Metal roof structure lightning protection design
The lightning protection device consists of three parts: flashing device, grounding down line and ground body. The roof lightning protection is part of the external lightning protection system, that is, the flashing device. Because the metal roof structure system is often used on the large -scale, large -area public building roof, it is easier to cause lightning strikes. Therefore, in the process of designing the metal roof system, it should be designed according to the six elements of lightning protection.
The lightning protection method of traditional buildings is to use Franklin regular lightning officer or lightning protection ground combined with lightning protection net. However, due to the uniqueness of the metal roof system composition material and structure, it has excellent conductivity. Under certain conditions, the metal roof system itself is a good flash device.
Using a large span metal roof system as a lightning -proof flasher of the building should meet the following requirements:
1) When there is no flammable items under the metal roof system, the thickness of the external pressure metal plate should not be less than 0.5mm;
2) When there are flammable items under the metal roof system, the thickness of the outer metal thin plate, the steel sheet should not be less than 4mm copper plates should not be less than 5mm, and the aluminum plate should not be less than 7mm;
3) Metal roof panels have no insulation layer, or the thickness of the insulation material should meet the national standard regulations. General PE, PVF2/PVDF coating materials or pillar protective layers with a thickness of less than 0.5mm or a polyvinyl chloride protective layer with a thickness of less than 1mm are not covered by insulation and overwriting;
The choice of the design of the lightning protection structure and the lightning of the roof system should meet the requirements of the specifications. The minimum excessive resistance value of the metal roof system and the main steel structure ground must be ensured.
The lightning protection design of the metal roof system should take into account the lightning protection design of the lightning protection components adjacent to the curtain wall, roof structure, and roof equipment building peripheral protection component.