Division 3.4 Indirect determination methods

Where no direct metering or analysis approach is available for a required data set, in particular for cases where net measurable heat is going into different production processes, the operator shall propose the use of an indirect determination method, such as:

1. (a)

   calculation based on a known chemical or physical process, using appropriate accepted literature values for the chemical and physical properties of substances involved, appropriate stoichiometric factors and thermodynamic properties such as reaction enthalpies, as appropriate;

2. (b)

   calculation based on the installation's design data such as the energy efficiencies of technical units or calculated energy consumption per unit of product;

3. (c)

   correlations based on empirical tests for determining estimation values for the required data set from non-calibrated equipment or data documented in production protocols. For this purpose the operator shall ensure that the correlation satisfies the requirements of good engineering practice and that it is applied only to determine values which fall into the range for which it was established. The operator shall evaluate the validity of such correlations at least once a year.