API RP 581 - Risk Based Inspection Technology

Last update: Jan 16, 2017

API RP 581, Risk-Based Inspection Technology, Third Edition, is a recommended practice developed and published by the American Petroleum Institute (API). Originally released in 2000 and last updated in April of 2016 (third edition), the purpose of this publication is to provide quantitative risk-based inspection (RBI) methods that support the minimum guidelines presented by API RP 580. This document details the procedures and methodology of RBI, an integrated methodology that uses risk as a basis for prioritizing and managing an in-service equipment inspection program by analyzing both the likelihood and the consequences of equipment failure. .

Risk-based inspection (RBI) is a methodology that involves quantitative assessment of the probability of failure (PoF) and the consequence of failure (CoF) associated with each equipment item in a particular process unit. A properly-implemented RBI program categorizes individual pieces of equipment by their risks, prioritizes inspection efforts, and provides guidance for risk mitigation efforts, such as changes in materials of construction, the addition of linings, changes in operating conditions, etc.

API RP 581 was based on the knowledge and experience of several global practitioners of RBI with extensive experience in its implementation. According to API 581, an RBI program has four major goals:

  1. Identify and measure risk for all covered equipment.
  2. Impart an accurate understanding of risks and risk drivers.
  3. Enable effective risk management.
  4. Reduce risks associated with operating processing facilities.


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June 3, 2013 By Greg Alvarado at Inspectioneering Journal

This is the third of four blogs in a series about Risk Based Inspection (RBI). You can read the previous blogs on a history and reasons for RBI and on starting to define risk. This post deals with the second half of the equation used to define risk...

May 28, 2013 By Greg Alvarado at Inspectioneering Journal

This is the second of four blog posts on Risk Based Inspection, or RBI. The first post covered a brief history and started the discussion on why you would want to use RBI. The next step is defining risk. 

May 20, 2013 By Greg Alvarado at Inspectioneering Journal

Anyone who knows me knows that Risk Based Inspection (RBI), and Risk Management, are a passion of mine, so my next few posts will feature these topics. These are not all-inclusive, but Inspectioneering.com has dozens of articles and you can join our LinkedIn Group for more.

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November/December 2012 Inspectioneering Journal
By Ryan Corn at Marathon Petroleum Company LP, and Matthew K. Caserta, PE at BASF

As refiners continue operating aging infrastructure, safe operation and equipment availability continue to be key components of a sustainable operation. When considering optimizing inspection projects, more and more refiners are making Risk-Based Inspection (RBI) an integral part of their plan processes. When applied properly, RBI can focus inspection efforts using risk as a basis for prioritizing and managing an in-service inspection program.

March/April 2009 Inspectioneering Journal
By Lynne Kaley at Trinity Bridge LLC / Trinity Bridge Digital

The API Risk-Based Inspection (API RBI) methodology has been used in the Refining and Petrochemical industries to manage the overall risk of a plant since the mid-1990's as a methodology for focusing inspection efforts on the process equipment with the highest risk. API RBI provides the basis for making informed decisions on inspection frequency, the extent of inspection, and the most suitable type of NDE. In most processing plants, a large percent (80-90%) of the total unit risk will be concentrated in a relatively small percentage (10-20%) of the equipment.