D.C. Mun. Regs. tit. 25, r. 25-C410
A circulation system consisting of pumps, piping, return inlets and suction outlets, filters, and other necessary equipment shall be provided for complete circulation of water within the swimming pool, spa pool, or sauna.
Circulation system equipment shall be designed to turnover one hundred percent (100%) of the nominal pool water volume in the amount of time specified in Table 604.2 of the 2012 International Swimming Pool and Spa Code (ISPSC). The system shall be designed to give the required turnover time based on the manufacturer's recommended maximum pressure and flow of the filter in clean media condition.
TABLE 604.2 TURNOVER TIME
CLASS OF POOL | MAXIMUM TURNOVER TIME" (liours) |
D-1 | 2 |
D-2 with less than 24 inches water depth | 1 |
D-2 with 24 inches or greater water depth | 2 |
D-3 | 1 |
D-4 | 2 |
D-5 | 1 |
D-6 | 1 |
a Pools with a sand bottom require a one (1) hour turnover time.
Circulation systems shall circulate treated and filtered water for twenty-four (24) hours a day.
The circulation rate shall be permitted to be reduced during periods that the pool is closed to the public, provided that acceptable water clarity conditions are met prior to reopening the pool for public use. At no time shall the circulation rate be zero.
Surface skimming systems shall be in accordance with Table 604.3 of the 2012 International Swimming Pool and Spa Code (ISPSC).
TABLE 604.3 SURFACE SKIMMING SYSTEMS
CLASS OF POOL | SURFACE SKIMMING SYSTEM |
D-1 | Zero-depth trench located at static water level or other skimming systems |
D-2 | Auto skimmer, zero depth trench or gutters |
D-3 | Auto skimmer, zero depth trench or perimeter device |
D-4 | Single or multiple skimmer devices for skimming flow |
D-5 | Skimmers prohibited m side area |
D-6 | Auto skimmer, zero depth trench, or gutter |
The installation of skimmers in the side areas of D-5 pools is prohibited.
D.C. Mun. Regs. tit. 25, r. 25-C410