Dear Bunker Folk
There seems to be a gap in understanding of ISO 4259. In the Standard the reproducibility only applies to a single test result. ISO 8217 informative Annex F, F5 Resolving disputes) points the reader to ISO 4259 Clause 10, which is the ISO procedure for establishing the true result is case of dispute. In this procedure the sample is tested at two different laboratories and the average value taken as the true result. Even under this procedure if the sulphur limit was 1.00% and the result 1.02% then the fuel would not be compliant with Marpol. So, in effect the method to establish the true result in ISO 4259 and Marpol Annex V1 procedure are much the same. Which ever method you use the reproducibility that can be used only for a single test result has no significance after two tests have been made.
Trust this clarifies the situation.
Chris Fisher

Excellent point Chris. But I wonder, in practice, how often Clause 10 comes into play in commercial sulphur disputes? Suppliers tend to refer to the 95% Confidence limit that is deemed acceptable under ISO 4259 when interpreting a single test result. Does every argument between supplier and buyer over sulphur end up with subdivisions from one representative sample being tested at two different laboratories, as per ISO 4259 Clause 10, or is this quite rare?

The purpose of a specification is to fix a limit or limits to the true value of the property considered. In practice, however, this true value can never be established exactly. The property is measured in the laboratory by applying a standard test method, the results of which can show some scattering as defined by the repeatability and reproducibility. There is, therefore, some uncertainty as to the true value of the tested property. True value, as defined by ISO 4259, represents the average of an infinite number of single results obtained by an infinite number of laboratories. Therefore this true value can never be established exactly.
It is important that a test method is selected that is sufficiently precise to determine whether or not the product satisfies the specifications.

I am afraid this is a typical way of disguising "ratcheting" down the specs, which EPA has become an expert at in order to justify its "politically correct" existence. As far as the USCG, I do not blame them; they are just "washing their hands" by passing the buck to the EPA.

This is symptomatic of the dysfunctional US and EU governments and support bureaucracies, with all their salaries and benefits paid by the taxpayers, while we have tens of millions of unemployed, and bankrupt states like California (or Greece, or Spain, or...) that cannot pay its employees.

Just like Eugen Ionesco's theater of the absurd, just that we have to pay the bills.

Unless the marine bunker community takes a united stance with IMO, EPA, etc. to mass-refuse compliance with concocted "look good" requirements, we will see this ridiculous job-killing and shipping business destruction continue.

Anybody volunteering to lead the effort?