API 526 is a standard published by the American Petroleum Institute (API) that defines the nominal sizes and pressure ratings for pressure relief valves (PRVs). It serves as a key reference for valves used in ASME Section VIII-compliant pressure vessel systems.

Key Features:

• Nominal sizes: Standard inlet/outlet dimensions ranging from 1″ x 2″ to 8″ x 10″
• Pressure classes: ANSI Class 150, 300, 600, 900, 1500, and 2500
• Flow capacities: Based on sizing formulas from API 520 Part I
• Valve type: Typically flanged, spring-loaded safety relief valves
• Compatibility: Designed to integrate with ASME, API 520, and API 527 standards
  
  

Purpose and Benefits:

• Simplifies engineering design by standardizing valve dimensions and capacities
• Enables interchangeability across manufacturers offering identical size and capacity ranges
• Facilitates maintenance and spare part management through consistent sizing and stocking