The basic principle of lightning protection grounding is to connect the metal structure of a building or equipment to the earth so that its potential is equal to the earth potential, so as to avoid damage to the building or equipment caused by the high potential difference generated by lightning strikes. In the steel structure, metal components such as steel columns and steel beams can be used as lightning protection grounding conductors.

Specific methods and steps:

1. Determine the design scheme of lightning protection and grounding system

Before the lightning protection grounding of the steel structure, it is necessary to formulate a scientific and reasonable lightning protection and grounding system design scheme according to the actual situation and design requirements of the building. The scheme should clarify the grounding resistance value, the form of the grounding grid, the grounding electrode material, etc.

2. Install the grounding electrode

According to the design scheme, select the appropriate grounding electrode material and location for installation. The grounding electrode is generally made of angle steel, steel pipe and other metal materials, the length is generally about 2.5m, and the depth of driving into the ground is not less than 2m. The distance between the grounding electrodes should not be less than 5m.

3. Connect to the grounding grid

A plurality of grounding electrodes are connected with 40x4mm hot-dip galvanized flat steel to form an annular grounding grid. Welding should be used when connecting, and the welding place should be treated with anti-corrosion. The buried depth of the grounding grid should not be less than 0.6m.

4. Connect the steel column and the steel beam

The steel columns and steel beams are connected with the grounding grid to form an electrical path. Welding or bolt connection can be used when connecting, and the connection should be treated with anti-corrosion.

5. Test the ground resistance value

After the installation of the lightning protection grounding system is completed, it is necessary to use a grounding resistance tester to test the grounding resistance value. The value of the ground resistance should meet the design requirements and should generally not be greater than 4Ω. If the grounding resistance value does not meet the requirements, it can be adjusted by increasing the number of grounding electrodes and improving the soil resistivity.

6. Regular inspection and maintenance

Lightning protection and grounding systems need to be inspected and maintained regularly to ensure that they are in good working order. Before the thunderstorm season every year, the grounding system should be comprehensively inspected, and repairs or replacements should be carried out in time if problems are found. At the same time, when the building or equipment is renovated or repaired, attention should also be paid to the protection and maintenance of the grounding system.