The national annex
What it contains
Section titled “What it contains”The national annex is the country-specific supplement to a given part of the Eurocodes. Typically:
- the values of the nationally determined parameters — partial and combination factors, for example,
- zone maps: snow, wind, seismic base acceleration,
- the choice among selectable procedures where the standard allows more than one,
- supplementary, non-contradictory information.
What it does not contain: amendments to the text of the standard. The national annex fills in the places the standard left open; it does not override it.
Why it is needed
Section titled “Why it is needed”Because the standard is common and the conditions are not. Snow load in Scandinavia and in Hungary cannot be the same; nor can seismic risk in Greece and in the Netherlands.
Beyond that, countries’ safety philosophy can differ, and the standard respects that.
What it means in practice
Section titled “What it means in practice”A Hungarian project
Section titled “A Hungarian project”Work with the parameters of the Hungarian national annex: snow and wind zone, terrain category, factors. These are settings in the software, and it is the designer’s responsibility that they are right.
A foreign project
Section titled “A foreign project”That country’s national annex applies. The logic of the structure travels; the input data does not. Designing abroad.
Software settings
Section titled “Software settings”If a design program “calculates to the Eurocodes”, that does not mean with the Hungarian national annex parameters. It has to be checked.
The common mistake
Section titled “The common mistake”Carrying over the settings of an earlier project without updating the zone data. The calculation is then flawless and the result wrong — and this kind of mistake is hard to spot, because nothing signals it.
So the action data is recorded separately, in writing, at the start of the project — and that is where the design check starts too.
Where to obtain it
Section titled “Where to obtain it”The national annexes are available with the standards through the national standardisation body, and are paid for along with the text of the standard.
The point
Section titled “The point”“To the Eurocodes” is not a specification on its own. Always state which country’s national annex and which edition the design was made to.