Pipe bomb
Encyclopedia
A pipe bomb is an improvised explosive device
Improvised explosive device
An improvised explosive device , also known as a roadside bomb, is a homemade bomb constructed and deployed in ways other than in conventional military action...

, a tightly sealed section of pipe
Pipe (material)
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...

 filled with an explosive material
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...

. The containment provided by the pipe means that simple low explosives can be used to produce a relatively large explosion, and the fragmentation of the pipe itself creates potentially lethal shrapnel
Fragmentation (weaponry)
Fragmentation is the process by which the casing of an artillery shell, bomb, grenade, etc. is shattered by the detonating high explosive filling. The correct technical terminology for these casing pieces is fragments , although shards or splinters can be used for non-preformed fragments...

.

Premature detonation is a hazard of attempting to construct any homemade bomb
Bomb
A bomb is any of a range of explosive weapons that only rely on the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy...

, and the materials and methods used with pipe bombs make unintentional detonation incidents common, usually resulting in serious injury or death to the assembler.

In many countries the manufacture or possession of a pipe bomb is a serious crime
Crime
Crime is the breach of rules or laws for which some governing authority can ultimately prescribe a conviction...

, regardless of its intended use.

Design

The bomb is usually a short section of steel water pipe containing the explosive mixture and closed at both ends with steel or brass caps. A fuse is inserted into the pipe with a lead running out through a hole in the side or capped end of the pipe. The fuse can be electric with wires leading to a timer and battery or can be a common fuse
Fuse (explosives)
In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...

. All of the components are easily obtainable.

Generally, high explosives such as TNT are not used, because these and the detonator
Detonator
A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common....

s that they require are difficult to obtain. Such explosives also do not require the containment of a pipe bomb.

Instead, any sort of explosive mixture the builder can find or make is used, and some of the explosive mixtures used, such as black powder, match heads or chlorate mixtures are very prone to ignition by the friction and static electricity generated when packing the material inside the tube or attaching the end caps—accounting for many injuries or deaths amongst builders. If sharp objects, such as nails or broken glass, are added inside the bomb in an attempt to increase the amount of injury, these also add to the risk of premature ignition.

Operation

Pipe bombs concentrate pressure and release it suddenly, through failure of the outer casing. Plastic materials can be used, but metals typically have a higher bursting strength and so will produce more concussive force. For example, common schedule 40 1-inch wrought steel pipe has a typical working pressure of 1010 psi, and bursting pressure of 8090 psi, though the pipe sealing method can significantly reduce the burst pressure.

The pipe can rupture in different ways, depending on the rate of pressure rise, and the ductility
Ductility
In materials science, ductility is a solid material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire. Malleability, a similar property, is a material's ability to deform under compressive stress; this is often characterized...

 of the casing material.
  • If the pressure rise is slow, the metal can deform until the walls become thin and a hole is formed, causing a loud report from the gas release but no shrapnel.
  • A rapid rate of pressure rise will cause the metal to act as a crystal and shatter into fragments, which are pushed outward in all directions by the expanding gases.

Modes of failure

Pipe bombs can fail to explode if the gas pressure buildup is too slow, resulting in bleed-out through the detonator ignition hole. Insufficiently tight threading can also bleed gas pressure through the threads faster than the chemical reaction pressure can rise.

They can also fail if the pipe is fully sealed and the chemical reaction triggered, but the total pressure buildup from the chemicals is insufficient to exceed the casing strength; such a bomb is a dud
Dud
A dud is an ammunition round or explosive that fails to fire or detonate, respectively, on time or on command.Duds are still dangerous and have to be deactivated and disposed of carefully. Poorly designed devices A dud is an ammunition round or explosive that fails to fire or detonate,...

 but still potentially dangerous if handled, since an external shock could trigger rupture of the statically-pressurized casing.

Uses

Pipe bombs are by nature improvised weapons, and typically used by those without access to military devices such as grenade
Grenade
A grenade is a small explosive device that is projected a safe distance away by its user. Soldiers called grenadiers specialize in the use of grenades. The term hand grenade refers any grenade designed to be hand thrown. Grenade Launchers are firearms designed to fire explosive projectile grenades...

s. In Northern Ireland
Northern Ireland
Northern Ireland is one of the four countries of the United Kingdom. Situated in the north-east of the island of Ireland, it shares a border with the Republic of Ireland to the south and west...

