Generally ~ the reverse order of construction to gradually reduce
the height. Where space in not confined, overturning or explosives
may be considered.
Piecemeal ~ use of hand held equipment such as pneumatic
breakers, oxy-acetylene cutters, picks and hammers. Care should be
taken when salvaging materials and other reusable components.
Chutes should be used to direct debris to a suitable place of
collection (see page 185).
Pusher Arm ~ usually attached to a long reach articulated boom
fitted to a tracked chassis. Hydraulic movement is controlled from
a robust cab structure mounted above the tracks.
Wrecking Ball ~ largely confined to history, as even with safety
features such as anti-spin devices, limited control over a heavy
weight swinging and slewing from a crane jib will be considered
unsafe in many situations.
Impact Hammer ~ otherwise known as a ``pecker''. Basically a large
chisel operated by pneumatic power and fitted to the end of an
articulated boom on a tracked chassis.
Nibbler ~ a hydraulically operated grip fitted as above that can be
rotated to break brittle materials such as concrete.
Overturning ~ steel wire ropes of at least 38 mm diameter
attached at high level and to an anchored winch or heavy vehicle.
May be considered where controlled collapse is encouraged by
initial removal of key elements of structure, typical of steel framed
buildings. Alternative methods should be given preference.
Explosives ~ demolition is specialised work and the use of
explosives in demolition is a further specialised practice limited to
very few licensed operators. Charges are set to fire in a sequence
that weakens the building to a controlled internal collapse.
Some additional references ~
BS 6187: Code of practice for demolition.
The Construction (Health, Safety and Welfare) Regulations.
The Management of Health and Safety at Work Regulations.
Demolition -- Methods