Reference materials are used to ensure accuracy and consistency of measurements, and their classification and grading are essential to meet different needs. The international and Chinese classifications differ and cover a wide range of substance categories. Reference materials are divided into primary and secondary levels, with the first stage for high-precision measurements and the second stage for routine applications. They play an important role in the International System of Units, engineering characteristics, technical evaluation, product quality assurance, etc. Standards and working reference materials complement the needs of practical work, and the correct use of these reference materials can effectively ensure the reliability of measurement results.
Classification of reference materials
International Classification Methodology:
United States: Reference Standards are classified by chemical composition, physical properties, and engineering/technical properties.
Reference Materials International (COMAR): Provides classifications for steel, non-ferrous metals, inorganic, organic, physical and technical, biological and clinical, quality of life and industry.
Chinese Classification Method:
CHINA: Classified by iron and steel composition, non-ferrous metals, building materials, nuclear materials, polymer materials, chemical products, geology and minerals, environmental chemistry, clinical and pharmaceutical, food, coal and oil, engineering technology and physical properties, etc.
Classification of reference materials
Tier 1 Reference Materials (GBW):
Characteristics: Extremely high accuracy and long-term stability for high-precision measurements and method evaluation. It is often used to develop and calibrate instrument standards to ensure the accuracy and consistency of measurement results.
Production and approval: The metrology administrative department of the State Council is responsible for production and approval to ensure that its quality meets national standards, reliability and wide recognition.
Secondary Reference Materials (GBW(E)):
Characteristics: It has relatively low accuracy and stability, and is suitable for general measurement and quality control. It is mainly used for routine inspection and control in daily production to help ensure that the product quality meets the basic requirements.
Production and approval: The metrology administrative department of the State Council is also responsible for production and approval, but its standards and control requirements are more relaxed than those of first-class reference materials. Suitable for different application scenarios and measurement needs.
The role and main uses of reference materials
Role in the International System of Units: Reference materials are used to define and reproduce the basic units as well as to derive the units, ensuring the uniformity and reliability of the International System of Metrology.
Standardization of engineering characteristic quantities: In the measurement of engineering and physical quantities, reference materials help ensure the consistency and accuracy of data, promoting compatibility between different systems and devices.
Technical and method evaluation: Used to evaluate the accuracy of new technologies and methods, by comparing reference materials, validating and calibrating measurement techniques and experimental methods.
Quality Assurance: In product quality monitoring, environmental monitoring, and laboratory quality control, reference materials are used as a reference to ensure the accuracy and reliability of test results.
Metrology Arbitration: Provide fair and reliable measurement basis, help resolve quality disputes, and provide objective evidence for various measurement disputes.
Precautions for the use of reference materials
Selection and application: When using reference materials, the appropriate reference materials should be selected according to the specific measurement purpose, and their characteristics and certificate information should be detailed to ensure their applicability and accuracy.
Stability and preservation: In order to maintain the long-term stability of the reference material, it is necessary to follow the specified storage conditions, such as temperature, humidity, etc., to avoid environmental factors affecting its properties.
Avoid misuse: When using reference materials, ensure that the selected substances meet the actual needs and avoid using unsuitable substitutes that may affect the accuracy of the measurement results.
Standards vs. working reference materials
Standard samples: Standard samples are physical samples used to validate and implement standards, and they help to ensure the accurate expression and consistency of technical specifications. Standard samples often have well-defined characteristics and calibration values that can be easily referenced and measured intuitively by technicians.
Working Reference Materials: Working reference materials are reference materials prepared according to actual work needs, and their accuracy is usually lower than that of national reference materials. These substances are used for routine quality control and monitoring to meet the needs of specific operations and measurements.
Some of the reference materials currently in use in CHINA
Class 1 Reference Materials: including iron and steel, non-ferrous alloys, high-purity metals, gases, rocks and soils, coal, chemical products and biological substances, etc., these reference materials have high precision and long-term stability, and are mainly used for high-precision measurement and method evaluation.
Secondary Reference Materials: Covers similar classifications, such as iron-to-steel, non-ferrous alloys, etc., but has a wider range of applications, lower accuracy and stability, and is mainly used for general measurement and quality control.
summary
The scientific classification and grading of reference materials is essential to ensure the accuracy of experiments and measurements. There are different ways to classify reference materials internationally, such as the classification systems used by the United States and international reference material information databases covering a wide range of fields. In CHINA, there is a detailed classification according to the type of substance and the field of application. In addition, reference materials are divided into primary and secondary grades to meet different precision requirements and uses. Primary reference materials are used for high-precision measurements and research, while secondary reference materials are used for general measurements and quality control. Reference materials play a central role in the reproduction of the International System of Units, the standardization of engineering characteristic quantities, technical evaluation, and product quality assurance. Proper selection and use of reference materials is key to ensuring measurement accuracy, while standards and working reference materials provide additional support for the needs of practical work and the implementation of standards.
