Feature Article - January 2020
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Planning for Flexibility & Wellness

The Ongoing Evolution of Natatorium Design

By Dave Ramont


Natatorium wall and ceiling surfaces are now given more consideration for longevity, reflectivity, acoustics and corrosion resistance, according to Berkshire, who added that poor lighting in older facilities resulted in lackluster water. But he stresses that overhead lights must be serviceable. "To satisfy both concerns, modern lighting systems incorporate LED light sources with deck area serviceability, combined with surfaces that reflect the light to provide a bright and inviting environment. Natural lighting is often desired, but special attention must be given to control glare on the pool water."

Bershire explained that as facilities incorporate more programming, mechanical systems have had to evolve, since successful programs translate into more bather loads over longer periods of time. This results in greater loads of organics and pollutants to the pool water with less time for systems and staff to maintain the water. To account for this, higher turnover rates have been incorporated into modern pool designs, including the secondary and supplemental disinfection systems. "The evolution of variable frequency drive units has provided smart pump controls, allowing us to design pools with the ability to slow the water flow down when water quality and program usage allows," said Berkshire. "Wi-Fi connections to the smart pool controllers allow staff to monitor and control the systems with smart phones and tablets to ensure better water quality and reduce staffing."

For indoor facilities, controlling chloramines is a major consideration, and Berkshire said there is no silver bullet to solve this issue. "A coordinated effort of smart pool controllers, supplemental disinfectants such as ultraviolet, ozone and advanced oxidation systems, and natatorium air handling systems can ensure that chloramine issues are minimized or eliminated."

Air and water exchanges are another tool facilities are implementing. And new chemical controllers can now measure and monitor free versus total chlorines in the pool water, and control turnover rates, levels of supplemental disinfectants and other parameters to control chloramines, added Berkshire.

Hester agrees that the issue of chloramines continues to be a hot topic. "There are even industry suppliers who have developed building conditioning systems that are specific to removing chloramines from the surface of the pool, thereby improving indoor air quality." He mentions competition pool projects at Michigan State and Purdue that have taken a comprehensive re-design approach from the pool and mechanical engineering team. "The Model Aquatic Health Code (MAHC) also has a special ad hoc committee that's currently meeting and looking to set the bar with best industry practices."

In Alabama, the Huntsville Aquatics Center recently finished renovations, adding a 50-meter competition pool and warm-water instructional pool to the existing multipurpose pool. The three pools are located in separate areas of the facility, hosting recreation and lap swimming, recreational diving board use, water exercise and instruction, triathlons, swim and dive competitions, Paralympic and Special Olympic events, water polo and private parties/events.

Between the pools, there is seating for more than 2,000 spectators. "In the old natatorium we have collapsible bleacher seating for approximately 800. In the competition pool the stadium that overlooks the pool is all permanent seating. Over 300 of the seats have chair backs, arm rest and cup holders. The rest of the stadium is bleacher seating," said David Kalange, aqua activities manager in Huntsville. He added that the competition pool utilizes a bulkhead, allowing for different setup options.

Ricky Wilkinson is director of general services for the city of Huntsville, and he explained that the new pools use regenerative media filtration systems. The original pool system was converted to high-efficiency sand filters, and the heating and ventilation units were also upgraded.

The ventilation systems for the new pools were designed to combat the usual air quality issues, according to Wilkinson. "We have four dedicated units for the new competition pool and one for the instructional pool. These units pull roughly 85 to 90% outside fresh air into the pool environment and use the balance of makeup air from the environment. In both pools the ductwork was installed high in the area with the diffusers 'washing' air down the exterior walls. Each pool has a separate ducted exhaust. The grilles for the exhaust were placed low (at deck level in the competition pool) in an effort to pull the air from down the walls and across the pool surface to evacuate the chloramines."

Back at the Midco Aquatic Center, Carlson explained that all four bodies of water (including the splash pad) have their own filtration system and UV system. "Each body of water presents its own challenges based on bather load and time of year." The pools use regenerative media filters, and the competition pool uses two due to its size. "Each room has air-handling units to help control the air quality. If there's an issue with chloramines, we would superchlorinate the pool. Our maintenance staff does a great job tracking free chlorines to avoid any issues with chloramines," said Carlson.