During certification audits, some auditors often ask auditees to deviate from the standard. One of the obvious manifestations is the inability to distinguish the concept of calibration and verification. For example, according to the actual needs and the provisions of China's legal metrology management, the organization's measuring devices can meet the requirements through calibration, but the auditor issued a "no verification" of the failure report, mandatory organizations to implement the control of verification, and mandatory organizations to the professional metrology department for verification, to the organization has caused greater economic losses. Economic loss to the organization.
ISO1OO12-1 "quality assurance requirements for measuring and testing equipment" standard "calibration" is defined as:
"in the specified conditions, in order to determine the value of measuring instruments or measurement systems or physical gauges or standards, or the value represented by the material and the relative value of the material and the relative value of the material. Substance represented by the value and the corresponding known value of the measured set of operations between the relationship.
Note:
1. The results of a calibration can be used to assess the error in the value of a measuring instrument, measuring system or physical gauge, or to assign a value to the markings on any scale;
2. Calibration can also be used to determine other metrological characteristics;
3. The results of a calibration can be recorded in what is sometimes referred to as a certificate of calibration or a calibration report;
4. Sometimes the results of an approval are expressed as a Corrected values, calibration factors or calibration curves.
ISO/IEC Guide 25-199O General Requirements for the Technical Competence of Calibration and Inspection Laboratories defines "calibration" as:
"the provision of evidence by means of calibration to confirm compliance with specified requirements (ISO 84O2/DADI-DADI-94). 84O2/DADI-3.37, note added for the purpose of this guide).
Note:
1. In order to interface with the management of measuring instruments, the purpose of the calibration is to calibrate the deviation between the indicated value of the measuring instrument and the corresponding known value of the quantity, so that it is always less than the maximum permissible error specified in the standards, protocols or specifications relating to the management of measuring instruments.
2. According to the results of the verification of measuring instruments to make the decision to continue to use, investigate, repair, downgrade the use or declaration of obsolescence. Any inertia, when the test is completed, the test should be recorded in the special record of the measuring instrument.''
The International Organization for Weights and Measures gives the definition of calibration as:
"The procedure for ascertaining and confirming that a measuring instrument conforms to the legal requirements, which consists of checking, marking and/or issuing a certificate of calibration."
According to the above definition, it can be seen that calibration and verification are fundamentally different. The two can not be confused, not to mention equivalent. The main differences between the two are discussed below.
First, the purpose of different
The purpose of calibration is against the measurement standard, evaluation of the measurement device value error, to ensure that the value is accurate, belonging to the bottom-up traceability of a group of operations. This evaluation of the error in the display value should be based on the organization's calibration procedures to make the corresponding provisions, according to the calibration cycle, and make a good record of calibration and calibration marking. Calibration in addition to assessing the error in the display value of the measuring device and determine the relevant measurement characteristics, calibration results can also be expressed as a correction value or calibration factor, specific guidance for the operation of the measurement process. For example, a machining organization to use calipers, calibration found with the measurement standard has been compared with O.2mm, this data can be used as a correction value, in the calibration logo and records marked in the calibration of the value of the standard compared to the larger out of the O.2mm value. In the use of this measuring instrument (calipers) for the physical measurement process, minus O.2mm out of the corrected value of the measured value of the physical measurement. As long as the purpose of traceability can be achieved, a clear understanding of the measuring instruments of the value of the error, that is, to achieve the purpose of calibration.
The purpose of the inspection is a mandatory comprehensive assessment of the measuring device. This comprehensive evaluation belongs to the scope of the unity of value, is the top-down value transfer process. Accreditation should be assessed whether the measuring instrument meets the specified requirements. This requirement is the measurement of the measurement device calibration specification of the error range. Through the verification, assessment of the measurement device error range is within the specified error range.
Two, different objects
The object of calibration is a mandatory calibration outside the measuring device. China's non-compulsory calibration of measuring devices, mainly in the production and service delivery process using a large number of measuring instruments, including incoming inspection, process inspection and final product inspection of measuring instruments used.
The object of inspection is the measurement of China's metrological law clearly stipulates the mandatory verification of measuring devices. People's Republic of China *** and the State Measurement Law "Article IX clearly states:" Measurement of the people's government at or above the county level of the administrative departments of the measurement of social utility measuring instruments, departments and enterprises, institutions, the use of the highest measurement standard instruments, and for trade settlement, safety and security, medical care and health, environmental monitoring listed in the directory of the work of the strong inspection of measuring instruments, the implementation of mandatory verification. Not in accordance with the provisions of the application for verification or unqualified verification, shall not be used." Therefore, the object of verification is mainly three major categories of measuring instruments. These are:
1. Measurement benchmarks (including international [measurement] benchmarks and national [measurement] benchmarks
ISO 1OO12-1< measurement and testing equipment quality assurance requirements" is defined as follows:
International [measurement] benchmarks: "Recognized by the international agreement, the international as a reference for all relevant quantities. internationally as the basis for the fixing of values for all other metrological datums for the quantity in question."
National [metrological] datum: "A metrological datum recognized by an official decision of the State as the basis for the fixing of all other metrological datums of the quantity in question at the national level
2. [Metrological] standard
The ISO 1OO12-1 standard defines a 'metrological' standard as; 'a physical gauge, measuring instrument, standard substance or system for defining, realizing, maintaining or reproducing a unit or one or more known quantities and for transferring them by comparison to other measuring instruments (examples: a. 1 kg in a mass standard; b. a standard block; c. a 1O0 Ω standard resistor; d. a Weston standard cell)."
