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Pyrotechnics
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Pyrotechnics is the science of materials capable of undergoing self-contained and self-sustained exothermic chemical reactions for the production of heat, light, gas, smoke and/or sound. Pyrotechnics include not only the manufacture of fireworks but items such as safety matches, oxygen candles, explosive bolts and fasteners, and components of the automotive airbag.
Pyrotechnic devices combine high reliability with very compact and efficient energy storage, in the form chemical energy which is converted to expanding hot gases either through deflagration or detonation.
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Pyrotechnics is the science of materials capable of undergoing self-contained and self-sustained exothermic chemical reactions for the production of heat, light, gas, smoke and/or sound. Pyrotechnics include not only the manufacture of fireworks but items such as safety matches, oxygen candles, explosive bolts and fasteners, and components of the automotive airbag.
Pyrotechnic devices combine high reliability with very compact and efficient energy storage, in the form chemical energy which is converted to expanding hot gases either through deflagration or detonation. The controlled action of a pyrotechnic device (initiated by any of several means, including an electrical signal, optical signal or mechanical impetus) makes possible a wide range of automated and/or remote mechanical actions; for example, deployment of safety equipment and services, precisely timed release sequences, etc. The majority of the technical pyrotechnic devices use propellants in their function, a minority use materials that are classified as primary or secondary explosives to obtain very fast and powerful mechanical (mostly cutting) actions; for example cable cutters or exploding bolts.
Individuals responsible for the safe storage, handling, and functioning of pyrotechnic devices are referred to as pyrotechnicians.
Pyrotechnic Effects
Explosions, flashes, smoke, flames, fireworks or other propellant driven effects used in the entertainment industry are referred to as pyrotechnic special effects, theatrical effects, or proximate pyrotechnics. Proximate refers to the pyrotechnic device's location relative to an audience. In the majority of jurisdictions, special training and licencing must be obtained from local authorities to legally prepare and use proximate pyrotechnics.
Many musical groups use pyrotechnics to enhance their live shows. Some of the earliest bands to use pyrotechnics were Queen, Pink Floyd, and KISS. The band Rammstein uses a large variety of pyrotechnics, from flaming costumes to face-mounted flamethrowers. Also Nightwish and Lordi are known for their vivid pyrotechnics. Many professional wrestlers have also used pyrotechnics as part of their entrances to the ring. One example would be Bill Goldberg, who used pyrotechnics during his in ring entrance in both World Championship Wrestling (WCW) and World Wrestling Entertainment (WWE).
Modern pyrotechnics are, in general, divided into categories based upon the type of effect produced or manufacturing method. The most common categories are:
- Airburst - Hanging charges designed to burst into spheres of sparks.
- Binary kits - Powders divided into oxidizer and fuel intended to be mixed before use.
- Comets (meteor) - Rising shots resembling shooting stars.
- Preloaded Comet
- Preloaded Mine - Tubes containing a lift charge intended to project stars, sparks, confetti or streamers.
- Preloaded Smoke Pot - Cartridges designed to release a mushroom cloud of smoke.
- Preloaded Report (concussion tube) - Tubes designed to create a loud report.
- Falls - Devices intended to drop like falling stars.
- Fireballs / Mortar Hits - Containers creating mushroom clouds of flame.
- Flame Projector - Columns shooting pillars of flame.
- Flare (Torch) - Short, high intensity flames or various colours.
- Flash Cotton (Sparkle String) - Cotton string impregnated with nitrocellulose.
- Flashpaper - Sheets of nitrocellulose resembling tissue paper.
- Flash Pot - A container for creating a bright flash and smoke.
- Flash Tray (split mine) - A long tube creating a wide, bright flash.
- Gerb (including fountain, whistle, and waterfall) - A fountain of sparks.
- Lance - A small brightly coloured fountain that produces few sparks.
- Line Rockets - Whistling gerbs travelling across wires.
- Multi-Tube Article (multi-shot plate, multiple shot repeater boards and bombardo boards; designed to function in sequence) - Multiple effects chained together.
- Pre-Mixed Powder - Powders intended to create various effects. (Concussions, flashes, etc.)
- Squib - A small, pre-matched device typically used to replicate bullet hits.
- Strobe - A device intended to create bright repetitive flashes.
- Wheel (Saxon) - Tubes that create a spinning wheel of sparks.
