Feature Article - November 2021
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So Fresh, So Clean

Keys for Improving Air and Water Quality in Indoor Pools

By Chris Gelbach


Maintenance Is Key

To maintain good air and water quality, ongoing maintenance of the proper water balance and chemical levels is essential. But an environment that seems off-putting to patrons who enter the natatorium can provide even more basic feedback that something needs addressing.

"Number one is to get rid of the chloramines so you're not going to be turning your guests away—you're not going to have those people come in and say, 'Woah, it's horrible in here.' It's going to be a much more enjoyable experience," said Mike Fowler, commercial territory sales manager for a provider of aquatic systems headquartered in Cary, N.C.

The same is true of other readily apparent issues, like excess humidity. "If you have an indoor pool and you walk into the room and it's all steamy and everything's wet, you know there's a problem with your air handling of the water," said Charlie Luecker, director of commercial for a national distributor of commercial swimming pool equipment based in Concord, Calif. "Water is going to corrode the metallic components in the facility when it's like that, so you know if you either get a dehumidifier or some air circulation within the facility, that will cut down the dangers associated with corrosion."

Even if you can cajole swimmers into doing everything right, there's no way to avoid combined chlorine in pools entirely. "That chemical process is going to take place, but with proper systems and equipment design and proper operator attention to maintaining the water quality and water balance, the production of combined chlorine can be minimized and dealt with in a way that it has the least influence on indoor air quality," said Darren Bevard, P.E., principal for Counsilman-Hunsaker.

Secondary Sanitation Considerations

To further improve water quality, many facilities turn to secondary disinfection and oxidation systems such as UV, ozone, advanced oxidation process (AOP) and other systems. "Everyone is always trying to find the silver bullet," said Post. "I would say that UV is still the proven technology, but that's also been out there for a while so everyone's trying to find other answers."

Kappel cautioned that some of these newer options are less vetted and tested for their effectiveness in natatorium environments. "Ultraviolet technology and ozone technology are tried and true, they're certified, validated and have all the scientific credentials, all the testing certificates to prove that these are valid and real technologies," he said. "So those are to me standards that we can build upon—those are foundational products."

Like with any products, even the most proven ones in this category only work if they're properly maintained. "We see a lot of times an operator says, 'well I have UV, and I still have poor air quality and I still have chloramines,' and it may be that the UV lamps haven't been replaced or maintained or cleaned," Post said. "You can't just slap it on and it solves all the issues. The operator has to understand how it works and what the purpose of it is and maintain it properly so that it's effective."

A New Understanding

According to Post, the old HVAC theory involved the idea of air warming up and starting to rise naturally, so the returns and ductworks were always placed up high, whereas we now know that bad air filled with chloramines often lingers near the water surface.

"Now the better HVAC designers, the better HVAC systems know how to use that source capture, that low draw trying to pull that [bad chloramine-filled air] and that's been a change," Post said. "But you still see facilities today that don't utilize that and that still use the old modeling."

To respond to this new understanding, more products are available for retrofits and technologies are being incorporated in the design of new HVAC systems to capture chloramines and disinfectant byproducts at their source near the pool surface and exhaust them out of the facility. This technology can be helpful as part of a holistic approach to better air and water quality.

"Treating the water itself is not 100%, treating the air itself if not 100%. It requires those two components to come together, and to best treat it," Kappel said. "So the evacuator gets the stuff that's formed before the water can get pulled back every four to six hours through the treatment system."