Lightning Protection for Container Houses

The lightning protection measures for container houses should be combined with their metal structural characteristics, ensuring safety through the rational configuration of lightning protection devices, grounding systems, and equipotential bonding. The specific measures are as follows:

I. Configuration of Lightning Protection Devices

1. Selection of Air Terminals
   Container houses typically use metal roofs as air terminals, which must meet the requirements of the "Design Code for Protection of Structures against Lightning" (GB 50057). If the metal plate thickness is ≥0.5mm and there is no flammable material covering it, it can be directly used as an air terminal. For non-metallic roofs, a ∅14 hot-dip galvanized round steel lightning strip should be installed to form a grid (≤10m×10m for Class I lightning protection buildings, ≤20m×20m for Class III).

2. Down Conductor Installation
   Utilize the container's steel structure as down conductors to ensure the rapid导入 (import, here meaning 'conduction into') of current into the ground. If additional down conductors are required, ≥Φ8mm galvanized round steel or ≥48mm² galvanized flat steel should be used, evenly arranged around the house with spacing in accordance with regulations (≤18m for Class II lightning protection, ≤25m for Class III).

3. Lightning Rod Supplementation
   In areas with active lightning or when the house is taller than surrounding buildings, lightning rods can be added. The tip of the rod should be at least 1-2 meters above the roof, made of galvanized round steel or steel pipe to enhance its ability to attract lightning.

II. Design of Grounding System

1. Grounding Devices
   The metal shell of the container must be reliably connected to the grounding electrode to form an equipotential body. The grounding electrode can be a hot-dip galvanized steel pipe (G∅50) or angle steel, buried at a depth of ≥1 meter and ≥3 meters away from the house foundation. If the soil resistivity is high, additional artificial grounding electrodes or grounding resistance reducers should be installed.

2. Grounding Resistance Requirements
   For Class I lightning protection buildings, the grounding resistance should be ≤10Ω, and for Class III, ≤30Ω. After construction, actual measurements should be taken. If the requirements are not met, additional grounding electrodes should be installed or the grounding grid expanded.

3. Connection of Grounding Flat Steel
   The roof lightning protection system should be connected to the grounding bar provided by the container (no less than 2) through 40×4 hot-dip galvanized flat steel, ensuring good contact and clear identification.

III. Equipotential Bonding and Insulation Protection

1. Equipotential Bonding
   All non-functional conductive bodies (such as metal doors, windows, and pipes) should be connected to the metal shell of the container to form an equipotential body, avoiding potential differences caused by side-flash lightning or induced lightning.

2. Internal Insulation Protection
   Lay flame-retardant insulating mats with an insulation voltage of ≥5kV in the aisles, covering the gaps between equipment cabinets to prevent current from conducting to the human body through the ground.

IV. Handling of Special Scenarios

1. Areas with Active Lightning
   If the house is not within the original lightning protection coverage area, a complete lightning protection system, including air terminals, down conductors, and grounding devices, should be separately configured and connected to the grounding bar through flat steel.

2. Multi-Module Combined Houses
   Modules should be connected through flat steel or copper strips to ensure the continuity of the overall lightning protection system and avoid impedance to lightning current shunting due to poor connections.