Which buildings are vulnerable to lightning strikes?
A: The location, structure, and height of buildings are different, and the chances of being struck by lightning are also different. There are buildings that are vulnerable to lightning strikes.
1. Isolated buildings on the plains and wilderness.
2. The buildings on the top of the river, lake, and Tushan.
3, groundwater outcrop, particularly humid place, underground there is conductive mineral or soil resistivity of the building.
4. Buildings in the valley mouth.
5. Metal roofs, metal sinks, brick and wood structure buildings.
6. Buildings above 19.7 meters above the ground.
7. Buildings higher than 25 meters in buildings.
Second, residential lightning protection device can use the steel construction of the grounding pole?
A: The residential lightning protection device should make full use of the underground natural grounding body as the grounding electrode, such as metal pipes, sewers, steel reinforced concrete foundation reinforcement, etc., but there are explosion and fire hazard pipelines, such as gas pipes, oil pipelines can not be used as grounding pole. In addition, water pipes and heating pipes cannot be used as ground electrodes. Because lightning strikes on such pipelines, overvoltages may occur on the pipelines and endanger personal safety. While using the natural grounding body, an artificial grounding pole should be set up to make the grounding resistance meet the requirements (10 ohms in general).
It must be pointed out that it is not possible to use only reinforced concrete foundations as grounding electrodes because: (a) Lightning currents penetrate the concrete from concrete and enter the ground, which may cause concrete cracks and gradually be damaged, affecting the foundation strength; ) The grounding resistance of concrete varies with the dry and wet soil. It is very low when wet and high when dry. Lightning strikes when dry, due to the high grounding resistance unfavorable to the release of lightning currents, affecting the lightning protection effect. Therefore, for houses or warehouses that store flammable and explosive materials, the grounding pole should not be used only as a base steel bar, and an artificial grounding pole should be provided as a lightning protection grounding pole.
Third, when the height of the building is required to install a lightning rod and why?
Answer: It is customary to install lightning rods or lightning protection nets when the height of a building exceeds 19.7 meters; lightning rods or lightning protection nets must be installed above 25 meters in buildings. But this does not mean that the lower buildings will not be in danger of being struck by lightning. Buildings that are dangerous for storage of flammable and explosive materials should be equipped with lightning rods (nets) if they are not very low, and lightning rods (nets) should be installed in buildings that are in the wilderness.
The protection angle of the lightning rod (that is, the angle formed by the connection between the most protruding point of the protected structure and the needle top and the needle itself) is below 60 degrees for general buildings and below 45 degrees for dangerous locations.
Fourth, what are the requirements for grounding deflectors for lightning protection and how is it connected to the grounding electrode?
Answer: The lightning down conductor can be used with a galvanized iron wire or flat iron with a section of not less than 35 mm2; of course, the copper wire can be used. However, the copper wire is too expensive and is easily stolen; aluminum wire is generally not suitable because of the aluminum wire. The mechanical strength is poor, it is easily damaged and broken, and corrosion is very unreliable.
The deflector should take the shortest route and try to avoid bending.
The connection between the down conductor and the underground grounding pole should be welded. Generally, oxyacetylene welding power arc welding should be used. It should not be soldered to ensure good and firm contact. If the family does not have a condition to do so, crimping can also be used, such as bolting. In order to be reliable in compression, a loose-proof spring washer must be added. Before the crimping, the connection part must be rust-removed and cleaned so as to expose the metal luster. The outer surface of the joint can be treated with a preservative such as water tar.
5. What are the requirements for grounding of lightning protection devices?
Answer: The artificial grounding pole of the evasion mine device is the same as the grounding pole of the protective grounding, but the grounding resistance can reach 10 ohms (the general requirement of the protective grounding is less than 4 ohms). Grounding electrode buried depth should be 0.5 to 0.7 meters underground.
6. Can a lightning rod be installed on an outdoor TV antenna?
A: Some residents install a metal rod 0.5 to 1 meter above the antenna on an outdoor TV antenna for lightning protection, and then ground it. This is a dangerous practice.
