Because flow measurements are so critical to many processes, the industry standard is to calibrate annually, even though that might not be necessary. In many cases, this is done in an attempt to demonstrate to a quality auditor that instruments within the process are under control. For most companies, annual calibration is performed as a traditional ritual with no scientific basis behind it, other than it being the longest duration of time they are willing to risk before finding a potential problem.
In many instances, yearly calibrations are not necessary, as some flowmeters require calibration only once every three or four years depending on the process fluid, operation, and criticality. In other cases, a flowmeter may require calibration much more frequently, possibly on a monthly basis, to maintain a safe, efficient, or regulatory compliant operation. It’s also important to realize that calibration intervals are not always fixed, meaning that they might fluctuate based on usage or historical performance.
How do you determine when to calibrate a flowmeter? By setting up a calibration plan that follows best practices for flow calibration.