, there have been hundreds of pipe bomb attacks since the mid 1990s (towards the end of the "Troubles
The Troubles
The Troubles was a period of ethno-political conflict in Northern Ireland which spilled over at various times into England, the Republic of Ireland, and mainland Europe. The duration of the Troubles is conventionally dated from the late 1960s and considered by many to have ended with the Belfast...

"). Most of the attacks have been launched by loyalist
Ulster loyalism
Ulster loyalism is an ideology that is opposed to a united Ireland. It can mean either support for upholding Northern Ireland's status as a constituent part of the United Kingdom , support for Northern Ireland independence, or support for loyalist paramilitaries...

 paramilitaries
Paramilitary
A paramilitary is a force whose function and organization are similar to those of a professional military, but which is not considered part of a state's formal armed forces....

 opposed to the 1994 ceasefires, especially the Red Hand Defenders
Red Hand Defenders
The Red Hand Defenders is a loyalist paramilitary group in Northern Ireland. It was formed in 1998 by loyalists who opposed the Belfast Agreement and the loyalist ceasefires. Its members were drawn mostly from the Ulster Defence Association and Loyalist Volunteer Force...

 (RHD) and Orange Volunteers
Orange Volunteers
The Orange Volunteers or Orange Volunteer Force is an Ulster loyalist and Protestant fundamentalist paramilitary group in Northern Ireland.-Origins:...

 (OV). However, they have also been used by Irish republican
Irish Republicanism
Irish republicanism is an ideology based on the belief that all of Ireland should be an independent republic.In 1801, under the Act of Union, the Kingdom of Great Britain and the Kingdom of Ireland merged to form the United Kingdom of Great Britain and Ireland...

 paramilitaries and by anti-drugs vigilante
Vigilante
A vigilante is a private individual who legally or illegally punishes an alleged lawbreaker, or participates in a group which metes out extralegal punishment to an alleged lawbreaker....

 group Republican Action Against Drugs
Republican Action Against Drugs
Republican Action Against Drugs is a vigilante group active mainly in the Derry, Strabane and Newry areas of Northern Ireland. It targets those whom it claims are drug dealers...

 (RAAD).

As well as users such as criminals, paramilitaries and militias they also have a long tradition of recreational use for amusement or mischief with no intention to cause injury to anyone. Due to the dangers of premature ignition and of shrapnel, pipe bombs are much more dangerous than alternatives such as dry ice bomb
Dry ice bomb
A dry ice bomb is a simple bomb-like device. While the simplicity and ease of construction, high bursting pressure, and sound make this dry ice activity appealing for recreational purposes, it can be unpredictable and dangerous, and has led to many injuries - and dry ice bombs are illegal in many...

s or spud guns.

Notable incidents

  • On 4 May 1886 a pipe bomb was thrown during a rally at Haymarket Square in Chicago, Illinois, United States
    United States
    The United States of America is a federal constitutional republic comprising fifty states and a federal district...

    . It reached a police line and exploded, killing policeman Mathias J. Degan. The bomb was made from gas-pipe
    Pipe (material)
    A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...

     filled with dynamite and capped at both ends with wooden blocks.
  • On 20 October 1930 William Kogut, an inmate on San Quentin's death row
    San Quentin State Prison
    San Quentin State Prison is a California Department of Corrections and Rehabilitation state prison for men in unincorporated San Quentin, Marin County, California, United States. Opened in July 1852, it is the oldest prison in the state. California's only death row for male inmates, the largest...

    , tore up decks of playing cards and used them to make a pipe bomb, which he used to kill himself.
  • On 27 July 1996 Eric Rudolph used a pipe bomb in the Centennial Olympic Park bombing
    Centennial Olympic Park bombing
    The Centennial Olympic Park bombing was a terrorist bombing on July 27, 1996 in Atlanta, Georgia, United States during the 1996 Summer Olympics, the first of four committed by Eric Robert Rudolph...

     during the 1996 Summer Olympics
    1996 Summer Olympics
    The 1996 Summer Olympics of Atlanta, officially known as the Games of the XXVI Olympiad and unofficially known as the Centennial Olympics, was an international multi-sport event which was celebrated in 1996 in Atlanta, Georgia, United States....

     in Atlanta, Georgia
    Atlanta, Georgia
    Atlanta is the capital and most populous city in the U.S. state of Georgia. According to the 2010 census, Atlanta's population is 420,003. Atlanta is the cultural and economic center of the Atlanta metropolitan area, which is home to 5,268,860 people and is the ninth largest metropolitan area in...

