Section SPS 390.14 - Circulation systemsA water circulation system consisting of pumps, piping return inlets and suction outlets, filters and other necessary equipment shall be provided that complies with all of the following requirements:
(1).TURNOVER RATE. Circulation system equipment shall be designed to produce a turnover rate as specified in Table 390.14-1 or Table 390.14-2. Note: See ch. SPS 390 Appendix for further information.
Table 390.14-1
Maximum Turnover Ratesa
Area/Basin Typeb | Maximum Turnover Rate (hours)c |
Swimming/Diving | 6 |
Activity | 2d |
Interactive Play Attraction | 0.5 |
Lap Lanes | 6 |
Leisure River | 2 |
Plunge | 1 |
Runout Slide | 1 |
Vortex | 1 |
Wave | 2 |
Cold Soak | 4 |
Wading Pool | 1 |
Whirlpool | 0.5 |
a Calculate an average turnover time for multi-sectional basins.
b For pool types not listed herein, contact the department.
c Based on flow and pressure drop with a clean filter condition.
d Or as otherwise approved by the department.
Table 390.14-2
Therapy/Exercise Turnover Times
Temperature in ºF | Loada (gals/person) | Maximum Turnover Time (hours) |
< 72 - 93 | >= 2,500 | 4 |
< 72 - 93 | >= 450 | 2 |
< 72 - 93 | <= 450 | 1 |
> 93 - 104 | N/A | 0.5 |
N/A Not applicable
a The number of persons is equal to the posted patron load.
Note: A therapy area within a multi-section pool having a temperature of < 93 oF is considered to be an activity pool.
(2). SEPARATE SYSTEMS. The circulation system shall be separate for each public swimming pool or water attraction.(3). SEPARATION FROM SLIDES AND PLAY FEATURES.(a) Except as provided in pars. (b) and (c), public swimming pool or water attraction circulation systems may not serve slide or spray features.(b) A maximum of 10 percent of the required circulation system rate may be provided for the lubrication of slides or to spray features.(c) Flow in excess of the required circulation rate may serve slides and spray features.(4). ACCESSIBILITY. Circulation system equipment, including but not limited to pumps, skimmers, filters, gauges, meters and thermometers, shall be readily accessible for inspection, repair or replacement.(5). COMPONENT STANDARDS. Equipment that is within the scope of ANSI/NSF 50, circulation system components and related materials, shall be listed by an acceptable listing agency to meet ANSI/NSF 50 or equivalent.(6). INSTALLATION. (a) Pool equipment and related piping shall be supported to prevent damage from misalignment and settling.(b) Pool equipment shall be installed in accordance with manufacturer's printed instructions and as specified in this chapter. If there is a conflict between the manufacturer's printed instructions and requirements of this chapter, the requirements of this chapter shall take precedence.(7). VELOCITIES AND PIPE SIZING REQUIREMENTS.(a) Velocities in the circulation system may not exceed: 1. Ten feet per second in discharge piping other than copper.2. Eight feet per second in copper discharge piping.3. Six feet per second in suction piping.4. One and one-half feet per second through suction grates.(b) Pool piping shall be sized to permit the rated flows for filtering and cleaning without exceeding the maximum design head of the pump.(8). GAUGES AND FLOW METERS. (a) A pump suction compound gauge shall be included in all circulation systems.(b) A pump discharge gauge shall be located upstream of all throttling valves.(c) A filter pressure gauge shall be included serving all filters in circulation systems.(d) A flow meter capable of displaying flow during filtration shall be included in all circulation systems.(9). TESTING. Circulation system piping that is installed onsite shall be subjected to an induced static hydraulic pressure test at 25 pounds per square inch for at least one hour.(10). FILTERS. (a)Design. Filters shall be specified so that when operated and maintained in accordance with the manufacturer's printed instructions, the system provides the water clarity required in ch. DHS 172.(b)Maximum flow rate.1. Filters other than high rate sand filters shall be specified so that the maximum flow rate does not exceed those under ANSI/NSF 50.2. High rate sand filters shall be specified so that the maximum flow rate does not exceed 15 gallons per minute per square foot or bed surface area.(c)Pressure release. 1. Pressure-type filters shall be provided with a means to permit the release of internal pressure.2. Filters incorporating an automatic air vent as the principal means of air release shall have a lid that provides a slow and safe release of pressure as a part of the design and have manual air release in addition to the automatic release.3. Separation tanks used in conjunction with a filter tank shall comply with subd. 2.4. The following statement shall be placed within the area of the air release so as to be clearly visible: "WARNING. DO NOT START UP THE SYSTEM AFTER MAINTENANCE WITHOUT FIRST OPENING THE AIR RELEASE AND PROPERLY ASSEMBLING THE FILTER AND SEPARATION TANK."(11). CIRCULATION PIPING. (a) Circulation piping shall be listed as meeting one of the following methods:1. ANSI/NSF 50 by a listing agency acceptable to the department.(b) All circulation piping shall be listed to withhold a pressure 50 percent greater than the maximum design pressure.(12). PUMPS AND MOTORS.(a) All circulation pumps shall be capable of providing the design flow rates at one of the following minimum total dynamic heads:1. Eighty feet for diatomaceous earth filters.2. Seventy feet for sand or cartridge filters.3. Fifty feet for vacuum filters.4. A maximum total dynamic head value recommended by the filter manufacturer that allows the filter to function under all operating conditions.(b) Pumps located below the waterline of a basin shall have isolation valves installed on suction and discharge lines.(c) Pumps located above the waterline of the pool shall be self-priming or the system shall be designed to provide a means for priming.(d) Intake strainers shall be provided upstream of all circulations pumps on pressure filter systems.(e) Mechanical seals shall be corrosion resistant.(13). RETURN INLETS AND SUCTION OUTLETS. (a) Inlets and outlets shall be provided and arranged to produce a uniform circulation of water and maintain the distribution of sanitizer residual throughout the pool.(b)Return inlets. 1. Return inlets shall be designed and installed so as to not constitute a hazard to the patron. Note: An example of an inlet installation constituting a hazard to a patron is an inlet installed on a racing lane cross.
