Up to and including 120 mm .
The standard was significantly updated in 2019, superseding the 2009 version. It is published under various national adoptions, such as BS EN 10225-1 in the UK and DIN EN 10225-1 in Germany. en 10225-1 pdf
This part of the standard applies specifically to steel . It defines strict thickness limits based on the steel's delivery condition and yield strength: S355NLO (Normalized): Up to and including 200 mm . Up to and including 120 mm