B. Development carried out on industrial land for the purposes of an industrial process consisting of—
(a)the installation of additional or replacement plant or machinery,
(b)the provision, rearrangement or replacement of a sewer, main, pipe, cable or other apparatus, or
(c)the provision, rearrangement or replacement of a private way, private railway, siding or conveyor.
B.1 Development described in Class B(a) is not permitted if—
(a)it would materially affect the external appearance of the premises of the undertaking concerned, or
(b)any plant or machinery would exceed a height of 15 metres above ground level or the height of anything replaced, whichever is the greater.
B.2 In Class B, “industrial land" means land used for the carrying out of an industrial process, including land used for the purposes of an industrial undertaking as a dock, harbour or quay, but does not include land in or adjacent to and occupied together with a mine.