Implosion is by far the most impressive method of demolishing a building. However, due to their specialized nature, implosions are used in less than 1% of demolition projects. Implosion is the process of using explosives to knock out a building’s main supports, causing the building to collapse from the inside out.
Buildings are imploded in one of two ways. If space permits, explosives are fitted into the building’s left columns, making it fall to the side when detonated. Cables are often used to control the building’s collapse, making this method a safer option. If space is limited, the second method involves placing explosives in the building’s lower support system and middle sections, causing the building to fall onto itself.
Implosions require the knowledge of experts called “blasters” and are often used to demolish large structures in urban areas. A successful implosion requires the following steps:
- Blueprint examination: Blasters study blueprints of a building to determine which areas need to be blasted.
- Site preparation: Crews prepare a site by taking out the non-load-bearing walls, weakening supporting columns, and wrapping columns with fencing for a cleaner fall with less flying debris.
- Determine explosives: Blasters select an explosive based on the building’s materials. Dynamites release shockwaves and are best used to obliterate concrete columns. RDX can expand up to 27,000 feet per second to slice through steel structures.
- Load explosives: The explosives are bored into columns, generally in support columns and a few upper stories to make it easier to break the building into smaller pieces.
- Time detonation: Blasters first build up an electrical charge. When the current is sent through the wire, it heats up and ignites the flammable substance, setting off the main explosives. Blasters can time their detonations by setting slow-burning materials to delay the explosions.