specified in section
Regulations of Connecticut State Agencies, any annular space between the
outside of the piping or casing and the natural materials penetrated by a well
or geothermal bore hole shall be filled with suitable material to make this
space as impervious to the movement of fluids and competent to support the
piping or casing as are the natural materials surrounding the well or
geothermal bore hole. The annular space for a geothermal bore hole shall be
grouted in accordance with subsection (g) of this section. The driller may fill
the annular space with the natural materials excavated during the drilling of a
water supply well to meet the following requirements:
(1) The annular space shall be filled as
completely as possible from the bottom of the casing to the land surface
without any depressions, voids, holes or channels;
(2) The driller shall employ whatever
techniques are effective for the existing conditions to achieve maximum
density, strength and impermeability of the fill material; and
(3) The surface of the fill material shall be
sloped away from the casing.
(b) In locations where potentially
contaminating or corrosive fluids are encountered, or impermeable natural
materials cannot be adequately placed and compacted to where geologic
conditions or the isolation distance may not be adequate, the annular space
shall be grouted for the full length of the casing, or the portion thereof
below the frost line or pitless adaptor, so that no fluids may move in the zone
needing to be grouted.
driller shall only use the following grouts in the process of drilling wells or
geothermal bore holes, or in the abandonment of wells or geothermal bore holes:
(1) Bentonite cement grout: A mixture of
cement grout or sand cement grout with a minimum of ten (10) per cent bentonite
added to reduce shrinkage.
Bentonite clay grout: A mixture of mined, processed bentonite clay and potable
water with not less than two (2) pounds of bentonite clay for every gallon of
(3) Cement grout: A mixture
of portland cement, sand, and potable water. The mixture is commonly composed
of one (1) bag of portland cement weighing ninety-four (94) pounds, an equal
volume of dry sand, and five (5) to six (6) gallons of water.
(4) Concrete grout: A mixture of portland
cement, sand, gravel and water.
Natural grout: A mixture of water and natural materials excavated during
drilling of a well. The materials shall be placed by whatever techniques are
effective for the existing conditions to achieve maximum density, strength, and
impermeability of the fill material.
(6) Neat cement grout: A mixture of not more
than six (6) gallons of water to one (1) bag of portland cement weighing
ninety-four (94) pounds.
cement grout: A mixture of not more than two (2) parts sand to one (1) part
portland cement, and not more than six (6) gallons of water to each ninety-four
(94) pound bag of portland cement.
(8) Sand clay grout: A mixture of bentonite
clay and sand in equal proportions, and water.
(d) Notwithstanding subsection (c) of this
section, a well driller shall use salt water resistant grout to seal the
annular spaces in a water supply well when such water supply well is located
within seventy-five (75) feet of a roadway where road salt is applied or in a
coastal area in which the water supply well may be subject to brackish or salt
water. Any additives to the grout other than silica sand and water shall meet
NSF International/American National Standards Institute standard 60.
All closed-loop geothermal bore holes,
upon installation of loop piping, shall be grouted with one of the following
(1) Grout 111, as
developed by Brookhaven National Laboratories for use with copper piping
typically employed in a direct exchange geothermal system, or as directed per
High grade bentonite or thermally enhanced bentonite compounds based upon the
manufacturer's recommendation; or
(3) Other grouting materials approved by the
department in consultation with the Department of Public Health.
(f) Grouts shall be mixed and
installed in accordance with the manufacturer's specifications. Grouts may be
used whether consolidated or unconsolidated formations are encountered. All
closed-loop geothermal system bore holes shall be grouted within seven (7) days
of the completion of drilling. After installation of piping, the bore hole
shall be covered with a protective layer of grout at least one (1) foot thick
and three (3) feet in diameter, centered over the bore hole. Detectable
underground tape shall be installed above all bore hole locations.
(g) All closed-loop geothermal system bore
holes shall be filled using the tremie method. The entire bore hole shall be
filled with grout beginning at the bottom of the bore hole. The tremie employed
shall be properly sized for the type of grout used, the ground conditions
encountered, and the type of loop system installed. The minimum bore hole
diameter shall be that specified by the manufacturer and subject to industry
approved standards. Drilling mud and cuttings shall not be mixed into the bore