Lightning grounding pressure equalizing ring

The grounding design of the building is to use the building foundation as the natural grounding body. The grounding method of the raft foundation is the same as usual, or the distribution of the grounding trunk according to the construction drawing will be all the lightning protection down the line, the power distribution room, the strong and weak electricity. Wells, pipe wells, elevator shafts, and machine rooms that need to be connected are connected by steel bars to form a complete integrated grounding grid, so that this area forms an equipotential.

Due to the special nature of the raft foundation, it is equivalent to covering the entire foundation with a layer of waterproof material with extremely high resistance value. It cannot be directly introduced into the earth like other foundations. The grounding resistance value is higher, and it can be done by artificial grounding device. To meet the requirements, a number of grounding wires (hot-dip galvanized flat steel or round steel) are taken from the ground around the building about 1 meter underground (the column with the down conductor) for the artificial grounding device.

If the grounding resistance is not enough to meet the design requirements, the manual grounding device is added.

In the architectural design, when the height exceeds the radius of the ball (one class is 30 meters, the second class is 45 meters, and the third class is 60 meters), a pressure equalizing ring is set every 6 meters. In the design, it is required to set a pressure equalizing ring every 6 meters. The purpose is to connect the metal doors and windows of the upper and lower layers within 6 meters height with the pressure equalizing ring. Each layer is provided with a pressure equalizing ring, and the metal door and window pipes, etc. It is integrated with the equalizing ring and welded with the lightning protection down conductor.

The equalizing ring installation is made by welding the main ribs in the surrounding beams in the peripheral structure of the building. When the main reinforcement in the beam is ≥16mm2, two main ribs are used. When the main reinforcement in the beam is ≥12 mm2, four main ribs are used. The steel bar as the equalizing ring has a welded connection with each of the lightning protection down conductor bars. The reinforced steel is φ12, and the lap length is 6 times of the maximum pressure of the pressure equalizing ring or the down conductor. The welding is double-sided welding, no slag inclusion, pores, and the weld seam is full.

The lightning protection grounding voltage equalization ring method is:

1. When the lightning protection building height h≥45m; the third type lightning protection building height h≥60m), a pressure equalizing ring shall be installed;

2. (The compartment setting) must be reliably welded to the lightning protection down conductor and connected to various metal doors and windows.

However, some drawings refer to the underground grounding grid as a pressure equalizing belt.