16 Del. Admin. Code § 4464-7.0

Current through Register Vol. 28, No. 7, January 1, 2025

Section 4464-7.0 - Filtration System

7.1 General Requirements - Each pool shall have its own filtration system.

7.1.1 All filters shall bear the manufacturer's name, the model #, the surface area and the filter shall be NSF listed. All filtration systems shall be sized such that the maximum allowable filtration rates are not exceeded and shall be operated such that the passage of unfiltered water will be prevented.

7.1.2 The filter effluent water shall have a turbidity of one (1) NTU or less.

7.1.3 All filters shall be capable of being totally drained through a manual valve or by disconnecting a union, and all filtration surfaces shall be accessible for inspection, maintenance or replacement.

7.1.4 Filters that require backwashing shall have a pressure gauge(s) for determining the time to backwash, and a site glass for observing the backwash water clarity.

7.1.5 The backwash discharge line shall terminate above the drain entry point by a distance of at least twice its diameter.

7.1.6 All pressure filters shall be equipped with manual or automatic air release valves, or shall be self-purging.

7.1.7 If a manual air release valve is present, specific instructions explaining its use shall be provided and shall be conspicuously posted on or near the filter.

7.1.8 In multiple filter installations filter piping shall be valved such that each filter can be isolated for repairs, while other filters remain in service.

7.2 Rapid Sand Filters

7.2.1 All media shall meet all of the specifications of the filter manufacturer.

7.2.2 In multiple filter installations filter piping shall be valved such that each filter can be individually backwashed.

7.2.3 The filtration rate for rapid sand filters shall not exceed three (3) gpm per square foot of filter area, or the NSF listed flow rate, whichever is less.

7.3 High Rate Sand Filters

7.3.1 All media shall meet all of the specifications of the filter manufacturer.

7.3.2 The filtration rate for high rate sand filters shall not exceed twenty (20) gpm per square foot of filter area, or the NSF listed flow rate, whichever is less.

7.4 Diatomaceous Earth Filters

7.4.1 If diatomaceous earth filters are equipped with a pressure type separation tank, there shall be no manual valves on the effluent line, and the following statement or equivalent shall be conspicuously posted on the top of the separation tank and at the pump control switch "Do not start the pump without opening the manual air release on the separation tank and checking to make sure that the top of the separation tank is securely attached."

7.4.2 Any manufacturer's instructions for the proper use of this separation tank shall display either on the top of the separation tank or on the wall nearby. The filtration rate for diatomaceous earth filters shall not exceed two (2) gpm per square foot of filter area, or the NSF listed flow rate, whichever is less.

7.4.3 Diatomaceous earth filters that have an NSF listing for slurry feed shall not exceed a filtration rate of 2.5 gpm per square foot of filter area.

7.5 Cartridge Filters

7.5.1 All pools with cartridge filtration systems shall have at least one (1) spare cartridge for each cartridge in use, which is clean and ready for installation, along with at least one (1) vat which is capable of submerging all of the cartridges from one filter vessel.

7.5.2 Pools with modular media cartridge filtration shall have at least one (1) spare cartridge for each type of cartridge in use, which is clean and ready for installation.

7.5.3 When cartridges become clogged to the extent that cleaning does not restore them, or they become damaged, they shall be discarded.

7.5.4 The filtration rate for cartridge filters shall not exceed three hundred seventy-five one thousandths (.375) gpm per square foot of filter area, or the NSF design listed flow rate, whichever is less.

16 Del. Admin. Code § 4464-7.0

19 DE Reg. 309( 10/1/2015) (Final)