In recent years, buildings have been repeatedly struck by lightning. Is the higher the building, the greater the risk of being struck by lightning? How should buildings be protected against lightning? With these questions in mind, the reporter interviewed Guan Xiangshi, a Chinese expert in lightning protection and a member of the IEC/TC81/WG3 Lightning Protection Committee of the Electrical Commission.

The higher the building, the greater the risk of being struck by lightning

Guan Xiangshi said that it is normal for buildings to be struck by lightning. The higher the building, the closer it is to the thunderstorm, the greater the risk of being struck by lightning.

The Burj Khalifa was first built in 2004 and officially opened in 2010. It is currently the world's largest building and has been struck by lightning multiple times. It is understood that lightning located 3 to 5 kilometers above the ground can generate an average voltage of over 100 million volts. However, the tip of the Burj Khalifa is made of 4000 tons of steel and serves as a lightning rod, protecting the entire building from lightning strikes. Therefore, despite experiencing several lightning strikes, the Tower of Harry remained unscathed.

The television tower that was struck by lightning in the world is the Ostankino Radio and Television Tower in Moscow, known as the "European Tower". The radio and television tower is 573.5 meters high and has been struck by 143 lightning strikes in 4 and a half years. In China, however, in April 2010, the spherical body above the Oriental Pearl TV Tower Tower in Shanghai was struck by lightning and caught fire. The Oriental Pearl TV Tower Tower in Shanghai is equipped with lightning rods. Why can't it stop the "attack" of lightning? Actually, lightning protection can only intercept lightning strikes, "Guan Xiangshi said." The correct name for a lightning rod should be 'lightning arrester'. As the name suggests, a lightning arrester is designed to intercept lightning strikes

Guan Xiangshi said that from the perspective of building lightning protection, steel bars or steel structures inside reinforced concrete structures can be used as lightning arresters to intercept lightning discharges. Generally, the impact is not significant after being hit by direct lightning strikes. It should be noted that non-metallic objects caught fire due to lightning strikes, as well as secondary damage caused by the falling of wall tiles and other materials on the surface of buildings. However, this problem is difficult to solve. For example, it is impossible to wrap the sphere on the Oriental Pearl TV Tower Tower as the transmitting antenna with steel, so that its antenna will not send signals. The reason why the lightning strike of Oriental Pearl TV Tower Tower in Shanghai caught fire was that the thermal insulation layer in the small ball made of glass fiber reinforced plastic material was non flame retardant. To prevent lightning strikes and fires, the insulation layer can be replaced with flame-retardant materials.

Guan Xiangshi said that lightning strikes on buildings are still a rare event, and we cannot overly worry, but we cannot relax our vigilance.

Lightning protection for high-rise buildings requires both internal and external repairs

Building lightning protection is divided into external lightning protection and internal lightning protection. The external lightning protection devices include lightning arresters, down conductors, and grounding devices, while the internal lightning protection devices include shields, equipotential connections, surge protectors, etc. Guan Xiangshi believes that the external lightning protection work of buildings in China is relatively good, while the internal lightning protection work is relatively weak. The lightning protection of electrical and electronic systems inside buildings should become the focus of lightning protection for high-rise buildings.

Guan Xiangshi said, "Nowadays, people can hardly live without electronic products. However, electrical and electronic devices are very delicate and sensitive. If they are subjected to direct lightning strikes or electromagnetic pulses from lightning strikes, they can easily cause damage to electrical and electronic systems as well as fires, resulting in significant direct and indirect losses. Currently, lightning protection measures inside buildings are easily overlooked

Statistical analysis and extensive lightning disaster investigations indicate that most lightning injury incidents and lightning disasters are caused by the lack of lightning safety measures and incomplete lightning protection devices. The inadequate lightning protection devices in existing buildings are the main cause of lightning accidents in buildings.

Guan Xiangshi suggests that in order to avoid and reduce losses caused by lightning disasters, qualified professional lightning protection testing institutions should conduct regular inspections on schools, hospitals, hotels, and high-rise buildings; When designing and constructing lightning protection devices, the construction unit should comprehensively consider factors such as geology, soil, meteorology, environment, characteristics of protected objects, and lightning activity laws, and adopt safe, reliable, technically, economically reasonable design and construction, as well as lightning protection equipment, devices, and devices that meet standards in terms of technology and quality, to ensure the safety of building lightning protection and the safety of people's lives and property. In addition, it is necessary to strengthen the popularization of lightning protection science knowledge among the public, enhance their awareness of lightning protection, disaster prevention and self rescue capabilities, so as to stay away from lightning disasters and protect lives.