- Fog machine
A fog machine (also called a smoke machine) is a device which emits a dense vapor that appears similar to
fog orsmoke . This artificial fog or smoke is known astheatrical smoke and fog within the entertainment industry. Most fog machines create the fog by either vaporizing awater andglycol -based orglycerine -based fluid or a mineral-oil-based fog via atomization. For glycol-based fogs, the fluid ("fog juice") is injected into a heated block, and evaporates quickly. The resulting pressure forces the vapor out of the exit. Upon coming into contact with cool outside air the vapor forms a fog.Some fog machines use
dry ice to produce a fog ofcarbon dioxide .Uses of fog machines
* Fog machines are used to create spooky effects in plays such as "
Dracula ", "A Christmas Carol ", and "Macbeth ". Fog machines are also frequently used inHalloween displays such ashaunted house s or forests. Because of greater availability and reductions in prices between 2003 and 2005Fact|date=February 2007, fog machines have become widely used for domestichalloween decorations.* Fog machines are also useful for industrial purposes, such as visualising the flow of air, such as over a surface in a
wind tunnel or testing filters in air conditioning. Fire fighters also use fog machines in their training.* Because of the reflective and refractive qualities of the smoke created by fog machines, they are often used in
nightclub s to enhance the effects of lighting andlaser arrangements (see alsolight beam ).*
Haze machine s, (also called haze generators or hazers), are taking over the job of fog generators for highlighting lighting orlaser effects. Haze machines are often seen with bands and bigger venues when a lighting effect may need to be visible in the air. Haze machines use the same fluids to create fogs and were included on studies of health effects from exposure to theatrical smoke and fog.Adverse effects on respiratory health
Although often believed to be safe to breathe, exposure to mineral oil, glycol and glycerin-based theatrical fogs produced from fog or haze machines have been associated with adverse short and long-term effects on respiratory health in exposed performers and crew members, especially those with respiratory problems (such as asthma). One should therefore avoid breathing generated smoke or fog. [cite journal | author = Sunil Varughese, Kay Teschke, Michael Brauer, Yat Chow, Chris van Netten, and Susan M. Kennedy | title = Effects of theatrical smokes and fogs on respiratory health in the entertainment industry | journal = American Journal of Industrial Medicine | volume = 47 | issue = 5 | pages = 411–418 | publisher = Wiley InterScience | date= 2005 | doi = 10.1002/ajim.20151] It is safer to add smoke effects digitally in postproduction of films than to use theatrical smokes on set. Glycol-based fog is associated with headaches, dizziness, drowsiness and tiredness in those exposed. These results would be expected given that glycols share some chemical similarities to alcohols and given the small size of fog particles making it easy for them to enter the bloodstream. Symptoms of wheezing and chest tightness were associated with longterm exposure to theatrical smoke and fogs.
ee also
*
Dry ice , occasionally used for creating theatrical “smoke”.References
External links
* [http://www.rosco.com/us/technotes/fog/how_mach_work.asp Rosco U.S. - How Fog Machines Work]
* [http://www.chicagoartistsresource.org/?q=node/15352 Article on Respiratory Problems from Glycol-based fogs used in Broadway performances]
* [http://www.actorsequity.org/docs/safesan/finalreport.pdf Actor's Equity Study on Health Effects from the use of Theatrical Smokes and Fogs in Broadway performances]
* [http://www.ukslc.org/Technical_Articles/Maintenance/Cleaning_A_Smoke_Machine.html Uk Sound And Lighting Community - Cleaning A Smoke Machine]
* [http://www.fogmachineinfo.com Information about modern commercial fog machines and tips about how to use them effectively]
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