We selected an ISO 17025 Calibration Laboratory so we are done!
Many consumers feel that once they have selected an ISO 17025 Calibration Laboratory the process is complete.
Imagine you are diagnosed with a tumor. The next step is to pick a surgeon to have it removed. Anyone that went to Medical School and is board certified is capable and competent, right?
If it were a brain tumor, would you go to an oral surgeon? Would you see a neurosurgeon to have your wisdom teeth removed? Would you want a heart surgeon to remove a tumor on your leg?
Yes, these questions are a bit rhetorical. The reality is not every ISO 17025 accredited calibration laboratory is capable and competent to perform your specific calibration. Medicine has specialties and so does Calibration. A calibration laboratory's competence is stated in their Scope of Accreditation.
The Scope of Accreditation tells you what specialties (Disciplines) have been validated by an independent accreditation body and what is the best measurement they can provide. These 2 pieces of information are critical when selecting a calibration provider.
Every measurement has a +/- in the result. Imagine a pressure gage that has increments of 5 psi. The reading falls between the increments. What is the measurement? You are reading between the lines, Do you make your best guess? Have 10 people make the same measurement. How will you report the resulting measurement? This +/- is referred to as the measurement uncertainty and exists with every measurement. An ISO 17025 accredited laboratory will have a stated measurement uncertainty for each discipline on its scope of accreditation.
This measurement uncertainty allows the end user to evaluate a calibration laboratory's best measurement capability. This really does make a difference. If you need a device calibrated that can measure 1 psi does it make sense to have it calibrated by a laboratory that has its best measurement capability of +/- 5 psi?
Review the Scope of Accreditation and best measurement capability before issuing a purchase order.
How to get the BEST calibration quote
Think about how you use the item that is going to be calibrated. Here is the information you need to provide your calibration provider:
- A unique identifier for each item submitted for calibration.
- Specific calibration points to checked or number of measurements across a range.
- The calibration interval- how often it needs to be calibrated.
- Any specific industry standards or procedures to be followed.
- Calibration report to contain before and after data.
- Calibration report to contain measurement uncertainty.
Some calibration companies charge extra for the above services and you need to specify this on your RFQ to determine the total cost.
Wouldn't it be nice if there was a checklist:
Laboratory Accreditation Bureau- LAB- an independent 3rd party accreditation body has developed a guide for the Purchasing and Evaluation of Calibration. Appendix A and B in this document are checklists that will guide you in evaluating potential calibration suppliers.