BS EN ISO 4259-1:2017+A2:2020

What is ISO 4259‑1 about? 

ISO 4259‑1 specifies the methodology for the design of an Interlaboratory Study (ILS) and calculation of precision estimates of a test method specified by the study. ISO 4259‑1 defines the relevant statistical terms, the procedures to be adopted in the planning of ILS to determine the precision of a test method, and the method of calculating the precision from the results of such a study.  

The procedures in ISO 4259‑1 have been designed specifically for petroleum and petroleum related products, which are normally considered as homogeneous. However, the procedures described in 4259‑1 can also be applied to other types of homogeneous products.  

Careful investigations are necessary before applying ISO 4259‑1 to products for which the assumption of homogeneity can be questioned. 

Who is ISO 4259‑1 for?  

4259‑1 on precision of measurement methods and results is relevant to: 

• Petrochemical industry 
• Lubricant laboratories 
• Regulatory bodies 
• Certification bodies 
• Chemists 
• Chemical engineers 

Why should you use ISO 4259‑1? 

Petroleum products are mixtures derived from crude oil and have the same physical and chemical properties. 

For purposes of quality control and to check compliance with specifications, the properties of commercial petroleum products are assessed by standard laboratory test methods. Two or more measurements of the same property of a specific sample by a specific test method, or, by different test methods that purport to measure the same property, will not usually give the same result. It is necessary to take proper account of the fact, by arriving at statistically based estimates of the precision for a method. ISO 4259‑1 defines the minimum particular and unusual circumstances for the purpose of estimating precision.‍ The two parts of ISO 4259 encompass both the derivation of precision estimates and the application of precision data. Both parts of ISO 4259 combine the information encompass both the derivation of precision estimates and the application of precision data. They combine the information regarding the determination of the precision estimates and the information for the utilization of test data. 

Overall, ISO 4259-1 is helpful as it provides guidance on precision which means closeness of agreement between the results obtained by applying the same test procedure several times on the same materials and under prescribed conditions. You can thus determine an objective measure of the degree of agreement expected between two or more results obtained in specified circumstances.