API RP 551 (R2024) Process Measurement, Second Edition

About this publication

The API RP 551 (R2024) Process Measurement, Second Edition is an essential reference for instrumentation engineers, process control specialists, design engineers, owner-users, operators, maintenance teams, consultants, and technical professionals who need dependable guidance for process measurement system selection, design, implementation, and commissioning. API’s official publication announcement for the second edition states that this recommended practice provides recommendations about the selection and design of process measurement systems and also supplies information on their implementation and commissioning.

Built for real-world engineering, plant, and project use, API RP 551 is especially valuable for professionals working across the full instrumentation life cycle. Current summaries for this publication state that it covers selection, design, installation, commissioning, and operation, which makes it a practical working reference rather than a narrow topic guide. That broader scope is exactly what gives it lasting value for owner-operators, EPC teams, instrumentation departments, and technical libraries supporting refinery and process-industry work.

A major strength of API RP 551 (R2024) is that it remains a current reaffirmed edition of a well-established process measurement reference. API’s 2016 product announcement identified this as the Second Edition, published in February 2016, at 233 pages, under product number C55102. Current market listings identify the reaffirmed version as API RP 551 (R2024) and note that the document remains current after reaffirmation in 2024, with the reaffirmed product commonly shown under C55102R. That makes this title especially attractive for buyers who want a recognized API instrumentation reference without relying on outdated or superseded material.

For buyers in refining, petrochemical, gas processing, and broader process industries, this title fills an important need. Process measurement affects control, reliability, safety, and operating performance, so a reference that helps teams approach instrumentation selection and application more consistently is useful across design, troubleshooting, upgrades, and plant support work. Because this document is focused on process measurement rather than general instrumentation theory alone, it fits well into practical engineering libraries used by professionals who need direct application guidance.

At 233 pages, this is a substantial but still manageable professional reference. It is detailed enough for serious technical use while remaining practical for regular office, plant, and project review. For many buyers, that balance makes it a smart addition to instrumentation, process engineering, and industrial standards libraries.

Why This Standard Matters

The API RP 551 (R2024) Process Measurement, Second Edition is a strong choice for professionals who need a recognized API reference for process measurement and instrumentation system design. It is especially well suited for:

• Instrumentation and control engineers

• Process and plant engineers

• Owner-users and operating companies

• EPC and project teams

• Maintenance and commissioning personnel

• Technical and industrial reference libraries

Product Features

• Official API RP 551 recommended practice

• Second Edition, currently shown as reaffirmed in 2024

• Focused on process measurement and instrumentation system application

• Covers selection, design, implementation, commissioning, installation, and operation of process measurement systems

• Valuable for engineers, consultants, operators, and technical teams

• Strong addition to instrumentation, process engineering, and refinery reference libraries

Product Details

• Title: API RP 551 (R2024) Process Measurement, Second Edition

• Publisher: American Petroleum Institute

• Edition: 2nd

• Published: February 1, 2016

• Reaffirmed: 2024

• Number of Pages: 233

• Product Codes: C55102 and reaffirmed listing C55102R