Current through August 26, 2024
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.
