Firework

Fireworks are classified as low explosive devices and form a distinct variety of pyrotechnics, whose definition also generally includes devices for military and industrial use. Fireworks are used primarily for aesthetic and entertainment purposes. An event of firework display is called fireworks or fireworks event.

Fireworks (devices) take many forms to produce the four primary effects: noise, light, smoke, and floating materials (confetti for example). They may be designed to burn with colored flames and sparks. Displays are common throughout the world and are the focal point of many different cultural and religious celebrations.

Fireworks are generally classified as to where they perform, either as a ground or aerial firework. In the latter case they may provide their own propulsion (skyrocket) or be shot into the air by a mortar (aerial shell).

The most common feature of fireworks is a paper or pasteboard tube or casing filled with the combustible material, often pyrotechnic stars. A number of these tubes or cases are often combined so as to make, when kindled, a great variety of sparkling shapes, often variously coloured. The skyrocket is a common form of firework, however, the first skyrockets were used in war. The aerial shell is the backbone of today's commercial aerial display, a smaller version for consumer use is known as the festival ball in the United States. Such rocket technology has also been used for the delivery of mail by rocket.

Improper use of fireworks may be dangerous, both to the person operating them (risks of burns and wounds) and to bystanders; in addition, they may start a fire if landing on flammable material. For this reason, the use of fireworks is generally legally restricted. In the United States, fireworks are classified as either consumer or display fireworks based upon the amount of pyrotechnic composition an item contains. Display fireworks are restricted by law for use by professionals. Consumer items are available to the public and are smaller versions containing limited amounts of material to reduce potential dangers.

Fireworks classifications in the United States

The United States government has classified fireworks and similar devices according to their potential hazards.

Old explosives classes

Fireworks and other potentially explosive materials were formerly classified into three types by federal law, Class A, Class B, and Class C.

Class A

These are usually high explosives, such as dynamite.

Class B

These are display fireworks, usually used at large events. They are generally more powerful than consumer fireworks, and usually require a license to use.

Class C

Class C fireworks are "common fireworks", or consumer fireworks. This includes sparklers, fountains, and other fireworks available at stands. These are permitted by federal law.

New explosives classes

The U.S. government now uses the UN explosives classification system. Two are used for fireworks.

Code 1.3G

These are professional display fireworks (equivalent of Class B), and require a license.

Code 1.4G

These are consumer fireworks, available for purchase under federal law. It is the equivalent of Class C.

Code 1.4S

These are very mild devices, and are usually referred to as "novelties" instead of "fireworks". These include "party poppers" and noise-makers, and can be used indoors safely.

See the fireworks article for the history of these devices and their usage.

Common pyrotechnic compounds

The different colors seen in fireworks are usually known as 'stars'. They consist of four basic ingredients; fuel, oxygen-producing chemicals, color-producing chemicals, and a binder that will hold all of this together to form pellets. Chlorine compounds are used to intensify or brighten colors. Common chemicals that produce different colors are:

Red

Strontium and lithium compounds are used to produce a red color. Li₂CO₃ (lithium carbonate) produces red of medium brightness, while SrCO₃ (strontium carbonate) produces bright red.

Orange

Calcium compounds, such as CaCl₂ (calcium chloride), create orange bursts.

Yellow

Sodium compounds, such as NaNO₃ (sodium nitrate) are used to create yellow.

Green

Barium compounds, containing BaCl+ (barium chloride ions) is used to produce bright green colors.

Blue

Blue is produced by copper compounds, most notably CuCl (copper chloride) at a low temperature. It is the hardest color to produce.

Purple

Purple can be produced by a combination of strontium (red) and copper (blue) compounds; rubidium compounds may also be used.

Gold

Gold sparks are produced by charcoal, iron, or lampblack.

Silver and white

Powders of titanium, aluminum, and magnesium (and some alloys thereof) create silver and white flashes.

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