6(1)This paragraph has effect for the purposes of paragraphs 2 to 5.U.K.
(2)“Building” includes any structure.
(3)A building (or, in the case of paragraph 5, apparatus or pipe-line) is within 50 metres of a work if all or part of it is within that distance.
(4)In the case of a work under the surface of the ground, a reference to a building (or, in the case of paragraph 5, apparatus or pipe-line) within 50 metres of that work includes a reference to a building (or apparatus or pipe-line) all or part of which is within 50 metres of any point on the surface below which the work is situated.