North Carolina Administrative Code
Title 15A - Environmental Quality
Chapter 02 - ENVIRONMENTAL MANAGEMENT
Subchapter C - WELL CONSTRUCTION STANDARDS
Section .0200 - CRITERIA AND STANDARDS APPLICABLE TO INJECTION WELLS
Section 02C .0222 - GEOTHERMAL AQUEOUS CLOSED-LOOP WELLS
Universal Citation: 15A NC Admin Code 02C .0222
Current through Register Vol. 39, No. 6, September 16, 2024
(a) "Geothermal Aqueous Closed-Loop Wells" means wells that house a subsurface system of closed-loop pipe that circulates potable water only or a mixture of potable water and performance-enhancing additives such as antifreeze, corrosion inhibitors, or scale inhibitors for heating and cooling purposes. Only additives that the Department of Health and Human Services' Division of Public Health determines not to adversely affect human health in compliance with G.S. 130A-5 shall be used.
(b) Permitted by Rule. Aqueous Closed-Loop Geothermal Wells are permitted by rule when constructed and operated in accordance with the rules of this Section.
(c) Individual Permits. If an individual permit is required pursuant to Rule .0217 of this Section, then an application for permit renewal shall be made at least 120 days prior to the expiration date of the permit.
(d) Notification. In addition to the requirements set forth in Rule .0211 of this Section, notification for systems designed to serve a single family residence shall be submitted two or more business days prior to construction and at least 30 days for all other installations. The notification shall be submitted to the Director and to the county health department. The notification shall be made using one form per facility supplied by the Director and shall include:
(1) the well owner's name, address, telephone
number, email address (if available), and whether the owner is a federal,
State, private, public, or other entity. If the well operator is different from
the owner then the same information shall be provided for the well
operator;
(2) the physical location
of the well facility;
(3) a
description of the proposed injection activities;
(4) a scaled, site-specific map showing the
following:
(A) any water supply well and
surface water body; septic system including drainfield, waste application area,
and repair area; and any other potential sources of contamination listed in
Subparagraph (e)(5) of this Rule within 250 feet of the proposed injection
wells;
(B) property boundaries
within 250 feet of the parcel where the proposed wells are located;
and
(C) an arrow orienting the site
to one of the cardinal directions;
(5) the types and concentrations of
additives, if any, to be used in the closed-loop geothermal well system. Only
additives approved by the Department of Health and Human Services shall be used
in any closed loop geothermal well system;
(6) plans and specifications of the surface
and subsurface construction details of the system;
(7) the heating and cooling system
installation contractor's name and certification number, address, email address
(if available), and telephone number;
(8) a description of how the items identified
in Part (d)(4)(A) of this Rule will be protected during well construction;
and
(9) any other information
necessary for the Department to ensure compliance with
G.S.
87-84.
(e) Well Construction.
(1) Only tubing that meets the specifications
in Chapter 12 of the North Carolina Mechanical Code shall be used, which is
hereby incorporated by reference, including subsequent amendments and editions,
and can be accessed at no cost at http://www.ncdoi.com/osfm/.
(2) Drilling fluids and water produced during
well construction shall be managed to prevent direct discharges to surface
waters as well as violations of groundwater and surface water quality
standards. Plans for such preventive measures shall be retained onsite
throughout the construction process.
(3) The well shall be constructed in a manner
that surface water or contaminants from the land surface cannot migrate along
the borehole annulus at any time during or after construction.
(4) The well shall be located such that:
(A) the injection well is not in an area
where surface water or runoff will accumulate around the well due to
depressions, drainage ways, or other landscape features that will concentrate
water around the well; and
(B) the
injection well is not in an area that requires a person to enter confined
spaces to perform sampling and inspection activities.
