3 replies to this topic

[Tolinorton]

Does measurement of uncertainty depends only on testing equipment?

 

Which are the main factors which effects the value of measurement of uncertainty? (please see the attached analysis report for gasoline)

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•  gasoline analysis report.pdf   127.09KB   13 downloads

[P.K.Rao]

Yes. Every equipment has some bias. Bias also contributes to uncertainty. Uncertainty applies to a test method when conducted under same/similar conditions of test. Please refer to ISO 17025.  EURACHEM/CITEC GUIDE is good guide for determining measurement uncertainty. I have published several papers on Quantifying Measurement Uncertainty in earlier Refinery Technology On Line (a website not operating now) by statistical methods. Please write to  me if you need a training..

[Tolinorton]

Dear P.K.Rao,

 

Does Administrative instruction (AI) for petroleum products of any country should contain values of measurement of uncertainty.

[P.K.Rao]

Every test method should contain levels of uncertainty. Administrative instructions can also contain uncertainty levels (optional).  Not necessary if admin instructions refer to a specific test method because the test method includes the uncertainty. ASTM/IP test  methods include these uncertainty levels as repeatability and reproducibility. Uncertainty should be estimated in house for any test method developed in house or not covered in the test method.