ISO 4126-1
Safety devices for protection against excessive pressure—Part 1: Safety valves
Published by International Organization for Standardization (ISO)
The CFR incorporates ISO 4126-1 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
ISO 4126-1:2004, Second edition 2004-02-15
As the CFR lists it: “ISO 4126-1:2004(E): Safety devices for protection against excessive pressure—Part 1: Safety valves, Second edition 2004-02-15”
- Listed in 49 CFR 171.7(w)(18); required by49 CFR 178.274 ↗
How to read it
- Where to get itISO Store ↗
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.
ISO 4126-1 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.