Metrology Terms and Definitions

As defined in ISO-8655(1): 2005, Section 3:

  • Adjustment: Setting of the apparatus, ensuring the metrological performance, as specified
  • Calibration certificate: The document reporting the result of calibration
  • Calibration: The set of operations that establish the relationship between the dispensed volume and the corresponding nominal or selected volume of the apparatus
  • Certificate of conformity: The document issued under the rules of a certification system, stating that conformity is achieved
  • Conformity testing: Systematic examination to determine whether the requirements specified, especially in a metrological sense, are fulfilled
  • Dead air volume: Air volume between the lower part of the piston and the surface of the liquid
  • Dead liquid volume: For positive displacement pipettes, burettes, dilutors and dispensers, the amount of liquid which does not belong to the dispensed volume and which is within the cylinder
  • Maximum permissible error: The upper or lower permitted extreme value for the deviation of the dispensed volume from the nominal or selected volume
  • Nominal volume: The volume specified by a pipette’s manufacturer and used for identification and for indication of the pipette’s measuring range
  • Random error: The scattering of individually dispensed volumes around the mean of all the dispensed volumes
  • Supplier's declaration: The document by which a supplier gives written assurance that an apparatus conforms to the requirements of ISO 8655: 2002
  • Systematic error: The recurring difference between the dispensed volume and the selected volume
  • Uncertainty of measurement: A parameter associated with the dispensed volume, characterizing the dispersion of the volumes that could reasonably be attributed to the dispensed volume
  • Useful volume range: That part of the nominal volume which allows dispensing under observance of the maximum permissible errors
  • User adjustment: Pipette adjustment employing only the means at the user’s disposal