Section 4 – Pool Project Design Considerations
4.1 Tile Industry Standards
The Tile Council of North America (TCNA) provides an installation method for the proper installation of tile in swimming pools, fountains and water features. TCNA provides Method P601 for swimming pools and Method B417 for tile tubs, fountains and curbs which can be found in the current version of the TCA Handbook for Ceramic Tile Installation. To obtain a copy of the current TCA Handbook for Ceramic Tile Installation please contact TCNA at 100 Clemson Research Blvd., Anderson, SC 29625, +1.864.646.8453 (F) +1.864.646.2821 or by e-mail at literature@tileusa.com.
The American National Standards Association (ANSI) provides guidelines for tile installation and requirements for product testing and performance in the American National Standard Specifications for the Installation of Ceramic Tile (A108 and A118). To obtain a copy of the current American National Standard Specifications for the Installation of Ceramic Tile please contact TCNA at 100 Clemson Research Blvd., Anderson, SC 29625, +1.864.646.8453 (F) +1.864.646.2821 or by e-mail at literature@tileusa.com.
Please refer to International Residential Code, International Building Code and/or United States Consumer Product Safety Commission Publication No. 362 “Safety Barrier Guidelines for Home Pools” at www.cpsc.gov for more information, or, contact your local building officials for swimming pool codes and requirements.
LATICRETE International also provides installation methods and details for swimming pool and submerged installations and is available at www.laticrete.com/ag, method ES-P601, ES-P601D, ES-P602, ES-P603, ES-P604, ES-B417A, and ES-B417B.
4.2 Structural Considerations
It is not unusual for people to look at an in-ground swimming pool and see nothing more than a hole in the ground, filled with water where people relax, have fun and enjoy life. But there is much more to it than just a “hole in the ground”. Out of sight is a solid foundation on which the pool is created, along with plumbing, lighting, and sanitation equipment. For swimming pools, fountains and water features located above grade within structures, there are more structural considerations to take into account.
Loads – The following aspects must be taken into account during the load calculations process; pool filling, alternating thermal loads, internal stress of the concrete pool shell with regard to the reduction of shrinkage cracks, support of other structural components during construction, and loads resulting from normal operation of the pool.
It is easy to forget, and therefore not to take into consideration, the weight of water and the effect this weight has on the structure containing that water. Water weighs 8.34 pounds per gallon (1 kg/L). For an average size swimming pool of 15' × 30' × 5' (4.5 × 9 × 1.5 m), the weight of the water comes to approximately 140,400 pounds (63,700 kg). For a 164' × 82' × 6.6' (50 × 25 × 2 m) Olympic size swimming pool the weight of the water comes to over 5,500,000 pounds (2,490,000 kg). No matter how you look at it, these are tremendous weights which create a constant force on the structure of the pool. If the pool is in-ground, the soil and the traffic (live) loads in the area immediately surrounding the pool must be taken into consideration. A properly designed and compacted drainage layer under the pool and a backfill with suitable soil, which is properly installed and compacted, is very important to the long term success of the pool.
A pool, fountain or water feature located on elevated floors within, or on a structure means the proper detailing of the pool is not only critical to the pool structure but also to any spaces located underneath the pool. First, the structure must be designed to handle the weight; and second, provide waterproofing protection to any spaces below or adjacent to the pool.
Buildings with elevated swimming pools must be designed to accommodate the excess live load provided by the weight of the water within the structure of the pool. For example, a pool that is 15' × 30' × 5' (4.5 × 9 × 1.5 m) and contains water that weighs 140,400 lbs (63,700 kg) equates to a live load of 312 psf (1,532 kg/m2) for just the water. Most commercial buildings are designed for a live load of 70 – 130 psf (344 – 640 kg/m2) so the design professional must take into consideration the weight of the water, on top any additional anticipated live load minus the water. If the pool is in a room that is 30' × 60' (9 × 18 m) and the designed live load is 70 psf (344 kg/m2) then the room has a total live load capacity of 126,000 lbs (57,270 kg). The weight of the water itself exceeds the designed live load of the structure and does not include any other anticipated live loads.
