R392-302-23. Filtration

(1) The manager shall ensure that a filter system: (a) has a way to isolate each individual filter for backwashing or other service; and (b) is designed to allow the pool operator to easily observe the discharged filter backwash water to determine if the filter system is clean. (2) The manager shall ensure that a pool uses one of the following filters: (a) a rapid rate sand filter; (b) a high-rate sand filter; (c) a precoat filter; or (d) a cartridge filter. (3) The manager shall ensure that each filter complies with the standard NSF/ANSI/CAN 50 -- 2021 Equipment and Chemicals for Swimming Pools, Spas, Hot Tubs, and Other Recreational Water Facilities. (4) The manager shall ensure that a gravity and pressure rapid rate sand filter system is: (a) designed for a filter media rate of three gallons or less per minute per square foot of bed area during maximum head loss; (b) equipped with a filter bed surface area that is sufficient to meet the design rate of flow required by Table 1 for the required turnover; (c) equipped with an influent pressure gauge, vacuum gauge, or compound gauge, as determined by the filter type, to show the condition of each filter; (d) equipped with an air-relief valve at or near the high point of the filter or piping system; and (e) designed with any necessary valve and piping to allow: (i) filtering of pool water; (ii) individual backwashing of each filter: (A) to a system as required in Subsection R392-302-7(4); and (B) at a minimum flow rate of 15 gallons per minute per square foot of filter area; (iii) isolation of each individual filter; (iv) complete drainage of the filtration system; and (v) convenient maintenance, operation, and inspection. (5) The manager shall ensure that a pressure rapid rate sand filter system has an access opening of at least a standard size 11-inch by 15-inch manhole with a cover. (6) The manager shall ensure that each high-rate sand filter system is: (a) designed with a maximum filter media rate in accordance with the manufacturer's recommendations that allows for proper backwash rates; (b) equipped with: (i) a filter bed area sufficient to meet the design flow rate required by Table 1 for the required turnover; (ii) an influent pressure gauge to show the condition of the filter; and (iii) an air-relief valve at or near the high point of the filter; and (c) installed in compliance with the manufacturer's recommendations for each system component. (7) The minimum filter media rate may be reduced as required in Subsection (6)(a) if: (a) more than one high-rate sand filter is installed and operating; (b) the filter system includes a valve downstream of the filters that is designed to regulate the backwash flow rate; or (c) the circulation system is equipped with a variable frequency drive to allow the system flow rate to be adjusted during a backwash cycle. (8) The manager shall ensure that each precoat filter system: (a) is designed with: (i) a filtering area that is compatible with the design pump capacity as required by Subsection R392-302-19(1)(m); (ii) a filter media rate that: (A) is a maximum of two gallons per minute per square foot of effective filtering surface without continuous precoat media feed; or (B) is a maximum of 2-1/2 gallons per minute per square foot with continuous precoat media feed; (b) with a continuous feeder device that feeds precoat media: (i) is accurate to within 10%; (ii) is continuously within a calibrated range that is adjustable from two to six mg/L; and (iii) is at the design capacity of the circulation pump; (c) is designed and constructed with materials that will withstand normal continuous use without significant deformation or deterioration that could adversely affect filter operations; (d) is supplied with potable water delivered through an air gap as required in Section R392-302-6; (e) is equipped with: (i) an influent pressure gauge, vacuum gauge, or a compound gauge to show the condition of the filter; and (ii) an air-relief valve at or near the high point of the filter or piping system; and (f) is designed to facilitate: (i) cleaning by: (A) backwashing; (B) air-bump-assist backwashing; (C) automatic or manual water spray; or (D) agitation; and (ii) complete and rapid draining of the filter system. (9) If fabric is used, the manager shall ensure that filtration area is determined based on effective filtering surfaces. (10) The manager shall ensure that: (a) diatomaceous earth filter backwash water is discharged as required in Subsection R392-302-7(4) through a separation tank; and (b) personal protective equipment suitable for preventing inhalation of diatomaceous earth or other filter aid material is provided for pool operator use. (11) In a vacuum filter system installation where the circulating pump is rated at two horsepower or higher, the manager shall ensure that an adjustable high vacuum automatic shut-off device is provided to prevent damage to the pump. (12) The manager shall ensure that a cartridge filter system is: (a) designed and constructed with: (i) sufficient filter area to meet the design pump capacity as required by Table 1; (ii) a maximum filter media rate of 0.375 gallons per minute per square foot of effective filter area; and (iii) materials that will withstand normal continuous use without significant deformation or deterioration that could adversely affect filter operations, such as polyester fiber; (b) equipped with: (i) an influent pressure gauge, vacuum gauge, or compound gauge to show the condition of the filter; (ii) an extra set of cartridge filters; and (iii) an air-relief valve at or near the high point of the filter system; and (c) cleaned in accordance with the manufacturer's recommendations.