Heat, humidity and chemicals in pools combine to create harsh environments that are hard on buildings and hard on equipment. He is involved in both investigation/forensic and new design projects. The maintenance and cleaning of active condensation control or weep systems can be difficult, particularly on skylights located directly above the pool(s). Few, if any, building types present the risks and challenges found in indoor swimming pool facilities. Ensure the chemistry of the water is correct. Q Duct® In this case, tracer smoke will be ‘pushed’ from the building through any breaches in the air barrier and be identifiable at the building exterior (Figure 2). It is important to understand simply providing more exhaust air than outside air is not sufficient to maintain negative pressure. But if you're inside, you might . However, it is important to realize the building code is intended for non-humidified/‘general-use’ buildings, and does not specifically cover special buildings such as natatoriums and museums—both of which require atypical interior conditions. In buildings, such differentials can result from mechanical system operation, wind, stack effect, or a combination thereof. Airflow is the main contributor to water vapor and heat transport in the enclosures of most buildings. Get the information you need to ensure a project is designed according to the latest requirements. Jason S. Der Ananian, PE, is a senior staff engineer at SGH, specializing in building enclosure design and building science. Water vapor diffusion, or the movement of water vapor driven by vapor pressure differentials, is typically a slow process that can result in long-term moisture accumulation or condensation within the building enclosure cavities; it is controlled by a vapor retarder. This infrared image of an exterior natatorium wall was taken during the winter in a heating climate. PalDuct™ Natatoriums are commonly part of a larger complex of buildings. This type of corrosion often produces little to no outward evidence; rather, it affects the steel’s structure, leading to sudden, brittle failure. The architect should write the field testing requirements of air barriers into the project specifications. Inspection of the air barrier should not be pushed to the punch list phase—testing of air barrier mockups should be performed before cladding installation to ease identifying and repairing of breaches. The recipe for good air quality is a result of facility and system design, operations and programs in this space. A member of ASHRAE, he has published papers on topics including window flashing, whole-building energy simulation tools, and moisture migration in asphalt shingle roofs, along with quality control of air barriers during construction. Architectural materials and methods delivered right to your inbox. Design continuous insulation for the enclosure and minimize the incidence of thermal bridges and structural penetrations through the insulation. These pressure differences can exert significant force on air barrier systems, making it necessary for air barriers to have continuous structural support. What is happening behind stucco and manufactured stone? This common confusion between air barriers and vapor retarders often results in poorly designed natatoriums and short-term failure of building enclosures. Please check the box below to confirm you would like to be added to Kenilworth Media’s various e-mail communications (includes e-newsletters, a survey now and then, and offers to the design-build industry*). Interior partitions that separate interior high-humidity zones from adjacent, non-humidified or even unconditioned interior zones are an oft-overlooked component of the natatorium air barrier system. The first step is not about the dehumidifier itself, but … With far higher interior moisture loads than typical buildings and a potentially corrosive interior environment, natatoriums put structural and enclosure systems to the test, especially in cold or even mixed climates. Even with high-performance coatings, owners should expect some maintenance and eventual recoating of steel components. Design a continuous air barrier system for the exterior enclosure, including exterior and interior components that separate the natatorium from adjacent spaces. The wall of glass separating the pool space from the cold out‐door air is always a concern for natatorium design. Moisture loads and controls in natatoriums Success requires coordination between multiple trades at multiple points in the schedule, such as roof-to-wall intersections and window/curtain wall perimeters. The air barrier in a building is more than just a single material. For a deeper dive into the specifics on choosing and dimensioning the right dehumidifier for your indoor swimming pool, please sign up for our “Selection Guide – Swimming Pool Dehumidification”. Sanford Health Systems mission is centered on the health and wellness of their patients. The wall of glass separating the pool space from the cold outdoor air is always a concern for natatorium ventilation design. However, in natatoriums, even the absence of a vapor retarder rarely produces the same level of damage as an improperly designed/built air barrier system. Shelley Hill Pools has over 40 years of experience providing in ground, concrete, indoor, built in, and infinity pools, in new york, hudson valley. Moving air carries both heat and