Spare No Expense
If cost is no issue and you're looking for an extraordinary effect, check out liquid nitrogen foggers.
Even by casino standards, the Crown Casino in Melbourne, Australia, is pretty spectacular. With two state-of-the-art theatrical venues, over 30 bars and restaurants and, of course, the obligatory forest of gaming tables and slot machines, the Crown is a wildly popular destination for thrillseekers of every stripe. If you are a theatrical technophile, however, the real show is in the atrium, where a massive fountain, designed by Wet Design of Sun Valley, California, spills out an hourly display of bubbly, boiling whitewater. What sets this fountain apart from other dancing water spectacles is two Dry Fogger Mammoth liquid nitrogen foggers buried in the car park below, provided by one of the more interesting companies you are likely to encounter, the appropriately named Interesting Products of Chicago.
"Liquid nitrogen effects are not just like water, they are water," says Larry Schoeneman, president of Interesting Products (www.interestingproducts.com). "The great thing is, they don't leave any moisture behind." Once the moisture in the fog is no longer exposed to the cooling effect of the liquid nitrogen, it quickly gets reabsorbed by the air and disappears. Anyone familiar with the trademark puddle left behind by ordinary dry-ice foggers will appreciate being able to fill a stage with low lying fog without creating slip hazards for performers. The European tour of Riverdance, for example, carried two Dry Fogger Mammoths to avoid upending any of those reeling feet.
In addition to leaving no moisture behind, thus creating no safety hazards or water damage, liquid nitrogen (generally known by the moniker "LN2") has two other main advantages over more traditional dry-ice or glycol-based fog machines: the fog sits close to the ground and dissipates quickly, making it easier to control; as well as being odorless, nontoxic and non-staining.
Liquid nitrogen systems fall into two basic categories. In the first type of system, the atmospheric effect is created inside a closed tank. The resulting fog is then pumped out to where it is needed. This creates a rolling, billowing fog that hugs the ground. (If you have ever seen a film where the lead character appears in heaven, wading through a waist-high cloud of angelic fog, you were probably looking at an LN2 effect.) While the machine itself creates a low level of noise, it can be placed away from the stage, making this effect essentially silent.
The second kind of effect, the so-called "burst" effect, is created in the open air, where a nozzle sprays out LN2 through the air, producing a white blast of fog that can be directed straight up, like a geyser. This type of effect creates a rather loud hissing sound, restricting it to environments with a high noise level, like rock concerts or theme park shows. Burst effects are more dependent on the local humidity and work best in areas that are hot and humid.
Liquid nitrogen effects work by creating a miniature weather system and manipulating temperature, humidity and something known as the dew point. The atmosphere's ability to hold humidity increases with temperature. When the atmosphere reaches total saturation (100% humidity) at a particular temperature, it has reached the "dew point." Any rapid increase in water being forced into the air or decrease in temperature will force the extra water to be condensed into tiny droplets of water--or fog. When the temperature of a water-saturated atmosphere drops, a fog of water vapor appears. San Francisco's trademark fog banks are created when warm air comes into contact with cold water welling up from the ocean depths just outside the Golden Gate Bridge. As the air cools, the extra humidity has nowhere to go and out come those famous Sam Spade fog banks.
Likewise, when a burst of very cold liquid nitrogen is fired into warm, humid air, whether inside a contained tank or out in the open, it suddenly and drastically chills the air, dropping it below dew point, releasing the water and creating a billowing fog. The effect is more pronounced if the air is preheated and preloaded with water, which is why most liquid nitrogen effect machines contain large boilers, which produce steam. By firing the nitrogen into the steam, the dew point changes drastically and instantly. Result: a fog bank worthy of George Sterling's "cool, grey city of love."
All this romantic fogmaking doesn't come easy, or cheap. Liquid nitrogen is difficult to handle because of its extremely low temperature (about 320 degrees below zero Fahrenheit) and must be delivered in specially designed 180-liter or 240-liter vacuum bottles, known as "dewars." For large-scale, permanent applications, bulk storage tanks are installed and refilled from insulated tank trucks. Nitrogen itself is not toxic--70 percent of our atmosphere is made of it--but it can cause problems in high concentrations, because it dilutes the oxygen that we need to survive. Care must be taken when designing LN2 effects that the fog is not allowed to pool in a low-lying area, such as a pit, where it would lower the oxygen concentration and make it difficult for a performer to breathe. In these extreme situations, oxygen deprivation could lead to lightheadedness or loss of consciousness. While this situation is extreme and avoidable, care must be taken when designing the effect. Many large-scale LN2 systems contain oxygen-monitoring sensors to alert technicians if the percentage of breathable oxygen dips below the OSHA requirement of 19.5 percent.
So, how much does all this cost? It is difficult to put a price tag on LN2 systems because they are so often custom built, but be prepared for that second mortgage. The Dry Fogger Mammoth from Interesting Products (currently seen in Cirque du Soleil's KÀ at the MGM Grand in Las Vegas or La Nouba in Orlando) lists at around $32,000, which doesn't include the facility plumbing or storage tank, let alone the liquid nitrogen itself, which pumps through the machine at two gallons a minute. Of course, for some people, the cost is worth it: KÀ has four of them.
Liquid nitrogen sits atop the list of low-lying fog effects in scale, beauty, safety and, unfortunately, cost. But if you've got that rich uncle, and you want the queen of fog effects, there is nothing like it.
