# Directive 2009/45/EC of the European Parliament and of the Council of 6 May 2009 on safety rules and standards for passenger ships (Recast) (Text with EEA relevance), Division .6: A main transverse bulkhead may be stepped provided that it meets one of the following conditions:

Extent: E+W+S+N.I.

.1 the combined length of the two compartments, separated by the bulkhead in question, does not exceed either 90 % of the floodable length or twice the permissible length, except that, in ships having a subdivision factor equal to 1, the combined length of the two compartments in question shall not exceed the permissible length;
.2 additional subdivision is provided in way of the step to maintain the same level of safety as that secured by a plane bulkhead;
.3 the compartment over which the step extends does not exceed the permissible length corresponding to a margin line taken 76 mm below the step.

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Source: https://www.legislation.gov.uk/eudr/2009/45/annex/I/chapter/2/part/B/part/2/division/7/division/2/division/.6 (the official version)
Page: https://openlegislation.uk/eu-directive-2009-45/annex-I/chapter-2/part-B/part-2/division-7/division-2/division-.6
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.