300px, A basic pyrotechnic device
A gerb is a type of
firework
Fireworks are Explosive, low explosive Pyrotechnics, pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large numbe ...
which produces a jet of
sparks, usually lasting between 15 and 60 seconds. It is a thick-walled tube filled with
pyrotechnic
Pyrotechnics is the science and craft of creating fireworks, but also includes safety matches, oxygen candles, explosive bolts (and other fasteners), parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demol ...
composition and possessing a choke, which is a narrowing in the tube. Gerbs are often referred to as 'fountains'.
Operation
Gerbs in operation
Sometimes a small charge of
black powder
Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...
is added to the bottom of a gerb to make it finish with a bang: this charge is known as the 'bounce'. These are commonly used at sporting events.
Gerbs intended for use indoors near a proximate audience, such as at a rock concert, typically have shorter durations (from to 30 seconds) and heights (4 to 50 feet).
Gerbs are usually measured in terms of time and height. For example, a 4×4 burns for 4 seconds at a height of 4 feet.
History
Eric Newby's book ''
The Last Grain Race'' (chapter two: "Mountstewart") contains a 1938 reference to what appears to be the original gerb — in effect a mortar bomb fired from a mortar.
Hazards
Causes of the 2003
The Station nightclub fire
A fire occurred on the evening of February 20, 2003, at The Station, a nightclub and music venue in West Warwick, Rhode Island, United States, killing 100 people and injuring 230. During a concert by the rock band Jack Russell's Great White, an ...
in West Warwick, Rhode Island involved the use of gerbs,
as did a 2015 fire in the Colectiv nightclub in Bucharest, Romania.
References
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category:types of fireworks