Section 435.10 - Skimming Facilities(1) All swimming, wading and special purpose pools shall be designed so that approximately 50% of the recirculation rate shall be drawn from the top surface of the pool.(2) When skimming devices, or deck drains for water-level deck-type swimming and wading pools are not used, an overflow channel shall extend completely around every swimming and wading pool. The channel, channel outlets and piping shall be capable of removing at least 50% of the recirculated water and shall be equipped to carry away sputum and other floating matter in an effective way. The channel shall be so designed as to accomplish the following results: (a) provide effective skimming action over the entire pool surface;(b) intercept, in addition to the normal overflow, all splash water to prevent flooding or washing of the walkways around the pool;(c) prevent, so far as possible, waters that have entered the channel from being washed back into the pool;(d) provide for easy inspection and cleaning; and(e) present no accident hazard to bathers. Outlet openings of gratings in the overflow channel shall be at least twice the area of the outlet piping. Drainage from the channels can be returned to the pool water recirculation system ahead of the filters (ordinarily at the balancing tanks or at pump suction), provided that, unless channels are self cleaning, provisions shall be made for diverting the channel water to waste when cleaning the channel or walkway.
The overflow channel should provide an acceptable hand hold for bathers and should not be less than three inches deep.
(3) In all swimming, wading and special purpose pools where skimming devices are used they shall satisfy the following requirements:(a) At least one shall be provided for each 500 square feet, or major portion thereof, of pool surface area. When surface skimmers are used in special purpose pools as the sole overflow system, one surface skimmer should be provided for each 100 square feet.(b) Each shall be automatically adjustable to variations in water level over a range of at least three inches .(c) Each shall be designed with a weir length which permits a flow of not less than 20 gallons per minute per lineal foot of weir.(d) Each shall be provided with an easily removable and cleanable basket or screen through which all overflow water must pass to trap solids.(e) Each shall be equipped with a throttling device for balancing purposes.(f) Each shall be designed for a flow-through rate of at least 30 gallons per minute. The total design capacity of all skimmers in any pool shall be approximately 50% of the required filter flow of the recirculation system.(g) Each shall be of substantial, durable, and corrosion resistant material. The freeboard around any pool in which skimming devices are used shall be no more than six inches, unless a hand hold is provided.