Electromagnetic flow meter calibration (magmeters)

Electromagnetic flow meter calibration involves comparing the meter’s flow output against a traceable liquid flow reference standard to determine the instrument’s K-factor accuracy and any deviations from the specified performance. The calibration certificate records the indicated flow, reference flow, error and measurement uncertainty at each calibrated point. UKAS accreditation provides independent assurance that the calibration methods and reference standards meet ISO/IEC 17025:2017 requirements.

Electromagnetic flow meters require electrically conductive liquids. They work with water, aqueous solutions, acids, alkalis, slurries and most food-grade liquids. They are not suitable for non-conductive liquids such as hydrocarbons, oils or pure deionised water. Labcal’s standard liquid flow calibration uses water as the reference liquid. If your application involves a different conductive liquid, contact us to discuss whether additional calibration steps are needed.

In pharmaceutical manufacturing under GMP guidelines, annual calibration is standard. For food and beverage applications under BRC or SQF standards, annual calibration is also typical. The calibration interval should be set by your quality management system based on the instrument’s role, accuracy requirements and the historical drift observed in previous calibration records.

Labcal’s UKAS calibration service is laboratory-based. Electromagnetic flow meters are sent to our laboratory in Lymington for calibration against our traceable reference flow standards. For instruments that are difficult to remove from their installation, our engineers can advise on how to plan calibration around scheduled maintenance downtime. In-situ verification services are not currently part of our standard UKAS scope.

The K-factor (or meter factor) is the conversion constant relating the meter’s signal output to the actual flow rate. Manufacturers set the K-factor during production, but it can drift over time due to coating or fouling of the electrodes, wear and electronic ageing. UKAS calibration determines the current K-factor against a traceable reference, allowing the meter factor to be updated in the transmitter or the correction to be applied in the data system.