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.