The clearly articulated focus of Risk-Based Thinking in ISO 9001:2015 has some people scratching their heads. What exactly does this mean? Where is the checklist? Where do I start?
Topics: Standards and Compliance
I recently attended a Quality MeetUp and the discussion centered around ISO 9001:2015. Most had not read 9001:2015 so the discussion focused on what documents are required.
The central theme to ISO 9001:2015 is Risk and this really moves the discussion away from mandatory and required documents to a more holistic strategic approach.
While documents will be necessary and integral to achieve compliance with 9001:2015 the old paradigm of a checklist really is not the most effective approach.
Topics: Standards and Compliance
Throw it out, its cheaper than having it calibrated…
Or is it?
Time and time again, I’ve heard this line. There is a belief that somehow a calibration has an expiration date and is a guarantee that the item will be “in tolerance” until the date on the calibration sticker. Meanwhile someone is using one of your freshly calibrated torque wrenches as a hammer because they can’t remember where their trusty Estwing ran off to. As a third-party calibration lab, we see all sorts of wrong ways to use instruments. Micrometers used as “C” clamps. Weights and masses used as door stops. Length standards used as pry bars. Surface plates used as grinding benches. Thread plugs used as taps. And that’s just a list off the top of my head, I’m sure if I asked a couple of other techs they could give me a dozen more.
So, after all of that you still want to say, its due for calibration. Buy a new one it’s cheaper. If so, then you are missing the whole point of traceability, because it works backwards, not forwards. Calibration today gives us a reasonable assurance that an instrument was good in the past, not necessarily the future. When we calibrate an item and then calibrate the item again at some point in the future, and its meets a tolerance both times, we can make an educated guess that between those two points in time the item was still in tolerance. If we decide to throw it our once the sticker says it is expired, then we call into question every measurement that the instrument was used for since it was calibrated.
As a calibration lab, we are exhaustive in our need to ensure that our instruments have not experienced a breakdown in traceability. This includes making sure they remain in properly trained hands, are transported responsibly, that they aren’t exposed to environments that could cause damage, and being diligent in reporting any anomalies that could point to an erroneous state of operation. We do this because when an item fails to meet specifications, we need to establish when it failed, not just that it failed.
Is it really cheaper?
As a calibration lab, of course you expect me to tell you to calibrate more stuff, but I haven’t always worked in a calibration laboratory.
In a former life, I was involved where a decision to “throw it away” was made. The company was using torque wrenches to set up machines to make a product that was regulated by the federal government. The torque wrenches were low cost and came with a “Certificate of Accuracy.” No actual data, just a pretty three by five card that said certificate. They would put a sticker on them when they arrived and throw them away one year later. They maintained this practice for years. Eventually during an audit, this practice was revealed, and the regulatory body wanted a corrective action.
The regulatory agency was not satisfied with the notion of “moving forward we will calibrate our torque wrenches.” They wanted data that proved that every product that those disposable torque wrenches touched was proven to meet the specifications for the product. With thousands of batches of product being threatened by a recall, the study was completed at the cost of hundreds of man hours and found no direct link could be established.
This company calibrates their torque wrenches now. It’s cheap insurance.
The release of ISO 9001:2015 has many companies reevaluating how they do business. Why? While inherent in every business model, the concept of Risk-based thinking now requires a more articulated approach to measure inputs and outputs.
A quick Google search will show about 500,000 results for verification vs. calibration. Obviously, there is a wide range of answers to what appears to be a simple question.
Keeping Food Safe, with Calibration
I’m a foodie, and I’ve told foodie friends of mine for years that they should never trust their food thermometer unless it’s been calibrated. While doing my weekly shopping the other day I spotted this item. “Smoky Pecan and Bourbon Seasoned Beef Flat Iron Steak.”
Topics: Standards and Compliance
FAQ's on Uncertainty
As a certified calibration technician and technical manager for a calibration lab, I’ve fielded a lot of questions from customers on uncertainty over the years. Here are a few of the most common and useful.
What is measurement uncertainty?
Measurement uncertainty is way to quantify the “grey area” that surrounds a measurement. A 1 inch measurement with an uncertainty of ± 0.1 inch means that the “true” value could be as small as 0.9 inch or as large as 1.1 inch, but is most likely very close to 1 inch.
Does uncertainty need to be on my certificate?
Yes, a measurement without an uncertainty ends the traceability chain. It is also required by ISO 17025. You may ask to have uncertainty omitted from your certificate, but you should be aware of the consequences.
Why is my uncertainty more than half the tolerance? What about 4:1?
It is not uncommon for devices to have a tolerance that is the same as their resolution. When resolution is considered it adds about 0.6 of the resolution to the measurement uncertainty. Test ratios (TAR & TUR) do not consider the unit under test so 4:1 cannot be calculated from the calibration certificate.
What is coverage factor?
Coverage factor is how likely the “true” value is to fall within the stated measurement uncertainty. It is typically stated as k=x, where x is some whole number. A k factor of one is approximately 68%, two is about 95% and 3 is 99.7%. Most calibration companies report measurement uncertainty at a coverage factor of k=2.
Can I just report the uncertainty from the certificate when I calibrate my gages?
No. The measurement uncertainty from your calibration certificate is just one factor of a proper uncertainty budget which must be created in order to report a proper measurement uncertainty of the device you are calibrating.
How do I apply temperature uncertainty to my dimensional gages?
When considering temperature uncertainty in dimensional measurement, you must multiply the coefficient of thermal expansion of the material being measured, by the length being measured, by the temperature uncertainty. When performing the calculation be aware of units and make sure they are the same. For imperial units the units should be (μin/in/°F) *(in)*(°F) and the result will be in μin. When you look up the coefficient of thermal expansion it might be listed with °R (Rankine), these are the same “size” units as °F, just with a different zero.
What is a scope of accreditation?
An accredited calibration company will have a published scope of accreditation. This will list the calibration parameters that they have been assessed to perform. In the case of an ISO 17025 accredited calibration company this will also include a CMC (Calibration and Measurement Capability) for each of the parameters listed.
Why does XYZ company charge extra for uncertainties? Can they do that?
Because they can, and it is a bit of a “grey area.” If the calibration is not accredited, then there is no requirement. If the calibration is accredited, then the certificate must have “the uncertainty of measurement and/or a statement of compliance with an identified metrological specification or clauses thereof” (ISO/IEC 17025:2005 5.4.1.b). Different accreditation bodies view the second half of this statement differently, and this gave rise to this multitier approach to service offerings.
Topics: Measurement Uncertainty