So Fresh, So Clean
Keys for Improving Air and Water Quality in Indoor Pools
Better air and water quality is essential for the health and comfort of pool patrons. Studies have estimated that at least 50% of elite and competitive swimmers suffer from bronchial respiratory disorder and that the occurrence of asthma is higher among swimmers than nonaquatic endurance athletes. Chlorine and other pool chemicals are thought to be contributing factors.
Chlorine reacts with compounds in sweat, urine, stool and other substances called amines to form chloramines. In addition to problems for swimmers who spend a lot of time in the pool, these chemicals can result in symptoms like red, irritated eyes and dry skin and hair that can turn patrons off from swimming.
According to the CDC, if you smell "chlorine" in indoor pools, what you're actually smelling are the chloramine gases that result from chlorine reacting with pee, poop, sweat, dirt, skin cells, personal care products and other substances.
To minimize this, the CDC recommends that people:
- Never swim or let kids swim with diarrhea.
- Use the toilet before getting into the water.
- Shower before getting into the water—rinsing off for one minute removes most of the dirt and substances from your body.
- Wear a bathing cap while in the water.
- Don't pee in the water.
The Battle to Change Behavior
Unfortunately, even some high-profile athletes like Michael Phelps have stated in the past that they pee in the pool, and that "chlorine kills it, so it's not bad."
Bob Kappel, channel manager of recreational water and life support systems for an international provider of aquatics water treatment and disinfection solutions, sees this as a common attitude among elite swimmers, and noted the example of a conversation among several Olympic Trials competitors.
"When I suggested to them that well, if you have to pee, just get out of the pool and pee, [my friend] looked at me and he said, 'Bob, that will not happen. I guarantee you that will never happen because we have a limited amount of time in the water. We have to swim as hard as we can for as long as we can during that given period. You don't want to cool down once we're doing our reps, and he goes, 'we're peeing in the pool, and that's not going to change.'"
While this attitude may be disgusting yet almost understandable for elite athletes, American pools have also accepted inferior attention to hygiene from recreational pool-goers than is the norm in European countries like Germany.
"It's ingrained in their psyche that before I get into a pool, I'm going to take the soapy shower, and that's just something that society understands and does," Kappel said. "We've gotten away from all this in the U.S. … some people want to jump into the pool after just exercising at the gym. So what we need to get across to people is the fact that a swimming pool is basically a community bathtub, and it's for everybody's good that we try to get into that bathtub as clean as we can."
The result of such efforts in Germany is that codes can call for much lower levels of chlorine because they have much lower levels of the organic load that contributes to chloramines coming off their bathers. "There's this system concept. If we got people cleaner going into the pool and not peeing in the pool, we could probably run lower chlorine levels, lower the pH a little bit, and then we can wind up with less chlorine in the water making their hair brittle and drying out your skin and maybe having chlorine reactions. And we would have better indoor air quality too," Kappel said.
According to Kevin Post, principal for the aquatic design firm Counsilman-Hunsaker, a lot of this comes down to enforcement. "I used to run a pool in Texas, and we spent more time enforcing the shower rule than anything else because everyone walked out of the bathrooms dry," Post said. "If facilities truly enforce this rule, then they would see—they don't realize how much they can help themselves by doing this."
Better communication can also be helpful. People may know that they are supposed to shower before entering the pool, but don't know why it's important. Like Phelps, they may see chlorine as a cure-all, when it isn't. And they may fail to realize that people can help themselves through better behaviors that ultimately reduce their chance of getting the dry eyes, dry skin and dry hair that cause many pool-goers discomfort.
Better design decisions can also facilitate better patron behavior in some respects. For example, Post's firm often makes the recommendation for deck showers—this makes it easier both to enforce shower rules and for users to take a quick rinse before entering the pool. "A lot of facilities will do a lot of deck showers. If you put 10 or 20 for the swim team, the swim team has no reason to not rinse off before they get in the pool," Post said.
Post noted that in addition to the chloramine-creating power of urine, sweat, lotions, detergents and other products people may be wearing, facility managers should also take care to use the right cleaning products in their facilities.
