When do we need calibration of equipment used in testing laboratories? (NT TR 226)

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  • Report #: NT TR 226
  • Approved: February 1994
  • Author(s): Esa Vitikainen
  • Hits: 1


One of the most important elements in a testing laboratory quality system is a practical, well-functioning equipment management system.

The validation of equipment with respect to use can be carried out at various levels of uncertainty, depending mostly on the technical capability of the equipment, the requirements set by the clients of the laboratory or by the standard or test method used. Costs can be saved if no calibration is needed, or if calibration can be performed using the most suitable and simplest way, which produces the acceptable uncertainty level for the measurement in question.

The purpose of this report is to give recommendations for testing laboratories with respect to calibration, and to present tools and data for facilitating the planning of a practical equipment assurance system.

A process in the planning of an equipment assurance program is presented, as well as charts for selecting measuring equipment, and their calibration levels are given for the basic quantities length, mass, force, time, temperature, voltage, resistance and current. The uncertainties given in the charts are intended as direction-giving, not as accurate values. The measuring ranges do not necessarily cover all the measuring needs of a testing laboratory.However, they might be useful in industrial measurements.


Nordtest is a trademark of Nordic cooperation in conformity assessment. The emphasis of Nordtest is to develop, promote and innovate Nordic test methods and pre-normative activity. Nordtest endeavours to remove technical barriers to trade and promotes the concept: “Approved once, accepted everywhere”.