"Member States should lay down the parameters usable in their
territory, hereinafter 'the nationally determined parameters'.
Member States should use the recommended values provided by the
Eurocodes when nationally determined parameters have been identified in the
Eurocodes. They should diverge from those recommended values only where
geographical, geological or climatic conditions or specific levels of protection
make that necessary."
Commission Recommendation 2003/887/EC
Nationally Determined Parameters
EN Eurocodes recognise the responsibility of regulatory
authorities in each Member State and have safeguarded their right to determine
values related to regulatory safety matters at a national level where these
continue to vary from State to State.
EN Eurocodes provide for National Choices full sets of recommended
values, classes, symbols and alternative methods to be used as Nationally
Determined Parameters (NDPs).
When Member States lay down their NDPs, they should:
- choose from the classes included in the EN Eurocodes, or
- use the recommended value, or choose a value within the recommended range of values, for a symbol where the EN Eurocodes make a recommendation, or
- when alternative methods are given, use the recommended method, where the EN Eurocodes make a recommendation;
- take into account the need for coherence of the NDPs laid down for the different EN Eurocodes and the various parts thereof.
When the EN Eurocodes are used for the design of construction
works, or parts thereof, the NDPs of the Member State on whose territory the
works are located shall be applied.
Member States are encouraged to minimize the number of cases where
recommendations for a value or method are not adopted for their nationally
determined parameters. By choosing the same values and methods, the Member
States will enhance the benefits of the use of the EN Eurocodes.
The European Commission urged Member States to reduce divergence from the
recommended values provided by the EN Eurocodes. […]