Section We 602.37 - Closed Loop Geothermal Wells(a) The setback and protective well radius requirements specified in We 602.06 through We 602.12, shall not apply to closed loop geothermal wells.(b) A closed loop geothermal well shall be located no less than:(1) Fifty feet from a well used for potable water supply; and(2) Twenty five feet from a septic tank or effluent disposal area.(c) During advancement of the borehole, the licensed contractor shall follow the observation and record keeping requirements of We 602.20.(d) The thermal loop used in the borehole shall be: (1) Constructed of high-density polyethylene (HDPE) with heat fused couplings; or(2) An equivalent loop material and couplings that can be demonstrated to reduce the potential for groundwater contamination by resisting degradation and leakage.(e) The borehole shall be grouted as follows: (1) The entire length of the borehole shall be grouted;(2) The borehole shall be grouted in one, continuous effort from the bottom of the borehole using a tremie line;(3) The grout used in the borehole shall be:a. A high-solids bentonite grout;b. A cement-sand based grout;c. A bentonite-sand based grout; ord. Any other grout that has been demonstrated to reduce shrinkage and cracking during multiple heating and cooling cycles; and(4) The following materials shall not be used as backfill in the borehole when used alone: d. Drilling by-products; ore. Other non-cemented or non-grouted, heterogeneous or homogenous mixture of aggregates.N.H. Admin. Code § We 602.37
Derived From Volume XXXVII Number 2, Filed January 12, 2017, Proposed by #12083, Effective 3/1/2017, Expires 3/1/2027.