By: Campbell, Drew, Stage Directions, Sep2006
Even by casino standards, the Crown Casino in Melbourne, Australia, is pretty spectacular. With two state-of-the-art theatrical venues, over 30 bars and restaurants and, of course, the obligatory forest of gaming tables and slot machines, the Crown is a wildly popular destination for thrillseekers of every stripe. If you are a theatrical technophile, however, the real show is in the atrium, where a massive fountain, designed by Wet Design of Sun Valley, California, spills out an hourly display of bubbly, boiling whitewater. What sets this fountain apart from other dancing water spectacles is two Dry Fogger Mammoth liquid nitrogen foggers buried in the car park below, provided by one of the more interesting companies you are likely to encounter, the appropriately named Interesting Products of Chicago.
"Liquid nitrogen effects are not just like water, they are water," says Larry Schoeneman, president of Interesting Products (www.interestingproducts.com). "The great thing is, they don't leave any moisture behind." Once the moisture in the fog is no longer exposed to the cooling effect of the liquid nitrogen, it quickly gets reabsorbed by the air and disappears. Anyone familiar with the trademark puddle left behind by ordinary dry-ice foggers will appreciate being able to fill a stage with low lying fog without creating slip hazards for performers. The European tour of Riverdance, for example, carried two Dry Fogger Mammoths to avoid upending any of those reeling feet.
In addition to leaving no moisture behind, thus creating no safety hazards or water damage, liquid nitrogen (generally known by the moniker "LN2") has two other main advantages over more traditional dry-ice or glycol-based fog machines: the fog sits close to the ground and dissipates quickly, making it easier to control; as well as being odorless, nontoxic and non-staining.
Liquid nitrogen systems fall into two basic categories. In the first type of system, the atmospheric effect is created inside a closed tank. The resulting fog is then pumped out to where it is needed. This creates a rolling, billowing fog that hugs the ground. (If you have ever seen a film where the lead character appears in heaven, wading through a waist-high cloud of angelic fog, you were probably looking at an LN2 effect.) While the machine itself creates a low level of noise, it can be placed away from the stage, making this effect essentially silent.
The second kind of effect, the so-called "burst" effect, is created in the open air, where a nozzle sprays out LN2 through the air, producing a white blast of fog that can be directed straight up, like a geyser. This type of effect creates a rather loud hissing sound, restricting it to environments with a high noise level, like rock concerts or theme park shows. Burst effects are more dependent on the local humidity and work best in areas that are hot and humid.
Liquid nitrogen effects work by creating a miniature weather system and manipulating temperature, humidity and something known as the dew point. The atmosphere's ability to hold humidity increases with temperature. When the atmosphere reaches total saturation (100% humidity) at a particular temperature, it has reached the "dew point." Any rapid increase in water being forced into the air or decrease in temperature will force the extra water to be condensed into tiny droplets of water--or fog. When the temperature of a water-saturated atmosphere drops, a fog of water vapor appears. San Francisco's trademark fog banks are created when warm air comes into contact with cold water welling up from the ocean depths just outside the Golden Gate Bridge. As the air cools, the extra humidity has nowhere to go and out come those famous Sam Spade fog banks.
Likewise, when a burst of very cold liquid nitrogen is fired into warm, humid air, whether inside a contained tank or out in the open, it suddenly and drastically chills the air, dropping it below dew point, releasing the water and creating a billowing fog. The effect is more pronounced if the air is preheated and preloaded with water, which is why most liquid nitrogen effect machines contain large boilers, which produce steam. By firing the nitrogen into the steam, the dew point changes drastically and instantly. Result: a fog bank worthy of George Sterling's "cool, grey city of love."
All this romantic fogmaking doesn't come easy, or cheap. Liquid nitrogen is difficult to handle because of its extremely low temperature (about 320 degrees below zero Fahrenheit) and must be delivered in specially designed 180-liter or 240-liter vacuum bottles, known as "dewars." For large-scale, permanent applications, bulk storage tanks are installed and refilled from insulated tank trucks. Nitrogen itself is not toxic--70 percent of our atmosphere is made of it--but it can cause problems in high concentrations, because it dilutes the oxygen that we need to survive. Care must be taken when designing LN2 effects that the fog is not allowed to pool in a low-lying area, such as a pit, where it would lower the oxygen concentration and make it difficult for a performer to breathe. In these extreme situations, oxygen deprivation could lead to lightheadedness or loss of consciousness. While this situation is extreme and avoidable, care must be taken when designing the effect. Many large-scale LN2 systems contain oxygen-monitoring sensors to alert technicians if the percentage of breathable oxygen dips below the OSHA requirement of 19.5 percent.
So, how much does all this cost? It is difficult to put a price tag on LN2 systems because they are so often custom built, but be prepared for that second mortgage. The Dry Fogger Mammoth from Interesting Products (currently seen in Cirque du Soleil's KÀ at the MGM Grand in Las Vegas or La Nouba in Orlando) lists at around $32,000, which doesn't include the facility plumbing or storage tank, let alone the liquid nitrogen itself, which pumps through the machine at two gallons a minute. Of course, for some people, the cost is worth it: KÀ has four of them.
Liquid nitrogen sits atop the list of low-lying fog effects in scale, beauty, safety and, unfortunately, cost. But if you've got that rich uncle, and you want the queen of fog effects, there is nothing like it.
By: Campbell, Drew, Stage Directions, Sep2006
posted by James at 8:46 PM
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