Consideration for excess dead load should also be taken into consideration. In most cases the mass of the structure and its supporting members, and therefore the dead load, are increased to handle the excessive loads created by the water.
Requirements of Design – Swimming pools, fountains and water features are complex in nature. Although they appear to be simple (essentially a vessel filled with water) they are far more than that. These pools have to take into consideration the proper design and, placement and installation of the plumbing, electrical/lighting, and, if the pool is indoors, proper air circulation and dehumidification.
Swimming pools, fountains and water features should also be waterproofed to keep the water within the vessel and from causing damage to surrounding areas. The proper placement of a suitable waterproofing product is essential to keeping water where it belongs. Swimming pools located in elevated floors or on the roof of a building may require the placement of a “sandwich” type waterproofing membrane. Typically, this sandwich type membrane is an alkali-resistant, bladder type product and is placed between pours of concrete to provide a permanent barrier against water penetration to the structure below.
Deflection – Systems over which tile or stone will be installed, shall be in conformance with the International Building Code (IBC) or applicable building codes for the desired application. Historically, for ceramic tile and paver applications, the maximum allowable deflection should not exceed L/360 under total anticipated load; and, for stone the maximum allowable deflection should not exceed L/480 of the total anticipated load.
The ceramic tile industry abides by the following note on deflection: the owner should communicate in writing to the project design professional and general contractor the intended use of the tile installation, in order to enable the project design professional and general contractor to make necessary allowances for the expected live load, concentrated loads, impact loads, and dead loads including the weight of the tile and setting bed. The tile installer shall not be responsible for any floor framing or sub-floor installation not compliant with applicable building codes, unless the tile installer or tile contractor designs and installs the floor framing or sub-floor.1
4.3 Types of Structural Movement
Swimming pools, fountains and water features are structures, and, like all other structures are subjected to different types of structural movement. Thermal movement, moisture expansion and contraction, and, differential movement are typically experienced in this type of construction.
Thermal Movement – All building materials expand and contract when exposed to changes in temperature and moisture. There are two (2) factors to consider in analyzing movement caused by thermal variation: 1) the rates of expansion of different materials (also known as the linear coefficient of thermal expansion), and, 2) the anticipated temperature range exposure. The primary goal in analyzing thermal movement is to determine both the cumulative and individual differential movement that occurs within the components of the pool assembly, especially above the water line.
While a pool is filled with water, the area below the water line will see little in the way of thermal movement. Any changes in temperature are minimal and slow. The structure of the pool, and any tile installed in the pool, will be able to adjust with this temperature change. However, the tile or stone installed between the water line and the coping can see significant changes in temperature in a very, very short amount of time. For instance, if a dark colored tile or stone (which can reach temperatures in excess of 120°F [49°C] in direct sunlight) is suddenly exposed to water at 72°F (22°C) then an extreme amount of thermal contraction can occur. As the tile is allowed to dry then thermal expansion occurs again. Movement caused by thermal expansion and contraction can create problems with a tile or stone installation, including cracking and/or loss of bond. Extreme thermal contraction can also occur when a pool is drained and allowed to remain empty and dry for extended periods of time. In open-air pools and fountains, higher alternating thermal loads may occur due to weather conditions.
The thermal expansion of tile is determined using ASTM C372 “Standard Test Method for Linear Thermal Expansion of Porcelain Enamel and Glaze Frits and Fired Ceramic Whiteware Products by the Dilatometer Method.” For certain types of tile the following test method may be used; ASTM C484 “Standard Test Method for Thermal Shock Resistance of Glazed Ceramic Tile.” The coefficient of thermal expansion for all elements of the installation system, including substrate, must factor into the calculation for the total anticipated movement.
