Paragraph 2.29 requires that an accessible bathroom is located on the same storey as the principal bedroom defined in paragraph 2.25b. In a dwelling where accommodation is set out over three storeys or more, it would be reasonable for a twin room, or a double bedroom (as an alternative to the principal bedroom) to be located on the same floor as the accessible bathroom required by paragraph 2.29 providing that the relevant requirements for circulation are demonstrated for that type of bedroom.