Questions regarding the static grounding of equipment pipelines?

Refer to the Standard for Static Grounding Design in Petrochemical Industries SH3097-2000

If the equipment or pipeline has already been lined, it’s pointless to use a jumper even then. The specific approach is to control the material flow rate ； The static electricity in the equipment and pipes is led out through a conductor and then grounded.

Pay attention to controlling the flow rate, and carefully check the hazardous chemicals used in your company; if the resistivity is not high, there are generally no major issues. The lining is made of non-conductive, anti-corrosive material; bridging it outside the pipe is ineffective as it cannot dissipate static electricity.

The generation of static electricity and the accumulation of static charge • Static electricity refers to the relatively stationary charge carried on insulating materials (or isolated conductors). It is a charging phenomenon that occurs when electrons are transferred between materials as a result of contact and friction between different objects. •Electrostatic charge can only accumulate on the surface of objects; it cannot flow as easily as electric current in conductors, which is why it is called electrostatic charge. (1) Mechanism of electrostatic generation • The energy required for an electron to break free from the binding of the atomic nucleus is called the electron work function. •It reflects the strength of the nuclear binding force or attraction toward electrons; the work required to remove electrons varies from one atom or substance to another. •When two objects are in contact with each other and in friction, and they are in close contact at a distance of less than 25×10-8 cm, the electrons experience forces in opposite directions; the difference between these forces – the net force – is equal to the difference in the work required to extract the electrons. A double layer is formed because the two objects carry electrostatic charges of opposite signs. •The double layer is not static electricity; when two substances move relative to each other, such as when solids rub against one another, liquids flow through pipes, or powdered materials slide inside bags, some electrons do not have time to return to their original positions and leave along with the substances, thereby ending up carrying a net charge – which is static electricity. •The amount of static charge is related to the difference in electron work functions of the two materials in contact; the greater this difference, the greater the difference in their properties, and thus the more static charge there is. It is also related to the speed of movement – the higher the speed, the more static charge there is. Static electricity accumulates on the inner walls of pipes or within the material due to friction between the material and the pipes. As mentioned on the second floor, \"if the equipment or pipes are already lined, then it’s pointless to use bonding straps.\" The specific approach is to control the material flow rate ； The static electricity in the equipment and pipes is drawn out through a conductor and then grounded.”

If the lining material is not conductive, it’s pointless to ground the outer surface electrically. The main thing is to control the flow rate.