As we all know, the lightning rod is actually a lightning lead. Mounting a lightning rod on the TV antenna increases the possibility of lightning strikes on the antenna. The lightning rod should be really beyond the effect of preventing the protected object from being struck by lightning. In addition to the lightning rod should have a certain height and appropriate grounding resistance, it also requires a certain distance between the lightning rod and the object to be protected, otherwise it will cause counterattack.
Thunder strikes the TV antenna and lightning waves can be introduced along the feeder line to threaten people and the TV. Even if lightning strikes only the lightning rod, it may cause counterattack and induced overvoltage on the antenna feeder. Both of these overvoltage voltages are extremely high, and their voltage waves propagate into the room along the feeder line. They also threaten the safety of the person and the TV.
Therefore, lightning rods cannot be installed on the TV antenna or near the antenna. The correct approach is: (a) Install lightning arresters or discharge gaps to prevent lightning waves from intruding into the room. (b) The thunderstorm days will disconnect the antenna feeder from the TV and ground, or thrown outdoors. In this way, even if the lightning strikes the antenna, the lightning wave will not invade the room, thus ensuring the safety of the human body and the television.
Seventh, the ten methods of outdoor lightning protection
A: The thunder and lightning often hit the peak of the highest object in the outdoors, so isolated tall trees or buildings are often the most vulnerable to lightning strikes. When people are thunder and lightning, they should abide by the following rules in the outdoors to ensure safety.
1. Don't stay on high-rise platforms during thunderstorms. It is not advisable to enter isolated huts and guard booths at open locations.
2, away from the building exposed pipes, gas pipes and other metal objects and electrical equipment.
3. It is not appropriate to avoid thunderstorms under a big tree. If it is absolutely necessary, you must keep a distance of 3 meters from the trunk, squat down and close your legs.
4, if the lightning, the head, neck, hand ants crawling, hair erected, indicating the occurrence of lightning, should immediately squat on the ground, so you can reduce the risk of lightning, and take away the metal worn by the body Jewelry and hairpins, necklaces, etc.
5. If you experience thunderstorms in the outdoors and cannot leave a tall object, you should find some dry insulation immediately on the ground, and put your feet together and sit on it. Do not place your feet on the ground outside the insulation. Because the water Conductive.
6. When you are sheltering from thunderstorms in the outdoors, you should be careful not to hold it by your hands and hold your knees with both hands. Keep your chest close to your knees and lower your head as much as possible because the head is most vulnerable to lightning strikes compared to other parts of the body.
7. When a thunderstorm is heard within a few seconds of seeing the lightning in the open air, it means that you are in a dangerous environment near the thunderstorm. At this time, you should stop walking. Feet should be close together and immediately squat. Do not pull people together. It is best to use them. Plastic rain gear, raincoats, etc.
8. During thunderstorms, it is not advisable to hold an umbrella in the wilderness or to hold badminton rackets, golf clubs, gimmicks, etc.; it is not advisable to carry out outdoor ball games. It is very dangerous to carry out golf, football and other sports during thunderstorms; it is not advisable to be on the water. Stay by the water; it is not advisable to wash clothes, fish, swim, play in the river.
9. In thunderstorms, it is not advisable to open a motorcycle quickly, ride a bike fast and run wild in the rain. The greater the body's stride, the greater the voltage and the easier it is to hurt people.
10, if you see the high-voltage line in the outdoors by the lightning strike fracture, you should be vigilant at this time, because there is a step voltage near the breakpoint of the high-voltage line, people living nearby do not run at this time, but should feet together, jump off the scene .
8. What if someone is struck by lightning?
Answer: 1. After the human body has suffered a lightning strike, it often appears as a "dead-dead" state. At this time, emergency measures should be taken to rescue it. The first is artificial mouth-to-mouth resuscitation. The earlier the artificial respiration is performed after a lightning strike, the better the recovery of the injured person's body, because the human brain is in a deadly risk of oxygen deficiency for more than ten minutes.
2. Secondly, a heart massage should be performed on the wounded and the hospital should be promptly notified of the rescue treatment.
3. If the victim is caught in a fire caused by a lightning strike, he should immediately let the injured lie down so that the flame does not burn the face. He also poured water on the wounded person or wrapped the wounded in thick coats, blankets, etc. to extinguish the flames.