Moisture Movement – As noted earlier, building materials (including concrete) will experience changes when exposed to varying amounts of moisture. Typically, building materials will expand as they gain moisture and contract as the moisture leaves the system. Tile is one such building material. It would be important to check with the tile manufacturer to see if their product is suitable for use in submerged installations. Tile with a low absorption rate (<3%) would be better suited for use in submerged installations, especially in climates where freeze/thaw occurs (see Section 5.1 for more information).
Differential Movement – Differential movement is another factor to take into consideration when installing tile or stone in swimming pools, fountains and water features. Most of the forces that act upon a building will act upon a swimming pool installation; live loads, dead loads, thermal expansion and contraction, seismic loads, creep, and settling must still be accounted for and factored into the design and construction of these structures and the differential stresses exerted by these forces must be alleviated in movement joints.
4.4 Movement Joints
Controlling Stresses with Movement Joints – Movement joints serve to allow changes in the shape of the overall construction (e.g. thermal movement, settling, shrinkage and swelling of the concrete structure, etc…) as well as displacements against each other to occur without causing damage to the pool shell, or to the tile or stone installation. Arrangement, dimensions and formation of the movement joints depend on many factors, including expected changes in shape of the structural components and their tile or stone cladding.2
Guidelines for Movement Joints – As a guide, when no project specific movement joint design exists, for submerged installations of tile or stone, movement joints can be installed every 8' to 12' (2.4 to 3.6 m) in each direction in the finish layer and installation system. Movement joints should also be placed where tile work abuts restraining surfaces (e.g. perimeter walls, steps, etc…), where dissimilar surfaces meet, at any change in plane, and around pipes or penetrations. Movement joints should be placed over all designed joints in the shell of the pool, fountain or water feature, and these joints should be carried to the surface of the tile or stone installation directly in line with their original placement in the shell. Depending upon the size and construction method of a pool shell, some of the joints in the structure may require a special type of water stop filler material. This material will allow for a significant amount of movement to occur in the structure of the pool but will not allow water to escape through the joint.
It is important to make sure that the project architect or engineer shows locations and details of movement joints on project drawings.
Figure 4.1 – Indoor water park wading pool with clearly defined movement joints.
Movement Joint Treatment – Movement joints should be treated with a suitable sealant and installation should be done in conjunction with TCA Handbook for Ceramic Tile Installation EJ-171 “Movement Joint Design Essentials.” The performance requirements of certain special locations, such as swimming pools, dairies, food plants, etc…, may exceed the minimum requirements of the sealant specifications given above. Therefore, follow recommendations of experienced manufacturers as to specific sealants suitable in the job environment. In some of these environments, a program for regular maintenance of sealant in joints may be required3. In most cases, the use of a 100% silicone (e.g. LATICRETE® Latasil™ used with LATICRETE 9118 Primer) or urethane sealant will be recommended for submerged installations.
4.5 Swimming Pool/Fountain Construction Considerations
We will take a look at both in-ground and elevated swimming pool construction considerations
Structurally, in-ground swimming pools can be exposed to all sorts of conditions and forces that can have a profound effect on not only the long term success of the pool, but also on any tile or stone installation in the pool or on the pool deck.
The ideal site for placement of an in-ground pool, fountain or water feature is level with good quality soil. In many cases the site is not level and there are subsoil problems. These problems can include too much rock (ledge), poor soil type, compaction, high water table, or the need for the removal of soil and replacement with compacted fill. The need to have the soil inspected can be very important to make sure that the pool will have no structural problems in the future. A proper soil inspection can also provide information on where the best area to place the pool would be.
The steps to in-ground pool construction are as follows;
Layout and Positioning – Layout and positioning should be conducted with the assistance of a qualified, licensed surveyor. The surveyor can make sure that the placement of the pool is within guidelines for distance from the boundaries and also if the boundary adjacent to the pool is in the correct position. In other words, survey the entire property to make sure you are not excavating outside of the property lines. Pool boundaries are marked with paint prior to the commencement of excavation and are typically larger than the actual finished dimensions of the pool.
