BS 7118-2:1989

This standard BS 7118-2:1989 Measurement of fluid flow: assessment of uncertainty in the calibration and use of flow measurement devices is classified in these ICS categories:

• 17.120.01 Measurement of fluid flow in general

This part of ISO 7066 describes the procedures for fitting a quadratic, cubic or higher degree polynomial expression to a non-linear²⁾ set of calibration data, using the least-squares criterion, and of assessing the uncertainty associated with the resulting calibration curve. It considers only the use of polynomials with powers which are integers.

Because it is generally not practicable to carry out this type of curve fitting and assessment of uncertainty without using a computer, it is assumed in this part of ISO 7066 that the user has access to one. In many cases it will be possible to use standard routines available on most computers; as an alternative the FORTRAN program listed in Annex C may be used.

Examples of the use of these methods are given in Annex D.

Extrapolation beyond the range of the data is not permitted.

Annex A, Annex B, Annex C, Annex D and Annex E do not form integral parts of this part of ISO 7066.

Procedures for fitting a quadratic, cubic or higher degree polynomial expression to a non-linear set of calibration data using the least squares criterion and assessing the uncertainty associated with the resulting calibration curve.