A: The location, structure, and height of buildings are different, and the chances of being struck by lightning are also different. There are buildings that are vulnerable to lightning strikes.
1. Isolated buildings on the plains and wilderness.
2. The buildings on the top of the river, lake, and Tushan.
3, groundwater outcrop, particularly humid place, underground there is conductive mineral or soil resistivity of the building.
4. Buildings in the valley mouth.
5. Metal roofs, metal sinks, brick and wood structure buildings.
6. Buildings above 19.7 meters above the ground.
7. Buildings higher than 25 meters in buildings.
Second, residential lightning protection device can use the steel construction of the grounding pole?
A: The residential lightning protection device should make full use of the underground natural grounding body as the grounding electrode, such as metal pipes, sewers, steel reinforced concrete foundation reinforcement, etc., but there are explosion and fire hazard pipelines, such as gas pipes, oil pipelines can not be used as grounding pole. In addition, water pipes and heating pipes cannot be used as ground electrodes. Because lightning strikes on such pipelines, overvoltages may occur on the pipelines and endanger personal safety. While using the natural grounding body, an artificial grounding pole should be set up to make the grounding resistance meet the requirements (10 ohms in general).
It must be pointed out that it is not possible to use only reinforced concrete foundations as grounding electrodes because: (a) Lightning currents penetrate the concrete from concrete and enter the ground, which may cause concrete cracks and gradually be damaged, affecting the foundation strength; ) The grounding resistance of concrete varies with the dry and wet soil. It is very low when wet and high when dry. Lightning strikes when dry, due to the high grounding resistance unfavorable to the release of lightning currents, affecting the lightning protection effect. Therefore, for houses or warehouses that store flammable and explosive materials, the grounding pole should not be used only as a base steel bar, and an artificial grounding pole should be provided as a lightning protection grounding pole.
Third, when the height of the building is required to install a lightning rod and why?
Answer: It is customary to install lightning rods or lightning protection nets when the height of a building exceeds 19.7 meters; lightning rods or lightning protection nets must be installed above 25 meters in buildings. But this does not mean that the lower buildings will not be in danger of being struck by lightning. Buildings that are dangerous for storage of flammable and explosive materials should be equipped with lightning rods (nets) if they are not very low, and lightning rods (nets) should be installed in buildings that are in the wilderness.
The protection angle of the lightning rod (that is, the angle formed by the connection between the most protruding point of the protected structure and the needle top and the needle itself) is below 60 degrees for general buildings and below 45 degrees for dangerous locations.
Fourth, what are the requirements for grounding deflectors for lightning protection and how is it connected to the grounding electrode?
Answer: The lightning down conductor can be used with a galvanized iron wire or flat iron with a section of not less than 35 mm2; of course, the copper wire can be used. However, the copper wire is too expensive and is easily stolen; aluminum wire is generally not suitable because of the aluminum wire. The mechanical strength is poor, it is easily damaged and broken, and corrosion is very unreliable.
The deflector should take the shortest route and try to avoid bending.
The connection between the down conductor and the underground grounding pole should be welded. Generally, oxyacetylene welding power arc welding should be used. It should not be soldered to ensure good and firm contact. If the family does not have a condition to do so, crimping can also be used, such as bolting. In order to be reliable in compression, a loose-proof spring washer must be added. Before the crimping, the connection part must be rust-removed and cleaned so as to expose the metal luster. The outer surface of the joint can be treated with a preservative such as water tar.
5. What are the requirements for grounding of lightning protection devices?
Answer: The artificial grounding pole of the evasion mine device is the same as the grounding pole of the protective grounding, but the grounding resistance can reach 10 ohms (the general requirement of the protective grounding is less than 4 ohms). Grounding electrode buried depth should be 0.5 to 0.7 meters underground.
6. Can a lightning rod be installed on an outdoor TV antenna?
A: Some residents install a metal rod 0.5 to 1 meter above the antenna on an outdoor TV antenna for lightning protection, and then ground it. This is a dangerous practice.
