The Calibration of Measuring Equipment

measuring instrument

Calibration entails documenting and ascertaining deviation of a measured value from a high accurate standard that is retraceable. The value that is measured from the instrument that is used is therefore compared to a known value of the test standards under the specified reference conditions with the help of measuring procedures that are reproducible. Thus, it does not entail any manipulation of the instrument that does not change.

Purpose of Calibration

Here are some three major reasons why it is important to have your instruments calibrated:

  • To ensure the accuracy of the readings
  • To ensure that the readings are consistent with other measurements
  • To ensure reliability of the instrument in terms

Calibration ensures that the measuring instrument is retraceable to national standards. Most importantly, it guarantees the quality of a given product in terms of internationally comparable measurement results, thus offering legal security in terms of product liability, approval tests and audits.

Traceability : Relating your measurements to others

Results of measurements are useful only if they can relate to related measurements especially those made in a different place, at a different time, by a different person and with a different instrument. These measurements give room for manufacturing processes to be put under control from day to day and from one factory to the other. Exporters and manufacturers require these measurements to determine if their products will satisfy the specifications of their clients. A majority of countries have an established system of accreditation for their calibration laboratories where an assessment is made in comparison to the laid down criteria and international standards. Overall, measurements can only be compared if they share a common measurement unit.

Uncertainty : How Accurate are your measurements?

Measurements are used to make decisions; therefore, if the quality of the measurements is poor then the subsequent decisions will be poor. The uncertainty in the measurement is a numerical estimate of values that are spread and may be attributed to quantity.

It is a measure of quality that provides a means of assessing and minimizing risks as well as possible consequences of poor decisions. Thus, uncertainty in measurement is important just like the measurement itself. Measurements are traceable when you can relate them to an established system of measurement through a chain of comparisons that is unbroken with each of the stated uncertainties.

Reliability : Can I trust the instrument?

Most of the measuring instruments have specified accuracy that is greater than the required. In instances where you are only interested in knowing whether the instrument can be relied upon, uncertainties and corrections are negligible. Even then, a number of instruments are not reliable with at least one in every six instruments being judges as unfit. This rate of failure is characteristic with that recorded by a majority of calibration laboratories that is not related to complexity or cost. Consequently, reliability is determined on the basis of the absence of behavior that might indicate the instrument is faulty. A calibration certificate is only issued when the instrument has been proven reliable and satisfies the purpose for which it is intended.

Achieving Traceability in your measurements

Many quantities of practical interest like comfort, loudness or color are not easily defined as they relate to human attributes. Others like flammability, thermal conductivity and viscosity are sensitive to conditions where the measurement is taken. Therefore, tracing these measurements may not be possible. As such, the international measurement community establishes documentary standards that define how the quantities can be measured as well as provide a means of comparison of quality or health and safety requirements.

In order to achieve traceable measurement, the following elements must be taken into consideration”

  • Competent staff with the ability to interpret the procedure or standard as well as use the instrument
  • A calibrated measuring instrument
  • An recognized and appropriate definition of how quantity is measured

Traceability is guaranteed when these factors are included in the measuring process.

Adjustment : What calibration is not

Calibration does not mean that instruments must be adjusted in order for it to read as true. Generally, adjustments that are to be made as part of calibration usually detract from reliability of the instrument as they weaken the history of stability of the instrument. Moreover, adjustment can also prevent calibration from retrospective use.

Ultimately, calibration of instruments is just but a basic requirement of maintenance, that is, a procedure established to ensure every business using instruments or machinery must conduct periodically in their instruments or machinery requirement.

No Comments

    Leave A Comment

    1047 Serpentine Lane, Suite 500, Pleasanton, CA 94566
    Call us today 1-877-799-0922
    Malcare WordPress Security