　Generation of static electricity: Static electricity is an objective natural phenomenon that can be generated in various ways, such as through contact or friction. The characteristics of static electricity are high voltage, low charge amount, small current, and a short duration of action. Static electricity is a stationary charged particle. It usually results from friction and separation; friction generates heat, which activates the molecules within a material, and when two substances are separated, electrons may transfer from one substance to another. 　　When electrons are transferred, a lack or excess of electrons can create an electric field, and this electric field is what we know as static electricity. The amount of this electric field generated depends on the materials that are rubbed or separated, on the amount of friction or separation that occurs, as well as on the relative humidity of the surrounding environment. 　　A substance in which electrons (or charge) can be easily transferred between atoms is called a conductor. Substances that cannot transfer electrons (or charge) are called insulators. Both conductors and insulators can acquire charge under the action of electrostatic forces. 　　Factors such as the body’s own movements or contact, separation, friction, or induction with other objects can generate static electricity of several thousand volts or even tens of thousands of volts. 　　Static electricity causes serious harm in various fields. Triboelectric charging and human static electricity are two major hazards in the electronics industry. 　　The main measures for static electricity protection during the production process are static electricity leakage, dissipation, neutralization, humidification, shielding, and grounding. 　　The human body static electricity protection system mainly consists of anti-static wrist straps and ankle straps, as well as work clothes, shoes and socks, hats, gloves or finger covers, and it has functions such as preventing static electricity leakage, neutralizing it, and shielding it. 　　Electrostatic protection is a long-term systematic effort; any mistake or oversight at any stage can lead to the failure of this protection effort. 　 Dangers of static electricity: Static electricity is present everywhere in our daily lives; we carry high levels of static voltage on our bodies and around us, ranging from several thousand volts to tens of thousands of volts. It might not be apparent in everyday life, but walking on a fiber-optic carpet can generate an electrostatic charge of around 35,000 volts, while flipping through plastic manuals can result in about 7,000 volts. For some sensitive instruments, such voltages can be fatal. 　　Electrostatics mainly studies the applications of static electricity, such as electrostatic dust removal, electrostatic copying, and electrostatic biological effects. More importantly, there are electrostatic protection technologies aimed at addressing the risks associated with static electricity in industries such as the electronics industry, oil industry, arms manufacturing, textile industry, rubber industry, as well as in aviation and other related fields, with the goal of reducing losses caused by static electricity. In recent years, due to the rapid advancement of science and technology, the widespread use of microelectronics, and the increasing complexity of electromagnetic environments, the electromagnetic effects of static discharge, such as electromagnetic interference (EMI) and electromagnetic compatibility (EMC) issues, have become problems that need to be addressed urgently. On the one hand, the widespread use of polymer materials with very high resistivity, such as plastics and rubbers, along with the increased speed of modern production processes, leads to the accumulation of large amounts of static electricity. On the other hand, the production and use of static-sensitive materials, such as light oils, **, and solid-state electronic devices, mean that industrial and manufacturing enterprises are increasingly affected by static electricity, which can cause quite serious consequences and losses. It can inadvertently destroy expensive electronic devices, resulting in annual losses of hundreds of billions of dollars for the electronics industry. At Xinghang Industry, electrostatic discharge causes failures in rocket and satellite launches, disrupting the operation of Xinghang’s aircraft. On July 29, 1967, a serious accident occurred on the U.S. aircraft carrier Forrestal: a missile aboard an A4 aircraft ignited suddenly, resulting in losses of $72 million and injuries to 134 people. The investigation found that the missile’s shielding connections were defective, and static electricity was the cause of the ignition. At the end of 1969, within less than a month, explosions occurred one after another due to static electricity generated during the tank cleaning of three 200,000-ton super tankers in the Netherlands, Norway, and the United Kingdom. 　　In recent years, there have been over 30 serious fire and explosion accidents caused by static electricity in petrochemical enterprises in our country. Many industrially developed countries have established institutions for static electricity research. China began carrying out some research on static electricity in the late 1960s, and since the 1980s, research in this field has progressed at a very rapid pace in China. In 1981, the Electrostatics Committee of the Chinese Physical Society was established, and the first national conference on electrostatics was held. National and regional conferences on electrostatics have been held continuously, the scope of research and application in this field has expanded, and the research team has grown stronger. 　 Example of static electricity: Static electricity is visible in certain forms, and electric charges can affect the electronic components that you come into contact with in your daily work. Unfortunately, these effects are very dangerous and not so obvious. 　　Typical static voltage: Many of the routine activities you carry out every day can generate charge on your body, which poses a potential risk to your electronic components. 　　Loss of electrostatic discharge capability: You can feel a 3000-volt electrostatic discharge, and you only perceive static electricity during lightning strikes; however, even a small charge can damage your semiconductor components. Many of the components used in your device can be damaged by voltages of less than 1,000 volts, and some can even be damaged by voltages below 10 volts. 　　