8.32.160   Water recirculation and filtering system.
   A.   Generally. The water recirculation system, consisting primarily of piping, pumps, filters, water conditioning and disinfecting equipment, together with other standard accessory equipment, shall be adequate to clarity and disinfect the entire contents of the pool in eight hours or less. Except that indoor exercise pools shall be designed to provide a six-hour turnover. The recirculation system shall operate continuously when the pool is open for use.
   B.   Piping. Piping systems shall be:
      1.   Designed to carry the required quantity of water at a velocity of not more than ten feet per second when located on the discharge side of a pump and not more than six feet per second when located on the suction side of a pump, unless accompanied by an approved hydraulic design;
      2.   Of sufficient strength to withstand operating pressure;
      3.   Made of nontoxic material;
      4.   Reasonably resistant to corrosion under conditions of operation;
      5.   Installed so that pipes and fittings which pass through the pool structure shall not project in a manner which is hazardous to users of the facility;
      6.   Meet or exceed National Sanitation Foundation standards.
   C.   Identification. Piping systems shall be identified by name tags or appropriate colors painted or located at conspicuous points.
   D.   Hair Strainer. The recirculation system shall include a removable strainer to prevent hair, lint, etc., from reaching the pump and filters. Strainers shall be of corrosion-resistant material, with openings having a total area equal to four times the area of the recirculation pump suction pipe.
   E.   Pool Cleaning System. A pool vacuum cleaning system shall be provided. In integral systems, connection shall be provided in sufficient number and located in the pool walls and said connection is recommended to be at least ten inches below the water line. In addition, automatic or self-cleaning systems may be installed if they are approved by the department. Vacuum systems are to be installed with positive-type shutoff valves in the equipment area. Vacuum system shall be operational only when the vacuum lines are attached during the cleaning process. Vacuum inlets are to be installed with International Association of Plumbing and Mechanical Officials-approved safety covers.
   F.   Inlets. Adjustable pool wall inlets shall be provided on all pools. Inlets shall be of sufficient number, properly designed, sized and installed to produce uniform circulation throughout the pool. There shall be a minimum of six inlets. At least one inlet shall be located within five feet of each corner and in each step alcove. Inlets shall be on a closed loop piping system. Where the width of the pool exceeds thirty feet, bottom returns will also be required. Bottom returns shall be flush with the pool bottom or of such design as to prevent injury to bathers. Returns will be considered to have an area of influence described by a radius of fifteen feet.
   G.   Drains. Pools shall be equipped with at least one main drain located in the deepest portion. Drains shall be covered by grating, which are not readily removable by bathers and which have safe openings at least four times the area of the drain pipe. Drains shall be spaced at intervals of not greater than one each twenty feet of pool width in the deepest portion. All drains shall have appropriate plumbing features so as to prevent the possibility of entrapping suction.
   H.   Water Treatment Chemical feeders, mixing tank, and other equipment maybe required where the continuous addition of certain chemicals is deemed by the department to be necessary for the treatment and filtration process.
   I.   Flow Indicator. An accurate rate-of-flow indicator shall be installed and located so that the rate of recirculation will be indicated. Indicators shall be accurate to five percent under all conditions of flow. The indicator shall have a range of at least one hundred fifty percent of normal flow rate.
   J.   Sight Glass. Pressure filter systems shall be equipped with a sight glass installed on the waste discharge pipe.
   K.   Air Relief Valves. Each pressure filter shall be equipped with an air relief piping system connected at an accessible point near the crown. Automatic air relief systems may be used in lieu of manual systems.
   L.   Access to Equipment. Filters shall be designed, located and constructed to permit removal of filter manhole covers or heads for inspection purposes and replacement or repair of the filter elements or media. No filter or filtration system shall be installed beneath the surface of the ground or within any enclosure without adequate provision of access for inspection and maintenance.
   M.   Filtration Rate—Sand. The rate of filtration in high-rate filters shall not exceed an equivalent of twenty-five gallons per minute per square foot. Sufficient surface area of filter media shall be provided to achieve this rate.
   N.   Filtration Rate—Diatomaceous Earth. The rate of filtration of diatomaceous earth filters shall not exceed two gallons per minute per square foot of effective surface area.
   O.   Filtration Rate—Cartridge Type. The rate of filtration of cartridge filters shall not exceed 0.375 gallons per minute per square foot of effective surface area.
   P.   Acceptable Filters. Only those filter types which meet the standards set forth by the National Sanitation Foundation will be acceptable.
   Q.   Gauges. Pressure gauges shall be installed on the inlet and outlet manifold of filters.
   R.   Cross-connection Control. Cross-connections between potable water and the circulation system or water reservoir of any pool are prohibited. Potable water for make-up water purposes may only be introduced into the reservoir across an air gap of at least twice the diameter of the pipe, not less than six inches above the overflow level, three inches above the overflow rim of a float-controlled make-up water feed tank, or by a backflow prevention device meeting American Water Works Association standards.
(Ord. 1990-81 § 7, 1990: Ord. 1984-42 (part), 1984: prior code § 23.60.010(P))