moisture. The authors’ firm has investigated dozens of natatoriums throughout the country and witnessed firsthand the swift and severe nature of failures that can result from improper design and construction. The proper control of water and air temperatures, air relative humidity, air ventilation and pool water chemistry balance will all contribute to the air quality in the natatorium. by Jason S. Der Ananian, PE, and Sean M. O’Brien, PE, LEED AP Still others may have functioned well from an enclosure standpoint, if not for significant shortcomings in the mechanical systems’ design or operation. One such practice is to pressurize or depressurize the building or individual spaces by using fans or by manipulating the HVAC system, and then using a tracer smoke source over the interior or exterior surfaces of the building enclosure. While quantitative testing is useful from an overall performance standpoint, a qualitative leak assessment should always be done in natatoriums due to the potential for condensation problems even at small leakage sites. (This is not an exhaustive list of all design concerns, but focuses on primary issues with the building enclosure and interior environment. IR thermography (per ASTM E1186) is another useful and efficient qualitative method to locate discontinuities in the air barrier. The BlueDuct underground air duct supplies air to the linear diffusers in the natatorium ventilation area at the base of the tall glass. Avoid using stainless steel in applications that are deemed ‘safety-critical’ or where components will not be frequently wetted or cleaned. Even small holes or discontinuities in the air barrier can allow significant air leakage and greatly reduce the system’s effectiveness, especially in buildings with high moisture levels. ), Notes Sean M. O’Brien, PE, LEED AP, is an associate principal at the national engineering firm Simpson Gumpertz & Heger (SGH), specializing in building science and building enclosure design and analysis. Typically, they design a ventilation system which brings in an excess amount of outdoor air in order to control any potential odor problems. For swimmers, a humidity range of 50 to 60% is most comfortable. Even though ASHRAE 62.1-2016 allows for as low as 0.48 cfm/ft2 of outdoor ventilation, it is the opinion of CaptiveAire that 1.0 cfm/ft2 of outdoor air and the use of Demand Control Ventilation (DCV) should be used for user comfort and humidity control. It is impractical to achieve a perfectly airtight enclosure, and even small amounts of air leakage can result in condensation. Design tips The following should be considered when designing natatoriums: • Design enclosure systems to include air barrier, vapor retarder, and thermal insulation systems that are sufficient and continuous • Use the mechanical system to maintain negative air pressure within the building ventilation systems can seem a little daunting. (back to top). Your account gives you unlimited free access to our e-book Collection, Newsletter Archives and our Digital Editions of the Construction Specifier. Our swimming pool ventilation systems come with a 10 year warranty on the material and sewn joints, will suffer no corrosion problems and the system is designed specifically to match the project requirements, including the option of nine standard colour choices or printing of specific colours, messages or logos to suit the design. Imagine yourself at your favorite swimming pool. For a detailed understanding of the design plan you might undertake, our documents cover four, five, six and eight-lane pools. These blower doors are also used for imposing pressure differential for qualitative testing. The 2011 ASHRAE Handbook–HVAC Applications recommends maintaining a negative pressure of between 12 and 37 Pa (0.25 and 0.77 psf) in the natatorium to minimize moisture and odor migration. From eSociety, November 2018. The test results can be used to compare the subject’s airtightness to similar buildings or against criteria set by industry standards and governing building codes; it can also be used to determine how readily the HVAC system can be adjusted to control pressure and reduce leakage. The watercube—Beijing’s National Aquatic Center—may be an extreme example, but even the most basic of natatoriums can present challenges for design professionals when it comes to thermal and moisture control. Blower door testing per ASTM E779, Standard Test Method for Determining Air Leakage Rate by Fan Pressurization, is intended to characterize the airtightness of the building enclosure. Guide to Ventilation for self-builders and renovators fresh air by design. In these cases, specialty alloys such as those containing higher levels of nickel and molybdenum (e.g. This poorly painted steel diving platform stair experienced heavy corrosion due to direct wetting. Since the driving force behind water vapor diffusion is relatively minimal, vapor barriers can contain small holes, such as fastener penetrations, and do not require sealed laps to be effective. As part of this project phase, mockups of the air barrier should include typical transitions (e.g. DESIGN CONSIDERATIONS FOR POOLS AND SPAS (NATATORIUMS) John W. Lund Geo-Heat Center SWIMMING POOLS According to ASHRAE (1999a), the desirable temperature for swimming pools is 27oC, however, this will vary from culture to culture by as much as oC.If the 5 The wall of glass separating the pool space