API 550
Manual on Installation of Refinery Instruments and Control Systems, Part II—Process Stream Analyzers, Section 1—Oxygen Analyzers
Published by American Petroleum Institute (API)
The CFR incorporates API 550 by reference, which makes the edition it names part of the regulation. The CFR requires the edition it names, which may not be the newest. To enforce any other edition, the agency must publish the change in the Federal Register.
The edition the CFR requires
API RP 550, Fourth Edition, February 1985
As the CFR lists it: “API Recommended Practice 550, Manual on Installation of Refinery Instruments and Control Systems, Part II—Process Stream Analyzers, Section 1—Oxygen Analyzers, Fourth Edition, February 1985 (“API 550”)”
- Listed in 33 CFR 154.106(c)(2); required by33 CFR 154.2107 ↗
How to read it
- Read it freeAPI IBR Reading Room ↗
Read-only online access to the API standards federal regulations incorporate, with a free account.
A free or purchased copy may not be the edition the CFR names; check it against the edition above. Every incorporated standard can also be inspected at the National Archives (NARA) and at the agency named in the section that lists it.
API 550 is copyrighted by its publisher; RegKnot shows its title and the editions the CFR names, not its text. Read from the eCFR's incorporation-by-reference sections, current as of October 26, 2026. The regulation text governs. All standards the CFR requires.