"A lot of cleaning products are ammonia-based or quaternary products, and those create chloramines as soon as they touch chlorine," Post said. "So if you use that product on your deck, every time somebody gets out of the pool that chlorine water is basically off gassing chloramines right from your deck. Same thing with using it in your locker rooms … There are bleach-based products that are more appropriate for chlorinated water."
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."
A Systems Approach
Kappel expressed frustration that in many cases, there remains a separation between the systems responsible for the air and water quality in many indoor aquatic facilities that often begins in the design phase—and no communication between the people who put the separate systems in.
"The pool designs and the building design, where the air handler resides, are usually two separate design firms," Kappel said. "They're not talking, right from the start … We're set up to fail in that there are two separate design firms that have no purpose to talk to each other—the integrator component is missing from the middle."
This separation can also create problems throughout the facility's operation. Bevard noted the example of one facility In Mississippi where the pool recirculation pumps were slowed down with the sole purpose of reducing energy consumption. "Obviously, the water chemistry went in the toilet until that was discovered, but that was done and the pool operator wasn't involved in that decision," Bevard said.
Currently available technologies allow these systems to instead work together to improve both the air and water quality—if the integration is allowed to happen. "If you're monitoring combined chlorine in the water, you can have a feedback loop that ramps up the UV system if necessary, or changes HVAC system settings or even potentially enters a purge mode if requested," Bevard said. "Those technologies do exist."
Kappel likewise noted that these technologies can do things like ramp up the fan speeds and outside air dampers to bring more fresh air in in real time — and recreation managers can help make it happen by getting the HVAC and pool designers together at the onset of the project.
"I think it's up to the facility, to operators, to go ahead and facilitate that dialogue, and I think that's the key right there because it is not happening with new design even to this day," Kappel said. "At the end of the day, they're the ones paying everybody and they're the customers and they should put some demands on what they actually want to see happening."
Control and Monitoring
Luecker noted that while chemical controllers have been around since the 1970s, there have been huge advancements in the things they can monitor. "They do a lot more facility monitoring than they used to, and it's huge because you can't stay abreast of the changes that are happening as they happen in your pool water by trying to dose it once an hour or every three hours," Luecker said. "The controller turns that pump on and off based on need and demand, and the demands on a 100-degree day when you have 400 kids jumping in your pool is different than a cloudy day with 12 people in your pool."
Fowler noted that some states require that facilities log in their chemical record more than once a day. "But if you have a facility that's open all day and fully loaded, you might want to have someone just keep eyes on those things at least two to three times a day at minimum just to make sure things don't get out of balance," he said.
He also noted that if your budget doesn't allow for you to spring for a chemical controller, UV or ozone system or other helpful technology now, they can be added later. "There are always ways you can add things after the fact," Fowler said. "Just start slow, do something. But the main thing here is just to make sure you're maintaining your proper level of your chemicals."
Luecker agreed, noting that a supplemental disinfection system is helpful. "If you don't have one, you should contemplate adding that, particularly on an indoor pool," Luecker said. "And if your circulation system, pump filter or chlorination system is deficient in any way, then you should work to address that …Try to find the items that are most deficient to fix first and then add the supplemental things as you go on. Supplemental disinfection isn't going to solve a filtration problem."
To assist with the everyday basics like proper chemical usage, Luecker recommends training courses for pool operators such as the Certified Pool Operator (CPO) and the Aquatic Facility Operator (APO) programs. But experts admit that it's tough for facilities coming off pandemic-required facility closures.
"Preventive maintenance is the biggest key, and nowadays with staff reductions and the inability to hire folks and staffing shortages, I'm afraid that preventive maintenance has really taken a back seat and a lot of it is reactive maintenance," Kappel said.
When the equipment is properly maintained, problems are rare. "If you're being proactive and getting things changed up, the unit will never go down, unless it's some kind of very odd occurrence," he added.
Today's technologies and products are up to the task of ensuring better air and water quality. But operator competence and user courtesy play a huge role not only in making aquatic centers fun places to be, but clean and healthy ones too. RM