The advantages of Certified Reference Materials through Interlaboratory Studies

Certified Reference Materials play a crucial role in ensuring the accuracy and reliability of laboratory testing. One of the most rigorous ways to certify reference materials is through an Interlaboratory Study , a process that enhances credibility and compliance with industry standards. At Stanhope-Seta, we offer a comprehensive range of ISO 17034 Certified Reference Materials, validated through rigorous Interlaboratory Studies, to meet diverse testing needs.

What is an Interlaboratory Study (ILS)?

An ILS is a collaborative testing process typically involving multiple accredited laboratories from around the world. An ILS can be used as a consensus method for the characterisation of a Certified Reference Material, this approach is widely regarded as the most realistic and robust method for defining the measurand. The purpose for using this approach to evaluate the performance of a reference material across different laboratories, is to randomise the influence factors within the limits set by the measurement produce, providing statistical validation of its certified value (as defined in ISO 33405). The involvement of multiple independent laboratories eliminates bias and improves the associated uncertainty, offering a transparent certification process.

Using an ILS approach, under ISO 17034 accreditation, a reference material achieves global recognition as a trusted standard, making it invaluable to laboratories seeking high precision, repeatability and compliance with international regulations, like ISO 17025.

How is an ILS conducted?

It’s empirical the ILS process follows the requirements laid out in ISO 33405 and ISO 17034 to ensure the Certified Reference Material is statistically valid. Therefore, the following steps must be taken:

1. Protocol development – Protocols are developed for the Certified Reference Material, defining production procedures, laboratory selection requirements, sample handling, distribution networks and statistical requirements.
2. Selection of laboratories – Competent laboratories with expertise in the specific test method are chosen to participate. These labs are typically spread across different regions to account for variations in equipment and environmental conditions.
3. Distribution of test samples – A reference material batch will be produced, ensuring the sample set is homogeneous. Samples from this bath are then distributed to participating laboratories. Each lab follows a strict protocol to reduce variance and improve data validation.
4. Independent testing – Each lab analyses the material using the specified test method or protocol under controlled conditions, ensuring that all variables are accounted for in real-world testing scenarios.
5. Data collection & statistical analysis – The test results from all laboratories are compiled and subjected to statistical analysis, evaluating the measured for elements such as bias and uncertainty.
6. Certification issuance – If the reference material meets the required criteria, it is officially certified in accordance with ISO 17034. The certification should include all requirements listed in ISO 33401, providing users with a clear understanding of the material’s certified value, expiry data and associated uncertainty.

Seta Reference Materials

Our product range includes Reference Materials for various applications, each validated through an ILS to ensure the highest quality:

• Flash Point – Products like the Pensky-Martens Flash Point Certified Reference Material and Small Scale Flash Point Certified Reference Material are used to cross-check instrument performance and to assist in operator training. Learn more about Seta Flash Point Certified Reference Materials >
• MTVM – The purchase of Multi Test Verification Materials is recommended with new instrumentation to assist with installation and commissioning. MTVMs enable a user to validate different tests and instrumentation using the same sample material.
• STVM – Single Test Verification Materials provide a certified value for a single test method, they are a highly cost effective solution to help meet verification requirements for audited laboratories and those which comply with ISO 17025.

Each of our ILS Certified Reference Materials have been developed to meet the stringent requirements of international test methods, including ASTM, BS, EN, IP and ISO standards.

Why it’s important to know if your Certified Reference Material is characterised from an ILS

Many test methods mandate the use of Certified Reference Material that has been characterised using an ILS, this is due to relative bias between two or more methods. A good demonstration of this would be flash point methods, such as ASTM D92 (Cleveland Open Cup) and ASTM D93 (Pensky-Martens Closed Cup). While both test methods can be used to determine the flash point of a substance, the resultant flash point could not be compared as the value will be a function of the apparatus design, the conditions of the apparatus used and the operational procedure carried out. Learn more about flash point testing >

The value of ILS Certified Reference Materials in industry

ILS Certified Reference Materials offer a range of benefits across different industries, including:

• Regulatory compliance – All ISO 17025 laboratories are required to use Certified Reference Materials to meet stringent ISO, ASTM, and national regulatory standards. ILS certification ensures adherence to these requirements.
• Enhanced measurement confidence – Laboratories can trust that the reference material has been thoroughly validated, improving the credibility of their test results.
• Global consistency – The ILS process ensures that reference materials are suitable for use in different regions and across multiple laboratories, promoting standardisation.
• Reduced measurement uncertainty – The statistical validation of Certified Reference Materials helps reduce uncertainty, leading to more precise and reliable measurements.

Conclusion

The ILS certification of reference materials is an essential process that ensures their traceability and compliance with industry standards. For flash point testing, ILS certified reference materials are particularly important, as they directly impact safety regulations, quality control, and compliance. Laboratories that use these high quality reference materials benefit from improved accuracy, confidence in their results and alignment with global testing standards. At Stanhope-Seta, we are committed to providing the highest quality ISO 17034 Certified Reference Materials, ensuring laboratories worldwide can achieve accurate and consistent results.