Category Archives: Construction

Surge Tanks

A surge tank is a water containing vessel that takes water from a swimming pool perimeter gutter system. Swimmers create waves when they enter a pool, compete, swim laps, exercise or just play. The perimeter gutter system captures these waves, or surge of water, so that they do not rebound back into the pool. A perimeter gutter and surge tank system are important in that they assist competition pool water, or any pool with a gutter system, return to a quiescent state which is a faster pool. Competition or training pools that do not utilize a gutter and surge tank system are slower and antiquated.

Surge tanks are typically constructed of concrete and located in the filter room or under the pool deck adjacent to the swimming pool. Cast-in-place concrete allows the swimming pool designer to size the surge tank as needed to fit the site conditions. Pre-cast surge tanks can be used as well but the dimensions tend to be less flexible. The surge tank size depends upon the surface area of the swimming pool. Most local and state health codes require one (1) gallon of surge capacity for every one (1) sq ft of pool surface area. Only a few health codes require two (2) gallons of surge capacity for every one (1) sq ft of pool surface area. This should be confirmed with local or state health department regulations.

There is a lot going on inside a surge tank. Piping from the perimeter gutter to the surge tank enters at several locations. The number of gutter dropouts depends on the size of the pool. Main re-circulation piping pulls water from the surge tank to the re-circulation pump and filter system before it is chemically treated and returned to the pool. Special consideration is also needed for maintaining atmospheric pressure inside the vessel. Typically, an air relief vent pipe is satisfactory for maintaining this equalization. However, the vent line should be routed independently to atmosphere to ensure that noxious fumes and vapors from the surge tank are not introduced into the filter room or natatorium. A water level controller should be installed in the surge tank as well to monitor the water level and automatically activate the automatic water make up control valve should the water level drop below design levels. An access hatch is always required to access the interior of the surge tank for cleaning and routine maintenance. When surge tanks are constructed under the pool deck adjacent to the pool, they are usually placed next to the deep end of the pool. This approach saves on construction cost as one wall is common with the pool.
Surge tanks are installed on the fastest swimming pools in the world including Olympic Venues, Universities, High Schools, Elementary Schools and Municipal Aquatic Facilities. If your aquatic facility has a competitive pool, training pool or lap pool and a fast pool is desired then you will want a perimeter gutter system complete with a surge tank.

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Swimming Pool Gutters

Perimeter overflow systems are a critical part of any swimming pool. There are two main types of perimeter overflow systems; skimmers and gutters. Skimmers are often times the more simplistic and less expensive options as they are traditionally used for back yard or leisure-style pools. Gutters, however, can be used on any pool type and they can be constructed in an array of different shapes and sizes. Depending on the intended use for the pool, some gutters are better suited than others. The following will discuss the pros and cons of the four most common styles of gutters: deck level, fully recessed, roll-out, and parapet.

Deck Level Gutter

The deck level or “rim flow” overflow system features a gutter lip 1” above the elevation of the pool deck. This design enables even the weakest swimmer to egress with little effort over the water’s edge. This is often the most desirable gutter for the recreational and instructional swimmer. Program heavy natatoriums, where many classes are taught, often choose this design option. Deck level gutters are the least expensive gutter option as they require less concrete and forming compared to some of the other options.

The deck level gutter does not have back curb, therefore, water has the potential to “run” across the gutter grating or splash-out resulting in a wet pool deck. Because the water level in the pool is typically at or above the elevation of the adjacent perimeter slabs, surge tanks often will need to be fitted with overflow piping to prevent flooding.

Fully Recessed Gutter

Competitive swimmers and coaches prefer this design. The pool deck cantilevers over the gutter trough. The top of deck is approximately 12” above the water. The overhang provides the competitive swimmer with a visual reference plane for the underwater wall. The recessed gutter very effectively captures the wave amplitude and keeps the pool decks relatively dry. The disadvantage is that the high overhang makes egress from the pool rather difficult, and as a result, most people choose to use one of the pool ladders. This option is often used for natatoriums where competitive swimming is the predominant programmed activity. It should be noted, however, that fully recessed gutters are typically one of the most expensive gutter options.

Roll-Out Gutter

The roll-out gutter profile combines the features of the fully recessed and deck level configurations. It consists of a gutter lip and grate at the water level. The deck, approximately 5” above the water surface, forms a curb at the rear of the gutter grate. This curb contains much of the wave action and keeps the pool deck relatively free from water escaping the gutter assembly. The low configuration at the water’s edge still allows swimmers to egress easily. Unlike the fully recessed gutter however, the roll-out gutter does not provide competitive swimmers with a visual reference of the end wall above the water surface.

Roll-out Gutter with Parapet

A roll-gutter with parapet combines the roll-out gutter design on the sides of the pool with a parapet on the ends of  the pool. The parapet is very similar to the fully recessed gutter option with a 12” water to deck dimension and a visual reference plane for the underwater wall. The parapet utilizes a 6” curb from the pool deck to top of the gutter where the starting blocks would typically be located. This option is often times used when lap swimming is the primary use, but the pool is also used for other programming activities.

Other Tile Color Options

When discussing pools or water features most people associate them with the color, blue.  Water represents a refreshing, even relaxing or cool feeling of renewal.  This association is one reason why most pools and features contain primarily blue tile finishes or accents.  Nothing is wrong with blue, but in the world of tile there are so many other options that can be explored!