from the cold outdoor air is always a concern for natatorium ventilation design. Of course, you always have the right to unsubscribe from any communications you receive from us, should you change your mind in the future. Request A Quote. High moisture levels in natatorium environments greatly increase the risk of interior surface condensation on cold components, such as windows, doors, roof penetrations, and drains. The supplemental exhaust fan (or even the primary mechanical system fan[s]) is best controlled by a pressure sensor located near the pool ceiling that time-averages the pressure differential between the interior and exterior; a control system speeds up or slows down the exhaust fan accordingly to maintain a zero pressure difference between inside and out. This is counterintuitive to many designers, since a stainless steel component that never comes into contact with pool water would, at first glance, appear to have little risk of corrosion. Corrosion on painted structural steel can be caused due to exposure to airborne chlorine compounds. Natatorium design is a niche skill. Humid air from natatorium spaces that migrates into the exterior walls condense once reaching a surface below the air’s dewpoint temperature. Product: BlueDuct®. In cold and mixed climates, this water vapor may condense within the wall or roof as the temperature drops. Although it is possible for some projects to depressurize the building and locate the source of tracer smoke on the exterior, this method may be difficult because of the influence of wind and the risk tracer smoke rapidly dissipates before it is drawn into the interior through the air leakage site. Field testing of air barrier continuity Stainless steels are often used in swimming pools to combat corrosion, but even these specialty metals have their limitations—especially in chlorinated environments. Swimming pool area 2 38/43 0,40 * *Moisture removal is a design factor. Design a continuous air barrier system for the exterior enclosure, including exterior and interior components that separate the natatorium from adjacent spaces. Since spaces like offices, storage rooms, and gymnasiums are not usually designed to function under high-humidity conditions, moisture-laden airflow into those spaces through unsealed interior partition walls may lead to significant damage to interior components. Introduction One of the important, yet difficult stages of ventilation design of natatoriums is the selection of air distribution system. This is reflected in most building codes, which, until recently, made no mention of continuous air barriers and often do not require vapor barriers in warm or moderate climates (Climate Zones 1 through 4, as defined in American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 90.1, Energy Standard for Buildings Except Low-rise Residential Buildings. We present a methodology that augments Standard 62.1-2016s ventilation rates with minimum outdoor air multipliers to help designers represent a variety of pool types, spaces, and Unless it is controlled by an effective air barrier system, air will flow through the building enclosure cavities where it can condense on cooler surfaces as it travels toward the exterior. From the ASHRAE website: ANSI/ASHRAE Standards 62.1 and 62.2 are the recognized standards for ventilation system design and acceptable IAQ. Controlling air and vapor flow For SCC to occur, a susceptible grade of stainless steel (most standard chromium-nickel stainless steels, such as Types 304 and 316, fall into this category) must be placed in a corrosive environment and subjected to a tensile load. The air in a natatorium often contains nearly three times the moisture per unit volume as a typical, non-humidified building. When it comes to tough conditions for ventilation systems, it doesn't become much tougher than in swimming pool facilities. The ASTM E779 test procedure typically requires a range of induced pressure difference (pressurization and depressurization) from 10 to 60 Pa (0.2 to 1.25 psf). Several design strategies are effective at reducing the risk of interior surface condensation, including: Unlike ‘passive’ condensation control systems, such as thermally broken window frames, mechanical and electrical systems require regular maintenance to remain operational. Infrequently cleaned surfaces may corrode quickly once a film of chlorides builds up on their surfaces (Figure 7). design no matter the purpose, size and location of the natatorium: the HVAC system must work in harmony with systems that control water temperature and water quality. Designing a ventilation system for a swimming pool can be tricky. The indoor climate is controlled to 84°F with 50% relative humidity and the outdoor climate can be as cold as –30°F (below zero). Confirm, through a testing and balancing report, that the airflow into the pool space is less than the airflow back to the mechanical system. 