(5) The horizontal separation between the
geothermal aqueous closed-loop well and potential sources of groundwater
contamination that exist at the time the wells are constructed shall be no less
than as follows:
(A) Building perimeters,
including any attached structures for which a building permit is required, such
as garages, patios, or decks, regardless of foundation construction type 15
feet
(B) Septic systems, including
drainfield, waste application area, and repair area 50 feet
(C) Industrial or municipal sewage or liquid
waste collection or transmission sewer mains constructed to water main
standards as stated in the American Water Works Association (AWWA) Standards
C600 and/or C900 15 feet
(D)
Water-tight sewer lateral lines from a residence or other non-public system to
a sewer main or other wastewater disposal system 15 feet
(E) Other industrial or municipal sewage or
liquid waste collection or transmission sewer mains 25 feet
(F) Chemical or petroleum fuel underground
storage tank systems regulated under
15A NCAC
02N with secondary containment 50
feet
(G) Chemical or petroleum fuel
underground storage tank systems regulated under
15A NCAC
02N without secondary containment 100
feet
(H) Above ground or
underground storage tanks that contain petroleum fuels used for heating
equipment, boilers, or furnaces, except for tanks used solely for storage of
propane, natural gas, or liquefied petroleum gas 50 feet
(I) Land-based or subsurface waste storage or
disposal systems 50 feet
(J)
Gravesites 50 feet
(K) Any other
potential sources of contamination 50 feet
(6) The methods and materials used in
construction shall not threaten the physical and mechanical integrity of the
well and any tubing during its lifetime and shall be compatible with the
proposed injection activities.
(7)
Drilling fluids shall contain only potable water and may be comprised of one or
more of the following:
(A) the formation
material encountered during drilling; and
(B) materials manufactured specifically for
the purpose of borehole conditioning or well construction.
(8) Thermally enhanced bentonite slurry grout
shall be used. This grout shall consist of a mixture of not more than 22
gallons of potable water, one 50-pound bag of thermally enhanced commercial
Wyoming sodium bentonite, and up to 400 pounds of clean dry 50-70 mesh silica
sand. The amount of silica sand may be varied to achieve the thermal
conductivity desired of the grout. The thermally enhanced grout slurry shall
only be used in accordance with the manufacturers written instructions and
shall meet permeability standards in accordance with Rule .0107 of this
Subchapter.
(9) Bentonite grout
shall not be used:
(A) to seal zones of water
with a chloride concentration of 1,500 milligrams per liter or greater as
determined by tests conducted at the time of construction; or
(B) in areas of the State subject to
saltwater intrusion that may expose the grout to water with a chloride
concentration of 1,500 milligrams per liter or greater at any time during the
life of the well.
(10)
No additives that will accelerate the process of hydration shall be used in
grout for thermoplastic well casing.
(11) Grout shall be placed the entire length
of the well boring from the bottom of the boring to land surface or, if
completed below land surface, to the well header or manifold
connection.
(12) The grout shall be
emplaced by one of the following methods:
(A)
Pressure. Grout shall be pumped or forced under pressure through the bottom of
the casing until it fills the borehole or annular space around the casing and
overflows at the surface; or
(B)
Pumping. Grout shall be pumped into place through a hose or pipe extended to
the bottom of the borehole or annular space which can be raised as the grout is
applied. The grout hose or pipe shall remain submerged in grout during the
entire application.
(13)
If temporary outer casing is installed, it shall be removed during grouting of
the borehole in a way that maintains the integrity of the borehole and uniform
grout coverage around the geothermal tubing.
(14) If a permanent outer casing is
installed:
(A) The space between the interior
wall of the casing and the geothermal tubing shall be grouted the entire length
of the well boring from the bottom of the boring to land surface or, if
completed below land surface, to the well header or manifold
connection;
(B) The annular space
between the casing and the borehole shall be grouted with a grout that is
non-reactive with the casing or the formation;
(C) Grout shall extend outward in all
directions from the casing wall to borehole wall and have a thickness equal to
either one-third of the diameter of the outside dimension of the casing or two
inches, whichever is greater; and
(D) In no case shall a well be required to
have an annular grout seal thickness greater than four inches.
