London Building Acts (Amendment) Act 1939

This act only applies to inner London and is incorporated within the Building (Inner London) Regulations 1985.

Part III Construction of buildings - Section 20

Section 20 applies to any building more than 30 metres high.  It also applies to buildings higher than 25 metres if they cover an area of more than 930 square metres, and some commercial buildings (for example, shops and warehouses) that have a volume of more than 7100 cubic metres. For these buildings, extra fire-safety measures are usually needed and these include fire suppression systems (for example, sprinklers), smoke ventilation and access to the site by fire brigade personnel.

For Section 20 purposes, the height is measured at the centre of the face of the building where the height is greatest from the level of the footway, or the ground before excavation, to the level of the highest part of the interior of the storey.

Part IV Special and temporary buildings and structures - Section 30

Section 30 applies to the erection or retention of certain temporary buildings and structures that are not covered by the Building Regulations 2010.