How often should you calibrate?
The question is not whether to calibrate, but how often to calibrate? There is no 'one size fits all' answer. In most cases, requirements vary depending on the application, quality requirements, industry standards, performance or safety regulations. Calibration is often the key to reversing a recall, an out-of-tolerance situation, or a potential safety issue.
There are a few possible points to consider when assessing calibration frequencies so you can decide what is best for your process, equipment and application.
Manufacturer's recommended calibration interval.Manufacturers' specifications, usually found in the manual, state how often their tools should be calibrated. Please note that critical measurement applications may require different intervals, usually more frequent, more stringent or industry defined (ASTM 2570,ISO9000,ISO/IEC 17025, MIL-STD xxx).
Before a large critical measurement project.Suppose you take a plant in for testing, and that plant requires very precise measurements. Determine which instruments you will use for the specific test and ensure that these instruments are well within specifications before using them. Send them for calibration and "lock" them in storage so they are not used again before testing. Calibration before a critical measurement project is extremely important. If you want to make decisions or take action based on the measurement results, you want to ensure with a high degree of confidence that the standards used remain within tolerances.
After a large critical measurement project.Just as it is important to calibrate before a major critical measurement project, it is also important to calibrate afterwards. If you have reserved calibrated test instruments for a critical test, it is best to send the same equipment for calibration after the test. When the calibration results come back, you will know whether the tests performed on the instrument were complete and reliable. In some sectors, such as medicine, calibration may be necessary before and after a large critical measurement project. This ensures that the reference used can demonstrate whether an intolerance condition has occurred before, during and after the critical measurement project.
After an event. If your instrument has been impacted (for example, something tripped the internal overload protection or the device absorbed a physical shock), it is best to send it in for calibration to have its integrity checked. This is important because sometimes there is no visible physical defect on the device, such as a dent, scratch, or broken connector. Calibration verifies that the device and critical internal components are in good condition.
According to requirements. Some measurement tasks require calibrated, certified test equipment, regardless of project size. Please note that this requirement may not be explicitly stated, but simply expected based on industry standards. Always review the specifications and requirements of a process before testing. The most common requirement is annual calibration, but this can vary dramatically depending on the application, industry regulations or quality requirements.
Monthly, quarterly or semi-annually.If you mainly take critical measurements and perform them regularly, a shorter time between calibrations means less chance of questionable test results. Calibration at shorter intervals often yields better specifications. Users should look for trends in their calibrated equipment and periodically review and record changes. For example, as the equipment ages, it may happen that the equipment slips before the next calibration cycle. Reviewing trends or calibration results from year to year can help users understand when an instrument needs to be calibrated specifically for your application and use. Users can choose to calibrate instruments in shorter or longer cycles depending on the results they see over time.
Annual.If you perform a mix of critical and non-critical measurements, annual calibration tends to strike the right balance between prudence and cost.
Every two years. If you rarely make critical measurements and do not expose your meter to an event, calibration at long frequencies can be cost-effective.
Never.If your job only requires checking the gross voltage ("Yes, it's 480 V"), calibration seems like overkill. But what if your instrument is exposed to an event? Calibration allows you to use the instrument with confidence.
Keep learning
Determining the correct calibration intervals
Determine calibration intervals for Fluke products
Why calibrate test equipment?
related products
Calibration instruments
Test and measuring instruments
Get some help
Talk to an expert in calibration productsabout your equipment needs