3. China's Measurement Law and the Chinese people *** and the State mandatory verification of the work of measuring instruments detailed provisions, "Where used for trade settlement, safety and protection, medical and health, environmental monitoring, are subject to mandatory verification." In this detailed directory, has clearly stipulated that 59 kinds of measuring instruments listed in the scope of mandatory verification.
It is worth noting that this "detailed directory" of the second paragraph clearly emphasizes that "the catalog items, where used in trade settlement, safety and security, medical and health care, environmental monitoring, are the implementation of mandatory verification." This is the requirement listed in the 59 kinds of compulsory inspection catalog of measuring instruments, only for trade settlement and other four types of measuring instruments in the field, belong to the scope of compulsory verification. Although included in the 59 kinds of measuring instruments directory, but the actual use is not used for trade settlement and other four types of measuring instruments in the field, may not belong to the scope of the mandatory medical verification.
The above three categories outside the measuring device is non-compulsory verification, that is, the scope of calibration.
Three, different nature
Calibration is not mandatory, belonging to the organization's voluntary traceability behavior. This is a technical activity, according to the actual needs of the organization, the evaluation of measuring instruments value error, for measuring instruments or standard substances for the process of fixing the value. Organizations can specify the calibration specification or calibration method according to the actual needs. Provide their own calibration cycle, calibration marking and recording.
Accreditation belongs to the mandatory law enforcement, is the scope of legal measurement management. The verification protocol agreement cycle, etc., all in accordance with statutory requirements.
Fourth, based on different
The main basis for calibration is based on the actual needs of the organization to develop their own "calibration specifications", or with reference to the "verification procedures" requirements. In the Calibration Specification, the organization specifies its own calibration procedures, methods, calibration cycles, calibration records and marking requirements. Therefore, the Calibration Specification belongs to the organization to implement the calibration of the guiding documents.
The main basis for inspection is the "Measurement and Certification Regulations", which is the measurement of equipment testing must comply with the statutory technical documents. Which, usually on the measurement of testing equipment, measurement of the cycle, measurement characteristics, test items, test conditions, test methods and test results, etc. to make provisions. Measurement verification regulations can be divided into national measurement verification regulations, departmental measurement verification regulations and local measurement verification regulations. These regulations belong to the measurement of regulatory documents, the organization does not have the right to develop, must be approved by the authorized measurement of the department to develop
Fifth, the way different
Calibration can be used in the organization's self-calibration, school, or self-calibration and external school combined. Organization in the case of conditions, you can use self-calibration of measuring instruments for calibration, thus saving greater costs. Organizations to carry out self-calibration should pay attention to the necessary conditions, rather than relaxing the requirements of the management of measuring instruments. For example, it is necessary to prepare calibration specifications or procedures, calibration cycle, with the necessary calibration environment and have a certain quality of measurement personnel, at least one level higher standard measuring instruments, so that the calibration error as small as possible. In most areas of measurement, the measurement error of the standard should be no more than 1/3 to 1/10 of the error of the equipment being recognized in use. In addition, provisions should be made for calibration records and marking. Through the above provisions to ensure the accuracy of the value.
Accreditation must be qualified to the measurement of the department or a legally authorized unit. According to the current situation in China, most production and service organizations do not have the qualification of verification, only a few large organizations or professional measurement and verification departments have this qualification.
Six, the cycle is different
Calibration cycle by the organization according to the need to use measuring instruments to determine their own. Regular calibration can be carried out, but also irregular calibration, or calibration before use. The principle of determining the calibration cycle should be to minimize the risk of measuring equipment in use at the same time, to maintain minimum calibration costs. Can be based on the frequency of use of measuring instruments or the degree of risk to determine the calibration cycle.
The cycle of inspection must be carried out in accordance with the provisions of the "Certification Regulations", the organization can not determine their own. Inspection cycle belongs to the content of the mandatory constraints.
Seventh, the content of different
The content of the calibration and the project, only the evaluation of the measurement device value error to ensure the accuracy of the value of the content of the measurement device is a comprehensive evaluation, the requirements of a more comprehensive, in addition to including all the contents of the calibration, but also need to check the relevant items.
For example, the calibration content of a measuring instrument should include the technical ten conditions of measuring instruments＼ calibration conditions, calibration items and calibration methods, calibration cycle and the disposition of the results of the calibration, etc.
Calibration is a comprehensive assessment of the measuring device.
The content of the calibration can be determined by the organization according to the needs of their own. Therefore, according to the actual situation, the verification can replace the approval, while the calibration can not replace the verification.
Eight, different conclusions
The conclusion of the calibration is only to assess the error of the measurement device to ensure that the value is accurate, not required to give a qualified or unqualified judgment. Calibration results can be given "calibration certificate" or "calibration report".
Accreditation must be based on the "verification procedures" specified range of error in the measurement value, to give a qualified and unqualified judgment of the measuring device. Exceeding the "test procedures" for the range of error in the value of unqualified, within the specified range of error in the value of qualified. The result of the test is to give the "certificate of conformity".
Nine, the legal effect of different
The conclusion of the calibration does not have the legal effect of giving the "calibration certificate" is only marked with the error in the measurement value, belongs to a technical document. The conclusions of the test have legal effect, can be used as a measuring instrument or measuring device calibration of the legal basis of the certificate of conformity" belongs to the technical documents with legal effect.