APISafety & Relief Devices

API 520 Part I

Sizing, Selection, and Installation of Pressure-relieving Devices - Part I: Sizing and Selection

International
Safety & Relief Devices

Reference profile

Designation
API 520 Part I
Title
Sizing, Selection, and Installation of Pressure-relieving Devices - Part I: Sizing and Selection
Issuing body
API
Current edition
[verify]
Status
Library record: published; official standard status [verify].
Category
Safety & Relief Devices
1

Overview

Applies to the sizing and selection of pressure relief devices used in refineries and related industries for equipment that has a maximum allowable working pressure of 15 psig or greater.

2

Scope & Applicability

Covers

  • PRV Sizing
  • Rupture Disk Sizing
  • Two-Phase Flow
  • Relief Scenarios
  • Overpressure Protection

Does NOT cover (exclusions)

  • Exclusions are not documented in this library record. Confirm the official publication, neighbouring codes, the adopted edition, and jurisdictional boundaries before application.
3

Key Requirements

Lifecycle requirements

  • Sizing Relief Valves
  • Selecting Relief Devices
  • Process Safety Design
4

Technical Details

Applies to the sizing and selection of pressure relief devices used in refineries and related industries for equipment that has a maximum allowable working pressure of 15 psig or greater.

Components: Pressure Relief Valve (PRV), Rupture Disk, Pin-Actuated Device.

Where to find it in the codeRefer to the official table of contents and the sections cited by the project specification; section numbering can vary by edition.
5

Engineering Notes

  • Fundamental standard for sizing PSVs in process facilities.
6

Related Standards

  • API 520 Part II

    Companion or referenced standard; verify its exact relationship in the adopted edition.

  • API 521

    Companion or referenced standard; verify its exact relationship in the adopted edition.

  • API 526

    Companion or referenced standard; verify its exact relationship in the adopted edition.

  • API 527

    Companion or referenced standard; verify its exact relationship in the adopted edition.

  • ASME BPVC VIII-1

    Companion or referenced standard; verify its exact relationship in the adopted edition.

7

Source, Edition & Status

Publisher
API
Edition Year
N/A
Industries
Petrochemical, Refinery, Chemical, Oil & Gas
Content Status
published
Last Reviewed
2026-07-01
Last Updated
2026-07-01
Verified By
Engineering Reviewer
Official Link
N/A

This paraphrased summary is a discovery aid. Do not reproduce or substitute it for the copyrighted official publication or jurisdictional requirements.