    , United States. It killed two people and injured 111.
  • On 25 July 1997, during the July 1997 riots in Northern Ireland
    1997 nationalist riots in Northern Ireland
    From 6 July to 11 July 1997 there was a series of mass protests, fierce riots and gun battles in Irish nationalist districts of Northern Ireland. Irish nationalists and republicans, in some cases supported by the Provisional Irish Republican Army , attacked the Royal Ulster Constabulary and...

    , a well-known loyalist
    Ulster loyalism
    Ulster loyalism is an ideology that is opposed to a united Ireland. It can mean either support for upholding Northern Ireland's status as a constituent part of the United Kingdom , support for Northern Ireland independence, or support for loyalist paramilitaries...

     was found dead in Belfast
    Belfast
    Belfast is the capital of and largest city in Northern Ireland. By population, it is the 14th biggest city in the United Kingdom and second biggest on the island of Ireland . It is the seat of the devolved government and legislative Northern Ireland Assembly...

    . He is thought to have died in a premature pipe bomb explosion at an arms dump.
  • On 5 June 1999 a Protestant civilian was killed when a pipe bomb was thrown through the window of her house in Portadown
    Portadown
    Portadown is a town in County Armagh, Northern Ireland. The town sits on the River Bann in the north of the county, about 23 miles south-west of Belfast...

    , Northern Ireland. She was married to a Catholic man. Loyalist Volunteer Force
    Loyalist Volunteer Force
    The Loyalist Volunteer Force is a loyalist paramilitary group in Northern Ireland. It was formed by Billy Wright in 1996 when he and the Portadown unit of the Ulster Volunteer Force's Mid-Ulster Brigade was stood down by the UVF leadership. He had been the commander of the Mid-Ulster Brigade. The...

     (LVF) members were blamed, although the group denied responsibility.
  • On 20 April 1999 Eric Harris and Dylan Klebold
    Eric Harris and Dylan Klebold
    Eric David Harris and Dylan Bennet Klebold were American high school seniors who committed the Columbine High School massacre. They killed 13 people—including teacher Dave Sanders—and injured 24 others, three of whom were injured as they escaped the attack...

     used pipe bombs during the Columbine High School massacre
    Columbine High School massacre
    The Columbine High School massacre occurred on Tuesday, April 20, 1999, at Columbine High School in Columbine, an unincorporated area of Jefferson County, Colorado, United States, near Denver and Littleton. Two senior students, Eric Harris and Dylan Klebold, embarked on a massacre, killing 12...

    .
  • On 11 November 2001 an Ulster Defence Association
    Ulster Defence Association
    The Ulster Defence Association is the largest although not the deadliest loyalist paramilitary and vigilante group in Northern Ireland. It was formed in September 1971 and undertook a campaign of almost twenty-four years during "The Troubles"...

     (UDA) member died in a premature pipe bomb explosion during a riot in Belfast, Northern Ireland.
  • On 3 January 2002 another UDA member died in a premature pipe bomb explosion in Coleraine
    Coleraine
    Coleraine is a large town near the mouth of the River Bann in County Londonderry, Northern Ireland. It is northwest of Belfast and east of Derry, both of which are linked by major roads and railway connections...

    , Northern Ireland.
  • On 11 December 2010 a suicide bomber detonated one out of six pipe bombs close to a major shopping district in Stockholm
    Stockholm
    Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...

    , Sweden
    Sweden
    Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

    , killing himself with no other casualties. The incident is known as the 2010 Stockholm bombings
    2010 Stockholm bombings
    The 2010 Stockholm bombings occurred on 11 December 2010 when two bombs exploded in central Stockholm, Sweden, killing the bomber and injuring two people. Swedish Minister for Foreign Affairs Carl Bildt and the Swedish Security Service described the bombings as acts of terrorism.Taimour Abdulwahab...

    .
  • In January 2011 a potentially deadly pipe bomb was discovered
    2011 Spokane bombing attempt
    -Over view:On January 17, 2011, a radio-controlled, shaped pipe bomb was found and defused in Spokane, Washington along the route of that year's Martin Luther King Jr. memorial march...

     along the route of a Martin Luther King Jr. memorial march in Spokane, Washington
    Spokane, Washington
    Spokane is a city located in the Northwestern United States in the state of Washington. It is the largest city of Spokane County of which it is also the county seat, and the metropolitan center of the Inland Northwest region...

    . The bomb, which was shaped
    Shaped charge
    A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...

    , was defused and there were no casualties.
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