The Winning Edge
By Steve Nelson
As awareness of the operational costs of pools has deepened, helped along by years of rising utility costs, an increasing number of municipalities, YMCAs, and swim clubs have joined forces to build aquatic centers that can accommodate both competitive events and recreational activities. Fortunately, the understanding of natatorium-design efficiencies has also deepened. Satisfying all stakeholders in such an arrangement is a matter of solid design principles and sensitive scheduling and management, with both architects and administrators keeping the specific needs of swim-team members, spectators, recreational swimmers, and staff members in mind.
Operationally, dual-use natatoriums can be somewhat complicated. Ideally, the two separate pool spaces can be operated independently, with staff members able to keep participants in one program area from moving into the other. It all starts with an organized and efficient building plan.
Although there is no template for natatoriums, these specialized facilities have a defined flow and a number of important adjacencies that are necessary to make them work. For example, entry to wet spaces is always through wet locker/shower rooms, and the presence of separate competitive and recreational spaces normally means designing a secondary “wet hallway” through which male and female swimmers move from respective locker rooms to respective pools. And adding a spectator area to the competitive side, suddenly there are two circulation zones that, ideally, shouldn’t cross.
Break It Down
Even with these blocks of space tied into a relatively consistent arrangement, the specification of competitive and recreational areas requires consideration of a number of details:
• Building envelope. The two spaces are generally separated so the competition-space atmosphere (as well as the water) can be kept between 5 and 8 degrees cooler than in the leisure pool space. Typically separated in large part by glass, the two rooms will be equipped with a thermal barrier to guard against condensation issues, although these spaces can both utilize an operable skylight system. Such a system at the Upper Valley Aquatic Center in Hartford, Vt., is opened in conjunction with perimeter doors to give the space an outdoor feel in mild seasonal weather.
• Air handling. Building codes will determine the number of air changes required for a space of a particular volume, and the separate pools will require separate HVAC systems for dealing with moisture-laden air. The introduction of natural ventilation, as at Upper Valley, makes it possible to limit the use of the HVAC system, a natatorium’s highest energy-using equipment.
• Pool configuration and depth. Leisure pools often go from a zero-depth entry to a medium-depth end that is laned for lap swimmers, or separated for learn-to-swim, aqua-therapy, and water-aerobics programs. (The UpperValley recreational pool includes lap lanes with a 4-foot depth, which allows for a less-complex competitive pool next door.) Absent this, the depth of the competitive pool (a minimum of 2 meters is required) might be left unsloped, at least in part, to accommodate these uses. The specification of a diving well will also lead to changes in the slope.
• Competition pool size. While it would be nice to build a world-class, 50-meter pool, the reality is that this type of pool is expensive to build and operate, given the huge volume of water and the atmosphere that must be maintained. Most operators will therefore “settle” for a 25-yard, 25-meter pool that can host virtually all competitions and events.
• Water treatment. Dual-use facilities require doubling up on piping, pumps, filtration, sanitization, and heating units, with the systems kept separate to ensure each facility can run independently, as well as being accessible for maintenance purposes. Multiple systems will also lead to a corresponding increase in utility room square-footage. In the leisure pool, piping must match the purchased leisure elements, while careful planning and specification of additional piping can allow for the future switching out of play and spray equipment, the better to keep the facility fresh.
• Lighting. Glare issues must be dealt with in all aquatic environments; Improvements to glass and shade systems allow for greater use of natural light in these facilities. Operable skylights are glazed with translucent panels to diffuse direct sunlight. Competitive swimming requires 80 to 100 foot-candles of electrical lighting on the water, something best achieved with indirect illumination, that is, lighting directed upwards to reflect off a ceiling painted white to reduce glare, especially during backstroke events. Placing lighting fixtures at the perimeter of the pool creates challenges to consistent light distribution over the entire pool surface, but allows relamping when required from the pool deck.
• Building controls. Two systems will allow the independent control of operable skylights, lighting, and mechanical systems so that both pool spaces can be maintained efficiently. Automated systems can be regulated by sensing changes in light levels, motion, or levels of carbon dioxide in the space.
• Acoustics. Perforated metal decking, baffles, or banners are all effective at minimizing the echo-chamber effect that plagues some natatoriums. Care must also be taken when designing these spaces to ensure that the roof system doesn’t focus noise in the direction of lifeguards and swim coaches on the pool deck. The aim is to “pad,” where possible, opposing parallel surfaces; using sound-attenuating ceiling and wall panels helps to absorb excess noise.
• Spectator seating. Pool owners on a budget will sometimes opt for bleachers that are accessed from below, on the pool deck. Ideally, rows of bench seating in the competition-pool area will be raised on a plinth, or located on a balcony to give spectators an improved sight line over the entire water surface, with the biggest issue being a means of access. The best scenario allows spectators to enter a seating area directly from the building lobby with no access to locker rooms and other secured areas of the facility, keeping street shoes off the pool deck. Depending on the configuration chosen, specification of spectator seating may add to the volume of the competition space and affect related building systems.
• Locker rooms. In addition to the adjacency and circulation issues noted above, designers must also decide on the right mix of men’s, women’s, and family locker rooms, the specification of day lockers or cubbies, and also the possibility of locker rooms specifically for swim-team use. Separating age groups in locker rooms is done because it is more comfortable for each, and follows the logic that has made separate family-changing locker rooms—for families with very young children, people with disabilities, and fathers or mothers attending opposite-sex children—the industry standard in new facilities.
Aquatic centers are highly specialized spaces, particularly when competitive and recreational areas are combined under one roof. However, with ample programming and design sessions with pool staff and future program participants, a building plan can take everyone’s needs into account and lead to a first-class experience for all types of water sports and swimming enthusiasts.
Steve Nelson, AIA (firstname.lastname@example.org) is a partner with Wethersfield, Conn.-based Moser Pilon Nelson Architects.