Excavation – ALWAYS CHECK FOR UNDERGROUND UTILITIES PRIOR TO DIGGING. Once the boundaries are marked it is time to bring in the heavy equipment to dig the hole. Following the pool specifications and drawings, the excavation contractor will dig the hole to precise requirements (usually slightly larger than the finished pool size). Unless a large volume of dirt is needed on site for leveling or other purpose, then most of, or all, of the dirt removed from the hole will be transported off site. A hole dug out for a 15' × 30' (9.5 × 4.5 m) pool can yield as much as 130 cubic yards (100 m3) of earth.
Hydrostatic Pressure Relief Valve – During the excavation process it would be important to see if any ground water appears in the excavated area. Negative hydrostatic pressure and hydrostatic pressure under a swimming pool, fountain or water feature can have a significant effect on the pool structure and any finish within the structure. If there is a high water table, and no means have been created for relieving this pressure, then special considerations must be made and appropriate designs engineered4. If ground water is a possibility then the proper installation of a hydrostatic relief valve can help to eliminate potential problems down the road (e.g. finish delamination, floating pool, and more…). In many cases, a hydrostatic pressure relief valve is installed even if no ground water appears in the excavated area during construction. This will help to deal with any unforeseen or unanticipated problems that may occur in the future. Changes in the natural movement of water (caused by the excavated area in the ground), landscaping changes and the disposal of water when the pool has to be emptied for maintenance should all be anticipated during the design and construction of a pool or water feature.
Proper use of a hydrostatic pressure relief valve can also prevent a less common but potentially significant problem; the floating swimming pool. If there is a high water table or the potential for the hole in which the pool is placed to fill with water then there is the possibility that the pool can float right out of the ground when the pool is emptied. This is possible because anything can float (ships were actually made out of concrete during World War I and World War II). The mechanics of how something is able to float is very simple; as stated by the Archimedes Principle, if the weight of the water displaced by an object is greater than the weight of the object, then the object will float. For example, if a ship weighs 100 tons (90,700 kg) but displaces 120 tons (109,000 kg) of water then the ship will float; conversely, if the same ship displaces only 80 tons (72,600 kg) of water then the ship will sink. So, an empty pool can float if it weighs less than the water filling the hole beneath it! This is why it is rare to see a totally empty swimming pool in areas where the water table tends to be high.
Vapor Retarder – Another functional design element that must be utilized is a high quality vapor retarder. This material, typically a heavy gauge polyethylene sheet product or a reinforced polyolefin, is placed underneath a pool to prevent moisture vapor from entering into the system. Indoor swimming pools, fountains, spas and water features (especially on or below grade) should not only have a vapor barrier below the pool and deck, but also on the walls and ceilings to prevent moisture from penetrating into adjacent rooms or into the structure of the building. A high moisture vapor emission rate under a pool can have significant effect on the tile or stone installation, especially when the pool is emptied for maintenance.
Water Stop – As mentioned earlier, water stops are used within the concrete shell for large pools, fountains or water features. These water stops are designed to provide waterproof integrity in areas where a gap in the construction is required (e.g. movement joints or between wall and floor concrete pours – see Figures 1 and 2) in the pool shell. Typically, pools in excess of 40 – 50 ft (12.2 – 15.2 m) in any dimension require some type of movement joint through the pool shell and, therefore, require a water stop in the joint. These water stops are usually made of latex, neoprene or polyethylene and are placed as the concrete is being poured, so they become integral within the concrete.
