NR 812.15(4)(e)5.5. The inner casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues. NR 812.15 HistoryHistory: CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7-1-20; correction in (4) (intro.) made under s. 35.17, Stats., Register June 2020 No. 774; CR 21-070: am. (2) (c) Register July 2022 No. 799, eff. 8-1-22. NR 812.151NR 812.151 Heat exchange drillhole location and construction requirements. A heat exchange driller is responsible for constructing all heat exchange drillholes in accordance with the requirements specified in ss. NR 812.10 to 812.12 and all of the following requirements: NR 812.151(1)(1) License requirement. An individual who performs heat exchange drilling is required to be a licensed heat exchange driller except that a license is not required to perform heat exchange drilling if an individual is employed by a licensed heat exchange driller or a person registered as a business to perform heat exchange drilling and all other requirements under this section and ss. NR 812.10 to 812.12 are met. NR 812.151(2)(2) Approvals. A heat exchange driller shall obtain any approvals required in compliance with s. NR 812.09 (4) (w), (x), (y), or (z) prior to starting drilling and shall follow any conditions required by an approval. NR 812.151(3)(3) Notification of drilling. A heat exchange driller shall obtain a well notification permit from the department at least 24 hours prior to the start of drilling. NR 812.151(4)(a)(a) A heat exchange driller shall ensure that heat exchange drillholes are separated from potential contamination sources. A distance of 10 feet shall be maintained between a heat exchange drillhole and any of the following: 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.