Traceability improves quality control systems and reduces risk. All results must be reliable and meet industry standards within a laboratory setting. Traceability connects to calibration and the ISO/IEC 17025 requirements. Here is a guide to understanding how important traceability is.
The Definition of Traceability
The science of measurement defines traceability as the “property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement of uncertainty.”
Traceability allowed the accuracy of measurement results to be established. Measurement accuracy is an essential part of quality control. Therefore, standards for weights and measures are maintained by a National Measurement Institute.
A reference standard material without a traceability trail is of little value, so defining the traceability of laboratory standards is an essential requirement of ISO/IEC 17025.
It is the property of the result of a measurement of the value of a standard whereby it can be related to stated references, expressed in SI units, through an unbroken chain of calibration comparisons, all having defined certainties. A standard is universally accepted if other laboratories agree to adopt it as a reference for tests and measurements.
It is impossible to establish the traceability chain of standards within a laboratory. In that case, the standards can be sent for calibration at defined intervals. An accredited calibration laboratory and calibration results and the specified uncertainty values should be obtained along with the report specifying traceability to internationally acceptable standards.
How is Measurement Traceability Used?
Traceability is used to measure items that need greater accuracy than usual. This could be anything from a four-to-one greater accuracy to a 10-to-one greater accuracy. These are usually measured to a national standard, as advised by the National Institute of Standards and Technology (NIST.)
Traceability can be used to measure and calibrate all measuring equipment and instruments. In industries where tools and apparatus are measured, a standard of at least four-to-one greater accuracy is recommended.
Depending on the industry and items to measure, you may be required to show traceability to two standards.
When Can You Claim that Your Measurement is Traceable?
All the calibrations must be done at regular intervals. It is not enough that you once had your reference standard calibrated. Then you continue to use it without recalibrations over the years. The calibration of any measurement device only remains valid for a stated period. Therefore, traceability expires when the calibration expires.
Every calibration needs documentation. This means that the calibration results are documented in the calibration certificate. They must also follow the calibration steps according to a written procedure within its quality system. Calibration with a certificate is precisely a traceable calibration. It is also important to realize that it is reliable and can be proven traceable if they do the calibration with documented procedures.
Every step needs to include measurement uncertainty. If the uncertainty information is present in the calibration, you cannot claim it is traceable. The main reason is that you need to know and document the uncertainty to calibrate accurate measurement equipment with more accuracy. Another issue could be that the calibration procedure causes such considerable uncertainty that the calibration could be more excellent and traceable.
To get traceability in your lab, send your reference standard to an accredited calibration laboratory. With an accredited laboratory, you know that competent auditors have evaluated the laboratory, ensuring that everything is in the correct order. At SRP control systems, we can help you with traceability and calibrations. We have worked in the industry for over 40 years and can help your lab run efficiently.