2. There shall be at least 2 inlets per circulation system.3. Except as provided in subd. 4., the velocity of flow through any inlet orifice shall be in the range of 5 to 20 feet per second Note: See ch. SPS 390 Appendix for inlet velocity information.
4. For pools equipped with skimmers the velocity of flow through any inlet orifice shall be in the range of 10 to 20 feet per second.5. Except for leisure rivers, the minimum number of return inlets shall be based on at least one additional inlet per 300 square feet of pool surface area or fraction thereof.6. There shall be at least one wall return inlet for each 10 feet of stairway width, recessed bench length or swimout length or width or fraction thereof.7. Bottom return inlets shall be flush with the basin floor.8. Bottom return inlets shall be considered to have an area of influence of a radius of 10 feet. Note: See ch. SPS 390 Appendix for further explanatory material.
9. Wall return inlets may not extend more than one inch into a basin.10. Except for leisure rivers, there shall be a wall return inlet within 5 feet of each corner of a basin wall.(c)Suction outlets.1. Suction system flow through main drains shall be designed to accommodate 100 percent of the circulation flow rate in accordance with all of the following: a. All basins shall be provided with a suction outlet in the lowest point of the basin in the floor or the wall. Note: For main drains installed in diving wells, see Figure 390.11-1 and Table 390.11-1.
b. Where 2 or more drains connect within the circulation system, all drains minus any one in the set shall be designed to collectively convey 100 percent of the circulation flow rate.c. The distance between the bottom of the suction outlet grate and the opening of the suction pipe shall equal or exceed at least 1.5 times the inside diameter of the suction pipe.2. Suction outlet grates shall comply with at least one of the following requirements: a. A single grate having at least one dimension of length, width, diagonal or diameter that is at least 36 inches.b. Two or more grates of any size separated from other suction outlets by at least 3 feet.3. Suction systems shall be designed so that the maximum flow rates are not exceeded under operating conditions.4. Suction grates and covers shall be listed as conforming to ASME/ANSI A112.19.8.5. The maximum opening of any suction grate shall prevent the passage of a 1/2-inch sphere.6.a. Barriers shall be provided on all wave pool caisson walls.b. Openings in caisson barriers shall prevent the passage of a 4-inch sphere.7. Vacuum fittings are not permitted within public swimming pools or water attractions.(d)Surface skimming systems. 1. Surface skimming systems shall be included in the design of and installed to serve all basins.2. Surface skimming systems shall be designed and constructed to skim the basin surface when the water level is maintained within the operational parameters of the system's rim or weir device.3. Skimmers shall be located so as to maintain effective skimming action.4. Skimmer covers located on a walking surface shall be designed and installed to comply with all of the following requirements:a. The skimmer cover shall be appropriately seated.b. The skimmer cover shall be slip resistant.c. The skimmer cover shall be sufficiently strong so as to withstand normal use.d. The skimmer cover may not create a tripping hazard.5. Equalizer lines shall have an anti-entrapment cover or other entrapment protection in accordance with ASME/ANSI A112.19 when suction fittings are located in the wall of a basin.6. Where automatic skimming devices are used as the sole overflow system, at least one surface skimming device shall be provided for each 500 square feet or fraction thereof of water surface area.7. Circulation systems shall be designed to carry 100 percent of the rated circulation volume through the skimmers.8. The flow rate through automatic skimmers shall be no less than 3 gallons per minute per inch of skimmer weir width. Note: The maximum flow rate through skimmers is determined by the ANSI/NSF 50 rating.
9. Acceptable options for surface skimming systems shall be in accordance with Table 390.14-3. Table 390.14-3
Acceptable Surface Skimming Systems
Pool Type | Acceptable Surface Skimming Systems |
Swimming, whirlpools | Gutters, auto skimmers |
Activity | Auto skimmers, zero-depth trench, gutters |
Leisure River | Single or multiple weirs, gutters, zero-depth trench or auto skimmers |
Plunge | Auto skimmers, zero-depth trench, gutters, weirs |
Vortex | Skimmers are not allowed in the side area |
Wave | Zero-depth trench, skimmers, gutters, perimeter devices |
Zero-Depth Entry | Zero-depth trench, skimmers, gutters, perimeter devices. |
Other | As approved by the department |
10. When a gutter skimming system is used, the system shall be connected to a circulation system with an adequate surge capacity to permit all phases of operation.11.a. Except as provided in subd. 11. b., a zero-depth trench shall extend continuously from within 3 feet of one wall of the basin to within 3 feet of the opposite wall of the basin.b. Where the entire perimeter of the basin consists of a zero-depth entry, 50 percent shall be evenly-distributed zero-depth trench.Wis. Admin. Code Department of Safety and Professional Services SPS 390.14
CR 08-056: cr. Register February 2009 No. 638, eff. 3-1-09; correction in (10) (a) made under s. 13.92(4) (b) 7, Stats., Register February 2009 No. 638; correction in (1), (11) (a) 2., (13) (d) 9. made under s. 13.92(4) (b) 7, Stats., Register December 2011 No. 672.