Issues related to lightning protection in factory buildings

Reply 1# *nshiji168: It’s not easy to answer simply; it depends on the category of your building. If it is of category three, then it’s acceptable. You can refer to the Code for Design of Lightning Protection of Buildings (GB50057-94).

Putting aside regional classifications, building types, and height for now, I suggest designing it in the shape of a \"circle\"; based on your description, it should at least take the shape of a \"sun\".

This post was last edited by *nshiji168 on 2011-6-25 20:58. It is a factory building; thunderstorms should not occur frequently there. Is the minimum lightning protection rating category 3? I see that the third category involves a 20*20 grid; my factory is smaller than that, so it should be sufficient to install lightning protection strips around the perimeter. Is it necessary to also install lightning rods at the four corners? Is it necessary to use the rebar in the building’s columns as down conductors? Is it more complicated to use this method for the downlead? Should we still use flat steel to run it down from the roof? I think according to the specifications, two down conductors are sufficient for a roof of this size.

Classification of building lightning protection (Code for Design of Lightning Protection of Buildings (GB50057-94)). ) Article 2.0.1 Buildings shall be classified into three categories according to their importance, nature of use, likelihood of lightning incidents, and consequences, in accordance with lightning protection requirements. 　　Article 2.0.2 Buildings shall be classified as Category I lightning protection buildings in any of the following situations: 1. Buildings that manufacture, use, or store large quantities of **, **, explosives, and other pyrotechnic materials, where an explosion caused by electrical sparks could result in severe damage and casualties. 　　II. Buildings in areas with explosion hazards of Zone 0 or Zone 10. 　　III. In buildings with Zone 1 explosion hazards, explosions caused by electrical sparks can result in severe damage and casualties. 　　Article 2.0.3 Buildings shall be classified as Category II lightning protection buildings in any of the following situations: 1. Buildings that are under first-level protection as key cultural relics. 　　II. Particularly important buildings such as **-grade auditoriums, office buildings, large exhibition and fair venues, large railway stations, state guesthouses, **-grade archives, and important water pumping stations for urban water supply. 　　III. Buildings such as **level computing centers and international communication hubs that are of great significance to the national economy and are equipped with a large number of electronic devices. 　　IV. Structures of **quality that are manufactured, used, or stored in such a way that electric sparks are unlikely to cause explosions or significant damage and casualties. 　　V. Buildings in Zone 1 explosive hazard environments where electrical sparks are unlikely to cause an explosion or result in significant damage or casualties. 　　VI. Buildings in areas with explosion hazards of Zone 2 or Zone 11. 　　VII. Open steel enclosed gas tanks in industrial enterprises that pose an explosion risk. 　　VIII. Departmental and provincial office buildings, as well as other important or densely populated public buildings, where the expected number of lightning strikes is greater than 0.06 times per year. 　　IX. Ordinary civil buildings such as residential houses and office buildings, where the expected number of lightning strikes is greater than 0.3 times per year. 　　Note: The expected number of lightning strikes should be calculated according to Appendix 1 of this specification. 　　Article 2.0.4 Buildings shall be classified as Category III lightning protection buildings in any of the following situations: 1. Buildings that are under provincial-level key cultural heritage protection and provincial archives. 　　II. Departmental and provincial office buildings, as well as other important or densely populated public buildings, where the expected number of lightning strikes is greater than or equal to 0.012 times per year and less than or equal to 0.06 times per year. 　　III. Ordinary civil buildings such as residential houses and office buildings, where the expected number of lightning strikes is greater than or equal to 0.06 times per year and less than or equal to 0.3 times per year. 　　IV. General industrial buildings with an expected number of lightning strikes of 0.06 or more times per year. 　　V. Based on the impact of lightning strikes on industrial production and the resulting consequences, and taking into account factors such as local weather conditions, topography, geology, and the surrounding environment, the fire-hazardous areas 21, 22, and 23 that require lightning protection have been identified. 　　VI. In areas with an average number of thunderstorm days greater than 15 days per year, isolated tall structures such as chimneys and water towers with a height of 15 meters or more; in areas with an average number of thunderstorm days equal to or less than 15 days per year, isolated tall structures such as chimneys and water towers with a height of 20 meters or more.

Reply to 4# *nshiji168: If it is a regular factory building, the minimum lightning protection category required is Category 3. In Category 3, a grid of 20*20 units is used; since the area of the factory building is 13*6, which is smaller than that, it is sufficient to install lightning protection strips around the perimeter only. We use the four corners as lightning rods; for the down conductors, we can utilize the rebar in the building’s columns, or flat steel bars that are led down from the roof. The regulations specify that two down conductors coming from the roof are sufficient.

The proposed solution is also acceptable, but it should be emphasized that the rebar must be from peripheral components; it cannot be made from the rebar used in buildings, and flat steel should be used instead to create it. After finishing, conduct a pressure test to check the results. Can it be shaken?

This post was last edited by *nshiji168 on 2011-6-26 23:14. Thank you to the friend above; I’m wondering if it’s troublesome to use column rebar as downlead in construction According to the specifications, it is recommended that column reinforcement be used for Type 1 buildings. What about how to handle the grounding electrode? It’s my first time dealing with this, so I have no idea what to do. Thank you all. Just saw the reply above – why can’t column rebar be used as the downlead? I think the specifications allow it. Does any friend have similar lightning protection design drawings that I can refer to?