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What is Evaporative Snow
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Incorporating Evaporative Snow
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In Your Production Design
Global Special Effects is a pioneer
of the “evaporative snow” process. In order to help you
incorporate “evaporative snow” in your production design, we are providing you the following
explanation as to exactly what it is and how a snow machine works.
The “snow flake”
starts as a clear fluid in a reservoir or bottle usually found at the back of the
machine. A small plastic feed tube takes the fluid from the reservoir to a small nylon sock at the
front of the machine by means of a pump. The sock is mounted to the front end of a high output
blower. The sock material is a very fine mesh weave and acts like hundreds of very tiny bubble
wands, producing clusters of bubbles appearing as “flakes”. The “flake” size varies according to the
speed of the pump, and the amount of fluid reaching the sock. More fluid results in more and larger
clusters of bubbles or “flakes”.
The “flake” size is the key
to making any evaporative snow truly evaporative and residue
free. Ideally you want to set the flake size so that the snow evaporates just as the snow hits the
ground. Imagine for a moment blowing a traditional soap and water bubble with a bubble wand.
The air pressure in the bubble is greater than the surrounding air pressure, and keeps the bubble
inflated, much like a latex balloon. As air currents keep it aloft, it will remain intact until enough
water evaporates from it’s surface, the thinned film can no longer maintain surface cohesion and
the bubble’s internal air pressure causes it to burst. Evaporative snow fluid contains an advanced
evaporative solution to make the “flakes” disintegrate more rapidly. The combination of air
pressure and solution mixture produces a very esthetically pleasing, moderate snow fall. While
you can certainly create a blizzard effect with these machines, additional safety precautions must
be considered, as the snow will build up on the floor or stage, resulting in a slippery surface.
Air flow and evaporative snow
in your production design. First, all snow machines produce a
“cone” of snow which is smallest near the machine and disperses as you get farther away creating a
“curtain effect” (see the Overhead View diagram next page). You can increase the overall effected
area through the use of judiciously placed fans, both near the machine and on the ground. Fans
near the machine (some larger machines have these incorporated into their design) will help disperse
the snow into a larger area. Fans on the ground will also help with dispersion, as well as provide
beautiful updrafts and swirls. Often these machines are used in ballrooms for holiday parties and
occasionally in arenas. The key to coverage in a larger venue (or when you want to make it snow on
the audience at a theatre) is not determined as much by the number of machines as it is by the air
handler’s circulation in the room itself. Air handlers in arenas and many modern ballroom facilities
are designed to re-circulate thousands of cubic feet of air per minute. Experiment with air handler’s
currents to circulate snow around the venue. Staggering the placement and alternating the direction
of the snow machines so that the edges of the air streams from the machines interact in opposing
directions is another technique for creating a swirling effect.
Back lighting and to some extent side lighting
is vital to the audience’s visual experience.
If lit from the front only, the effect’s visibility will be poor at best. Lighting can be especially
challenging in a ballroom or other “total environment” setting or venue, when your audience will be
viewing the snow from multiple angles and positions. Ideally you want your lighting to come from
above, yet below the snow machines. Obscuring the snow machines in the dark above the light
sources allows the snow to capture light, adding a sense of wonder to your event.
Noise reduction is another factor
to be considered in your production design. To a large
extent it can be covered with music. Global Special Effects engineers have developed the quietest snow
machines using better sound insulation, and quieter blowers such as the T-1600 Snow Machines series.