Types of damage caused by static discharge Static electricity can lead to either potential failures or catastrophic failures in electronic components. 　　1. Potential forms of failure-------Results leading to threshold leakage. 　　2. Forms of catastrophic failure-------It occurs in two forms (direct and potential). 　　When a direct catastrophic failure mode occurs, a single component is damaged at some point and can no longer function. This type of electrostatic discharge damage is simple to detect, as it can usually be identified during testing. 　　When a potential failure occurs, electrostatic discharge weakens or damages the component at a certain point, but it will still pass the test. However, components that are damaged for a long time can cause poor performance, ultimately leading to system failure. Since potential failures occur during the final inspection or within the company’s control, the cost of repair is very high. Not only are such types of damage difficult to detect, but they also affect your company’s reputation on several occasions. When a failure mode involving static discharge occurs, it leads to current drift, but this does not result in a failure in the full sense of the term. However, during use, it may cause intermittent threshold leakage, leading to software loss or the storage of incorrect information. Patterns of chaos or potential failure may slip through your company’s quality control testing procedures, as they cannot be detected, sensed, or observed through normal testing processes. Just as you would not perform surgery in a contaminated operating room, you should never handle, assemble, or repair electronic components without adequate anti-static protection. Anti-static control methods: 1. Grounding. Grounding is very important for reducing the static charge generated on conductors. The human body is a conductor and serves as the main source of static electricity. Therefore, we must reduce the static charge generated on people who come into contact with sensitive anti-static components. The best way to prevent static electricity from forming on the human body is through grounding the body. 　　Several types of personal grounding devices In industry, wrist straps are the most commonly used grounding devices. A wrist strap will safely and effectively discharge the static electricity from your body. To function properly, a wrist strap needs to make proper contact with the skin. A dirty or loose wrist strap may retain the leaked static charge, rendering the anti-static control ineffective. Conductive footwear or foot grounding can be used or as a supplement to insufficient wrist straps. 　　Workstation grounding devices: Conductive or static-dissipating work surfaces are an essential part of an electrostatic safety workstation, especially in areas where assembly is done by hand. When wrist straps are used, it is necessary to have a clean work surface that is properly connected to a common grounding point. Conductive or static-dissipating materials can generate static charges, but when they are properly grounded, they can effectively dissipate those charges. 　　2. Isolation The next concept is the isolation of individual components and parts during storage or transportation. Isolated from a charged object or a charged electrostatic field. During storage or transportation, insulators are the best way to prevent damage caused by the release of static electricity. Since grounding cannot remove static charge or insulators, it is necessary to isolate sensitive components and parts from them. To isolate products from insulators, the best approach is to reduce the use of conventional plastics and other types of insulators in areas where there is no activity, during shipping, and during handling. Isolation can also be achieved by restricting access to the entire work area or workstation. 　　Finally, we take advantage of the fact that static charge cannot enter containers made of conductive materials or conductive layers. This effect is known as the Faraday cup effect. When storing and transporting electronic components or circuit boards, ensure that containers with characteristics similar to Faraday cups are used, as these containers will protect them from damage caused by static discharge. 　　Faraday cup: This type of Faraday cup is commonly used to control the release of static electricity. It consists of a metal bag, a conductive bag, or a covered container, and it can capture the static charges on its surface and remove them before it is opened. 　　3. Neutralization Since grounding and isolation cannot release charge from insulators such as synthetically made fabrics or conventional plastics, neutralization becomes important. The neutralization or removal of charges that naturally arise during the manufacturing process from insulators is known as ionization. Ions are simply charged particles present in the air; they are generated by natural energy sources, including sunlight, lighting, open-flame combustion, and radiation. 　　We can generate trillions of ions using an ion generator. This device uses high voltage to create a balanced mixture of charged ions, and fans are used to help these ions drift onto objects or areas in order to neutralize them. Ionization can neutralize static electricity on insulators within eight seconds, thereby reducing the potential damage it can cause. Ionization is not a substitute for grounding or isolation; it merely reduces the likelihood or risk of electrostatic discharge incidents. 　　4. Prevention Prevention is another important measure or tool for you. This is the most critical factor in static discharge control. Others or you, in work involving contact with electronic components, must be aware of the dangers of static discharge; understanding them and adapting to them is the most important thing that outweighs any static discharge control materials.

It is mainly to control the flow rate； In addition, an appropriate amount of antistatic agent can be selected based on the properties of the raw materials ； Enhance the electrical conductivity of the fluid itself

In our company, bridging is carried out on the outer wall of the pipeline or on the flanges; personally, I think it’s not useful, but this practice is still followed during the construction process, allegedly to eliminate static electricity

Pipelines are generally not coated for corrosion protection. Therefore, bypasses on the pipeline flanges are essential.

Carry out the bridging construction in accordance with the design requirements. Generally, after the construction is completed, the static grounding resistance should be measured, and the results should be recorded and filed.