Swimming Ahead

New Currents in Natatorium Design


Outdoor pools these days often resemble waterparks, with bigger and better features and increasingly upscale support areas. But indoor pools are also morphing, as facilities look to attract visitors encompassing all ages and interests.

"There are general trends to make indoor pools more interesting, fun and inclusive, incorporating a variety of elements that were once only found in exotic resorts or waterparks," said Allen Clawson, principal and managing partner at Cloward H2O, Utah-based design firm, specializing in "all things water," designing pools, waterparks, waterscapes, fountains and aquariums.. He described one recent design where a small natatorium incorporated a zero-depth entry with spray play elements and a small ripple wave, a current river, a vortex pool, two lap lanes, an indoor/outdoor hydrotherapy spa pool and a slide, all within 2,500 square feet. "The same facility would have been happy with a 30-foot by 60-foot rectangular pool just a few years ago."

It's true that indoor aquatic facilities now are installing separate pools under one roof to satisfy a wider range of user groups. Clawson pointed out how newly designed facilities are almost always combining leisure/recreation pools with competition pools in order to provide more general use. "Even the traditional natatorium facilities in schools and universities are adding rivers and activity pools to engage the larger demographic and make better use of the facility."

Multiple Demographics, Multiple Pools

"We're seeing an uptick in the demand for therapy areas," said Dave Schwartz, a principal at Waters Edge Aquatic Design, a Kansas-based aquatic engineering firm specializing in the evaluation, planning and design of aquatic centers. "These are distinct bodies of water with easy-entry ramps, lifts, steps, underwater benches with straps on them so you can hold yourself there and exercise, underwater jets and exercise equipment like treadmills and weight equipment that are in the water. And the water temperature could be 90 degrees or more."

Schwartz said these areas are also good for beginning swim lessons. "So the water temperature is the focus that we're seeing more and more drive how the designs fulfill the client needs."

Even the traditional natatorium facilities in schools and universities are adding rivers and activity pools to engage the larger demographic and make better use of the facility.

Schwartz said that competition and recreation pools can work together well, but water temperature is always the sticking point, since competitive swimmers like cool water but kids and older adults prefer it warmer. "So those two uses are a designer's challenge, how to balance that."

He pointed to a recent project where the diving area was separate from the lap area, since divers like warmer water than swimmers do, and that was perfect for adults or seniors to exercise in. If they couldn't swim they'd

just wear life jackets. "So there's ways to get around those differences. You have to identify what the client wants to do: What will the programs be? Who's going to use it? And how do you make that work?" The project also featured a recreation pool, so there are three separate systems. "It makes the filter rooms a little bigger, with a little more equipment, but that's the only way you can accomplish the temperature difference."


One thing that's advancing is the idea that aquatic recreation and wellness is for everybody, according to Doug Whiteaker, president of Water Technology Inc., a Wisconsin-based waterpark and aquatic planning, design and engineering firm. "It really has that appeal to the youth of all ages, especially us older people that want to be in the pool again and maintain our ability to be flexible."

He explained that while indoor pools are great for learn-to-swim programs, they're also becoming social outlets for older adults who want to work out and be among friends.

Whiteaker agrees that the trend in natatoriums is the desire for multiple water temperatures. "It used to be, let's just have maybe two: a warmer-water leisure pool and a cooler-water lap pool that can be used for high school swim teams or lap swimmers."

But now, he said, there's often four potential water temperatures: the competition pool is around 80 degrees while the leisure water is around 86 to 88 degrees. Water wellness/therapy pools might be 88 to 92 degrees, making them perfect for morning water exercise classes and afternoon learn-to-swim classes. Finally, the popular whirlpool spas operate at around 103 degrees.


When it comes to having multiple pools under one roof, Whiteaker says there are different points to consider regarding putting the pools in one room or in different rooms. "Acoustical separation is one of those things, and controlling operating expenses is another. Maybe we can shut down certain pools and not have to lifeguard them if they're not being used at certain times of the day." Additionally, if there's a competition pool that's holding training or events, "They can keep the leisure pool open and competition going on at the same time without sacrificing that level of service to the community."

Another consideration, especially in larger metropolitan areas, according to Whiteaker, is that as the United States becomes more ethnically diverse, certain populations aren't allowed in the presence of members of the opposite sex when swimming. Therefore, some areas might be equipped with shades so they can hold classes that appeal to these populations, with respect to their religious beliefs.


