Is this a requirement?

ASTM E3047-22 is a test method covering analysis of Ni alloys by spark optical emission spectroscopy, normally the chemist will make 3 or more burns/sparks/replicate analyses on a sample and the instrument will calculate an average, SD and RSD for the set of results and that average is taken as the result.
para 13.3 says this:
Examine the calculated% rsd for the average of the burns. The scope elements listed in the method quantification range will typically exhibit <3% rsd for the average of the burns. The lab may choose to make additional burns get a better estimate of the average and its variance.

our SOP says the chemist MUST achieve an RSD of less than 5% or the result cannot be used.

an auditor raised this as a non-conformance but having read the standard again, I think it is like someone saying: some people have blue cars, it’s not an instruction to go out and buy one.

 

Good day @andic
Remember- the audit is confirming ...
1) the organization’s own requirements for its quality management system;
2) the requirements of this International Standard;

The fact that your organization's SOP mandates is a solid basis for the nonconformance.

Hope this helps.

Be well.

 

Thanks for the reply, but NC was that the auditor said our SOP was not in conformance with the standard test method (the RSDs of the analyses on the demo were all less than 2% anyway).

So the SOP is not sufficient to ensure the test method is implemented. But my question is does the test method even ask for the 3%?

 

Yeah that doesn’t sound like a go/no go number to me. Your SOP is more strict.

 

Thanks for the input everyone. It’s not going to cost us anything to implement the change so we will us 3% “in line with best practices”. But my root cause analysis will be that it’s not really a requirement