When does the pipe flange need static jumper?

In the industrial field, pipe flanges are an important connecting element and are widely used in various pipelines and equipment. In certain specific locations, jumper wires need to be installed to ensure electrical continuity and prevent static electricity accumulation. So, when does the pipe flange need static cross-connection? Which flanges need jumper wires? Let's reveal them one by one.

Definition of industrial pipeline pipe flange cross-connection:

Industrial pipelines refer to pipelines used to transport gas or liquid within the enterprise, and their materials are usually metal, such as steel pipes, cast iron pipes, etc. When these pipelines are connected, metal flanges are used for cross-connection to ensure the safety and stability of the pipeline system. Cross-connection means connecting adjacent pipeline sections through metal flanges to form a continuous conductor, thereby effectively preventing the accumulation and discharge of static electricity. This cross-connection method not only meets national safety standards, but also ensures the smooth progress of industrial production.

Industrial pipelines to which this regulation applies must meet the following conditions at the same time: first, their maximum working pressure must reach or exceed 0.1MPa; second, the nominal diameter must be greater than 25mm; and finally, these pipelines must transport gas, steam, liquefied gas, or liquids with a maximum working temperature higher than or equal to their standard boiling point, or flammable, explosive, toxic or corrosive liquids.

When does the pipe flange need electrostatic cross-connection?

‌Pipe flange electrostatic cross-connection‌ refers to the installation of conductive elements at the pipe flange connection to reduce the potential danger caused by static electricity accumulation. Generally speaking, the following types of pipe flanges require electrostatic cross-connection:

1. Pipeline systems for flammable gas media.
Because when flammable gases form a mixture in the air, when their concentration is between the lower and upper explosion limits, only one high-energy electric spark will cause an explosion. Therefore, this type of pipeline system requires electrostatic cross-connection to eliminate static charges and avoid the generation of static sparks.

2. Pipeline systems for flammable and explosive liquid media.
Similarly, flammable and explosive liquids can cause explosions at corresponding air concentrations, requiring electrostatic jumpering.

3. Pipeline systems that handle flammable, explosive, and toxic media.
In such systems, in order to reduce danger, the pipe flanges require electrostatic jumpering.

Which positions of the pipe flanges require jumper wires?

1) Pipe flange jumper wire requirements

1. Long-distance pipelines: In large industrial projects, long-distance pipelines are a common scenario. In order to ensure the electrical continuity of the pipeline system, jumpers need to be installed at the flange connection every certain distance.
2. Connection of pipelines of different materials: When pipelines of different materials are connected, due to the difference in conductivity between the materials, jumpers need to be installed to eliminate the potential difference and prevent electrostatic sparks from causing danger.

2) Equipment flange jumper wire requirements

1. Equipment inlet and outlet: At the inlet and outlet of the equipment, the flange connection is usually dense. In order to ensure the electrical connection between the equipment, the flanges at these locations need to be installed with jumpers.
2. Grounding of large equipment: For large equipment, such as storage tanks, reactors, etc., in order to ensure that the equipment is well grounded, jumper wires need to be installed at the flange connection to ensure that the grounding resistance meets safety requirements.

Function and installation steps of jumper wires:

The main function of jumper wires is to ensure electrical connection between equipment, eliminate potential differences, and prevent static electricity accumulation from causing danger. When installing jumper wires, you first need to determine the flange position to be bridged, and then select the appropriate jumper wire material and specifications. Next, fix one end of the jumper wire to the flange bolt and connect the other end to the grounding system or adjacent equipment. During the installation process, pay attention to the tightness of the jumper wire and the reliability of the electrical connection.

Precautions for anti-static of pipe flange jumper:

Jumper wires are usually required at the connection between the pipeline flange and the equipment flange, and in places where electrical continuity needs to be ensured. Jumper wires can ensure electrical connection between equipment and prevent static electricity accumulation.

In actual operation, we often encounter such industrial pipelines. For these pipelines, especially those with static grounding requirements, we must conduct regular resistance value measurements. Once it is found that the resistance value between any connection joints or the resistance value to the ground exceeds the provisions of the relevant specifications or design documents, measures must be taken immediately, such as setting jumper wires between flanges or threaded joints, and grounding leads to ensure the safety and stability of the pipeline system.

When performing electrostatic jumper, the following points need to be noted:

1. The electrostatic jumper wire should maintain good contact with the ground so that the charge can flow to the ground effectively.
2. There should be no rust, oxidation or other substances that affect conductivity on the surface of the wire to ensure good electrical properties on the surface of the wire.
3. The electrostatic jumper wire should be set in places near the pipeline where electrostatic sparks are likely to be generated.
4. The length and cross-sectional area of the wire should be selected according to relevant national standards. In general, the resistance value should be less than or equal to 10 ohms.

Applicable scenarios for electrostatic jumper:

According to relevant specifications and standards, the following scenarios require the use of electrostatic jumpers:

1. Chemical companies: Containers loaded with flammable and explosive items should be placed on conductive floors and connected to ground wires. Wheeled carts, weighing scales, floor scales, etc. should also be connected to the grounding main line.
2. Petrochemical enterprises: During the production, processing, storage and transportation process, when equipment, pipelines, operating tools and human bodies may generate and accumulate static electricity and cause static electricity hazards, static electricity grounding measures should be taken.
3. Oil depot: A, B, C class liquid tank trucks or barrel facilities should be equipped with anti-static grounding devices connected to the tank trucks or barrels.

Fire protection design specifications for petrochemical enterprises: In places with explosion and fire hazards, grounding measures should be taken for equipment and pipelines that may cause static electricity hazards.

How to determine whether the flange needs to be bridged?

Not all metal pipe flanges must be bridged. Whether the bridge is required depends on whether the static electricity grounding requirements are clearly stated in the design documents. If the design documents cannot be viewed, it can be determined by measuring the resistance value between the flanges. When the resistance value exceeds 0.03Ω, a wire must be used for bridge connection. However, for gas pipelines and pipelines in petrochemical enterprises, the fastening method of the flange or the number of metal bolts can be used to determine whether the bridge is required, but this method may not be applicable to general industrial pipelines.

Read more: Pipe and flange connection or How to choose pipe flange material?