Drainage grates may be something swimmers are used to stepping over but those within the industry understand the importance of a carefully selected and professionally installed drainage system. Pool + Spa Magazine spoke to several drainage guru's to uncover the latest products and methods available in the market.
Prior to 1970, most pools were constructed as scum gutter pools, or with localised skimmer boxes. The descriptive "scum gutter" equipped pool typically has the entire inner perimeter of the pool stepped down to a wide ledge at the required mean pool water level, the ledge incorporates an open drain or a slotted grill covered drainage system which conveys overflowing pool water to the filtration plant (usually) via an underground catchment and top-up/balance tank. Often the remaining pool wall is upto 12inches/300mm higher than the scum gutter eliminating the possibility that pool water can overflow onto the adjacent pool surround.
There are several problems with this type of drainage; the necessary drop to the water level makes it difficult for lifeguards to see all areas of the pool, there is movement of soiled water from less of the total surface of the pool, cleaning and removal of debris is difficult unless you are in the pool and aesthetically, the scum gutters just don't stack up.
The term Wetdeck is often used as a generic term for the current state-of-the-art gutter and grate design. However, Wetdeck is a registered trademark of Swimplex Aquatics Pty Ltd. International Quadratics & Pierce Pool Supplies are a national distributor of Wetdeck® perimeter grate products.
Ted Hannon, Product Sales Manager of Swimplex Aquatics Pty Ltd believes that the change to the new current overflow drainage grates began in the 1990s. "From say 1990, almost all new commercial pools were designed using the current gutter and grate drainage system, and a lot of pre 1970 pools have since been converted during major over-hauls."
"Aesthetically, modern pools with a Wetdeck grate system look much better because the pool water level is at the same or near the same level as the surrounding concourse. There is also an increased safety level for swimmers as they can be seen by guards more easily."
"For domestic pools, only up-market pools and lap pools are being designed with a gutter and grate system, mainly because of the increased cost of forming and pouring the concrete gutter and also the cost of a separate water balance tank and increased reticulation."
Hannon, believes the gutter and grate systems require virtually no maintenance. "Generally, with all plastic grate systems, the only maintenance required is cleaning of body fats and sun cremes that adhere to the surface of the grate. Cleaning is normally done using a pressure washer. At times, stubborn soiling and dissolved minerals like calcium have to be removed by soaking the grate pieces in a weak acid solution and or scrubbing with a non-ammonia based detergent."
Most new commercial pools also utilise a gutter screen (316 stainless steel mesh) to capture debris, typically at the exit point from the gutter into the balance tank. Cleaning of theses screens completes the maintenance of the gutter and grate of a modern commercial pool.
In todays market there are several different types of grates available. Grates are manufactured from a variety of plastics and also from stainless steel. For more information visit www.interquad.com.au or www.swimplex.com.au
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