Supplement Feature - February 2010
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Serve & Protect

Aquatic Safety & Staffing

By Richard Zowie


Gas Phase Filtration and Indoor Pools

Many no doubt wonder what 2010 holds in store for aquatic safety. It's about looking at the problems pools have and search for ways to improve them.

One particular problem is how to improve indoor air quality. As people swim in a pool, jump into the water and splash around, the activity results in chloramines mixing into the air.

"The more splashing and more water features, the more atomization you have," said Mark Benard of a manufacturer that helps pools improve air quality. "Then, the more chloramines will be rapidly expelled into the air. Particularly in facilities like waterparks with tons of spray features and with kids running up to water and water slides. There's a lot of sweating. It's a real soup."

Chloramines develop when chlorine molecules become locked up with ammonia. Chloramine compounds are less effective at killing germs or viruses than regular chlorine compounds. Also, chloramines can emit a strong chlorine odor at pools.

Airborne chloramines, if they accumulate, can then burn the eyes and cause breathing problems. One recent example was the 2007 U.S. Swimming Championships in Indianapolis, where competition momentarily stopped due to swimmers being unable to breathe due to the poor HVAC processing of chloramines. This condition even has its own name—"Lifeguard Lung."

"In the 1970s, when indoor pools were first produced, there was no concern regarding energy," said Benard. "Then they started having energy concerns and noticed people started eventually getting sick from indoor pools. They'd cough and have irritation in their lungs and eyes. With a little research they found the sanitizing agent in pool—the chlorine—combined with ammonia and that along with sweat, natural body oils and diarrhea, this would result in chloramines. They found that it rests on the water's surface."

To combat this problem, Splash Universe is using a gas-phase air purification system—the first known use of such a system—in a waterpark along with dehumidification and proper air distribution.

When Splash Universe built 25,000-square-foot indoor waterparks in Dundee, Mich., and Shipshewana, Ind.,

it designed an HVAC system that would use the gas-phase air purification application to eliminate chloramines.

The gas-phase technology, first introduced in 2007, is actually a few decades old and has been used to eliminate gas contaminants when making paper or pulp, managing waste water and in other heavy industries.

Normally, chloramines as gaseous contaminants can easily pass through HVAC media filters. With the gas-phase filter technology, the chloramines are absorbed and eliminated from the air stream; the indoor pool air is then re-circulated through the HVAC system.

"With gas-phase filtration, they can capture chloramines since there's no other way to remove them," Benard explained. "You can't dilute them. The only way to capture them is chemically."

Splash Universe also supplements gas-phase filtration with ultraviolet radiation. This allows the facilities to consume less chlorine. Also, dehumidifiers remove excessive moisture, further helping gas-phase filtration do the job of preventing the build-up of chloramines.

While ultraviolet helps to reduce the amount of chloramines by sanitizing water, secondary sanitizers like chlorine are still needed.

"And if you're using chlorine you're still producing chloramines," Benard said. "The chemical media is very efficient. The real advantage of it is if you're not producing any chloramines for certain period of time, the media doesn't get consumed. It only starts to react when there's a demand for it. When you go through a period of time when nobody's swimming in the pool, media doesn't get consumed."

How often the filters get changed depends on how often they're used.

Proper ductwork is vital for sweeping all the chloramines off the pool water surface, and if the dehumidifiers don't have proper ductwork, there are pockets where chloramines can settle.

Instead of using metal ducts for air distribution in its facilities, Splash Universe uses fabric ducts. Unlike metal, fabric is cheaper to install, easier to hang across the ceiling above the pool and doesn't corrode.

Benard described the tube of fabric is one where holes are strategically punched in the side.

"Instead of a metal duct with a specific diffuser location, they can punch a multitude of holes to fine-tune where you want to distribute the air out of the fabric duct," he explained.

Splash Universe also uses heat-recovery dehumidifiers to provide free pool water heating and to control humidity. Instead of a 70 to 80 percent humidity range in normal indoor waterparks, humidity stays around 50 percent range.