Figure 4.2 – Typical shape and placement of water stop where floor and wall join in pool construction.5
Figure 4.3 – Typical shape and placement of water stop where floor and wall join in pool movement joint.6
Plumbing – Water in a swimming pool needs to circulate through a filtering system to remove dirt and debris, and to evenly distribute the pool chemicals. For in ground pools, fountains and water features most of the plumbing for the pool drains, pump system and filters have to be installed prior to the pouring or spraying of the concrete. The main drain(s) are usually located in the lowest point of the pool, so the entire contents of the pool will flow to the drains. The drain is tied into the pump system for easy draining or fast circulation of the water in the pool.
Figure 4.4 – Typical drain position and steel reinforcement prior to gunite application of concrete.
Figure 4.5 – Cut away view of a typical pool pump and filtration system.7
The filter system incorporates specially made filter sand or diatomaceous earth (a fine powder made from the chemically inert, fossilized remains of sea organisms called diatoms) as the filter medium or a cartridge type filter. In most regions, regulations dictate that all of the water in the pool (or its equivalent volume) must pass through the filter in a certain amount of time – typically between 30 minutes to six hours.
Figure 4.6 – Return port in a concrete shell pool7.
Lights and Electrical – Like the plumbing, the lighting and electrical installation must be done prior to the pouring or spraying of the concrete pool shell. In most cases, swimming pools and fountains are constructed with underwater lights. These lights are essentially used so swimmers can see what they are doing at night and, to a lesser extent, for aesthetic appeal. An incandescent light is sealed into a watertight fixture which is located in a niche in the pool shell. The electric wire runs into the fixture through a special seal which is designed to keep water away from the electrical elements. Fiber optics are becoming more and more popular in pools because they do not have to be embedded within the pool structure.
Electrical work for swimming pools and submerged applications was finally included in the National Electrical Code (NEC) Article 680 in 1968. Electrical work done in pools before this time may be of sub-standard quality. Modern light fixtures are designed to last for decades, however, poor water chemistry can weaken or degrade the fixture, gasket and fasteners which hold it together. Failure to inspect these fixtures and replace as necessary could result in costly damage to pool users or property. Modern lights are also designed to be used only while submerged to prevent overheating and should never be turned on when the pool is empty.
Observation Portals and Windows – Like plumbing and lighting, the placement of observation portals and windows is done prior to the pouring or spraying of the concrete. A structural engineer should be utilized to design how the window should be placed in the pool shell without compromising the strength and integrity of the pool shell, and to specify how the window frame should be mounted to the steel reinforcement.
The manufacturer of the window can dictate exactly what type of frame and sealant should be used based on several factors (e.g. size of the window, depth in the pool, size of the pool, and purpose of the window, etc…). The frame must be made of a non-porous, non-corrosive material and is, in most cases, stainless steel. A high quality silicone sealant is the most frequently used material to provide waterproof integrity between the window frame and pool shell. Proper inspection and maintenance of the sealant, window frame and pool shell are vital to ensuring that leaking does not occur in this critical area.8
4.6 Pool Deck
Almost every pool, especially pools which are located in ground, have a pool deck. These decks can be of any size, from just a few feet (1 – 2 m) extended from the edge of the pool to huge areas used for entertaining and aesthetic appeal. Since just as much time, if not more, is spent on the pool deck than in the pool itself, the proper design and size of the deck becomes important. Some things to take into consideration when designing a pool deck are construction materials (e.g. concrete or wood), finish materials (e.g. tile, stone, pavers), pool equipment (mechanized covers, plumbing covers, etc…), diving boards, slides, incorporating sun and shade, hot tub or spa, grilling area, and fencing.
Pool Deck Substrates – a majority of pool decks utilize concrete as the basic construction material. Concrete is relatively inexpensive, easily poured and makes an ideal substrate for the direct adhesion of tile or stone. In some instances, wood planking decks are constructed for aesthetic value, or for areas where concrete would be difficult to pour. Still other decks have concrete immediately around the pool and sand set concrete or stone pavers are used as the main decking material.
