New edition of the standard underpinning precision in all fuel testing

ISO 4259-1:2026 sets out how to determine precision data — repeatability and reproducibility — for petroleum product test methods.

2026-06-01

Repeatability and reproducibility are the figures that decide, in a report, whether two results genuinely differ or fall within the spread of the method.
The standard is the reference for those designing and validating test methods in the fuel industry — it does not describe one determination but how to describe any of them.
A change of edition indirectly affects every fuel method that relies on these rules when stating precision.
For a laboratory it is one of those documents absent from the scope of accreditation yet decisive for the correctness of report wording.