Our calibration laboratories for mass and force

The laboratory in Geldermalsen is equipped for the calibration of weights and weighing equipment:

• Range: weights from 1 mg to 2,000 kg, in OIML R111 classes F1, F2, M1, M2 and M3;
• Measuring room: climate-controlled at 20 ±0.5 °C, with continuous recording of temperature, humidity and air pressure;
• Equipment: precision balances and mass comparators for each range, plus lifting and transport equipment for mass pieces up to 2,000 kg;
• References: our own reference weights of a higher class, periodically calibrated with traceability;
• Software: our own R111 LIMS for weighing schemes, conventional mass, uncertainty budget and certificate;
• Weighing equipment: calibration according to EURAMET cg-18, in the laboratory or on site, and re-verification of verified scales as a Recognised Verifier (Erkend Keurder) under the Dutch Metrology Act.

Read more at weight calibration and scale calibration.

Mass measurements in the F classes are sensitive to the environment. Temperature differences between the weight and the reference cause air currents, and the density of the air determines the buoyancy acting on each weight. Our calibration room is therefore controlled at 20 ±0.5 °C. Temperature, humidity and air pressure are continuously monitored and recorded.

Incoming weights are first given time to reach room temperature before we measure them. How long that takes depends on the class, the size and the temperature difference on arrival.

MASSLAB has developed its own LIMS (Laboratory Information Management System), specifically for the calibration of weights according to OIML R111-1 and R111-2. The software:

• records each weight with a unique identification and its complete history;
• processes the ABBA and ABA weighing schemes, with automatic outlier detection and repeatability checks;
• calculates the conventional mass, with correction for air density based on the measured ambient conditions;
• draws up the uncertainty budget for each weight;
• generates the certificate and places it in the customer portal.

Because calculations and reporting are automated, there is less room for transcription and calculation errors. And we can respond quickly when a customer delivers a large batch of weights at once.

Our Elspeet facility houses the hydraulic force calibration benches on which we calibrate force measuring instruments:

• Tensile test bench: tension up to 500 kN (approx. 51 t);
• Compression test bench: compression up to 4,000 kN (approx. 408 t);
• Reference force transducers of 10, 50, 100, 500 and 4,000 kN, loaded in the same line of force as your instrument;
• Instruments: force transducers, load cells, dynamometers, force gauges, load pins, load shackles, hydraulic jacks and cylinders, and crane and hanging scales in tension up to approx. 51 t;
• Standards: ISO 376 and ISO 7500-1 where applicable, measurement uncertainty according to EURAMET cg-4;
• Results: in N, kN, kg or t, covering the complete measuring chain (transducer plus readout) if you send it along.

Read more about our approach at force calibration in tension and compression.

Your instrument is mounted in the line of force of the bench, in series with a calibrated reference force transducer. In increasing and decreasing load steps we compare the reading of your instrument with the force measured by the reference. This shows us the deviation at each measuring point, the hysteresis between loading and unloading and, with repeated series, the repeatability. Heavy crane scales that can no longer practically be loaded with weights are suspended in the tensile test bench in the same way; we convert the force to the kg or tonne reading using the local gravitational acceleration.

A calibration is only worth something if the result is traceable: it must be possible to trace it back, through an unbroken chain of calibrations, to the national and international mass standard. Our reference weights are periodically calibrated against references at a higher level in that chain, so that every measurement in our laboratory is traceable. The same applies to force calibrations: our reference force transducers are periodically calibrated with traceability, and we calculate the measurement uncertainty according to EURAMET cg-4. Every certificate states the references used.

MASSLAB is a Recognised Verifier of measuring instruments. Calibrations are performed according to internally established procedures based on the relevant requirements of ISO/IEC 17025. Where applicable, measurement results are stated with measurement uncertainty and supported by traceable measurement references. For most quality systems, such as ISO 9001, HACCP, BRC and IFS, a traceable certificate is sufficient. If you need an accredited certificate, for example because your own laboratory is accredited, we can arrange this on request through an accredited partner.

For weights in Geldermalsen the process is as follows; force measuring instruments follow the same steps in Elspeet, with the measurement taking place on the tensile or compression test bench.

From our laboratories we offer: