The term Improvised Explosive Device comes from the British Army in the 1970s, after the Provisional Irish Republican Army (IRA) used bombs made from agricultural fertilizer and semtex smuggled from Libya to make highly effective boobytrap devices or remote-controlled bombs. An IED is a bomb fabricated in an improvised manner incorporating destructive, lethal, noxious, pyrotechnic, or incendiary chemicals and designed to destroy or incapacitate personnel or vehicles. In some cases, IEDs are used to distract, disrupt, or delay an opposing force, facilitating another type of attack. IEDs may incorporate military or commercially-sourced explosives, and often combine both types, or they may otherwise be made with homemade explosives (HME).
An IED typically consists of an explosive charge (potentially assisted by a booster charge), a detonator, and an initiation system, which is a mechanism that initiates the electrical charge that sets off the device. An IED designed for use against armored targets such as personnel carriers or tanks will be designed for armour penetration, by using either a shaped charge or an explosively formed penetrator. IEDs are extremely diverse in design, and may contain many types of initiators, detonators, penetrators, and explosive loads. Antipersonnel IEDs typically also contain shrapnel-generating objects such as nails or ball bearings (known as shipyard confetti after the metal waste found in the shipyards of Belfast). IEDs are triggered by various methods, including remote control, infra-red or magnetic triggers, pressure-sensitive bars or trip wires. In some cases, multiple IEDs are wired together in a daisy-chain, to attack a convoy of vehicles spread out along a roadway.
IEDs made by inexperienced designers or with substandard materials may fail to detonate, and in some cases actually detonate on either the maker or the emplacer of the device (these unintended early detonations are known as pre-detonations, “own goals,” or “self-resolving bomb-tech removal” if the placer is killed in the detonation). Some groups, however, have been known to produce sophisticated devices that are constructed with components scavenged from conventional munitions and standard consumer electronics components, such as mobile phones, washing machine timers, pagers, or garage door openers. The sophistication of an IED depends on the training of the designer and the tools and materials available.
IEDs may use artillery shells or conventional high-explosive charges as their explosive load as well as homemade explosives. However, the threat exists that toxic chemical, biological, or radioactive (dirty bomb) material may be added to a device, thereby creating other life-threatening effects beyond the shrapnel, concussive blasts and fire normally associated with bombs. Chlorine liquid has been added to IEDs in Iraq, producing clouds of chlorine gas.
A vehicle borne IED, or VBIED, is a military term for a car bomb or truck bomb. These are typically employed by suicide bombers, and can carry a relatively large payload. They can also be detonated from a remote location. VBIEDs can create additional shrapnel through the destruction of the vehicle itself, as well as using vehicle fuel as an incendiary weapon.
Of increasing popularity among insurgent forces in Iraq is the HBIED or House Borne IED, coming out of the common military practice of clearing houses, insurgents will rig an entire house to detonate and collapse shortly after a clearing squad has entered.
- Pentagon Expects More IED Attacks As U.S. Casualties Rise (huffingtonpost.com)
- 16 Air Assault Brigade find huge weapons cache (waronterrornews.typepad.com)
- IED found near Pennsylvania train tracks. (thewesternexperience.com)