A basic theatrical effect, designed to create a jet or fountain of sparks, is referred to as a gerb. A gerb consists of a sufficiently strong and non-flammable container to hold the pyrotechnic compound. Typical pyrotechnic formulations consist either of flammable materials such as nitrocellulose and/or blackpowder or a mixture of a fuel and oxidizer blended in situ. A plug placed at one end of the container with a small orifice, called a choke, constricts the expulsion of the ignited pyrotechnic compound, increasing the size and aggressiveness of the jet.
Various ingredients may be added to pyrotechnic devices to provide colour, smoke, noise or sparks. Special additives and construction methods are used to modify the character of the effect produced, either to enhance or subdue the effect; for example, sandwiching layers of pyrotechnic compounds containing potassium perchlorate, sodium salicylate or sodium benzoate with layers that do not creates a fountain of sparks with an undulating whistle.
In general, such pyrotechnic devices are initiated by a remotely controlled electrical signal that causes an electric match, or e-match, to produce ignition. The remote control may be manual, via a switch console, or computer controlled according to a pre-programmed sequence and/or a sequence that tracks the live performance via stage cues.
Display Pyrotechnics
Display pyrotechnics, also known as commercial fireworks, are pyrotechnic devices intended for use outdoors, where the audience can be further away, and smoke and fallout is less of a concern. Generally the effects, though often similar to proximate pyrotechnics, are of a larger size and more vigorous in nature. It will typically take an entire day to setup a professional fireworks display. The size of these fireworks can range from 50mm (2") to over 600mm (24") diameter depending on the type of effect and available distance from the audience. In most jurisdictions, special fireworks training and licensing must be obtained from local authorities to legally prepare and use display pyrotechnics.
Consumer Pyrotechnics
Consumer pyrotechnics are devices readily available for purchase to the general public without special licensing or training. These items are considered relatively low hazard devices but, like all pyrotechnics, can still be hazardous and should be stored, handled and used appropriately. Some of the most common examples of consumer pyrotechnics encountered include recreational fireworks, model rocket motors, highway flares, sparklers and caps for toy guns. Pyrotechnics are also indirectly involved in other consumer products such as powder actuated nail guns, ammunition for firearms, and modern fireplaces
Fountains & Gerbs that whistles ,sparks, toy type novelties, Marine Distress flares,
12gauge Bird Bangers , Shell Crackers , Whistle Crackers must be fired from a 12 gauge pistols .rifles
,12gauge Flare Launchers
Safety
Pyrotechnics are dangerous and must be handled and used properly. Recently, several high profile incidents involving pyrotechnics have re-enforced the need to respect these explosives at all times. Proximate pyrotechnics is an area of expertise that requires additional training beyond that of other professional pyrotechnics areas and the use of devices specifically manufactured for indoor, close proximity use.
In 2003, improper use of pyrotechnics caused a fire in a Rhode Island nightclub called The Station. The Station nightclub fire was started when the fireworks the band Great White were using accidentally ignited flammable soundproofing foam. The pyrotechnics in question were not appropriate. The foam caused combustion to spread rapidly and the resulting fire led to 100 deaths, ostensibly because their quick escape was blocked by ineffective exit doors. While the type of foam used and the lack of a sprinkler system were important factors in the fire, the Great White fire could have been prevented had those involved paid even minimal attention to standard safety practices around the use of pyrotechnics.
A similar pyrotechnic-induced fire in 2004 destroyed the Republica Cromagnon nightclub in Buenos Aires, Argentina, killing 194 people.
Homemade Devices
A common low-budget pyrotechnic flash pot is built using modified screw-in electric fuses in a common light fixture. Such homemade flash pots and similar devices should not be used.
Homemade devices commonly fail to include the appropriate safety features and can provide numerous hazards, including:
- The firing circuit using direct unisolated AC line voltage, which is a shock hazard to the operator and bystanders.
- The use of high amperage fuses as ignitors can cause large main circuit breakers and building-wide and street level fuses to trip, due to the sudden inrush of hundreds of amps through a dead-shorted circuit
- With a home-made device, there is usually no indication of whether the source is powered. Screwing a powder-loaded fuse into an unknowingly powered socket will result in immediate ignition of the pyrotechnics, injuring the operator.
Proper commercial flash pots include safety features such as warning pilot lamps, preignition grounding, and safing circuits. They also use isolated and low-voltage power sources, and have keyed power connections to help prevent accidental ignition.
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