EN 12838:2000

Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Description of a continuous LNG sampling system
5 Description of a discontinuous LNG sampling system
6 Characteristics of the test rig
  6.1 Description of the test rig
  6.2 Measurement required
7 Suitability tests
  7.1 General requirements of test performance
  7.2 Operating procedure
  7.3 Calculation of suitability criteria for the tested
      sampling system
8 Suitability criteria for the LNG sampling system
9 Test report
Annex A (informative) Continuous LNG sampling system
Annex B (informative) Discontinuous LNG sampling system
Annex C (informative) Thermodynamic conditions for the
        transformation of LNG into natural gas
        C.1 General remarks
        C.2 Example of characteristic points
Annex D (normative) Test rig
Annex E (normative) Means required to evaluate the test rig
        E.1 General remarks
        E.2 Measuring device system
        E.3 Layout of measuring devices in test rig
Annex F (normative) Means required to evaluate a continuous
        LNG sampling system
        F.1 General remarks
        F.2 Measuring devices
        F.3 Layout of measuring devices in the tested sampling
            system
Annex G (normative) Means required to evaluate a discontinuous
        LNG sampling system
        G.1 General remarks
        G.2 Measuring devices
        G.3 Layout of measuring devices in the tested sampling
            system
Annex H (normative) Method of calculation of the accuracy of
        the test rig
        H.1 Mean values of physical properties derived from the
            analysis of the reference gas
        H.2 Calculation of the relationship of the physical
            property with time of the reference gas
        H.3 Mean value of a physical property of the reference
            gas
        H.4 Random error on a value of the reference gas
        H.5 Random error on all values of the reference gas
        H.6 Example of calculation
Annex J (normative) Method of calculation of the accuracy of
        a continuous LNG sampling system
        J.1 Deviation in relation to reference gas, of the
            physical property X derived from gas analyses
            obtained with the tested sampling system
        J.2 Random error of the tested sampling system
        J.3 Systematic error of the tested sampling system
        J.4 Statistical test on systematic error
        J.5 Example of calculation
Annex K (normative) Method of calculation of the accuracy of
        a discontinuous LNG sampling system
        K.1 Calculation of the regression equation of the
            reference gas
        K.2 Deviation of physical property X from regression
            equation
        K.3 Random error of the tested sampling system
        K.4 Systematic error of the tested sampling system
        K.5 Statistical test on systematic error
        K.6 Example of calculation

This standard specifies the tests to be carried out in order to assess the suitability of LNG sampling systems designed, in combination with an analytical device such as a chromatograph, to determine the composition of Liquefied Natural Gas.