(15) Grout emplacement shall not
threaten the physical or mechanical integrity of the well.
(16) The well shall be grouted within seven
days after drilling is complete or before the drilling equipment leaves the
site, whichever occurs first. If the well penetrates any water-bearing zone
that contains contaminated or saline water, the well shall be grouted within
one day after the casing is set.
(17) Prior to removing the equipment from the
site, the top of the casing shall be sealed with a water-tight cap or well
seal, as defined in
G.S.
87-85, to preclude contaminants from entering
the well.
(18) Well head completion
shall be conducted in a manner so as to preclude surficial contaminants from
entering the well.
(f) Well Location. The location of each well boring and appurtenant underground piping leading to all heat exchangers shall be identifiable such that they may be located, repaired, and abandoned as necessary after construction.
(1) The as-built locations of each well
boring, header pit, and appurtenant underground piping shall be recorded on a
scaled site-specific facility map, which shall be retained onsite and
distributed as specified in Subparagraph (i)(1) of this Rule.
(2) Each well boring and header pit shall be
located by a North Carolina registered land surveyor, a GPS receiver, or by
triangulation from at least two permanent features on the site, such as
building foundation corners or property boundary iron pins.
(3) Well boring and appurtenant underground
piping locations shall be identifiable in the field by tracer wire and warning
tape, concrete monuments, or any other method approved by the Director upon a
demonstration that such a method provides a reliable and accurate method of
detection.
(4) If tracer wire and
warning tape are used, then tracer wire consisting of copper wire of at least
14 gauge shall be placed adjacent to all horizontal piping during pipe
installation, and warning tape shall be installed directly above the horizontal
piping approximately 12 inches below final grade.
(5) If concrete monuments are used, then each
monument shall be located directly above each individual well, at the perimeter
corners of each well field, or in the center of each well cluster. Each
concrete monument shall be permanently affixed with an identification plate
constructed of durable, weatherproof, rustproof metal or other material
approved by the Director as equivalent, which shall be stamped with the
following information:
(A) well contractor
name and certification number;
(B)
number and depth of the borings;
(C) grout depth interval;
(D) well construction completion date;
and
(E) identification as a
geothermal well or well field.
(g) Testing.
(1) Closed loop tubing shall pass a pressure
test on-site prior to installation into the borehole. Any closed loop tubing
that fails the pressure test shall either not be used or shall pass a
subsequent pressure test prior to installation and after all leaks have been
located and repaired.
(2) The
closed loop well system shall pass a pressure test after installation and prior
to operation. Any pressure fluctuation other than that due to thermal expansion
and contraction of the testing medium shall be considered a failed test. Any
leaks shall be located and repaired prior to operating the system.
(h) Operation.
(1) The well shall be protected against
damage during construction and use.
(2) The well shall be operated and maintained
in accordance with the manufacturer's specifications throughout its operating
life.
(i) Monitoring and Reporting.
(1) The well owner shall submit the
as-built well locations as documented in accordance with Paragraph (f) of this
Rule to the Director and the appropriate county health department. The well
owner shall also record these documents with the register of deeds of the
county in which the facility is located.
(2) Upon sale or transfer of the property,
the owner shall give a copy of these records to the new property owner or
owners.
(3) The Director may
require any monitoring necessary to ensure compliance with
G.S.
87-84.
(4) The permitee shall report any leaks to
the Division during the lifetime of the well.
(5) A record of the construction,
abandonment, or repairs of the injection well shall be submitted to the
Director within 30 days of completion of the specified activities.
Authority
G.S.
87-87;
87-88;
87-90;
87-94;
87-95;
143-211;
143-214.2(b);
143-215.1A;
143-215.3(a)(1);
143-215.3(c);
Eff. May 1, 2012;
Readopted Eff. September 1,
2019.
Disclaimer: These regulations may not be the most recent version. North Carolina may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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