Section NR 811.51 - Fluoridation Sodium fluoride, sodium fluorosilicate and fluorosilicic acid shall conform to the applicable NSF/ANSI Standard 60 and AWWA standards B701, B702, and B703 in effect at the time of use. Other fluoride compounds which may be available shall be approved by the department. The following specific requirements shall be met:
(1) FLUORIDE CHEMICAL STORAGE. Fluoride chemicals shall be stored in accordance with the following requirements:(a) Fluoride chemicals shall be isolated from other chemicals to prevent contamination.(b) Fluoride chemicals shall be stored in covered or unopened shipping containers and stored inside a building.(c) Unsealed storage units for fluorosilicic acid shall be vented to the atmosphere at a point outside the building. The vent piping shall terminate a minimum of 24 inches above grade with a down-turned U-bend. The vent pipe opening shall be covered with a 24-mesh corrosion resistant screen.(2) FLUORIDE ACID HOUSING. Equipment for feeding fluoride in the acid form and unsealed acid storage containers shall be housed in accordance with the following requirements: (a) All chemical feed equipment, solution tanks, and acid containers shall be housed in a separate room within the pumphouse away from controls, electrical contacts, and other equipment subject to damage. Fluoride chemical feed installations shall be installed in a room separate from all other chemicals.(b) Unsealed acid storage units or solution tanks shall be vented to the outside in accordance with sub. (1).(c) Ventilation shall be provided for the room.(d) Entrance may be from inside the pumphouse but shall include a gasketed, sealed door to minimize the transfer of fumes outside the fluoride room.(3) CHEMICAL FEED INSTALLATIONS. Chemical feed installations shall:(a) Conform to the requirements of ss. NR 811.38 to 811.40.(b) Provide scales, loss-of-weight recorders, liquid level indicators, or graduated feed drums for determining the amount of chemical applied. The method shall be accurate to within 5% of the average daily change in reading. A meter shall be provided on the water fill line to a fluoride saturator.(c) Not allow fluoride addition before lime-soda softening or ion exchange softening.(d) Provide feeders accurate to within 5% of any desired feed rate.(e) Be such that the point of application of fluorosilicic acid, if into a horizontal pipe, shall be in the lower half of the pipe with the chemical injection nozzle projecting upward into the pipe as required by s. NR 811.39 (7) (f).(f) Provide chemical feeder settings in accordance with s. NR 811.39 (2) (c).(g) Provide adequate anti-siphon devices for all fluoride feed pumps or lines as required in s. NR 811.39 (2) (e).(h) Provide soft water for fluoride saturator makeup water. A meter shall be provided on the water fill line to a fluoride saturator.(4) SECONDARY CONTROLS. Secondary control systems for automatically controlled fluoride chemical feed devices shall be provided as a means of reducing the possibility for overfeed; these may include flow or pressure switches or other equivalent devices.(5) DUST CONTROL. Dust control shall meet the following requirements : (a) Provision shall be made for the transfer of dry fluoride compounds from shipping containers to storage bins or hoppers in such a way as to minimize the quantity of fluoride dust which may enter the room in which the equipment is installed. The enclosure shall be provided with an exhaust fan and dust filter which place the hopper under a negative pressure. Air exhausted from fluoride handling equipment shall discharge through a dust filter to the atmosphere outside of the building.(b) Provision shall be made for disposing of empty bags, drums, or barrels in a manner which will minimize exposure to fluoride dust. A floor drain shall be provided to facilitate the hosing of floors.(6) PROTECTIVE EQUIPMENT. Protective clothing, gloves, goggles or face shields and aspirator shall be provided.(7) TESTING EQUIPMENT. Equipment shall be provided for measuring the quantity of fluoride in the water using the analytical methods as specified in s. NR 809.113 (1), Table A. When also feeding phosphates, the electrode method is required. The Alizarin Visual method may be approved only in special cases where the owner can allocate the extra time needed for testing.(8) DILUTION EQUIPMENT. Where dilution of the chemical solution is necessary, a graduated container and transfer pump shall be provided.Wis. Admin. Code Department of Natural Resources § NR 811.51
CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.Amended by, CR 22-074: am. (1) (c), (2) (a), (3) (h) Register January 2024 No. 817, eff. 2/1/2024