Setting up a calibration process: all steps explained

Measurement instruments almost always have a (small) deviation. In order to quantify the deviation and determine whether the instrument still meets the requirements, it is necessary to calibrate the instruments periodically. Calibration is therefore often an integral part of quality management. 

Often all instruments are by default calibrated annually, but which steps should a good calibration process actually comply with and what else should you think about when setting up a calibration process? In this blog you can read all about it.

The calibration plan

A good calibration process is based on a well thought out calibration plan. The calibration plan defines what needs to be calibrated, how often and in what way. Do you need to create or improve a calibration plan? Then follow these steps.

Determine what you want to calibrate

List all instruments and indicate whether or not they are critical equipment. An instrument is critical if the measurements of that instrument significantly affect the safety, quality or proper operation of an installation. 

Critical instruments must be calibrated. Non-critical instruments can also be calibrated, but calibration is not always necessary. In the list you compiled, each instrument must be recorded in a unique way so that instruments cannot be swapped around unnoticed. Usually, the manufacturer's serial number is used for this, sometimes together with an own ID (TAG, asset number or equipment ID). 

Tip: If instruments are built into a specific installation or machine or belong to a specific technician, it is good to record this as well. You can of course only calibrate these instruments when they are not in use. If you record this properly, it will help you later when planning the calibrations.

Determine how you want to calibrate

For each instrument, record the details that are important for the calibration. These include: the measurement range, both the allowable deviation and the required accuracy of the calibration, and the calibration interval.

The permissible deviation and the calibration interval are sometimes the subject of discussion. Consider in advance what your choice is based on: will you follow the manufacturer's advice, your own (risk) assessment or are there (legal) standards that must be followed? In any case, make sure that you properly record what your choice is based on. This will help you later on to determine how to deal with deviations.

Now that you've done this, you can establish a standard operating procedure (SOP) for the calibrations. In it you lay down which steps you have to go through during the calibration, which measuring points you use, what requirements the calibration equipment should fulfill (for example, how much more accurate should the calibration standard be compared to the measurement instrument) and how the results should be interpreted.

By doing this you ensure uniformity, and the calibration process becomes verifiable and repeatable whether you perform it yourself or (partially) outsource it. 

Determine how you want to document
"If it's not documented, it's not done" is a well-known saying. Keeping up-to-date records is an important aspect of the calibration process. Internal and external audits often ask for valid calibration certificates. You don't want to spend unnecessary time on this, and you want the validity of the data to be beyond dispute. Therefore, make sure that you structure the documentation process and design it efficiently. You do this by securely storing the data in a central location so that all calibration data can be easily accessed by employees and auditors.

Employee commitment

Now that you have a nice plan in place, it needs to be put into practice. For a proper implementation it is important that the people who will perform the calibrations are well trained and feel involved. This means that they are familiar with the contents of the SOPs, that they know what is asked of them and how to deal with deviations. For involvement, it can help to share some underlying information even if it is not directly necessary for performing the work. You are more likely to get back good information that helps to improve the calibration plan and keep it up to date, when employees feel involved. This of course applies to your own employees, but also to externals, in case  calibration activities are outsourced. 

The execution

When calibrating, you perform the steps of the calibration plan. In general, the following steps are part of the calibration work:

• Entry check: Check the instrument for defects and the like. Often this is a visual check possibly supplemented by function tests or safety checks;
• Perform calibration. Here you compare the instrument at specific measurement points with a reference and record the deviation;
• If the instrument falls outside the tolerances, you can possibly adjust the instrument, so that it falls within the specifications again. This is not always possible, desired or allowed;
• Document the calibration results.

Organize your calibration processes with AutoCal+

AutoCal+ makes keeping a calibration plan and performing calibrations a lot easier. 

First of all, you enter the instruments you want to calibrate. Here you can immediately enter additional information, such as the measurement range, the allowable deviation, comments, instructions, pictures etc.  Per instrument or per group of instruments you can indicate on which points the calibration should be done and which standards should be used. AutoCal+ will then guide you through the calibration per measurement point, immediately showing an alert in case of any deviation.

After completing the calibration, the results are displayed in a graph and table. The results are directly saved in AutoCal+. If you want, you can download them directly as a PDF report or have them (re)viewed by your colleagues. Thus, no additional actions are required for documentation. This saves a lot of time and allows you to quickly move on to the next calibration or other work. AutoCal+ also creates a historical overview of all your calibration data, which is ideal for analyzing trends. This allows you to make a technically sound decision regarding the calibration interval.

Finally, AutoCal+ helps to keep an overview of the calibrations, because you can create dashboards. Based on the current data you can see at a glance which calibrations have been performed and which still have to be done. 

Would you like to get to know more about the calibration software of AutoCal+? Call us at +31 79 203 31 33, fill out the contact form or start a free trial. We are happy to help you simplify your calibration processes.

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