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Standard Interpretation



Standard: 2003 NELAC
Section: 5.5.6.3.1
Link to relevant standard

REQUEST:

I'm trying to determine if NELAC requires that the weight sets used to verify balances prior to use MUST be Class 1.

TNI FINAL RESPONSE:

(Quality System Expert Committee/NELAP Accreditation Council, 3-x-11)

A laboratory may use any class to verify the balance if the weights are traceable to a national standard.

A Class 1 (or "S") weight is normally considered a reference standard, but may be used as a working standard. If the laboratory has designated the weight as a reference standard, the weight may only be used for calibration (i.e. calibrating/checking working standards).

Standards that are used for daily calibrations (5.5.5.2.1) must be traceable to NIST. The Class1 or �S� weights can be used to verify the working standards, since these are traceable to NIST.