What types of pipelines require bonding and static grounding?
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Hello everyone. I would like to ask: for caustic soda plants, which types of pipes need to be electrically grounded and bonded? Is it only the pipes carrying flammable fluids? But some people say that all type of pipes need to be handled this way, including plastic pipes. As for pipes carrying water or chlorine, I don’t think it’s necessary to do so. Are there any regulatory requirements regarding this? Thank you
The idea that static grounding is only necessary for flammable and explosive pipelines is a misconception; many designers, including those with years of experience in this field, may hold this mistaken belief. In fact, it should be: In environments prone to explosions and fires, where objects may pose a risk of static electricity, industrial static grounding measures should be taken. Note that this refers to all objects in explosive and fire-hazardous environments, rather than those that transport or come into contact with such media. One more point: For objects in environments where there is no risk of explosion or fire, if static electricity could interfere with production processes, affect product quality, or cause electric shock to people, static grounding should be implemented. For chlor-alkali production, hydrogen is involved, and the plant areas are essentially located in hazardous zones; therefore, grounding is essential. Refer to: HG20675-1990T Code for Design of Static Grounding in Chemical Enterprises
There are still many pseudo-experts and safety managers who have only a superficial understanding of the regulations and interpret them out of context
It depends on whether the design documents specify requirements for static grounding; if not, it is necessary to measure the resistance, and if it exceeds the specified value, a bypass connection must be made. There are many standards involved: GB50235-2010\GB50156-2012\GB50028-2006\GB50517-2010\GB50074-2014\GBT20801.4-2006\HGT20675-1990\TSGD0001-2009\SH3501-2011\SHT3097-2017
What about bridging? How is the copper wire bridging between flanges explained?
Bridging can be roughly divided into two situations: one is bridging of flanges or joints, with various standards existing; these mainly fall into two categories. 1. If the resistance value is >0.03 ohms, a separate bridge is required for the flange (it may not be necessary if the value is lower). 2. If there are at least 5 flange bolts, no bridging is needed. The second method is pipeline bridging: when the clear distance between parallel pipelines is less than 100 mm, bridging is carried out every 20 meters ； The clear distance between intersecting pipes is less than 100 mm; splices should be used, etc. Different standards have different requirements. Of course, the pipelines involved in such bridging all meet anti-static requirements. There are many standards listed on the 4th floor; take a look at them. The answers found online cannot be used as legal evidence; to find genuine grounds, one must refer to the standards.
I checked clause 4.3.3 of the standard SH3097-2000; it states that it is sufficient to have two bolts for the flange. What standard do the 5 bolts you mentioned refer to?
GB50074－2014 Code for Design of Oil Depots GB50156 Code for Design and Construction of Automobile Gasoline and CNG Stations
Flange cross-connection occurs due to the poor electrical conductivity of gaskets; the purposes of such cross-connection are, firstly, safety, and secondly, to ensure the accuracy of the instruments
The second floor is the correct answer; it has little to do with the medium inside the pipes, and the main factor to consider is flammable materials in the environment