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Calibration Weights

Northern Balance supply a full range of calibration masses (test weights) to enable carry out checking of weighing equipment.

Which weight class do I require?

Test weights are supplied in a different classes appropriate for the testing of balances and scales with different resolutions. The OIML classes as used in Europe are as follows :

Class E1 - These weights are stainless steel and only appropriate for use in Metrology Laboratories. Usually to enable calibration of lower classes.These weights are the highest accuracy class, and are intended to be used for traceability between national mass standards and OIML class E2 weights and lower. The maximum permissible error from nominal value at 1 kg is +/- 0.5 mg.

Class E2 - for use in calibration and testing of balances with displayed resolution of 0.01mg and lower. I.e. 5, 6 and 7 place balances.Suitable for use for traceability of OIML class F1 weights and lower; also with OIML accuracy class I weighing instruments. The maximum permissible error from nominal value at 1 kg is +/- 1.6 mg.

Typically used for the calibration of weighing instruments with a high number of scale divisions to achieve special accuracy. For example, they are used in the calibration of mass comparators used in calibrating weights.

Class F1 - Suitable for use for traceability of OIML class F2 weights and lower; also with OIML accuracy class I weighing instruments. The maximum permissible error from nominal value at 1 kg is +/- 5 mg.

Typically used for the calibration of weighing instruments with a high number of scale divisions to achieve high accuracy. For example, they are used in the calibration of analytical top pan balances.

Class F2 - Suitable for use for traceability of OIML class M1 weights and lower; also with OIML accuracy class II weighing instruments. Intended for use in high value commercial transactions such as gold and precious stones. The maximum permissible error from nominal value at 1 kg is +/- 16 mg.

Typically used for the calibration of weighing instruments with a higher than normal number of scale divisions to achieve better than trade accuracy. For example, they are used in the calibration of analytical top pan balances with a resolution of 0.01 g.

Class M1 - Suitable for use for traceability of OIML class M2 weights and lower; also with OIML accuracy class II weighing instruments. The maximum permissible error from nominal value at 1 kg is +/- 50 mg.

Typically used for the calibration of weighing instruments that are in use for trade or weighing of patients for example. If an instrument has more than 5,000 scale intervals, a 20 kg weight should be calibrated to half M1 tolerance.

Class M2 - Suitable for use for traceability of OIML class M3 weights; also with OIML accuracy class III weighing instruments. Intended for use in normal commercial transactions where goods are sold by weight. The maximum permissible error from nominal value at 1 kg is +/- 160 mg.

Class M3 - Suitable for use with OIML accuracy class III or IIII weighing instruments. The maximum permissible error from nominal value at 1 kg is +/- 500 mg.

What material are the weights made from?

  1. Aluminium
  2. Stainless steel
  3. Brass
  4. Cast iron


What certification do my weights require?

Calibration weights are usually supplied with calibration certification of a standard appropriate for use.

  1. Northern Balance Calibration chart : This is a secondary calibration against our primary calibrated UKAS standards and is appropriate for carrying out daily/weekly checking of balances and scales when an external company such as Northern Balance carry out regular service and calibration.
  2. Local standards.

E1 Test WeightsM1 Test Weights

Northern Balance supply a full range of calibration masses (test weights) to enable carry out checking of weighing equipment.

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