The installation of tile and stone over a concrete pool deck, whether interior or exterior, can be done by using the LATICRETE materials as stated in Section 8 “Pool Deck and Natatorium Tile Installations” and by following industry guidelines for tile installation.
Slope To Drain – a properly constructed pool deck will provide a slope which will evacuate water to a drain or to gutters placed on the ground to take water away from the pool deck. This helps to shed water from the deck and to prevent freeze/thaw conditions from damaging the concrete or pool beam during cold weather months.
Movement Joints – according to the TCA Handbook for Ceramic Tile Installation EJ-171 the guidelines for placement of control joints in an exterior tile or stone installation are every 8' – 12' (2.4 – 3.7 m) in each direction. Interior pool decks should have control joints placed every 20' – 25' (6.1 – 7.6 m) in each direction unless the pool deck, and any subsequent tile or stone installation, is exposed to direct sunlight. If so, then treat the tile or stone application as if it was on an exterior deck and place the control joints every 8' – 12' (2.4 – 3.7 m) in each direction.
For exterior decks, the minimum joint width for joints placed in the tile or stone installation is 3/8" (9 mm) for joints spaced 8' (2.4 m) on center and 1/2" (12 mm) for joints spaced 12' (3.7 m) on center. Minimum widths must be increased by 1/16" (1.5 mm) for each 15°F (8.3°C) tile surface temperature change greater than 100°F (38°C) between summer high and winter low. Decks exposed to the sky in northern climates usually require 3/4" (19 mm) wide joints spaced 12' on center.9
Cure Time – it is necessary to allow for the proper curing of the tile or stone installation materials (e.g. membrane, thin-set, grout, sealant, etc…) before exposing to traffic or submersion. Please check the data sheets for minimum cure time of each LATICRETE® product used in the installation by visiting www.laticrete.com or by calling LATICRETE Technical Service at 1.800.243.4788, x235.
4.7 Safety and Code Considerations
Building Codes – The health and safety of swimming pool users should be the primary concern during the design, construction and enjoyment of the pool. As such, the International Building Code (IBC) and International Residential Code (IRC) address the design and implementation of swimming pool enclosures, safety devices and barrier requirements. The United States Government has also addressed the concerns of properly placed and constructed safety barriers along with entrapment dangers from suction fittings with the passing of H.R. 1721: The Virginia Graeme Baker Pool and Safety Act in December 2007.
Safety Codes – The Virginia Graeme Baker Pool and Safety Act encourages States to improve their pool and spa safety laws to educate the public about pool and spa safety by establishing a grant program administered by the Consumer Product Safety Commission.
While local building codes will mandate any requirements of pool or fountain construction guidelines, the necessity for safety after the pool is finished is tantamount to local, state and government legislators as well as home and property owners. Taking into account the fact that drowning is the second leading cause of death in children aged 1 to 14 in the United States, proper implementation of safety devices and barriers is important.
The best way to reduce child drowning in residential pools was for pool owners to construct and maintain barriers that would prevent young children from gaining access to pools. However, there are no substitutes for diligent supervision in both residential and commercial pools. Swimming pool barrier guidelines are designed to prevent a child from getting over, under or through the barrier and gain access to the pool. As outlined in the United States Consumer Product Safety Commission Publication No. 362 “Safety Barrier Guidelines for Home Pools”, some basic guidelines for preventing a child from climbing over a barrier include;
Solid Barrier – no indentations or protrusions should be present, other than normal construction tolerances and masonry joints.
Fence Made Up Of Horizontal and Vertical Members – if the space between the tops of the horizontal members is less than 45" (1,140 mm), the horizontal members should be on the swimming pool side of the fence. The spacing of the vertical members should not exceed 1-3/4" (44 mm). This size is based on the foot width of a young child and is intended to reduce the potential for a child to gain a foothold. Any decorative cutouts in the fence, the space within the cutouts should not exceed 1-3/4" (44 mm). If the difference between the tops of the horizontal members is more than 45" (1,140 mm), the horizontal members can be on the side of the fence facing away from the pool. The spacing between vertical members should not exceed 4" (100 mm). This size is based on the head breadth and chest depth of a young child and is intended to prevent a child from passing through an opening. Again, if there are any decorative cutouts in the fence, the space within the cutouts should not exceed 1-3/4" (44 mm).
