19
SMOKE AND PYROTECHNIC EFFECTS

A very important ingredient in concerts (and television music award shows), especially with rock & roll and heavy metal bands, is some type of medium that allows the beams of colored light to be seen by the audience. This is especially important for air light or air graphics, or when moving luminaires are doing beam animation. The patterns created over and around the musicians would not be visible if we didn't have some means to accent the beams (Figure 19.1). Theatrical smoke or, more correctly, what appears to be smoke is actually not smoke created from combustible materials. Even though Rosco Laboratories received an Academy Award in the Scientific and Engineering category in 1984 “for the development of an improved nontoxic fluid for creating fog and smoke for motion picture production,” the Actor's Equity Association resisted its use on behalf of its member dancers and actors, who felt that the smoke was damaging to their lungs (see Chapter 9). The Entertainment Services and Technology Association (ESTA) also joined the standards discussion and produced a pamphlet in 1996 called “Introduction to Modern Atmospheric Effects.” New ANSI standards based on work by ESTA are currently under public review.

SMOKE

Technically classified as a pyrotechnic as related to fire and safety codes, smoke is used in many theatrical, theme park, and corporate shows, as well as rock & roll shows. The release of solid particles into the air is controlled by laws in many locations. Smoke is lighter than air and tends to be thick and billowy; therefore, air currents take the smoke wherever the wind or the hotter rising air wishes to go—not necessarily where you would like it to stay. Placement of smoke units can be a real science. Remember that buildings often do not turn the air conditioning or heating on until the audience is about to enter. In addition to doors opening and closing, even the heat from the lighting will influence where the smoke is carried. Most large hotels, convention rooms, and, in rare cases, arenas consider smoke to be a fire and safety issue, because fire alarms will be triggered when any smoke is sensed. The use of smoke has to be brought up during the advance survey site visit to make sure the alarms can be disengaged during programming sessions and performances. In many cases, a fire marshal will have to be present to inspect the machines and often is required to stay until the show ends, creating another show expense.

There is hardly another product area that has so much competition, so use the provider data provided later in Figure 19.7 and contact makers for more details. Most of the high-end units are DMX-512 controlled. A few units have fans built in. Some units are designed to be flown on the truss accompanied by a fan to disperse the smoke (Figure 19.2). There are small battery-powered units, as well as large models enclosed in road cases. Chapter 9 provides a more in-depth discussion of studies concerning smoke and haze.

HAZE

There is a definite difference between smoke and haze. Haze is designed to keep a fine mist, often based on water droplets or a nontoxic chemical, floating in the air, especially above the stage, to allow the light beams to be seen without obstructing the performer or video screens. The idea is to suspend these

particulates in the air for as long as possible. These units can also be DMX-512 controlled from the lighting console but are normally left to run for the entire production, unlike smoke. Reel EFX's DF-50 diffusion hazer (Figure 19.3) has been a leader in the field for many years and is widely used by touring lighting rental vendors. The fluid is used at a rate of less than 2 ounces an hour and produces a totally odorless haze that can only be detected visually. The system utilizes a triple-filtered system that breaks down the diffusion fluid (food-grade mineral oil blend) to

uniform 1-micron droplets or smaller. The unit is self-contained, requiring only the proper power rating and a sufficient amount of fluid. This unit, however, does use a chemical and has become the subject of discussion regarding the safety of haze (see Chapter 9).

Chauvet has a large touring unit called the Arena Hazer, which has a built-in fan (Figure 19.4) and is already in a road case for travel. Most, but not all, hazers use glycol, which is an alcohol; a few hazers use only water. The idea is to get the droplets to form either as a cloud (fog) or as a fine mist (haze) of fine, widely dispersed solid or liquid particles, which gives the air an opalescent appearance. How long these droplets stay in the air is the hang time.

FOG

Fog is described by weathermen as a “cloud that touches the ground.” Theatrical fog tries to imitate that effect by having a billowy white cloud stay close to the floor. For many years, theatres and tours relied on a modified 50-gallon drum that had a dryer hose sticking out of it. A basket was used to dip dry ice (CO₂) into a drum filled with hot water after the slab of dry ice was broken up with a hammer. A small

squirrel-cage fan was then turned on. This method presented a few problems. First, dry ice is expensive; second, it cannot be handled except with heavy gloves or the crewmen risk third-degree burns; third, as the water in the drum cools, it does not melt the dry ice as fast; fourth, well, you get the idea. It's a pain in the a--.

With all that going against it, you would think that great minds would have solved the problem quickly, but, no. There were attempts to take some of the dreaded dry ice and stick it in front of the chemical fog nozzle, cooling the fog to keep it near the floor. These were pretty feeble. Not until very recently have large fog units been adapted with cooling units. Antari has introduced the DNG-200 Low Fog Generator (Figure 19.5), which uses no dry ice but instead a heat exchanger and an air compressor to produce a large volume of ground-hugging low fog.

[Author's note: Almost all smoke, haze, and fog machines require the user to purchase a specific fluid to use in the manufacturer's machine. Do not use a fluid that is not specified for your unit. Read the labels carefully.]

Another approach that has proven effective uses only water. Interesting Products has marketed their liquid nitrogen fog machine (Figure 19.6) for years and has a proven track record of large output, reliability, and safety. This system is ideal for singers, as

it creates nothing but water—no chemicals, no fog fluids, no toxic odors. With dry ice, the vapor dissipates as the water becomes warmer; however, the nitrogen stays at the same temperature and pressure. It is good for very complicated uses, such as multiple positions from the same unit. The unit has not only DMX but also ACN and Remote Device Management (RDM) feedback signals. One cautionary note: Do not place personnel in an enclosed area with nitrogen fog without access to air.

See Figure 19.7 for a list of smoke, haze, and fog manufacturers.

FANS

Most of the effects created by fog, hazers, and CO₂ or LN₂ require a little assist to direct the effect to the

desired position on the stage. Some units have builtin fans, but most require assistance. Several fans designed specifically for the theatrical market have DMX control. Reel EFX's RE-Fan II Turbo (Figure 19.8) is one example of such a unit. Whatever you use, always be aware of smoke detectors and alarms, especially in hotel ballrooms. They can be set off by any of the smoke-, haze-, or fog-producing agents. Second, even though all are said to be nontoxic, they all carry warnings that irritation to eyes and lungs can occur in sensitive persons. Be sure to check with the artist before using these methods to generate smoke, haze, or fog. As stated before, in many states and municipalities, they are considered pyrotechnic devices, and you will be required to obtain a permit. See Figure 19.9 for a list of fan manufacturers.

PYROTECHNICS

There is not much to add to what has been stated in Chapters 2, 8, and 9. This is a highly specialized area of expertise that requires special training and in many cases a license. Do not think that fireworks that you can buy on the street are usable on the stage. Even smoke bombs or other devices that only produce smoke are not acceptable. The all require ignition and are therefore a pyrotechnic. Do not take the chance that the band Great White did. It simply is not worth it.