Webster’s Dictionary defines implosion as "a violent collapse inward". In the demolition industry, a blaster is usually trying to pull a structure away from adjacent exposures and towards an area large enough to contain the debris. Therefore, the only time a building is truly 'imploded' is when exposures (other structures or areas of concern) completely surround it. When this situation exists, the blaster has no choice; he must make the building collapse in on itself. This is by far the trickiest type of explosive demolition project, and there are only a handful of blasting companies in the world that possess enough experience—and insurance—to perform these true building implosions.
CONCRETE VS. STEEL
In the United States and Europe, support columns in most buildings are constructed of either steel 'H-beams' or concrete (with steel reinforcing bars). Some buildings actually have both.
DID YOU KNOW that these two types of support columns require two completely different types of explosives to cause their 'failure'?
Concrete columns are generally easier to destroy, and usually require a small amount of conventional dynamite packed into specially drilled holes. Steel beams, however, require a very high-velocity explosive to perform a 'cutting' action through the steel. A specialized explosive called RDX, made famous by NASA’s space program, is used to perform this task. This copper-encased explosive is physically attached to the beam, and upon detonation 'slices' at an incredible 27,000 feet per second. A small amount of conventional dynamite is also attached to the beam to 'kick' it out of place so the structure will fall uniformly, in a direction predesignated by the blaster.
When the excitement of the blast is over, a large, billowing cloud of dust is one of the most identifiable characteristics of a successful project.