- Shotcrete, gunite, or poured construction?
- What makes a fast pool?
- Concrete vs stainless steel gutter systems?
- Are all stainless steel perimeters the same?
- Recommended water depth for pools with starting platforms
- Should a commercial pool have diving equipment?
- How to determine adequate surge capacity?
- How are filters sized?
- How does a vacuum sand filter work?
- Are all pressure sand filters the same?
- Should a competition pool be 25 yards or 25 meters?
- How many lanes do I need?
- What kind of chemical treatment is best for my pool?
- Do I need a pool consultant?
- What should I look for in a pool builder?
- How can I design my indoor pool to prevent that bad smell?
Most commercial pool builders use shotcrete, a premixed pneumatically applied concrete that is acceptable for most applications. Some use gunite, which is mixed at the nozzle—a process which requires more skill but also more control over the quality of the final product. Gunite is therefore a preferred method but care should be taken to approve only experienced, qualified contractors. The resulting monolithic pool shell formed by shotcrete or gunite is a structurally sound and nicely contoured where it meets the floor. Poured concrete should only be used in poor soil conditions; it is more expensive, often requires expansion joints in the pool, is used by fewer pool contractors, and leaves corners and crevices where the walls join to the floor which collect dirt and are difficult to keep clean.
The simple answer is: fast swimmers. Records are often broken at major meets when top swimmers are in peak form, and there can be dramatic variation in the design of the individual pools where the meets are held. There are, however, two factors in pool design that definitely contribute to speed. The first is deep water; rebound off the floor can slow swimmers down significantly. The second is surge control at the water surface. This is accomplished by wide lanes, wave quelling racing lines, buffers between the racing lines and the pool walls, inlets placed so as not to impede the swimmer’s progress, and surge control gutter systems such as the C-series perimeters by Paddock. In pools that are not built exclusively for competition and deep water and/or wide lanes and buffers are therefore impractical, surge control gutter systems can have a dramatic effect on speed.
Concrete gutters are simply troughs to catch water at the surface and carry it to the filter through a system of drains and piping under the pool deck. They are almost exclusively used in conjunction with poured walls (see above). Concrete gutters cannot recirculate pool water all by themselves: they require a surge tank, along with a secondary network of piping to return filtered water to the pool. The use of concrete gutters, while still preferred by some designers, was practical before specialized pool construction techniques were developed in the 1960’s. Pneumatically applied concrete (shotcrete or gunite) allowed specialized pool contractors to build better pools at lower cost, and the advent of the stainless steel gutter rendered the concrete gutter, with all its limitations, obsolete. Much more than a trough, the stainless gutter is an integrated recirculation system that (1) eliminates buried piping under the shell and/or deck—often the source of leaks over time, (2) eliminates penetrations in the pool shell for return inlet fittings, (3) eliminates the need for a surge tank via surge weirs, without sacrificing rim flow capability for competitive swimming, (4) can be custom made to meet the design requirements of any new or existing pool, and (5) can include surge control features to enhance speed. And, Paddock’s modern gutter systems are as aesthetically pleasing as their concrete predecessors, as demonstrated by the patented, widely popular radius perimeters, and the addition of tile, available with all models.
Ha, Ha—that’s a good one.
In fact, the answer is, of course, no. Aside from all the added features Paddock offers (tile, radius curves, auxiliary surge recovery, etc. ), there are some basic quality standards every gutter system should meet.
Material: Paddock recommends Type 316L stainless steel for its inherently superior corrosion resistance properties. Type 304L (not 304) is acceptable but may require more maintenance.
Fabrication: Some suppliers ship bent pieces to the job site for assembly in the field, while Paddock perimeters are shipped as complete sections that have been fabricated, pre-fitted, and tested in the factory. While a skilled installer can overcome the challenges of assembling the gutter under field conditions, a factory fabricated gutter provides quality assurance that removes all doubt.
Inlets: Filtered water return inlets should be punched in the factory, not field drilled, and should be fitted with nylon jet nozzles to achieve the proper velocity to effect recirculation properly. Field drilled holes in the pressure tube may easily be misplaced, incorrectly sized, or inadvertently left unfiled, leaving metal shavings behind.
Grating: Protective grating should always be perpendicular to the pool wall (not parallel) to allow waves to easily enter the overflow channel. It should also have sufficient open area, at least 30%, for the same reason, and to prevent water from collecting on the grating.
Paddock recommends a minimum of 5 feet for standard (30”) platforms, with 6 feet preferred. Platforms should always be installed in the deep end wherever possible, and removed to storage when not in use. Swimmers should never be allowed to use starting platforms unless they are under the direct supervision of a certified instructor.
Only if there is a formal diving program in place, and if so, diving equipment should then only be used under the direct supervision of a certified diving instructor. One and Three meter diving boards should never be used for recreation.
