ISO 9001:2015 – Newsletter – Issue 135

Issue 135 – Should you calibrate instruments that measure the process?

ISO 9001:2015…

Should you calibrate instruments that measure the process?

I appreciate receiving emails with questions and/or comments from readers of this Newsletter… please continue to do so since it provides me with direction on where to aim the content of these publications.  In my last Newsletter (ISO 9001:2015 Newsletter Issue 134) we discussed the topic of  “How do you handle Customer audits?”, and now in this Newsletter we will discuss “Should you calibrate instruments that measure the process?”.

The ISO 9001:2015 Element numbering…

Element 4 – Context of the organization
Element 5 – Leadership
Element 6 – Planning
Element 7 – Support
Element 8 – Operation
Element 9 – Performance evaluation
Element 10 – Improvement

Should you calibrate instruments that measure the process?… Let me begin by saying that this exact same question came up in my early career days with a Client in the Toronto area.  At that time I was assisting them with conducting an internal audit and during my walk-through of their production process I noticed temperature and humidity gauges on the outside of their large enclosed conveyor systems (…they manufactured tobacco products).  The odd thing was that each of these gauges had a sticker placed directly next to them that stated “For Reference Only”.  I was curious, so I asked why and was told it was to keep auditors from asking about calibrating those instruments.

This identical question came up in a recent closing meeting, where a senior person was questioning my audit finding regarding two different instruments I stumbled upon in the production area while conducting an internal audit (…and which were not being calibrated either internally or externally… more on that later).  This person was suggesting that perhaps these tests were only used for reference information, whereas “real” tests would be conducted later in the lab using samples from the final product.

Why use measuring instruments to monitor a process?… Have you heard the expression “What gets measured gets managed”?  If you want any chance of controlling a process you’ll need to monitor/measure what’s happening within it as it transforms Inputs into Outputs… or said another way, understanding how the process takes raw materials and converts them into a final product which is then sold to your Customers.  Monitoring and measuring a process in many cases requires that some instruments be used along the way.  These could be inline/online instrumentation installed within the process which feeds its data to a central control room, or it could involve manually taking samples throughout the shift, and at various stages of the process, and then testing those samples for critical process characteristics.

No matter how this information is collected, it needs to be in real-time and it needs to be accurate, otherwise bad decisions will be made by making bad adjustments to the process.  You could wait until the final product comes out the end, then test that in the lab, then based on that go back and make adjustments to the process but that is way too late if the lab test results show it is off-spec.  The better way is to catch any problems as early as possible, and as far upstream as possible.

So if you agree that measuring the process while it is producing final product is critical… then why would you want to take a chance that the online instrumentation OR the grab sample test equipment is not measuring correctly?  Avoiding the expense of calibration by labelling everything as “For Reference Only” simply misses the point of WHY those instruments were installed in the first place.

Here’s another expression you may have heard “GIGO – Garbage In Garbage Out”… so if the data you give the person trying to control the process is garbage, then get ready to have garbage come out of the process.  Besides using the above line of logic when I faced resistance to calibrate instruments, I have also tried another approach… I ask them if they care if the instrument we are discussing is working or not… If they say not really, then I suggest they uninstall it and avoid any future process confusion caused by it… If they yes, the instrument is important, I then say “so why don’t you want to check it occasionally to see if its working properly?”.

Again try to remember that someone, at some time way back when, thought it was a good idea to have a measuring device inserted directly into the process, OR to grab a sample to be tested at a specific point in the process… why would you bother doing that if it wasn’t important?  The cost of producing off-spec product is much, much higher than the cost of calibrating an instrument.

Can calibration be done internally or do you have to go to an outside Vendor?…  One reason why I sometimes get resistance to “calibration” is that it will take some effort to get it done, and also the extra cost it would incur.  Let me start by saying that the ISO 9001:2015 Standard does not say that you have to go to an outside Vendor to calibrate a measuring instrument.  It only asks that you ensure the devices you use to measure, are in fact working properly.  This can in many cases be done internally by employees, who simply follow a prescribed procedure, and then keep a record to prove that that they did it.  If the “calibration method” is too complex, requiring a specific set of skills, then that may be a good reason to find an outside Vendor to do this for you.