Static grounding of pipelines

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Static grounding of pipelines is indeed troublesome; it’s hard to determine whether grounding is necessary. Although there are specific standards, it’s like a tongue twister. I use the process of elimination to determine which pipes need to be grounded, based on the properties of the medium, pressure, flow rate, and temperature.

Static electricity generated by excessive flow velocity of the medium in the export pipeline

1. Equipment for the production, storage, and handling of liquefied petroleum gas, flammable gases, and flammable liquids; storage tanks, pipelines, and units; as well as equipment and pipelines used for drying, mixing, and transporting flammable solid materials in powder or granular form that are prone to generating static electricity, along with bag-type dust collection devices for flammable dusts – in environments where explosions are a risk, such equipment and pipelines are prone to generating and accumulating static electricity. When anti-static grounding is required in the design, it must be ensured that proper grounding is carried out in accordance with the design specifications, in order to prevent static sparks from causing explosion accidents. In the absence of specific design requirements, the installation of the anti-static grounding system shall, in addition to complying with the provisions of **current standards and specifications related to anti-static grounding, also meet the following requirements: 1) The anti-static grounding system can be installed together with the grounding systems for protecting against induced lightning strikes and electrical equipment; the value of its grounding resistance shall comply with the regulations applicable to the grounding of systems for protecting against induced lightning strikes and electrical equipment ； It shall be used only as an anti-static grounding device, and the grounding resistance value of each grounding electrode shall meet the design specifications. 2) The anti-static grounding wires for equipment, units, pipelines, etc., should be connected separately to the grounding electrode or grounding main line; they shall not be grounded in series except for parallel pipelines. 3) The installation of the anti-static grounding should be connected to the fixed grounding terminals or bolts of equipment, units, etc., using M10mm bolts; it should also be equipped with a anti-loosening device and coated with electrical compound grease. Pipe strength when connected using welded terminals. The connecting bolts must not be reduced in size or damaged. 4) When the metal flange is fastened with metal bolts or clamps, an additional cross-grounding wire is not required. Before installation under corrosive conditions, the contact surfaces between two or more bolts and clamps should be degreased and rust-free, and lock nuts should be installed. 5) When the clear distance between metal pipes installed parallel to each other on non-metallic structures in an explosion-hazardous area is less than 100 mm, it is advisable to use metal wires for bridging every 20 m ； When the clear distance between intersecting metal pipes is less than 100 mm, metal wires should also be used for bridging. 6) For storage tanks with a capacity of 50 m3 or more, there should be no fewer than two grounding points; the distance between these grounding points should not exceed 30 m. They should be connected to the grounding electrode in a symmetrical manner around the bottom of the tank, and the grounding electrodes should be connected to form a closed circular circuit. 7) For floating storage tanks containing flammable or combustible liquids, in the absence of lightning protection grounding, copper flexible wires shall be used to make at least two connections between the top of the tank and the tank body itself; the cross-sectional area of such wires shall not be less than 25 mm². The germanium-coated cables of the floating electrical measurement devices shall be buried in the ground to a depth of not less than 50 meters, and the aluminum-clad, metal-bodied components shall be securely connected to the tank body at the point where they enter the tank. 8) In reinforced concrete storage tanks or vessels, the antistatic grounding conductors installed along their inner walls shall be connected to the fittings of the metal pipes and cables that are introduced, as well as to their metal enclosures; they shall also be led to the outer walls of the tanks and vessels to connect with the grounding electrodes. 9) For non-metallic pipes (non-conductive), equipment, etc., the metal wire mesh wound around their outer walls should be wound evenly and securely grounded. 10) For bag-type dust collection equipment for combustible dusts, the grounding terminals of the metal wires woven into the bags shall be grounded. 11) The belt-driven units, as well as their anti-static grounding brushes and protective covers for the belts, must all be grounded. 2. To prevent electric sparks generated in environments prone to explosion from causing an explosion, metal pipes introduced into such environments, steel pipes for wiring, aluminum coatings on cables, and metal enclosures must all be grounded at the entrance to the hazardous area.