The rule of thumb is to allow one gallon of storage for every square foot of surface area, although some state codes use other methods. Pools with large shallow areas (zero depth, etc. ), for example, have a higher percentage of surface area as it relates to the total volume in gallons, so obviously the one gallon per square foot of surface area requirement would be far higher than for a standard six lane pool of the same volume, which doesn’t make much sense. Surge weirs allow the pool to function as its own surge tank by allowing the water to be skimmed below the rim when the pool is empty; when swimmers enter, the water level rises, the weirs close automatically, and surge is carried over the rim into the gutter channel. In general, using surge weirs will allow the most pools to get close to the surge capacity requirement without adding a surge tank, since the overflow channel can also be figured in to make up the difference. Paddock’s Compak vacuum sand filter also doubles as a surge containment vessel.
Start with the total volume in gallons and divide by the desired turnover in minutes to get the design flow rate. Since most filters are designed to run at a maximum of 15 gallons per minute per square foot, simply divide the design flow rate by 15 to arrive at the minimum amount of filtration area needed. Then consult filter data tables to consider which options are best. Note that most health departments require a six hour turnover (360 minutes) for standard pools, but many pools—especially those designed for shallow water recreation—should have turnovers of four hours (240 minutes) or less to adequately clean the water.
Most sand filters function by mechanically straining solid impurities from the water. Water from the pool is forced into a pressure vessel, where filtration takes place at the top of the media bed by simple entrapment of particles. This results in shorter filter runs and frequent backwashes as the upper portion of the bed becomes clogged. By contrast, with vacuum sand filtration, water is drawn through the media, where electrostatic attraction between sand grains and the contaminant particles occurs. This process, called depth filtration, utilizes the entire media bed and results in the removal of extremely small particles. Under the vacuum, even tinier colloidal particles group together to form larger particles which can be removed, resulting in the clearest, cleanest water possible. Depth filtration means long filter runs—often four to six weeks, for which the Paddock Compak filters are famous—as opposed to pressure filters which often require daily backwashing, consuming significantly more water.
Theoretically speaking, yes; practically speaking, no. They all do the same thing by essentially the same means, but there is much variety in how they are constructed which does have an impact on their effectiveness. For instance, vertical filters (often called Hi-Flow) work well but take up a lot of room. Multi-cell filters maximize floor space but are often very tall and hard to get in and out of tight spaces. Horizontal filters are less expensive and easier to install (or replace), but the curved side shell means less efficient distribution of influent water above the media bed. Components may vary as well in all these styles mentioned above, and careful consideration should be given to the quality and performance of such things as overdrains, underdrains, valves, pressure relief, manway size, media bed depth, and freeboard. Finally, tanks are available in carbon steel with an interior lining, stainless steel (preferably Type 316L), and fiberglass, and even among fiberglass tanks there are various methods of construction. Care should be taken to investigate all options before deciding on any one type of filter over another.
We still get this question a lot. The short course standard in the United States is 25 yards. But, there are a lot of older 25 meter pools out there. Unless international competition is intended, there is no reason to build a new 25 meter pool. If people in your area are accustomed to swimming in 25 meter pools, a popular option is to build a 25 yard x 25 meter pool and have both options available.
Of course, the width of the pool is a cost issue, but more is always better. Swim meets can be excruciatingly long, and if heats can be combined a lot of time can be saved, even hours. Many older lap pools are six lanes, but eight is recommended, at minimum. Think about it: sixty events, four or five heats each, sun beating down (outside) or five hundred kids, coaches, and parents crammed together (inside) for at least six hours…you get the idea. A related question is deck space, and all we have to say is that the health department recommendation is for minimum deck width, and minimum does not mean adequate. We suggest doubling the minimum if you can. Remember, you can’t build it twice.
There are many perspectives on this, but what you need is a safe, simple, cost-effective sanitation method. The best we’ve seen is calcium-hypocloride in tablet form, and the best cal-hypo unit available is the Acc-Tab system by PPG. Liquid chlorine will work and might be cheaper in your area, but there are safety issues. For more info on this subject, go to www.puraquaproducts.com.
Aquatic consultants should be chosen carefully because they vary in experience, expertise, and price. Be careful—some so-called consultants are simply salesmen in disguise. If you are a small design firm planning a big natatorium, you could benefit from a qualified consultant with errors and omissions insurance. If you are a full service architecture firm, you can probably handle the same job with help from Paddock. For instance, the Rock Hill Aquatic Center featured on this website was built without a specialized aquatic consultant. By contrast, Paddock worked with a consultant on the Fun Valley project, also featured. It might be that, rather than employ a consultant to do complete planning, you might want a plan review only. If you think you need a consultant, contact Paddock and we can recommend one. If you are a consultant, let us help you!
Track record, bonding capability, construction expertise. Never qualify a residential builder for commercial work. If they have not demonstrated the ability to build a project like yours, they are probably not qualified to build yours. See our links page for a list of those pool contractors we recommend based on having completed many successful projects together. You won’t go wrong with any of them.
The best way is to install our Paddock Evacuator System which is specifically designed to improve air quality in your indoor aquatic facility. Our patents pending system captures chloramines at their source and evacuates them from the facility. See www.paddockevacuator.com for more information.