IEC 60567 is the IEC standard that governs the laboratory side of dissolved gas analysis (DGA). It specifies how free gases are collected from gas-collecting (Buchholz) relays, how gases dissolved in the insulating liquid are extracted, and how those gases are then quantified by gas chromatography. Where the companion sampling standard ends — at a correctly drawn oil sample arriving in the laboratory — IEC 60567 takes over. The interpretation of the resulting gas pattern is, in turn, the subject of a separate diagnostic standard.
What it covers
The standard describes the full chain from gas collection to reported concentrations. It covers the methods for sampling free gas from a gas-collecting relay, the transfer of an oil sample from its field container into the laboratory extraction apparatus, several distinct techniques for releasing dissolved gas from the oil, and the chromatographic separation and detection of the individual gases of diagnostic interest. It also addresses the preparation of gas-in-oil calibration standards and the quality-control practices — detection limits, calibration frequency, repeatability and reproducibility — that make results comparable between laboratories.
The current edition extends these methods, in a normative annex, beyond mineral oil to synthetic esters, natural esters, and silicone liquids. This matters because those fluids behave differently during extraction: they are more viscous, slowing the release of gas under vacuum, and the esters carry far more dissolved water, which is co-extracted and must be corrected for.
Why it matters in practice
DGA is the single most powerful early-warning tool for incipient faults in oil-filled equipment, but a gas result is only as trustworthy as the extraction method behind it. Different techniques recover different fractions of the dissolved gas, carry different detection limits, and suit different concentration ranges — high-completeness vacuum methods for the trace levels seen in factory acceptance testing, faster automated methods for routine service monitoring. Knowing which method a laboratory used is essential when comparing results over time or between laboratories, and when judging whether a low-level reading is real or sits within method noise.
This standard is also the reference point for verifying on-line gas monitors against laboratory analysis — a growing need as fixed monitors are specified on critical and hard-to-access assets.
How we use it
We treat IEC 60567 as the methodological foundation beneath every DGA result we interpret for clients. When we review data from a laboratory partner, we confirm which extraction method was used so that detection limits and reproducibility are correctly accounted for, and so that trace-level readings on acceptance samples are judged against the right method capability. For ester- and silicone-filled equipment — increasingly common in offshore and fire-safety-driven installations — we check that the laboratory applies the moisture correction the standard requires, since omitting it can distort the reported gas volume. Together with the field sampling standard it complements, IEC 60567 lets us tell a client not just what the gases are, but how much confidence the numbers deserve.