OAR 690-240-0043
Construction Standards
(1)
If permanent casing is needed in a ground source heat pump boring, it shall meet the standards set out in OAR 690-210-0190 (Steel Casing) through 690-210-0220 (Plastic Casing Joints) for steel and plastic.(2)
Site specific conditions shall be assessed to determine the best method and materials to be used for sealing the boring annulus to protect the groundwater resource and that method shall meet the standards set out in OAR 690-210-0300 (Drill Cuttings or Chips) through 690-210-0360 (Movement of Casing after Cement Grouting) for sealing wells.(3)
The diameter of the borehole for cased and uncased ground source heat pump borings shall allow placement of the heat exchange loop and grout pipe to the bottom of the boring as follows:(a)
For installation of a 3⁄4 inch loop, the diameter of the borehole shall be a minimum of 4 inches;(b)
For installation of a 1 inch loop, the diameter of the borehole shall be a minimum of 4 1⁄2 inches; and(c)
For installation of a 1 1⁄4 inch loop, the diameter of the borehole shall be a minimum of 5 inches.(4)
The type of sealing material used shall be compatible with the heat exchange loop material and permanent casing material used in the construction of the boring.
Source:
Rule 690-240-0043 — Construction Standards, https://secure.sos.state.or.us/oard/view.action?ruleNumber=690-240-0043
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