Pressure Relieving Systems based on API 520/521

E²G | The Equity Engineering Group, Inc., March 24, 2020

Course Description

  • 3 Day Course
  • Earn 2.4 CEUs

This Pressure Relieving Systems training course will provide attendees with practical experience involving Pressure Relief Devices (PRDs). This training course covers proper sizing, selection, and installation of PRDs to ensure adequate overpressure protection is provided and reduce hazards if a PRD discharges. The course content includes 3% inlet pressure drop requirements, sizing of PRDs in two-phase flashing service, and operation of PRDs and the effects of back pressure on valve stability and performance. In addition to the API 520/521 Standards, the course also covers protection of atmospheric storage tanks per API 2000 Standard and boilers per ASME Boiler & Pressure Vessel Code, Section I. The instructors will discuss the background and logic behind the document procedures and intersperse some example problems.

Course Outline

  • Pressure Relief Valve Design and Operation
  • Codes and Standards
  • PRV Sizing and Selection, Including Two Phase Flow
  • Rupture Disks/Other Devices Relief Device Installation
  • Relief Valve Inspection, Testing, and Repair
  • Relief System Design Philosophy
  • Determining Relief Loads for Process Upsets, Including Fire
  • Overpressure Protection

Additional Topics

  • Determining required relief loads for distillation towers
  • Sizing for two-phase releases
  • ASME B&PVC, Section VIII-1, Appendix M requirements for isolation valves
  • ASME B&PVC, Section VIII-1, UG-140 re-write on instrumentation
  • Determining inspection frequency of relief devices
  • Documenting PRD design basis to meet OSHA 1910
  • Evaluating overpressure scenarios
  • Effects of back pressure on relief valves
  • Protecting vessels from fire damage
  • Evaluating gas breakthrough
  • Setting pressure tolerances
  • Classroom exercises that illustrate procedures for determining
    • Relief rates,
    • Sizing selection, and
    • Installation of PRDs

Course Outcome

Upon completion of the Pressure Relieving Systems training course, students will have a basic understanding of the following:

  • The format, organizational structure, and use of the API 520/521 Standards
  • The application of good engineering judgement as it relates to the infamous “3% Rule”
  • Insight into the future direction of API 520/521 Standards
  • Compliance with OSHA and RAGAGEP policies
  • The importance of proper sizing, selection, and installation of PRDs

Who Should Attend

  • Federal and state regulatory personnel who oversee safety and environmental protection
  • Engineers who construct process systems and pressure vessel engineers
  • Process plant equipment and boiler owners/operators
  • Maintenance personnel who inspect and install pressure relief devices
  • Engineers involved in plant turnaround/upgrade projects
  • PRD manufacturer / technical sales representatives


Philip Henry, P.E.
Principal Engineer II

Robert Sadowski, P.E.
Consulting Engineer II

For more information or to register, click here.

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