Precautions for lightning rods and belts

(1) The lightning rod is not far enough from the antennas of the various equipment being protected. Some electronic equipment such as radar, satellites, and communication equipment's transmitting and receiving antennas are installed on the top of the building, which is higher than the lightning protection zone of the building. At this time, a certain height needs to be erected. Lightning rod. However, people often ignore the distance between the lightning rod and the antenna of the protected device. In fact, even if it is not a truly independent lightning rod, it needs to have a certain distance from the antennas of various devices to be protected, such as more than 3 meters. This is because the lightning rod is a lightning receptor, which can intercept tens of thousands of amperes and hundreds of thousands of amperes of lightning current. A strong lightning current will generate strong electromagnetic pulses around it. It has a large effect on device antennas that are too close. Impact. This will damage the receiving equipment. The lightning rod should be welded with the lightning protection strip in two directions, and the metal antenna base should be welded with the rebar in the beam on the roof that bears the weight of the antenna when making the equipment antenna support. In order to achieve the purpose of grounding. That is, although the lightning rod and the antenna base may finally be connected to the same grounding device, but also try to avoid directly connecting the lightning rod to the antenna base on the roof. In two cases, the impact of the lightning current intercepted by the lightning rod on the device antenna is very different, and multiple shunts may have been implemented in the middle.

(2) When using a steel pipe for the lightning rod, the steel pipe is not thick enough. In order to reduce the weight of the lightning arrester (such as the lightening rod of the glass fiber reinforced plastic shaft to reduce the bending of the shaft), the lightning receiver is a stainless steel tube for decoration. It is only a few tenths of a millimeter thick, and its cross-sectional area is far less than 50 mm 'specified by the IEC. It cannot withstand the strong mechanical and thermal effects of direct lightning strikes. It is an authentic appearance, and it will be completely damaged if it is struck by lightning. If some roofs use beautiful stainless steel railings to double as daughter walls and lightning protection belts, the thickness and cross-sectional area of ​​stainless steel pipes must be guaranteed.

(3) Part of the lightning protection zone falls. Partial lodging of the lightning protection belt often occurs due to roof maintenance and other reasons. It is not as easy to attract attention as the disconnection of the lightning protection belt.

It should be noted that the inspection of the corrosion condition of the air-termination device or the down-conductor is different from the inspection of the rust condition. If the cross-sectional area of ​​the rusty air-termination system or the down-conductor does not decrease significantly, its diffusion function will still be It just affects the service life. This situation should not be easily judged as unqualified, but maintenance treatment should be requested. When using lightning protection strips and lightning protection nets made of galvanized materials, except for the connection with the down-conductor, welding is needed. In other places, special lightning protection strips with dovetail support cards should be used to clamp the lightning protection strips. All adopt welding method of lightning protection belt and supporting steel bar. To reduce the damage of galvanized layer.

There are often many protrusions on the top of the building, such as metal flagpoles, diffusing pipes, steel ladders, metal chimneys, advertising stands, wind windows, etc. It should be checked whether they are welded into the lightning protection screen. Large metal components should have two Reliable welding with lightning protection belts. What is easy to miss is the cast-iron diffuser (ventilation hole) leading to the bathroom, which may often forget to equipotentially connect it with the lightning protection zone.

When the non-metallic roof can be excluded from the need for lightning protection, the metal parts of the roof structure below it should be regarded as qualified natural air-termination systems. This situation is often encountered when checking the simple finished product warehouse and should not be It is then urged to make a special air-termination device on the roof, as long as these metal beams are lowered and grounded as required.