Section 435.06 - Water Circulation and Filtration Systems(1) All swimming, wading and special purpose pools shall be equipped and operated with a system for recirculation and purification of the pool water. This system shall be capable of maintaining the water quality standards of 105 CMR 435.28 through 435.31. The over-all recirculation and purification system shall be so designed and constructed that the entire volume of the pool can be recirculated and filtered as follows: (a) swimming pools - once every eight hours,(b) wading pools - once every four hours,(c) special purpose pools - once every 1/2 hour,(d) water slide flumes - once every hour.(2) The equipment of the recirculation and purification system shall include: (c) hair and lint strainers;(d) provision for chemical feed;(e) provision for bactericidal treatment;(f) filter effluent flowmeter or meters;(g) balancing or float-control tank or above-rim fill-spout;(h) test kit(s) will be available to meet the requirements of 105 CMR 435.29 and must be capable of distinguishing free residual chlorine and combined chlorine;(i) all other equipment necessary to make the particular treatment process complete and efficiently operable.(3) The maximum permissible design filtration rate for pressure or gravity filters using sand or equivalent media shall be three gallons per minute per square foot of filter surface area. High rate filters shall not exceed 15 gallons per minute per square foot unless otherwise approved by the National Sanitation Foundation. The maximum permissible design filtration rate for all types of diatomaceous earth filters shall be 1.5 gallons per minute per square foot of filter area without continuous body feed and two gallons per minute per square foot with continuous body feed. The maximum permissible design filter rate for cartridge-type filters shall be 0.375 gallons per minute per square foot of filter area. One complete set of cartridges shall be available on the premises at all times to facilitate cleaning. Any filtration system or filtration rate other than those included in 105 CMR 435.00 may only be installed or used with the written approval of the Board of Health.(4) Suitable automatic equipment shall be provided and so installed as to permit adequate disinfection of all the pool water. Hypochlorinators shall be dependable in operation and equipped with a calibrated controlling device capable of being finely adjusted to the required rates, and shall have a feed-rate capacity of at least three pounds of chlorine per 24 hours per 10,000 gallons of pool capacity for all outdoor pools, and at least one pound of chlorine per 24 hours per 15,000 gallons of pool capacity for all indoor pools. Chlorine gas feeders and containers are prohibited.
(5) Where bromine is used as a disinfectant the equipment must provide for feeding on a continuous basis.(6) Filters, hair catchers, recirculation pumps, chemical and filter-aid feeders, chlorinators, operating valves, and other equipment shall be identified and easily accessible for operation and maintenance purposes.(7) Where carbondioxide (CO2) is used as a method of pH control, the following shall be provided:(a) CO2 shall be injected into the recirculation pipe. The recirculation pipe shall be of sufficient size and length to provide a minimum of five second contact time prior to bather contact.(b) CO 2 cylinders shall be anchored to prevent damage. Cylinders shall be inaccessible to the general public.(c) CO 2 cylinders should be stored in a protective enclosure at the exterior of occupied structures. If CO2 cylinders are located in the interior of occupied structures within an enclosed space of less than 60 square feet, they shall be placed in a ventilated enclosure. A louvered fresh air intake shall be provided near the ceiling. Mechanical exhaust ventilation shall be provided at the rate of one air change every three minutes and take suction from the floor as far as practical from the door and fresh air intake. Exhausted air shall be ducted to the exterior of the building through a continuous pipe of at least 11/2 inches in diameter with the point of discharge so located as not to contaminate air inlets to any rooms or structures.