NR 812.151(4)(b)(b) Prior department approval is required for any heat exchange drillhole located within 400 feet of a municipal water supply well. NR 812.151(5)(5) Temporary casing. A heat exchange driller may use any of the following materials for temporary casing for heat exchange drillholes: NR 812.151(6)(6) Pressure testing. Vertical heat exchange loop piping shall be pressure tested with potable water or an approved fluid in the loop, according to manufacturer’s specifications. NR 812.151(7)(7) Drilling fluids. Drilling fluid shall be less dense than the grout to facilitate proper sealing of heat exchange drillholes. NR 812.151(8)(8) Surface protection. A heat exchange driller shall protect heat exchange drillholes to prevent surface contamination from entering the drillhole during the drilling operation and when the driller is not at the drilling site. Drillholes may not remain open and ungrouted for more than 24 hours after completion. NR 812.151(9)(9) Grouting. All materials used to grout a heat exchange drillhole shall be approved for use under s. NR 812.091 and shall meet the requirements specified in s. NR 812.11. A heat exchange driller shall use one of the following materials to grout heat exchange drillholes: NR 812.151(9)(a)(a) Neat cement, if potable water or an approved fluid is continuously circulated in the loop pipe to prevent potential loop pipe deformation. NR 812.151(10)(10) Grouting method. A heat exchange driller shall use the following method to grout heat exchange drillholes: NR 812.151(10)(b)(b) For drillholes 25 feet in depth or more, grout shall be pumped through a tremie pipe under pressure according to the following requirements: NR 812.151(10)(b)1.1. The pipe shall be placed to the bottom of the drillhole and the grout shall be placed from the bottom up. NR 812.151(10)(b)2.2. The tremie pipe shall be kept submerged in the grout at all times during grouting. NR 812.151(10)(b)3.3. The tremie pipe may be pulled back during grouting as long as the end of the tremie pipe remains submerged in the grout. NR 812.151(11)(11) Fusion welding. Fusion welding connection for vertical heat exchange piping shall be done using socket fusion, saddle fusion or butt fusion type, in accordance with pipe manufacturer’s instructions or as referenced in ASTM D 2610, D 2683 and D 2657. Joint surfaces shall be clean and moisture free. NR 812.151(12)(12) Reporting. A heat exchange driller shall submit a report of the heat exchange drillhole project, on a form prescribed by the department, within 30 days following the date of completion of the project. NR 812.151(13)(13) Heat exchange fluids. Only department approved heat exchange fluids may be used in the piping placed in heat exchange drillholes. NR 812.151(14)(14) Filling and sealing. Unused heat exchange loops and drillholes shall be filled and sealed using the materials and methods specified in s. NR 812.26. NR 812.151 HistoryHistory: CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7-1-20. NR 812.152NR 812.152 Construction requirements for potable high capacity wells, potable school wells, and wastewater treatment plant wells. Potable high capacity wells, potable school wells, and wastewater treatment plant wells shall be planned and constructed according to the location, approval, and general requirements speecified in ss. NR 812.08 to NR 812.12, and according to all of the following requirements: NR 812.152(1)(1) Minimum diameter. The minimum casing and lower drillhole diameter for potable high capacity wells, potable school wells and wastewater treatment plant shall meet the following requirements: NR 812.152(1)(a)(a) Four inches for wells completed in unconsolidated formations.