Appropriate Handling of Out-of-Calibration Equipment

If you have ever found equipment that is out of calibration, then you know it is not something to take lightly. Whether you manufacture children’s toys or automobile tires, you know that the implications and ramifications of the decisions you make can be devastating for your company. Although the requirements from the ISO 9001 standard regarding equipment found to be out of calibration are simple and succinct, this is not something to take for granted. If you ensure that the processes for handling nonconforming equipment are in place and if you take into consideration the steps provided below, you will be ready to handle and perhaps avoid out-of-calibration conditions.

Equipment found out of tolerance

When calibrating your equipment and finding it to be out of tolerance, ISO 9001 requires you to consider the product that was inspected with such equipment as suspect product. Aside from quarantining the equipment for further adjustments and calibration, the first question you need to ask is: Does the calibration data suggest the equipment was broken, minimally out of tolerance, or grossly out of tolerance? Was it out of tolerance in the range in which it was used?

Review the calibration data in detail so that you can assess your confidence that the product that was inspected on this equipment is meeting specifications.

Your next questions are:

• How much product was inspected or tested using that equipment?

• How much product that passed inspection was sent to inventory or was shipped to the customer?

If you don’t have confidence that the out-of-tolerance equipment was capable of producing good results, then you must handle the suspect product as necessary, including segregation, quarantine, recall, reinspection or retesting (using recalibrated and approved in-tolerence equipment), and repair or rework the product. Some steps to take are listed below:

• Product that has not been shipped needs to be segregated immediately for subsequent inspection or testing.

• Product that is in the warehouse has to be pulled and retested or reinspected.

• If the product has already been shipped, the standard requires that you have a process in place for how you are going to recall it. If it was already delivered to the customer, the question is: How you are going to ask for the product back to inspect or test it again?

Perhaps if the customer uses your product as raw material and they have not used it yet, you may be able to go to their facility and conduct the inspection and testing there. If that is not possible, due to equipment and the setup you have in-house, then proceed with your recall process and conduct the reinspection or retest at your facility.

 

In all cases, you need to have a plan of action in place if the results of the reinspection or retesting of suspect product are unfavorable. Is it possible to repair or rework the product, or must it be scrapped and replaced?

The handling of equipment that is out of calibration must be a well-planned, documented process, preferably using the same control-of-nonconformance procedure already required by the ISO 9001 standard.

Preventive steps: importance of the data in the report

Too often when equipment is outsourced for calibration, you receive a calibration certificate that doesn't have the calibration data. This does not seem to be a problem until the equipment is found to be out-of-calibration. Having the calibration data is important in these occasions, because it gives you a chance to review the data and perhaps draw some conclusions as to why the equipment  is out of calibration. By the way, the following items to check are not only important to review when an instrument is found to be out of calibration but should be looked at frequently in order to get a feel for the characteristics of this instrument and how it was calibrated. Look for the following items in the calibration data:

• Is it being calibrated at the correct range or ranges?
• Was it found to be marginally out of calibration or grossly out?
• Was it in good shape and within specification every time it was calibrated?
• Can it go longer between calibrations?
• Does it go a shorter time between calibrations?

 

For example, if you calibrate a certain piece of equipment every six months, and every six months when you get the results, the equipment is in perfect tolerance, you may decide to increase the calibration cycle to every year based on these results. Perhaps not immediately but after three or four cycles of calibration, you can safely increase your time between calibration for the specific equipment. However even when you go to a one-year cycle, you will want to keep reviewing your calibration records to see if the equipment is always received by the calibration lab in tolerance, and if so, ensure the data is clearly confirming that.

As you continue to review your data, you may decide that a one-year calibration cycle is good, but perhaps you might want to increase it to even a greater span, such as every one-and-a-half years. You don’t, however, want to push the equipment to the limit. We are talking about being economical but still having the confidence that the product being inspected or tested meets specifications.

In some cases, when equipment is used extremely infrequently, it may be necessary to calibrate before use, rather than keep the equipment in a calibration cycle. However, appropriate labeling and planning will be necessary to ensure that equipment is ready to use when needed.

What to report on the calibration certificate

You—not the calibration technician or outsourcing company—need to decide what you want to see on your calibration report. If you plan well, then you will always have all the information available should discrepancies or out-of-tolerance conditions occur.

Here are some of the most important fields:

• Description of the equipment, equipment ID

• Location of the equipment. Who the owner is and if the equipment is assigned to certain employees.

• Calibration date and next due calibration date

• “As found” condition. This is very important and is essential for detecting if the equipment was found out of calibration or not. The idea is that when you first take the equipment in for calibration, you record whether the equipment was found in tolerance or out of tolerance.

• Calibration readings or the data. Sometimes calibration reports only contain the “as found” condition and state that the equipment was brought to tolerance, or is in calibration, but you don’t know if the equipment readings were marginal or if the equipment readings were actually out in several points of the range.

• Standard used to calibrate your equipment. The standard name, ID, description, the last calibration date and the next due calibration, and whether the standard is traceable to national (such as NIST) or international measurement standards.

• The name of the person conducting the calibration

• The procedure or method used

 

If you address these simple steps in your calibration process and management system procedures, then you will be prepared should any of your measuring and test equipment be found out of tolerance.

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