Chain Link Fence – the mesh size should not exceed 1-1/4" (32 mm) square unless slats, fastened at the top or bottom of the fence, are used to reduce mesh openings to no more than 1-3/4" (44 mm).
Fence Made Up Of Diagonal Members (Lattice) – the maximum opening in the lattice should not exceed 1-3/4" (44 mm).
Above Ground Pools – above ground pools should have barriers. The pool structure itself serves as a barrier or a barrier is mounted on top of the pool structure. There are two possible ways to prevent young children from climbing up into an above ground pool. The steps or ladder can be designed to be secured, locked or removed to prevent access, or, the steps or ladder can be surrounded by a barrier as previously described.
Some basic guidelines for preventing a child from getting under a barrier include;
Pool Barrier – the maximum clearance at the bottom of the barrier should not exceed 4" (100 mm) above grade, when the measurement is done on the side of the barrier facing away from the pool.
Above Ground Pool with Barrier on Top of Pool – if an above ground pool has a barrier on the top of the pool, the maximum vertical clearance between the top of the pool and the bottom of the barrier should not exceed 4" (100 mm).
Gates – swimming pool barriers should be equipped with a gate or gates which restrict access to the pool. A locking device should be included in the gate design. Gates should open out from the pool and should be self-closing and self-latching. If a gate is properly designed, even if the gate is not completely latched, a young child pushing on the gate in order to enter the pool area will at least close the gate and may actually engage the latch. When the release mechanism of the self-latching device is less than 54" (1,370 mm) from the bottom of the gate, the release mechanism for the gate should be at least 3" (75 mm) below the top of the gate on the side facing the pool. Placing the release mechanism at this height prevents a young child from reaching over the top of a gate and releasing the latch. The gate and barrier should have no opening greater than 1/2" (12 mm) within 18" (455 mm) of the latch release mechanism. This prevents a young child from reaching through the gate and releasing the latch.10
Standards – To aid in the proper design, construction, operation, sanitation, and safety of new construction pools and renovation of existing swimming pools and spas, the Association of Pool and Spa Professionals (APSA) has created, or is in the process of creating, a number of American National Standards Institute (ANSI) standards.
Another potential problem in swimming pools and spas is entrapment of pool users (especially young children) at suction fittings. The IBC and IRC include prescriptive safety measures intended to provide the safest possible recirculation system based on current science. These codes require that all pools and spas have dual drains that incorporate American Society of Mechanical Engineers (ASME) A112.19.8 listed suction fittings (drain covers), single 18" × 23" (460 mm × 585 mm) grates or larger, or, single approved channel drains. These systems should also incorporate ASME A112.19.17 listed safety vacuum release systems.
ASME A112.19.8 “Suction Fittings for Use in Swimming Pools, Wading Pools, Spas and Hot Tubs” establishes performance and material requirements for suction fittings, which provide the first line of defense against all entrapment hazards. ASME A112.19.17 “Manufactured Safety Vacuum Release Systems for Residential and Commercial Swimming Pool. Spa, Hot Tub and Wading Pool Suction Systems” establishes performance criteria for devices and systems intended to function as emergency vacuum breakers in case of entrapment.11
Some of these standards along with their scope include12;
ANSI/NSPI-1 2003 “American National Standard for Public Swimming Pools” – covers public swimming pools to be used for bathing and operated by an owner, licensee, or concessionaire, regardless of whether a fee is charged for use. Public pools covered by this standard include Class A (used for competitive aquatic sports), Class B and C (intended for public or semi-public recreational swimming, and Class F (wading).
