Haze machines, or haze generators (commonly referred to as hazers), are effects machines similar to

fog machine A fog machine, fog generator, or smoke machine is a device that emits a dense vapor that appears similar to fog or smoke. This artificial fog is most commonly used in professional entertainment applications, but smaller, more affordable fog mac ...

s, designed to produce an unobtrusive,

homogeneous Homogeneity and heterogeneity are concepts relating to the uniformity of a substance, process or image. A homogeneous feature is uniform in composition or character (i.e., color, shape, size, weight, height, distribution, texture, language, i ...

clouds suspended in the air intended primarily to make

light beam A light beam or beam of light is a directional projection of light energy radiating from a light source. Sunlight forms a light beam (a sunbeam) when filtered through media such as clouds, foliage, or windows. To artificially produce a li ...

s visible or create a subtle diffusion.

Properties

Unlike theatrical fog, which is typically intended to be dense and/or opaque, haze is generally very light and subtle. These properties allow a venue to be filled with haze prior to or during an event without creating an overtly distracting cloud. Haze typically has a substantially longer persistence ("hang time") than conventional theatrical fog. While conventional fog will hang in the air for several minutes, a haze effect filling the same volume of space can last upwards of an hour to several hours or more, depending on the size of the venue and the amount of

ventilation Ventilation may refer to: * Ventilation (physiology), the movement of air between the environment and the lungs via inhalation and exhalation ** Mechanical ventilation, in medicine, using artificial methods to assist breathing *** Respirator, a ma ...

. The fluid used in haze machines to generate the effects are either oil or water-based. Most oil-based haze fluids use a

mineral oil Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral source, particularly a distillate of petroleum, as distinct from usually edible vegetable oils. The name 'mineral oil' by itself is imprecise, ...

base, while water-based fluids use either a

propylene glycol Propylene glycol ( IUPAC name: propane-1,2-diol) is a viscous, colorless liquid. It is almost odorless and has a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH. As it contains two alcohol groups, it is classified as a diol. An al ...

glycerol Glycerol () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...

base. Although both formulations of fluid are referred to as haze fluid, the different formulations are neither compatible nor interchangeable. Propylene glycol/water haze fluid is sometimes referred to as "water based haze" to avoid ambiguity. Describing the fluid as "glycol" might cause stagehands to use automotive antifreeze, which contains ethylene glycol, and unlike propylene glycol, must not be used for this purpose because of its

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacteria, bacterium, or plant, as well as the effect o ...

Technology

Crackers

Crackers (also known as "oil crackers") were first developed in the 1960s. The fluid is usually, though not always, refined mineral oil. Crackers work by use of a spray pump powered either by electricity or compressed CO₂ passing through a dispersion head into a fluid reservoir. The compressed air

aerosol An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be generated from natural or Human impact on the environment, human causes. The term ''aerosol'' co ...

s the fluid, dispersing fine droplets. Because the haze is mechanically generated, this type of machine does not require any warm up time.

Pump spray

Pump spray haze machines use electricity or compressed CO₂ to power a spray pump connected to a mixing valve, which draws in and atomizes the fluid. Pump hazers also includes machines which function in the same manner as a

, pumping fluid into a heated chamber where it is vapourized to produce a cloud. Hazers which heat fluid to create an atmospheric effect only use mixtures of water and glycol or glycerine. Spray hazers which atomize fluid can use either a water-based or mineral oil fluid.

Aerosol

Smaller volumes of haze can also be generated from aerosol canisters containing mineral oil under pressure. Although to the density of haze generated and the volume of space that can be filled is significantly smaller than that of a haze machine, aerosol canisters have the advantages of portability, no requirements for electricity and finer control over the volume of haze generated.

Ultrasonic

Ultrasonic haze machines use

transducer A transducer is a device that Energy transformation, converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another. Transducers are often employed at the boundaries of automation, M ...

s submerged in a reservoir of fluid to create atmospheric effects. Although less common than some of the other technologies used to produce haze, ultrasonic hazers are promoted as generating their effects with much less noise than other technologies.

Faze machines

Faze machines, or fazers, can also be used to produce a haze-like effect. These machines are typically fog machines with a fan built in front to disperse the output, creating a haze-like effect. These machines are typically considered more cost effective, with prices ranging from as compared to haze machines with prices ranging from .

Fire detection

Although the atmospheric effect created by hazers produces a significantly smaller particle size, around one micrometre (um), compared to the effect generated by a fog machine (hence the finer composition of the "cloud"), the size of particle and effect varies by manufactures and type of fluid used. Because of this, haze is far less likely to set off fire alarms than fog machines or larger smoke particles.

References

*Entertainment Services & Technology Association (2005). ''Introduction to Modern Atmospheric Effects, 4th Edition.'', The ESTA Foundation. *Learn Stage Lighting (2013). "Hazers - Oil or Water Based?"
LearnStageLighting.com Oil Or Water Based
{{DEFAULTSORT:Haze Machine Stagecraft Special effects