What is Lightning Protection Testing?

Lightning Protection Testing in the building inspection industry involves systematically inspecting and measuring key components of a building's lightning protection system, such as air terminals, down conductors, grounding devices, equipotential bonding, and surge protective devices (SPDs), in accordance with national standards (such as the "Technical Specifications for Lightning Protection Device Testing of Buildings"). This ensures compliance with lightning protection requirements, including initial testing and periodic testing (generally annually for civil buildings, and every six months for buildings with explosive or flammable materials), to guarantee the lightning protection safety of the building.

1. Objects and Content of Testing

• Air Terminals: Inspect the material, specifications (e.g., round steel diameter ≥ 8mm), welding quality, anti-corrosion treatment, and protection range (rolling sphere method) of the lightning rod/tape/network.

• Down Conductors: Inspect the quantity, spacing, and layout, as well as the transition resistance of the connection to the air terminal.

• Grounding Device: Measure the grounding resistance (e.g., T1, T2, T3, T4 test points), and check the distance from the surrounding environment to ensure no soil subsidence.

• Equipotential Bonding: Test the transition resistance of the connection between cable trays, distribution boxes, etc., and the building's main grounding body, which is usually required to be no greater than 0.2Ω.

• Surge Protective Devices (SPDs): Check whether the installation location and performance parameters (e.g., voltage protection level) meet the requirements.

• Lightning Protection Zone Division and Electromagnetic Shielding: Evaluate the lightning protection zoning and internal electromagnetic compatibility measures.

2. Basis and Standards for Testing

• The "Technical Specifications for Lightning Protection Device Testing of Buildings" (e.g., GB/T 21714 series) is the main basis.

• Follow the "Electrical Installations of Buildings" series of standards (GB16895).

• Based on design documents and compared with national mandatory indicators.

3. Testing Process and Cycle

• Before testing: Develop a testing plan, notify relevant parties, and ensure the technical负责人 is familiar with the standards.

• Testing items: Initial testing (before completion acceptance) and periodic testing.

• Testing cycle:

　　• 6 months: Places with explosion and fire hazards (e.g., gas stations, chemical plants).

　　• 12 months: General civil buildings, ordinary factory buildings, etc.

• Before completion: New, renovated, and expanded projects must be tested and qualified before being put into use.

4. Testing Methods

• Visual inspection: Visual inspection of materials, installation, corrosion, etc. • Measurements: Grounding resistance, contact resistance, SPD performance, etc.

• Document review: Review of design drawings and construction records.

5. Qualification Requirements

• The testing agency must possess the appropriate qualifications, and the testing personnel must be professional.