Section 178-12-010 - GROUND WATER HEAT PUMP WELLS12-010.01Open Loop Heat Pump Wells:1. Water wells intended only to withdraw water must comply with 178 NAC 12004, Potable Water Wells.2. Water wells intended only to inject ground water must comply with Nebraska Department of Environmental Quality's Title 122 - Rules and Regulations for Underground Injection and Mineral Production Wells.12-010.02Closed Loop Heat Pump Wells: Water wells for closed loop heat pump systems must be constructed in accordance with the following standards. 12-010.02A For a closed loop heat pump system that has 10 or more boreholes, the following information must be submitted to the Department a minimum of 14 working days prior to initial construction. 2. Name and address of licensed water well contractor supervising the installation of the heat pump system; and3. A completed copy of the information referenced in 178 NAC 12-003.12A, showing proposed construction and installation of the closed loop heat pump system.12-010.02BLocation: All water wells constructed for closed loop heat pump systems must be located in accordance with 178 NAC 12-003.01. 12-010.02B1Location from a Public Water System Well12-010.02B1a The location of closed loop heat pump wells must comply with 178 NAC 12-003.01C item 1. Be aware that other state and local statutes and regulations may have more restrictive requirements. If locations do not comply with more stringent standards of other applicable state or local regulations, the Department may notify the appropriate authority, which could require the well to be decommissioned.12-010.02B1b Water wells constructed for a closed loop heat pump system must be located more than 100 feet from a non-community public water system well.12-010.02B1c A closed loop heat pump system must be located more than 1,000 feet from a community public water system well. The Department will consider approval for location of closed loop heat pump wells at closer proximity than 1,000 feet horizontal separation distance, when the licensed professional engineer or licensed professional geologist representing the owner(s) of the closed loop heat pump wells, demonstrates to the Director or Director's designee that such location will not constitute a pollution hazard to the safety of the water supply, and that the owner(s) of the community water system has no objection to the location of the closed loop heat pump wells.
The engineer or geologist must submit the supporting data as appropriate to make a case for approval of the proposed location of heat pump wells to the Department 30 working days prior to the date on which action by the Director or Director's designee is desired. The contractor must not begin construction until the Department has approved the location.
12-010.02CBorehole Diameter: The borehole diameter of a closed loop heat pump well must be of sufficient size to allow placement of the pipe and placement of a tremie to emplace the grout. The borehole diameter must be a minimum of 4 inches larger than the total OD of the loop pipes.12-010.02DPipe: Pipe material must be composed of polyethylene, grade p34, minimum cell classifications PE 355434C or PE 345434C, when tested under ASTM Standard 3350, incorporated herein by reference. (ASTM standards are copyrighted and available from the American Society for Testing and Materials International, 1916 Race St., Philadelphia, PA 19103; Phone 215-299-5585, Fax 215-977-9679, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959 USA; Phone: 610-832-9500; http://www.astm.org. Standards may be viewed during normal business hours at the Nebraska Department of Health and Human Services, Division of Public Health, 301 Centennial Mall South, 3rd Floor, Lincoln, NE 68509.)12-010.02EPipe Joining Method: Heat fusion methods for pipe joining must be the socket or butt heat fusion technique as referenced in ASTM Standards D3261 or D2683, both of which are incorporated herein by reference. (ASTM standards are copyrighted and available from the American Society for Testing and Materials International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959 USA; phone: 610-832-9500; http://www.astm.org; OR standards may be viewed during normal business hours at the Nebraska Department of Health and Human Services, Division of Public Health, 301 Centennial Mall South, 3rd floor, Lincoln, NE 68509.)12-010.02FPressure Testing: The installed system must be pressure tested to a minimum of 100 pounds per square inch (psi). After 6 hours it is permissible for the pressure to drop a maximum of 15% of the initial psi due to expansion of the HDPE piping. A pressure loss greater than 15% in 6 hours is an indication of a leak in the circulating system. If a pressure loss is detected, the cause must be properly repaired, the material replaced, or the well must be properly decommissioned.12-010.02GPurging a Loop System: After a loop system is installed and pressure tested, and prior to introducing additives to the circulating fluid, the entire loop, header and associated plumbing must be purged at a minimum rate of 5 feet per second to remove any debris that has entered the loop during construction.12-010.02HCirculating Fluids: When food grade propylene glycol is added to water for antifreeze protection, it must be non-toxic in nature when combined with the circulating fluid additives in a closed loop heat pump system. If needed, the addition of corrosion inhibitors and biocides may be used in circulating fluid if such additives are also:2. Compatible with food grade propylene glycol; and3. Non-hazardous materials upon disposal or a change of circulating fluid.12-010.03Completion of a Vertical Closed Loop System: Completion of a borehole for a closed loop heat pump well must be finished within 6 hours from the time the borehole is drilled. Drilling muds or cuttings cannot be used as completion materials. The tremie pipe must not be left in the borehole. 12-010.03A Systems that have 10 or more boreholes must be grouted full-length with high solids bentonite slurry in accordance with 178 NAC 12-003.06 item 5. (See Figure 11A)12-010.03B Systems that have fewer than 10 boreholes must be grouted full-length with high solids bentonite slurry in accordance with 12-003.06 item 5 when they are located less than 1000 feet of a community public water well (which requires prior written permission from the community). (See Figure 11B)12-010.03C Systems that have fewer than 10 boreholes and are located 1000 feet or more from a community public water well must use one of the following methods to complete construction of the boreholes: (See Figure 11C) 1. High solids bentonite slurry that meets the requirements of 178 NAC 12.003.06 item 5 must be used to grout the full length of the borehole, or2. Sand or gravel must be placed through the sodium bentonite fluid with a viscosity that allows the sand to settle through the fluid from the bottom of the borehole to the static water level by tremie or free fall method. A 5 foot interval of bentonite chips must be placed at the static water level, and the remainder of the borehole must be sand/gravel packed through the fluid to within 30 feet of the surface minus excavation for the header piping. The remaining annular space must be filled with non-slurry bentonite chips.12-010.04Horizontal Closed Loop System12-010.04A A horizontal closed loop heat pump system that is constructed by trenching or digging is exempt from the grouting requirements of closed loop systems provided that no part of the horizontal loop is constructed at or below the ground water level.12-010.04B A horizontal closed loop heat pump system constructed by boring or drilling must be grouted with high solids bentonite slurry grout that meets the requirements of NAC 12-003.06 item 5.12-010.04C All other construction standards for closed loop heat pump wells in 178 NAC 12-010 apply.178 Neb. Admin. Code, ch. 12, § 010