As we all know, the lightning rod is actually a lightning lead. Mounting a lightning rod on the TV antenna increases the possibility of lightning strikes on the antenna. The lightning rod should be really beyond the effect of preventing the protected object from being struck by lightning. In addition to the lightning rod should have a certain height and appropriate grounding resistance, it also requires a certain distance between the lightning rod and the object to be protected, otherwise it will cause counterattack.
Thunder strikes the TV antenna and lightning waves can be introduced along the feeder line to threaten people and the TV. Even if lightning strikes only the lightning rod, it may cause counterattack and induced overvoltage on the antenna feeder. Both of these overvoltage voltages are extremely high, and their voltage waves propagate into the room along the feeder line. They also threaten the safety of the person and the TV.
Therefore, lightning rods cannot be installed on the TV antenna or near the antenna. The correct approach is: (a) Install lightning arresters or discharge gaps to prevent lightning waves from intruding into the room. (b) The thunderstorm days will disconnect the antenna feeder from the TV and ground, or thrown outdoors. In this way, even if the lightning strikes the antenna, the lightning wave will not invade the room, thus ensuring the safety of the human body and the television.
Seventh, the ten methods of outdoor lightning protection
A: The thunder and lightning often hit the peak of the highest object in the outdoors, so isolated tall trees or buildings are often the most vulnerable to lightning strikes. When people are thunder and lightning, they should abide by the following rules in the outdoors to ensure safety.
1. Don't stay on high-rise platforms during thunderstorms. It is not advisable to enter isolated huts and guard booths at open locations.
2, away from the building exposed pipes, gas pipes and other metal objects and electrical equipment.
3. It is not appropriate to avoid thunderstorms under a big tree. If it is absolutely necessary, you must keep a distance of 3 meters from the trunk, squat down and close your legs.
4, if the lightning, the head, neck, hand ants crawling, hair erected, indicating the occurrence of lightning, should immediately squat on the ground, so you can reduce the risk of lightning, and take away the metal worn by the body Jewelry and hairpins, necklaces, etc.
5. If you experience thunderstorms in the outdoors and cannot leave a tall object, you should find some dry insulation immediately on the ground, and put your feet together and sit on it. Do not place your feet on the ground outside the insulation. Because the water Conductive.
6. When you are sheltering from thunderstorms in the outdoors, you should be careful not to hold it by your hands and hold your knees with both hands. Keep your chest close to your knees and lower your head as much as possible because the head is most vulnerable to lightning strikes compared to other parts of the body.
7. When a thunderstorm is heard within a few seconds of seeing the lightning in the open air, it means that you are in a dangerous environment near the thunderstorm. At this time, you should stop walking. Feet should be close together and immediately squat. Do not pull people together. It is best to use them. Plastic rain gear, raincoats, etc.
8. During thunderstorms, it is not advisable to hold an umbrella in the wilderness or to hold badminton rackets, golf clubs, gimmicks, etc.; it is not advisable to carry out outdoor ball games. It is very dangerous to carry out golf, football and other sports during thunderstorms; it is not advisable to be on the water. Stay by the water; it is not advisable to wash clothes, fish, swim, play in the river.
9. In thunderstorms, it is not advisable to open a motorcycle quickly, ride a bike fast and run wild in the rain. The greater the body's stride, the greater the voltage and the easier it is to hurt people.
10, if you see the high-voltage line in the outdoors by the lightning strike fracture, you should be vigilant at this time, because there is a step voltage near the breakpoint of the high-voltage line, people living nearby do not run at this time, but should feet together, jump off the scene .
8. What if someone is struck by lightning?
Answer: 1. After the human body has suffered a lightning strike, it often appears as a "dead-dead" state. At this time, emergency measures should be taken to rescue it. The first is artificial mouth-to-mouth resuscitation. The earlier the artificial respiration is performed after a lightning strike, the better the recovery of the injured person's body, because the human brain is in a deadly risk of oxygen deficiency for more than ten minutes.
2. Secondly, a heart massage should be performed on the wounded and the hospital should be promptly notified of the rescue treatment.
3. If the victim is caught in a fire caused by a lightning strike, he should immediately let the injured lie down so that the flame does not burn the face. He also poured water on the wounded person or wrapped the wounded in thick coats, blankets, etc. to extinguish the flames.
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