Our clients frequently have questions or doubts about calibration process.
With the eagerness to solve these questions, in this section you will find information that we hope will be useful for you.
Our clients frequently have questions or doubts about calibration process.
With the eagerness to solve these questions, in this section you will find information that we hope will be useful for you.
The measurement uncertainty is a parameter, associated to a result of a measurement, that characterizes the dispersion of the values that can reasonably be attributed to the measurement result. In the calibration certificates, according to EA-4 / 02M and CEA-ENAC-LC / 02 guides of the measurement uncertainty expressions in calibrations, this uncertainty must be expressed as "expanded uncertainty" of measurement and it is calculate by multiplying the standard uncertainty, which does not need to appear in the certificate, by the coverage factor k. The standard uncertainty is calculated by assessing the influencing factors that affect the measurement, including those from the calibrated equipment (repeatability, resolution, etc.), as well as those from the standard used and the calibration conditions. The standard uncertainty, and consequently the expanded uncertainty, does not depend on the error or value correction that the calibrated equipment may have.
The uncertainty with global null correction refers to the uncertainty that the calibrated equipment has if corrections are not made (the error that the equipment can have when measuring with it is not taken into account). It is calculated by adding the correction or error absolute value and the expanded uncertainty. The maximum uncertainty assigned to the instrument with global null correction is the sum of the maximum value of the expanded uncertainty and the absolute maximum value of the reading correction. The uncertainty of use, with or without global null correction, corresponds to the uncertainty that the calibrated equipment has under normal conditions of use, which does not have to coincide with the calibration conditions.
If the calibration is accredited, it is not necessary to attach it, since Enac, in the regular audits performed to the laboratory, directly supervises the correct traceability of the calibrations carried out with the Enac seal. If the calibration is not accredited but the magnitude and range calibrated is within the scope of accreditation, the standard traceability is covered by this accreditation. If the calibration is not accredited and Tradelab does not have accreditation in the calibrated magnitude or range, only will be provided a copy of the standard calibration certificate if requested at the time of requesting the calibration. However, Tradelab will provide a certificate copy if requested by the corresponding audit entity
To know if a calibrated equipment is suitable for its use, an acceptance or rejection criteria of the equipment must be previously established. This criteria has to be established based on the precision required in the measurements to carry out by the equipment and not necessarily to the specifications of the equipment manufacturer. Depending on the importance of the measurements or the risk of non-compliance with the required requirements, the maximum uncertainty that shall meet the equipment will be established. This uncertainty must be 3 to 10 times less than the semi interval tolerance assigned to the parameter to be measured.
The calibration period of the equipment depends on the use and how critical is the measure to be carried out with it. A typical period can be 1 year for equipment that are used frequently. After performing a second calibration, the results should to be compared with the first calibration, and estimate if the results in the following year can cause that the equipment does not meet the established criterion. If this was not the case, the calibration period could be extended. The calibration period is always established by the clients.
Once the equipment arrives at the facilities where calibration is carried out, Tradelab will perform the calibration in the shortest possible time. Usually in 10 working days you can have the calibration service ready, as long as there is no incident. In large volume deliveries and in different work areas, it is convenient to schedule the calibrations in advance in order to ensure that deadlines are met. Tradelab can set a date for that equipment that needs to be calibrated in less time and reduce the calibration time.