ISO 4126-4:2013 is part of the ISO 4126 series and specifies the general requirements for pilot-operated safety valves (POPVs) used in pressure relief systems. These valves are especially suited for applications requiring high flow capacity and precise pressure control.

Key Features:

• Valve type: Pilot-operated pressure relief valves
• Operating principle: The main valve is controlled by a pilot valve, which monitors system pressure and opens the main valve when necessary
• Advantages:
  • More accurate control of set pressure
  • Tight shut-off with minimal leakage
  • Higher flow capacity compared to conventional spring-loaded valves
• Performance criteria: Defines parameters such as set pressure, reseat behavior, leakage limits, and back pressure effects
• Application areas: Commonly used in refineries, LNG facilities, petrochemical plants, and power generation systems
  
  

Purpose and Benefits:

• Ensures safe and consistent operation of pilot-operated valves
• Provides a technical reference for designers regarding sizing, selection, and installation
• Works in harmony with other parts of the ISO 4126 series, especially ISO 4126-1 and ISO 4126-5