Category A measuring instruments:
1. The highest standard of measurement and measuring instruments
2. The first level of energy measurement instruments
3. In and out of the plant material accounting and bulk products out of the plant with the instrument
4. Safety and security, environmental testing, health care with and Included in the directory of measuring instruments for compulsory inspection of measuring instruments
5. Key raw materials, original components, outsourcing outsourcing parts of the key quality acceptance of the instruments
6. Key quality parameters of the product inspection instruments
7. Key parameters of the process control instruments
8. Valuable materials within the enterprise, the items tested with instruments
Class B measuring instruments:
1. New product technology development, new product development with appliances
2. Two or three energy measurement instruments
3. Material management within the enterprise with measuring instruments
4. Safety and security, environmental testing, medical and health care, and is not included in the directory of compulsory inspection of measuring instruments within the work of measuring instruments
5. General raw materials, original components, outsourcing outsourcing parts of the quality acceptance of instruments
6. Product quality of the general parameters of the inspection instruments
7. Process non-critical parameters in the control of instruments
C class measuring instruments:
1. Measurement of the administrative department of the State Council expressly allowed a one-time verification of measuring instruments. For example, bamboo ruler, glass thermometer, liquid cylinder, China's regulations, only for the first mandatory verification, out of calibration scrapped; directly with the water supply, gas supply, power supply departments with the settlement of domestic water meters, gas meters and power meters are also only for the first mandatory verification, the use of a limited period of time, due for replacement.
2. The implementation of the validity of the management, do not have to carry out periodic calibration of standard substances.
3. In the production process, it is not easy to disassemble, only as a general indicator of measuring instruments
4. Enterprise living areas as energy distribution, employee welfare or auxiliary production of measuring instruments.