Static wires and insulating flanges
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During operations at the dock, after a ship berths, measures need to be taken to eliminate static electricity or to prevent the effects caused by its transmission, in order to avoid the hazards it poses. Using a static grounding wire falls under the former category, while using insulating flanges belongs to the latter category. I searched the forum for posts related to these two methods, but there weren’t many of them. So which one is more effective? Also, in our company, according to the requirements of the headquarters in Germany, insulating flanges must be used. However, it’s not a problem if they are used solely on oil transfer arms, as these arms are suspended in the air and insulating flanges can effectively prevent the transfer of static electricity. But is it appropriate to use insulating flanges on metal hoses? Although the flange surface prevents static electricity, can’t it still propagate along the outer wall of the hose? So I don’t understand why the German headquarters requires the use of insulated flanges?
I’ve never heard of or seen the use of \"insulated flanges\" to prevent static electricity accidents.
During my training in Singapore, the pipeline connections at their docks indeed used insulated flanges; static electricity wires were not used. Are the relevant standards different in various places? Is that why?
Who has detailed diagrams of insulated flanges? Please share them.
On land, static grounding wires work well; on ships it’s not clear. One thing is certain: static electricity does not travel along hoses, and this is related to their non-conductive properties
Following our country’s standards ensures there are generally no mistakes! !
Ah, thanks to everyone above. I’m looking for diagrams of insulating flanges. A quick question: why doesn’t static electricity travel along metal hoses?
A so-called insulated flange refers to the use of insulating gaskets, bolts made of insulating materials, and bolt washers between steel flanges. Since there is no conductor between the two flange surfaces, an insulating flange can effectively prevent electrons from moving along the pipe.
According to Ministry of Transport standard JTJ 237-99, \"Code for Fire Protection Design of Oil Loading and Unloading Terminals\", section 7.3.4 states that when cross-cable connections between ships and the shore are used at oil terminals to prevent static electricity and stray currents, the terminal shall be equipped with an anti-static grounding system for ship connections, and explosion-proof switches connected to the ground shall be installed at the terminal. This grounding system shall be connected to the static electricity grounding systems of the equipment used for oil loading and unloading at the terminal.
The ship side takes care of its own area, and the shore side takes care of its own area； The ship must never be electrically connected to the shore; flanges must be used for insulation. This is because the zero potential of land and water is different. It is for this very reason that international standards (I’ve forgotten the name of the standard; you can look it up if you’re interested) also strictly prohibit connecting the ship’s grounding to the shoreside grounding.
Thank you so much. I’ve learned something new today. As per the requirements, antistatic wires and insulating flanges must never be used together. Why is that? Is it just unnecessary? Is it still for safety reasons?
The old-type Type I insulated flange consists of an insulating gasket placed between two butt-welded flat flanges, along with insulating sleeves on the fastening bolts and insulating bolt washers. The materials used for the flange insulation gaskets include oil-resistant rubber asbestos boards, neoprene boards, fabric-based neoprene boards, and polytetrafluoroethylene. Insulated bolt sleeves and bolt insulating washers are made from high-strength phenolic laminated fabric boards and pressed fabric tubes. Its features are: high rigidity, stable insulation performance, the need for a dedicated installation location, and high cost. Appropriate improvements have been made to the structure of traditional insulated flanges. In urban gas transmission and distribution projects, improvements are made in light of the low pressure characteristics of such projects (PN≤2.5MPa) as well as the pressure in the pipeline network (PN≤0.4MPa). In pipeline distribution projects, steel face flanges are used in place of butt-welded face flanges. The insulating gaskets for the flanges are made from materials such as polytetrafluoroethylene, oil-resistant rubber and asbestos sheets, and neoprene. The insulating sleeves for the fastening bolts and the insulating gaskets are combined into one unit, with the insulating sleeve being shortened by half to create an integrated, high-strength insulating sleeve gasket. Expand the bolt holes of the flange fitted with insulating gaskets so that insulating sleeves can be inserted through them ； This ensures that the inner diameter of the gasket meets the requirements of the bolts used in the original steel flange, thereby creating a steel flange with special functions; once assembled, it becomes a new type of insulated flange.
http://www.changhaopipe.com/images/jylf2.jpg http://www.changhaopipe.com/images/jyfl.jpg Insulated flanges refer to pipeline flange joints that meet both the sealing requirements necessary for buried steel pipelines and the electrical insulation requirements needed for corrosion protection in electrical engineering applications. It includes a pair of steel flanges, an insulating seal between the two flanges, flange fasteners and insulating parts for those fasteners, as well as a pair of short steel tubes that have been welded to each of the two flanges.