ANSI/NSPI-3 1999 “American National Standard for Permanently Installed Residential Spas” – covers permanently installed residential spas that are used for bathing and are operated by an owner. This standard is meant to cover certain aspects of the design, equipment, operation, installation, new construction, and rehabilitation of spas.
ANSI/NSPI-4 2007 “American National Standard for Above-ground/On-ground Residential Swimming Pools” – describes certain criteria for the design, manufacturing, testing, care, and use of above-ground/on-ground residential (Type O) non-diving pools and their components.
ANSI/NSPI-5 2003 “American National Standard for Residential In-ground Swimming Pools” – applies to permanently installed residential in-ground swimming pools intended for noncommercial use as a swimming pool by not more than three owner families and their guests and exceeding 24" (60 cm) in water depth and having a volume over 3,250 gallons (12,300 L). It covers specifications for new construction and rehabilitation for residential in-ground swimming pools and includes design, equipment, operation, and installation.
ANSI/IAF-8 2005 “Model Barrier Code for Residential Swimming Pools, Spas and Hot Tubs” – states requirements to establish layers of protection for young children against the potential for drowning and near-drowning in residential swimming pools, spa and hot tubs by limiting or delaying their access to the pool area.
APSP-10 “Standard for Performance Rating and Labeling of Pumps and Pump Motors Used on Swimming Pools, Wading Pools, Spas, Hot Tubs, Whirlpool Baths, and Water Features” – covers performance and labeling criteria for pumps and pump motors used in circulation systems on residential and public swimming pools, wading pools, spas, hot tubs, whirlpool baths, and water features. This standard applies to new and replacement installations.
International Building Code (IBC) provides basic information for swimming pool construction in Chapter 21 Masonry, Section 2103.5 and 2103.10.
These are just some of the representative standards available for swimming pools and spas. For more pool standards, complete standards or for updated standards please refer to the Association of Pool and Spa Professionals (APSP) website at www.apsp.org. For more information on your local pool and spa codes please visit the International Aquatic Foundation (IAF) website at www.iafh2o.org/.
1 TCA Handbook for Ceramic Tile Installation 45th Edition. Tile Council of North America, Inc. Anderson, SC, 2007, page 12.
2 Technical Committee Structural Engineering Work Group (December 1991) Shrinkage and Swelling of Reinforced Concrete Pools Effects On The Bonding Properties of Ceramic Cladding. Postfach, Switzerland: Bundesfachverband Öffentliche Bäder E.V.
3 TCA Handbook for Ceramic Tile Installation 45th Edition. Tile Council of North America, Inc. Anderson, SC, 2007, page 79.
4 Hunsaker, D.J. Pools from the Ground Up. Retrieved 5/8/2008, from http://www.chh20.com?Articles/PoolsfromtheGroundUp.aspx.
5 Water stop, Retrieved 7/1/2008 from http://www.alibaba.com.
6 Expansion Joint, Retrieved 7/1/2008 from http://www.alibaba.com.
7 Tom Harris How Swimming Pools Work, Retrieved 1/15/2008 from http://home.howstuffworks.com/swimming-pool2.htm.
8 Robledo, Rebecca (February 13, 2006). Windows to the Underworld: Designing and Building with Underwater Windows, Retrieved 7/3/2008 from http://www.allbusiness.com/arts-entertainment-recreation/869164-1.html.
9 TCA Handbook for Ceramic Tile Installation 45th Edition. Tile Council of North America, Inc. Anderson, SC, 2007, page 79.
10 United States Consumer Product Safety Commission. Safety Barriers Guidelines for Home Pools. Washington D.C.: United States Consumer Product Safety Commission.
11 Duren, Gary S. (2008, September). The Evolution of Pool and Spa Entrapment Prevention. Building Safety Journal, 51–52.
12 Standards. http://www.apsp.org/52/index.aspx.