With all the different types of piping options available on the market today, it can be difficult to know what type of pipe will appropriately suit your pool’s needs. Choosing swimming pool piping can be tricky because different applications require different types of pipe. Often times, swimming pool piping is chosen on a case by case scenario. When designing a swimming pool, it is crucial to choose the most appropriate types of pipe, pipe fixtures, and pipe furnishings. When chosen correctly, proper pipe selections can maximize the lifespan of your pool and provide a safe environment for your patrons.
Today, the industry standard for piping beneath the pool floor is concrete encased Schedule 40 PVC. In certain situations, it is preferable to use Schedule 80 PVC in lieu of Schedule 40. Schedule 80 is a stronger, more durable pipe that is often used when there are expansive soils in the area. If expansive soils are present, additional attention should be given to buried pool plumbing that is not under the pool shell and not encased in concrete. Many times, pipe failures occur at the transition points. A common transition point is the location where the below grade concrete encased pool piping meets a section of pipe that is not concrete encased. Pipe failures are common at these locations, especially if expansive soils are present. In order to minimize risk, it is important to always obtain a geotechnical report and to follow the recommendations provided within.
As a general rule, all exposed piping connected to the swimming pool system should be Schedule 80 PVC. This includes the large majority of the piping located in the mechanical room including the recirculation piping, filter face piping, and even the chemical feed lines from the chemical feeders to the recirculation line. Heater piping, however, should be connected to the swimming pool system with CPVC. It is possible to use short sections of stainless steel or copper piping to serve as heat sinks if the heat source is of a high enough temperature to adversely affect the pipe. For pool heating systems, it is believed that copper piping has the advantage of creating a heat dissipation line. This is beneficial should there be a malfunction in the heater valving which permits hot water to siphon back into the pipes if the pressure system (filter pump or inline pump) fails. However, it is not recommended to use copper piping for the entire length of pool heating loops. Copper piping, over a period of time, can sometimes lead to elevated levels of copper in the pool water and the eventual staining of pool finishes.
Besides choosing the types of pipe to use, it is important to use the proper fittings and furnishings to accompany the pipe. Valves, for example, are vital for proper functionality and operation of a swimming pool system. Valves 3” and larger should be butterfly type valves while valves smaller than 3” are generally PVC true union ball valves. All butterfly valves 8” and larger should be fitted with a watertight gear operator. When check valves are used, they should be located at least five pipe diameters away from pumps and fittings. Modulating float valves are used primarily in surge/balance tanks. These valves help to control the level of water in the surge tank itself. Modulating float valves should have a PVC body and a stainless steel wafer disc. It is important to ensure that all hardware is non-corrosive.
Key furnishings that commonly accompany swimming pool piping include link seals, water seals, and water stops. It is critical to know when to use each of these in order to minimize leakage from pipe penetrations. Link seals should be provided for all pipe penetrations when water is on both sides of a wall, or all locations were expansive soils are present. Link seals should provide a flexible watertight penetration. Water seals, on the other hand, should be used when link seals are not appropriate, i.e. when water is not on both sides of the pipe penetration or when expansive soils are not present. Depending on which ACI (American Concrete Institute) criteria that the pool is designed to adhere to, water stops may or may not be needed. ACI 350 requires a water stop to be used at all construction joints and shell penetrations for water containment vessels. ACI 318, however, does not require water stops at construction joints or shell penetrations.
Clearly, choosing the correct type of swimming pool piping and fixtures for your swimming pool can be an in depth process. Applicable local, state, and national code requirements should always be reviewed before selecting swimming pool piping. Current swimming pool owners and operators may want to consider an upgrade to their pool piping systems in order to meet today’s industry standards and to extend the life of their pool.