The same might apply to wellness and therapy pools: A lot of users are new to swimming suits and don't want to be on display, so keeping these pools in their own areas off the main circulation patterns of the building is a consideration. "How these all work, and how they're lifeguarded, are important design solutions that have to work best for each facility," Whiteaker said.

As facilities look to boost attendance by providing such varied offerings, from water sports to therapy and exercise to competition and play features, designers face new challenges. "Working flexible-use design elements into the aquatic plan affects water quality management, storage, deck space, changing facilities, etc.," Clawson said. "You can't just have folks bringing their personal gear, such as scuba gear or kayaks for kayaking class, without serious risk of impact to sanitation in the pool. So we either need to provide storage for kayaks and such or have provisions for a cleaning station for personal gear."

Add Some Fun

As far as "watertainment" features, Schwartz said there's still great interest in sprays, slides and interactive features. "But they do add to the humidity, they do add to the load that the HVAC system must be designed for, so this has to be carefully planned."


Whiteaker described how lazy rivers, a popular waterpark feature, have moved indoors and become a universally appealing amenity, with teenagers using them to float around and socialize while water exercisers utilize the fitness aspects. "There are user groups that want to do aqua fitness but don't necessarily want to get their hair wet. So they can walk and talk and have a fun time."

For facilities without the space or budget for a lazy river, Schwartz said the so-called current channels are a good alternative, which are smaller but still have the moving water. "You don't float in rafts because they're too small, but kids take noodles in there and bounce along, or folks can walk or swim against the current or turn the current off and have lessons in the standing water."

As far as waterslides, Schwartz said they're seeing a bigger demand for family slides. "The slides are wider, they're not as tall and they work in a little bit shallower water, but multiple people can go down at one time."

All of our experts agree that one huge challenge for natatoriums is air quality inside the facility. Air quality and humidity are the key challenges for indoor facilities.

Whiteaker explained how in the past, waterslides sometimes incorporated competition components to time you or clock your speed. "Well now, coming from Europe and Asia, we're starting to see waterslides that have LED screens, so you can set a theme where you push a button and it could be a blizzard theme or a nautical theme where you're sliding down and can actually see fish swimming over the top of you, or looking forward it looks like you're going to fly into a shark's mouth." The next user might experience a freight train or race car theme. "So there's lots of those interactive type devices that are becoming more desired by facilities today so they can have better entertainment durability for their clients," Whiteaker said.

But, Whiteaker added, having larger play amenities requires more lifeguard staff—one of a facility's largest operational costs. For instance, the inflatable obstacle courses have to be taken out, blown up, set up, disassembled, deflated and stored. "So some facilities say let's not put the big structures in, let's use more transparent structures that you can see through and we can minimize our staff costs."


Whiteaker said that not only are facilities now using basketball hoops and volleyball nets that can retract into the ceiling, but also the ninja warrior courses and similar components, and lifeguards can more easily see underneath them, maintaining a visual connection with users. "So it's just a pushing of a button that brings them down into the play zone. It's easy to do multiple times during the day, maybe using half the pool for lap swimming and half for the play features."

One feature still in demand is the classic diving board. Schwartz said that as a patron grows up, they experiment and develop diving skills. "It's a changed experience as they age, and you can't say that about a lot of things. It's one thing that's not going away."

Whiteaker agreed, describing how every time you go off a diving board, it's a unique experience. "You could do a cannonball or dive, try to make a small or a big splash. It's great for that hard-to-appeal-to age group—late tweens and teens. It becomes a friendly competition."

The Air in There

Accessibility issues are important discussions for indoor pools, since you want to be universally appealing while still utilizing precious space.

All of our experts agree that one huge challenge for natatoriums is air quality inside the facility. "Air quality and humidity are the key challenges for indoor facilities," Clawson said. "The sad fact is that many facilities suffer from poor air handling, which causes significant corrosion problems."

He said proper water chemistry maintenance is essential to good air quality, since air quality problems start with water quality problems. "We've all walked into an indoor pool and been bowled over by the strong chlorine smell, which is indicative of high combined chlorine (chloramines) and not actually the free active chlorine."


Schwartz explained that chloramines are the result of organics that people bring to the water combined with chlorine. As the chloramines become more volatile, they come out of the water, causing the smell, as well as breathing issues or skin rashes. Once they get into the air, the only treatment is to evacuate the air.

"That's an energy negative," Schwartz said. "You're trying to heat the air and keep it in there. So the best thing you can do is treat the water."

