North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 18 - ENVIRONMENTAL HEALTH › Subchapter A - SANITATION › Section .2500 - PUBLIC SWIMMING POOLS › Section 18A .2518 - CIRCULATION SYSTEM

Current through Register Vol. 39, No. 2, July 15, 2024
(a)
				  Public swimming pools shall be equipped with a water circulation
				  system.
(b) The water circulation
				  system shall circulate and filter the entire volume of public swimming pool
				  water four times or more in 24 hours. The water circulation system shall be
				  operated 24 hours per day at no more than the maximum velocity allowed under
				  Paragraph (d) of this Rule during the operating dates set out in the
				  permit.
(c) The water circulation
				  system piping shall be designed and installed so that the flow from the public
				  swimming pool shall be from main drains or the surface overflow system. If both
				  main drains and a surface overflow system are used, the water circulation
				  system piping shall be designed such that the flow of water from the public
				  swimming pool is simultaneous from the surface overflow system and the main
				  drains. Skimmer piping constructed after May 1, 2010 shall be sized to handle
				  100 percent of the flow rate determined by the Registered Design Professional
				  in the pool design. Perimeter overflow system piping constructed after May 1,
				  2010 shall be sized to handle 100 percent of the flow rate determined by the
				  Registered Design Professional in the pool design. Main drain piping
				  constructed after May 1, 2010 shall be sized to handle 100 percent of the flow
				  rate determined by the Registered Design Professional in the pool
				  design.
(d) Piping shall be
				  designed to carry water at a maximum velocity not to exceed six feet per second
				  for suction piping and not to exceed 10 feet per second for discharge piping,
				  except for copper pipe where the velocity shall not exceed eight feet per
				  second for discharge piping. Piping shall comply with NSF/ANSI Standard 14
				  Plastics Piping System Components and Related Materials, incorporated by
				  reference, including any subsequent amendments or editions, and available at
http://webstore.ansi.org/
at a
				  cost of one hundred sixty-five dollars ($165.00), and be free of visible water
				  leaks. Public swimming pools constructed after the effective date of this Rule
				  shall use plastic pipe made of a minimum of Schedule 40 PVC. Flexible pipe
				  shall not be used, except that flexible PVC hoses that meet the requirements of
				  NSF/ANSI/CAN Standard 50 Equipment and Chemicals for Swimming Pools, Spas, Hot
				  Tubs, and Other Recreational Water Facilities, incorporated by reference,
				  including any subsequent amendments or editions, and available at
http://webstore.ansi.org/
at a
				  cost of five hundred eighty dollars ($580.00) (hereinafter referred to as "NSF
				  Standard 50"), may be used when affixed to spa shells and rigid pipes do not
				  provide the necessary angles to connect water circulation system components.
				  Exposed pipes and valves shall be identified by a color code with a legend or
				  labels.
(e) The water circulation
				  system shall have a strainer with a basket to prevent hair, lint, and other
				  debris from reaching the pump. The owner of the public swimming pool shall keep
				  a spare strainer basket onsite at the public swimming pool. Strainers shall be
				  designed for use in pools with openings not more than 1/4 inch (6.4 mm) in size
				  that provide a free flow area at least four times the cross-section area of the
				  pump suction line and are accessible for daily cleaning.
(f) A swimming pool shall have a vacuum
				  cleaning system to remove debris and foreign material that settles to the
				  bottom of the swimming pool. Integral vacuum ports shall be located on the pool
				  wall at least six inches and no greater than 18 inches below the water level.
				  Skimmer vacuums may be used when connected to two or fewer skimmers that are
				  isolated from the remaining water circulation system piping. Integral vacuum
				  cleaning systems shall have valves and protective caps. Integral vacuum ports
				  constructed after May 1, 2010 shall have self-closing caps designed to be
				  opened with a tool. Portable vacuum equipment may be used to meet the
				  requirements of this Rule.
(g) A
				  flow meter, reading in gallons per minute, shall be installed in accordance
				  with the manufacturer's instructions. The flow meter shall measure flows
				  between the minimum circulation turnover rate required in Paragraph (b) of this
				  Rule and the maximum velocity permitted under Paragraph (d) of this Rule and
				  shall be accurate within 10 percent of true flow.
(h) A public swimming pool shall have a pump
				  or pumps with capacity to recirculate the public swimming pool water four times
				  or more in 24 hours. The pump or pumps shall not need to be primed, shall be
				  self-priming, or shall utilize an automated priming device labeled for use in
				  public pools by the manufacturer. Any single speed pump shall be capable of
				  maintaining required water turnover based on headloss calculations provided by
				  a professional engineer licensed under G.S. Chapter 89C, the measurements of a
				  flow meter installed in accordance with the manufacturer's instructions, or an
				  assumed total dynamic head of 65 feet of water. Any variable speed pump or
				  single speed pump utilizing a variable frequency drive shall be capable of
				  maintaining water turnover as required by Paragraph (b) of this Rule based on a
				  pump performance curve provided by the manufacturer and shall maintain the flow
				  rate determined by the Registered Designed Professional in the pool design.
				  Pumps shall be certified by NSF International as meeting NSF Standard 50 or
				  verified by an independent third-party testing laboratory to meet provisions of
				  NSF Standard 50 applicable to pumps. Verification conducted by an independent
				  third-party testing laboratory shall include testing and quality control
				  inspections.
(i) All public
				  swimming pools shall be equipped with water return inlets. The water return
				  inlets shall meet the following requirements:
(1) The water return inlets shall produce a
				  uniform circulation of water and maintain a uniform disinfectant residual
				  throughout the pool;
(2) There
				  shall be at least one water return inlet per 20 gallons per minute of return
				  water flow with a minimum of four water return inlets for any swimming
				  pool;
(3) Water return inlets shall
				  be located so that no part of the swimming pool is more than 25 feet of
				  horizontal distance from the nearest water return inlet; and
(4) Water return inlets shall be replaced
				  when damaged or missing.