62.1-2016s minimum ventilation rates for swimming pool, deck, and spectator areas may not always produce a durable facility with acceptable air quality. With a 114°F temperature differential separated by a wall of glass, the design team had no room for error. introducing outdoor air during the summer generally adds moisture to the space and in the winter removes moisture from the space . While an effective disinfectant, chlorine has the unfortunate side effect of being highly corrosive to typical steels and even some stainless steel alloys. The linear supply diffusers were all uniquely incorporated into a small raised floor at the base of the windows. Not only are they expanding their network of hospitals and clinics, but they are also providing for preventative care. Typically, three forms of moisture transportation can contribute to problems: Water leakage, which occurs when water finds a path into the building, is controlled through water management and waterproofing systems that are beyond this article’s scope. Use high-performance fenestration systems aligned with the thermal insulation, combined with active systems such as warm air washes, to minimize the incidence of interior condensation. refine, if necessary, installation methods in accordance with the design intent before construction proceeds. Our focus on quality and aesthetics has made us one of the leading providers of high-end pools in the community, which is why we are the top choice for many of your neighbors. As such, interior surfaces in natatoriums must be kept warm, often as high as 18.3 C, to prevent condensation. Removing cladding after construction is complete to locate air barrier discontinuities is often costly and disruptive to building occupants. Air flows from high to low pressure regions. Hanger rods for overhead components are the most commonly affected, although other formed metal components, which can contain residual tensile stresses from forming operations, can also fail due to SCC. The tests are conducted using calibrated fans (Figure 4) to pressurize or depressurize the building under controlled conditions. An indoor swimming pool has a remarkable chance of experiencing moisture problems, but with accurate load calculations of the pool evaporation rate, peak outside air loads, and the internal load in the space you can successfully design a healthy and enjoyable natatorium. When planning natatoriums, designers are concerned about preventing any unpleasant odors. DESIGN GUIDE Ventilation and air distribution. 2019 Handbook Sneak Peak: Behind the New Natatorium Chapter. ASTM E1186, Standard Practices for Air Leakage Site Detection in Building Envelopes and Air Barrier Systems, describes various qualitative methods to locate air barrier discontinuities. For engineers who must translate these objectives into design goals an integrated, sustainable approach is required. Uncontrolled airflow results in increased heating and cooling loads; it can also transport moisture or chlorinated air to areas where moisture or odor exposure is undesirable. These design goals must reconcile the intensive tasks of The centerpiece of this new facility is the natatorium. Confirm space pressures by direct measurement in addition to measuring supply/return quantities. This distance created a perfect stack to draw air from the leeward side and channel it up and through the natatorium. This work shall be used to: Mockups are also helpful for coordinating between trades. O’Brien is a member of the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE), co-chair of the New York City Building Enclosure Council (BEC-NY), and a frequent speaker and author on topics ranging from building enclosure design to energy efficiency. Types 904L and 254 SMO), which are more resistant to SCC, are likely necessary.1. Summary of design strategies Others were well-designed but poorly constructed, or poorly designed but built exactly as shown on the drawings. Design continuous insulation for the enclosure and minimize the incidence of thermal bridges and structural penetrations through the insulation. 1 651.209.00501.877.783.1520 team@aqcind.com, The BlueDuct® Swimming pool ventilation and air-conditioning was the first objective of the Menerga company. The most common form of corrosion in natatoriums is visible surface corrosion, which affects bare steel or steel with insufficient corrosion protection. Scot Hunsaker, president of Counsilman-Hunsaker, a St. Louis-based pool engineering, planning and design firm, sits on the board of directors of the National Swimming Pool Foundation (as does AB's president, Peter Brown), so he can't say the ventilation requirements come as any surprise. It is the most demanding air-conditioning and ventilation mode, where spatial comfort is insignificant. Finland (2003), due to failed stainless steel hangers. Since thermal bridges or insulation discontinuities in the enclosure can also result in surface temperature differentials, it is typically necessary to perform multiple scans—from both the interior and exterior, and with the building under positive and negative pressure—to isolate the contribution of thermal bridges and more accurately identify air leakage sites. Critical transitions, such as the roof-to-wall intersection, must be carefully detailed, as poor transitions can greatly reduce air barrier performance and mechanical system effectiveness in controlling building pressure. The mockups should be performed as many times as necessary for approval by the architect and/or third-party inspector. The magnitude of moisture migration via airflow can be 50 to 100 times that associated with water vapor diffusion alone. Several agencies and state building codes even require whole building air infiltration testing for new buildings. The centerpiece of this new facility is the natatorium. in natatorium design and dehumidifi-cation since its first installation in 1977.