Traditionally, you might super-chlorinate to treat this problem; add more chlorine to oxidize those chloramines. But Schwartz said that's more difficult now as chloramines are used for public water disinfection, so every time you backwash and add water for evaporation, you're adding chloramines. "The most effective thing we've found is to add a UV (ultraviolet) system on the treatment of the water and that will oxidize those chloramines." He said that older facilities that add these systems experience much better air quality within weeks.

Whiteaker said that as facilities are more often becoming destinations for wellness and fitness activities, managers are asking how they can get the very best air quality at the lowest operational expense. "So doing things like a medium pressure UV, which is supplemental sanitation to support the levels of chlorine, is really important. Doing source capture, where you capture the bad air down at the water/air interface so you can remove that out of the building. You can have the very best indoor pool, but if it's not appealing to people because the smell or their eyes are burning, then you've spent a lot of money that doesn't achieve the goals set forth by the community."

Design Concerns

Facilities are also increasingly conscious of energy-saving and more sustainable practices. "We look carefully for economies in the air handling, including heat recovery, condensate reclamation and others to minimize energy expended and water losses," Clawson said.



He also mentioned LED lighting, regenerative filters and the greater reliability and availability of variable frequency drives (VFDs) as being relevant today. "We're designing facilities today using about 30 percent less power and wasting 60 percent less water than was possible just five years ago."


Bringing more fresh air in can be beneficial and economical when weather conditions are right, and Schwartz said they try to exceed minimum exchange rate standards put forth by ASHRAE (American Society of Heating, Refrigerating and Air conditioning Engineers). He added that it's important for architects to design wall and roof systems to prevent water vapor from penetrating and freezing within the systems. In fact, when discussing the critical aspects of window design and pros and cons of using natural light, Schwartz said that it's more important than ever for design team members—architects, HVAC engineers, structural and pool people—to be more communicative.


Whiteaker agreed, explaining that there's an interdependency that's required, and selecting a design team with experience in aquatic facilities is critical. "That covers solar heat gain, solar orientation for glare, building materials, the different types of HVAC systems for heating and cooling. Making sure you don't get condensation on the glass in a cold weather environment, and laying things out to maximize usage and safety."

Inclusiveness is a big consideration these days. Depending on pool size, you need to have a primary and secondary method of entry/exit, per ADA guidelines. "Primary ADA is a ramp, zero-depth entry or a lift, but you can also do steps with handrails that are a certain configuration. That allows most folks to get in and out pretty easily," said Schwartz, adding that they design gutters to be deck level, making it easier to hoist yourself out of the water.

When designing zero-depth entries, water depths from zero to two feet are considered engaging water depths, according to Whiteaker. In depths of around two to three-and-a-half feet, not many social or programmatic activities take place. "So we try to make that transition from shallow water to deeper water in as little footprint as possible." He said accessibility issues are important discussions for indoor pools, since you want to be universally appealing while still utilizing precious space.

Indoor pools are more in demand than ever as people of all ages want to utilize the health and fitness benefits of water.

Deck drainage and surfacing are important to plan for, and Clawson said the industry has long struggled with surface issues. "Concrete is the material of choice, and a light broom finish accomplishes the slip-resistance. Yet, slip accidents on a broom-finished concrete surface are where we see the majority of injuries."

He said he's encouraged to see companies making big improvements in impervious, durable, cleanable, slip-resistant and resilient surfaces that significantly reduce injuries.

"And then having the right deck drains," Whiteaker added, "so you can cost-effectively put those in the right places and not have tripping hazards."


Clawson pointed out that while people come for water, the condition of the facility in general—especially locker rooms and restrooms—can easily prevent them from returning. So-called universal locker rooms are becoming more common, to accommodate families, assisted aging adults and transgender populations. "New flooring and fixture materials that better resist corrosion and can be easily cleaned are becoming more available. We also advocate the use of sanitation carts, utilizing an ozonated water spray instead of chemical sprays which are often harmful to materials," Clawson said.

Schwartz said that indoor pools are more in demand than ever as people of all ages want to utilize the health and fitness benefits of water. But, he added, high operating costs often scare those who are considering opening a pool. He thinks a coming trend will involve multiple partners coming together to share those costs, describing a project they're planning in Iowa where the city, county, schools, hospital, senior center, Boys and Girls Club, local university and community college are all joining forces. It's called a Healthy Life Center, and besides a therapy pool, lap pool and recreation pool, there will be other amenities specific to helping people live healthier lives, like basketball courts and exercise equipment. "I think it bears watching," Schwartz said. "Momentum is building. We didn't hear any negatives when this was being presented."