ACCREDITATION FOR CALIBRATION

Laboratories and companies using measuring instruments or measurement standards in their processes need to know the uncertainty of these measurements.

This knowledge is achieved by calibrating measuring instruments. A task which is mainly carried out by accredited calibration laboratories.

When performing calibration, a calibration laboratory defines the relationsship between a measuring instrument or the printed value of a measurement standard and the value of a reference standard. This reference value is established by the calibration laboratory and is traceable to the SI-unit system.

The result of a calibration can be expressed in terms of information about the views, the instrument provides for the respective reference values.

In many cases the measurement uncertainty of the measuring instrument will also be shown, which is given by the difference between the display of the measuring instrument or a measurement standards printed value and the reference value.

CALIBRATION AND ADJUSTMENT

Calibration is often confused with adjustment, where the measurement uncertaincy is usually set to be zero.

If a measuring instrument or a measurement standard is adjusted, it must be agreed with the customer, and the calibration laboratory must calibrate the measuring instrument or the measurement standard both before and after adjustment. For users of measuring instruments and measurement standard the history of the calibration results is critical in order to define the time interval between calibrations and to be able to assess the values measured with the measuring instrument or the measurement standard in day-to-day work.

SPECIAL ARRANGEMENT FOR CALIBRATION:

The Danish Safety Technology Authority authorizes laboratories to conduct verification of meters and measuring systems covered by The Danish Safety Technology Authority rules on metrological control according to Executive Order No. 322 authorising laboratories to carry out metrological control.

Key in order to be authorized is that the laboratory is accredited for calibration in the relevant field.

Authorisation is required to verify meters and measurement systems such as weights, water, electricity, thermal energy and petrol gauges.

AREAS OF CALIBRATION:

  • Acceleration and speed
  • Acoustics and ultrasound
  • Chemical
  • Density and viscosity
  • Geometry
  • Elektricity DC and LF
  • Elektricity HF
  • Flow
  • Force and torque
  • Hardness
  • Moist
  • Ionizing radiation
  • Magnetism
  • Mass
  • Optics
  • Pressure and vacuum
  • Reference material
  • Temperature
  • Time and frequency
  • Volume

RULES AND REGULATIONS:

Below are links or references to documents for the specific scheme.

EXECUTIVE ORDERS

ACCREDITATION STANDARD

  • DS/EN ISO/IEC 17025, 2017 General requirements for the competence of testing and calibration laboratories.
  • DS/EN ISO/IEC 17025, 2nd edition 2005-06-10 General requirements for the competence of testing and calibration laboratories.

ACCREDITATION REGULATIONS

GUIDELINES

In addition to the above requirements documents, that the calibration laboratory must comply with, there are a number of international guidelines that are relevant to the accredited laboratories and implemented through the accreditation regulations.:

  • EA-4/02:2013: Expression of the Uncertainty of Measurement in Calibration. Supplement 1 - 2. Examples. Pages 27 - 79.
  • EA-4/14:2003: The Selection and Use of Reference Materials.
  • EA-4/18:2010: Guidance on the level and frequency of proficiency testing participation.
  • ILAC G-8:03/2009: Guidelines on the Reporting of Compliance with Specification.
  • ILAC G19:08/2014 Modules in a Forensic Science Process
  • ILAC G-24:2007: ILAC Guidelines for the determination of calibration intervals of measuring instruments.

INTERNATIONAL INTERPRETATIONS

International interpretations concerning the link between the accreditation of laboratories and fulfilment of ISO 9001:

ACCREDITATION MESSAGES

Various accreditation messages(in Danish only) have been published to guide and describe evaluation practice and issues relevant for accredited calibration laboratories.

1. ACCREDITATION MESSAGES - AMF