISO 23552-1:2026 should be read in conjunction with related standards:

• ISO 23550:2018: General safety and control requirements for gas and oil burners and appliances.
• IEC 60730-1: General requirements for automatic electrical controls.
• IEC 60730-2-5: Requirements specific to automatic burner control systems.
• Additional regional standards may apply, as noted in the annexes for Europe, North America, and Japan.

By following these standards, manufacturers and integrators ensure that electronic fuel/air ratio controls deliver reliable, safe, and efficient performance across a broad range of fuel-burning equipment, fostering industry best practices and regulatory compliance.