During my career as a calibration engineer in an in-house calibration laboratory, one of our goals is to provide 100% calibration to all measuring instruments that are being used inside our facility that directly or indirectly affect product quality. But as the day passed, more and more instruments are being submitted and requested to be calibrated, so more and more instruments are now included to be registered and monitored (so our goal are targeted).
But as I observed and experienced during the visit at the site and interview with co- technicians, maintenance, and engineers, some instruments are not that critical in their usage or is not directly providing measurements, in other words, it does not need calibration.
In this blog post, in support for in-house calibration, I will share my experience on how to identify instruments that do not need calibration within your company, how to document those instruments, provide justification for implementation and the advantages (and disadvantages).
By determining those measuring instruments that do not require calibration will save us time, resources and energy. All measuring instruments that are identified will be labeled as ‘’Calibration Not Required”.
The importance of determining or identifying calibration not required instruments.
While performing a calibration in our measuring instrument is the main job, we should also determine what are those instruments that does not require calibrations.
Calibration-not-required is the term we used to define a measuring instrument that does not need calibration. It is a measuring instrument but with different purpose or usage.
Calibration-Not-Required also includes all instruments that are not included in the monitoring or recall list, which is related to internal calibration management, because the calibration is already performed by other factors for example by the equipment owner during preventive maintenance using another calibrated instruments or the unit itself has an auto calibration.
Below are Benefits once implemented:
- This will give us more focus on the Measuring & Test Equipment ( M&TE) that are more valid to be calibrated, meaning, we can filter out those directly in connection to the process or product produced.
- Determining what is not required to be calibrated save us time and energy ( energy related to physical and electrical or power), our load will be lessened where productivity will increase.
- Downtime of machine shot down due to scheduled calibration will be minimized.
- Easy monitoring of M&TE that are most likely to be calibrated. It will only include the most critical instruments for calibration.
- Avoid duplication of calibration. Some instruments usually installed in machines are already calibrated indirectly once assessed properly.
- Some M&TE are not critical to the process but are blindly submitted for calibration just to avoid some problem with the auditor.
- Save us some resources in terms of money (of course), when utilizing a third party calibration.
Disadvantages of Calibration Not Required Implementation
Usually, not all are happy in this procedure ( especially the quality personnel). Some confusions will be brought up where further discussions are needed to justify these procedures ( which is justifiable). And one main character that will challenge you are the auditors. When you placed a Calibration not Required Labels in some of your instruments, this is like a shiny object where they are always seen and questioned.
That is why doing this procedure requires a good knowledge of the operation of the process (and the M&TE itself) plus a great support of the users or the people involve in order to come up with the best justifications in which I will show you later in this post.
What needs Calibration?
Before we determine the Instruments that does not require calibrations, First, we will identify what needs calibration.
- All inspection, measuring and test equipment that can affect or determine product quality. This means that if you are using the instruments to verify the acceptance of a product whether to pass or fail based on the measured value you have taken, the instrument should be calibrated.
- Measuring equipment which, if out of calibration, would produce unsafe products.
- measuring devices having specified tolerances in their usage
- The instrument has the capability to provide a quantitative measurement, means that it measures a certain range with a given unit (mm, Kg, psi, etc) in comparison with a simple indicator which displays only a high or low and open or close.
- Equipment which requires calibration because of an agreement. An example is a customer before progressing into a contract will see to it that the equipment that will produce their product are calibrated.
- All measuring and testing equipment (standards) having an effect on the accuracy or validity of calibrations. These are the master standards that we used to verify other instruments or equipment for their accuracy or validity of readings.
- Required by auditors.
Steps In Implementing Calibration Not Required Procedure.
- Determine the instruments to be labeled with ‘calibration not required’ status
- Provide Justifications and have it approved
- Place Calibration-Not-Required Labels ( sticker)
- Update your records
How to Identify Instruments to be Labeled as Calibration Not Required?
Identification will commence once a new Instrument has been introduced or installed. This may be on-site or submitted in the internal calibration laboratory.
We will use below guide to identify those instruments not requiring calibration:
- The usage is not critical in your process.
- just to display a certain reading for a purpose of functionality check.
- Example of this is a pressure gauge installed in a machine where the displayed pressure indicates only if there is a presence of gas or liquid
- A Multimeter used ONLY for troubleshooting that indicates the presence of a voltage or a short and open within a line connection. But if the same meter is used for testing and measuring if there is a pass or a fail based on the measured value, the meter should be calibrated.
- The instrument functions as an indicator only, no tolerance specified in the process (for example: high or low)
- just to display a certain reading for a purpose of functionality check.
- Used as accessories only to support the main function of an instrument. You cannot perform a measurement without this accessory.
- Some example is a coil of wire used to amplify a current to be measured, or a hand pump used to create pressure.
- Its accuracy is established by a higher or reference to a higher or more accurate calibrated instrument within a group.
- It has a check standard within the group. for example, a pressure gauges that are connected in series to a more accurate calibrated gauges where they are compared or referenced to.
- A temperature gauge that has another temperature indicator monitored in a separate location or panel.
- If the instrument is verified regularly or continuously monitored by a calibrated instrument that is documented in a measurement assurance process.
- For example, a room thermometer which is regularly monitored by a separately calibrated thermometer.
- Calibration is performed during a preventive maintenance ( no need to include in our monitoring list)
- The instrument is part of a system or integrated into a system where the system are calibrated as a whole.
- For example, a thermocouple that is permanently connected to the oven. The oven and thermocouple are calibrated as one, but if the same thermocouple is being used to other units, calibration of the thermocouple is needed.
How to Implement the Placement of Calibration-Not-Required Label?
In order for us to legally implement the placement of ”calibration not required” status of a certain measuring instrument, have it justify and approved by the required authorities. In this way, we are not just documenting the process but we are informing the whole team. Also, in case the auditor will question the instrument, we have some evidence to show.
Below are some steps to follow for the approval and acceptance of the implementation:
- Create a form where we can put all the details of the Instruments ( you can name it Calibration-Not-Required Form). Ensure the form is a controlled document
- Put the reason why Calibration is not required. ( choose one or more in the list above for identifying).Example: The instrument functions as an indicator only that displays a high and low reading, no tolerance specified and it does provide a quantitative measurement.
- Have the form approved by the equipment owner, its supervisor, QA/QC personnel and the Internal Calibration Laboratory Head by placing their signature on the form.
- Once all have agreed and signed, place a ‘’Calibration-Not-Required’’ label. This should be clear and visible.
- Update and file your records.
We have seen the benefits and importance of identifying Calibration-Not-Required Instruments. Proper documentation and a good support by the related team is one key to successfully determine and close all related issues regarding this matter, furthermore, we should maintain a good relationship and communication.
Do not forget to get a copy of your cheat sheet in this link: calibrationawareness.com/cheatsheet
Thank you for Visiting My site, Please check my other post regarding the Elements in Implementing an Internal Calibration Lab.
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