In today’s design, people are wanting something different – Different color palettes, different textures, different shapes, different styles, etc.  The goal is to have their pool or feature stand out and be something unique.   The great thing is, that goal can be achieved!  Pool tile options have expanded well beyond that of the traditional glazed blues and blacks.

When a School, University, Community Center or any other facility would like to carry their “colors” throughout a building this can now include the pool.  The tile industry has increased the color offerings and materials that are applicable to pool installations.  Tile can be a single solid color, speckled, swirled, patterned, clear, iridescent, etc.   One of the other trends in tile is the natural stone-look that can be integrated into the pool.  Several manufacturers have introduced specific tile product series addressing this appearance with color ranges from the white/tans to the greys/black.  The tiles surface texture replicates actual stone and enhances the theme of naturalistic pools.

 

Tiles today are offered in several different sizes and shapes within one pattern as well as offering a variety of color blends.  Colors from reds, greys, whites, greens, beiges, tans and many more can be designed into a pool interior and even be utilized on pool decks.  The possibilities are endless….

 

Thermoplastic Pipe Expansion

Swimming pool piping is design is notorious for including long straight runs of pipe.  For pools that do include long runs of straight pipe sections, consideration may be given to the use of expansion loops or mechanical expansion joints to accommodate thermal expansion and contraction.  The ASTM Standard 2774 references “Underground Installation of Thermoplastic Pressure Piping”. This ASTM Standard 2774 contains specific information on the topic of expansion in pool piping.  Expansion and contraction of thermoplastic pipe is typically due to temperature changes to either the surrounding pipe embedment materials or changes in the pool water traveling in the pipe system. When temperature changes of the thermoplastic pipe does occur, changes to the piping network in the form of elongation or contraction will occur.  Therefore, in piping networks where there may exist sections of the pipe that are straight and without bends, expansion and contraction of the pipe can cause failures in the system.  Swimming pool piping networks that include PVC pipe used in straight runs nearing 100 LF should take special consideration to the potential expansion and contraction of the pool pipe.  In these instances the design of the pool piping system should have the coefficient of expansion calculated for determination if design accommodations for the expansion and contraction should be included.

In cases where expansion and contraction will be significant, inclusion of an expansion loop or even a mechanical expansion joint can be installed.  A pipe loop is a relatively easy item to include within the piping network.   This pipe loop, or offset, can alleviate the bending stresses that can occur when thermoplastic piping systems experience expansion and contraction.  If expansion joints are required, a detail for the expansion loop may include a specific dimension for the offset lengths.  Mechanical expansion joints work like a piston allowing the pipe to elongate or contract within the pipe run.  The installation of mechanical expansion and contraction joints is critical, particularly cleaning debris (sand, rock, dirt) out of the moving parts.  If small particles come in contact with the mechanical joint mechanism the joints seal can become compromised.

In most instances a linear pipe runs without interruption of bends, joints or pipe size changes is not common.  However, in situations where conditions do allow long pipe runs, your design should pay special attention for need of expansion and contraction loops and mechanical joints.

Epoxy Grout

Tile, known for its longevity, has proven to be the most durable finish for pool interiors. Selecting the material, size, shape and color of the tile is just one step in the process. Another consideration is the grout selection. Grout can influence tile appearance significantly. If you choose the right grout, it can blend perfectly with the tile color. Or you can choose a contrasting color to highlight the tile. But that also requires an outstanding tile installation. Selecting your grout can be a very important decision as far as aesthetics go. Additionally, there are two different categories of grout; cementitious grout and epoxy grout. Both options are viable solutions for tiled pools, but with certain design parameters, one typically will make a better solution for a specific installation.
Cementitious grout, otherwise known as sanded grout, has been the longtime solution for pools. The cementitious grout can be applied at either indoor or outdoor pool locations, its color does not fade or change and it comes at a lower cost. But this product has also been noted to have a greater likelihood of having issues down the road. There are typically two main causes of failure, with the first being pool water chemistry. The water chemistry often gets exacerbated in spas due to calcium and/or acid issues. The water will begin to leech minerals from the tile grout, which makes the grout will need to be replaced sooner. The other main cause of failure are tile dots. The dots, in Counsilman-Hunsaker specification, have been limited to where they cannot occupy more than one-third of the depth of the tile. The grout is not allowed to occupy the depth or surface area needed to fill the space between tiles. It should be noted that the dots can still be an issue with the epoxy grouts, but it’s not as likely.
Epoxy grout, a product that has become more widely accepted by the aquatics industry as of 2010, is finding its way on more and more pool projects. The epoxy product is known to last longer, but tends to discolor and typically be more expensive. There will usually be a 25%-35% premium, plus additional installation and labor charges. Applications where movement is critical, such as second floors, are ideal installations for epoxy grout. The grout can be used in outdoor pool applications in freeze-thaw environments, however, certain conditions must exist:
• There cannot be a high-water table
• The tile must be porcelain
• The pool should be winterized with water in it (not completely drained)
The exterior application also brings the concern of fading dark colors over time, darkening of light colors over time and in cases where high MVER/high water table exists, the drain rate of the pool water for maintenance becomes just as critical as the fill rate (nothing greater than one-inch per hour).
In project applications where the budget is limited or in the case where minimum trim tile is being installed, the cementitious grout can be considered as a value engineer option.