14 CAR § 20-104. Drip tubing and emitters

(a)(1) Emitter spacing can range from six inches to twenty-four inches (6” – 24”). (2) The emitters used in the tubing shall be pressure-compensating. (3) Pressure-compensating emitters have a relatively constant discharge rate over a wide range of pressures. (4) Emitter flow rate shall be: (A) Specified by the designer; and (B) Stated on the system plans. (5) The dripline pressure can range from five pounds per square inch to seventy pounds per square inch (5 psi – 70 psi). (b) Drip tubing shall be installed by one of the following methods: (1) Static plow; (2) Chain trencher; or (3) Vibratory plow. (c)(1) Static plow is the preferred method for inserting drip tubing into the soil. (2) The static plow shall be pulled, not pushed, through the soil. (d)(1) Chain trencher may be used for placement of the drip tubing in the soil. (2) The maximum chain trench width is four inches (4”). (e) Wet soil shall not be plowed because of smearing. (f) Drip tubing installed in natural soil shall be installed to a depth of six inches (6”). (g)(1) If capping fill material is used as part or all of the cover over the tubing, the installed depth of the tubing can range from one inch to five inches (1” – 5”) in the natural soil. (2) Drip tubing shall not be placed in the capping fill material. (3) In no case shall the cover over the tubing be less than six inches (6”). (h)(1) Settled depth of the cap shall not be more than eight inches (8”). (2) The capping fill material shall not contain more than: (A) Twenty-seven percent (27%) clay; (B) Sixty percent (60%) sand; or (C) Seventy percent (70%) silt. (3) Before the capping fill material is delivered to the proposed dispersal site, a textural analysis shall be provided. (4) A credit of up to fifty percent (50%) of the settled cap depth may be allowed in the adjustment of the seasonal water table. (5) The seasonal water table credit is at the sole discretion of the Department of Health.