Before calibration 1. Determine the equipment that needs to be calibrated Not all equipment in the laboratory needs to be calibrated. The impact of the equipment on the validity of the results and the metrological calibration should be evaluated based on the position and role of the equipment in the measurement process, and whether the equipment needs to be calibrated should be reasonably determined. Equipment that needs to be calibrated should be included in the calibration plan. 2. Preparation of calibration plan In the implementation of the specific conformity assessment process, the laboratory should establish a calibration plan for the equipment that needs to be calibrated. The plan should include the calibration parameters, range, uncertainty and calibration cycle of the equipment. Therefore, when formulating the calibration plan, the relevant content should be made clear so that clear and targeted requirements can be put forward during calibration, and it also facilitates confirmation after calibration. (1) Calibration parameters For single-parameter equipment, the calibration parameters should be determined according to the function of the equipment; for multi-parameter equipment, the parameters to be calibrated should be determined based on the actual use and the requirements of the corresponding technical standards to ensure that the parameters used are calibrated. (2) Calibration scope The laboratory should determine the scope of the equipment that needs to be calibrated based on the measurement range of the corresponding items in the accredited capacity appendix. The principle is that the calibration range of the equipment should cover the equipment that is open to the public. The scope of work to be carried out is the only way to ensure the metrological calibration of the measurement results. (3) Measurement uncertainty The measurement uncertainty (or accuracy level, maximum allowable error) of the equipment should meet the requirements of technical standards (such as verification procedures or calibration specifications or national standards, etc.) and national calibration level charts, and be adapted to the work being carried out. The measurement uncertainty of laboratory equipment should not be inferior to the measurement uncertainty of the equipment under test. (4) Calibration cycle The calibration cycle of the equipment should be determined according to the provisions of the corresponding technical methods (such as verification procedures or calibration specifications), and the calibration cycle can also be shortened or extended according to the frequency of use. When it is necessary to extend the calibration cycle, the calibration cycle can be determined in accordance with the provisions of JJF1139-2005 "Principles and Methods for Determining the Verification Cycle of Metrological Instruments", and the corresponding verification materials should be retained.

3. Calibration Agency Conformity Evaluation Equipment managers should fill out the "Equipment Calibration Agency Capability Conformity Checklist" for each piece of equipment that needs to be calibrated to ensure that the selected calibration agency can complete the equipment calibration work in accordance with the requirements of the calibration plan. At the same time, since the calibration agency provides calibration services for the laboratory and is an external supplier, the equipment manager should also fill out the "Supplier Evaluation Form" for the calibration agency and monitor the services it provides.

1. Determination of calibration date The accreditation criteria in clause 7.8.2.1 "Each report shall include at least the information" requires "date of receipt of the item", "date of implementation of laboratory activities" and "date of report issuance". After the calibration agency completes the calibration of the equipment, the equipment is stored in accordance with the prescribed conditions, and its calibration status is relatively fixed and generally does not change. Therefore, it can be understood that the equipment has obtained a new calibration status since the "date of implementation of laboratory activities". When determining the calibration date, the "date of implementation of laboratory activities" in the calibration certificate shall prevail. 2. Equipment transportation and storage In order to ensure the safe transportation of equipment to the calibration agency, the laboratory shall formulate corresponding measures based on the characteristics of the equipment to prevent the occurrence of technical performance damage due to improper handling during the transfer process. For equipment that needs to be stored in special environments, the storage conditions should also be notified to the calibration agency, preferably after the contract calibration. 1. Functional verification after calibration CNAS-CL01-G001:2018 "CNAS-CL01 "Application Requirements for the Accreditation Criteria for the Competence of Testing and Calibration Laboratories" 6.4.4 stipulates that "equipment that returns to the laboratory for calibration or maintenance reasons should also be verified by the laboratory after returning." Therefore, after the equipment returns to the laboratory from the calibration agency, the equipment manager should first verify whether its function and status remain normal. Only after a normal conclusion is reached can the equipment continue to be used. Continue to use. For equipment that does not meet the requirements, the reasons should be analyzed, the tracking procedures after equipment failure and the non-conforming work control procedures should be started, and the results issued before should be verified. At the same time, isolate the equipment to prevent misuse and repair the equipment. All records should be kept. 2. Confirmation of results Equipment managers should check whether the calibration results meet the requirements against the requirements of the calibration plan. BACL reminds that for equipment that meets the requirements, 3. Use of equipment After confirming that the equipment functions normally and its technical performance is continuously maintained, the equipment can continue to be used. The equipment manager should archive the calibration certificate and confirmation records, and replace the valid calibration mark for the equipment. The calibration work is basically completed.