Direct lightning protection (external lightning protection):

Air terminal (lightning rod, lightning protection belt, lightning protection net):

• Install lightning rods on top of tall buildings or key equipment.
• For large-area building roofs, lightning protection belts or lightning protection nets can be arranged.
• The lightning rod should meet the protection range (calculated by rolling ball method or angle method)

Downline:

• Introduce the lightning current collected by the air-termination device into the ground.
• Generally, they are arranged evenly along the four corners of the building or on the exterior wall to avoid concentration at a single point.
• Material: galvanized flat steel, round steel or copper conductor.

Grounding system:

• Discharge lightning current into the earth quickly and safely.
• It is recommended to form a joint grounding network with the building's working grounding, anti-static grounding, etc.
• Ground resistance requirements: generally ≤10Ω, important projects ≤4Ω.

Induction lightning and lightning wave intrusion protection (internal lightning protection)

Equipotential bonding:

• Various metal pipes, steel bars, equipment shells, and grounding systems must be reliably connected to avoid potential differences.

Block:

• Use metal shells, shielded cables, etc. to reduce electromagnetic induction.
• Especially important in weak current systems (signal, control).

Surge Protector (SPD):

• Install a first-level SPD at the power distribution cabinet at the incoming end of the building to discharge large energy.
• Install Level 2 and Level 3 SPDs step by step in front of floor distribution boxes and key equipment.
• SPD is required for communication lines and power lines.

Common design specification reference

• "Code for Lightning Protection Design of Buildings" GB 50057
• "Technical Specifications for Lightning Protection of Building Electronic Information Systems" GB 50343