First, pre-test check
1. Understand the environment and location of the lightning protection device, the nature of the use of the building, and the possibility and consequences of a lightning strike accident, and determine the lightning protection category of each building (structure).
2. Check the design drawings to understand the concealed construction.
Second, prevent direct lightning
1. The anti-lightning device shall be provided for the building (structure) of the petrochemical enterprise and the inner tower of the process device.
2. Towers, containers, etc., which are arranged in the open air within the process device, may not be provided with a lightning rod when the thickness of the can wall is ≥ 4 mm, but lightning protection grounding must be provided.
3. Gas tanks for combustible gas (liquid) must have ring-type lightning protection grounding and should comply with the following regulations:
(1) The scope of protection of the lightning rod (line) should include the entire tank;
(2) Fixed top steel tanks containing Class A and B flame arresters for flammable liquids. When the tank wall thickness is ≥ 4mm, no lightning rods (wires) may be provided;
(3) Class C liquid storage tanks may not be provided with lightning rods (wires), but lightning protection grounding must be provided.
(4) The floating roof metal tank may not be provided with a lightning protection device, but two soft copper strands with a cross-sectional area of ≥25 mm2 must be used to electrically connect the floating roof with the tank body, and the connection point is not less than two. (5) The pressure tanks may not be provided with lightning rods (wires), but lightning protection grounding must be provided.
Third, anti-static
1. Metal tanks, equipment, and pipes should have antistatic grounding.
2. Combustible gas (liquid) body, flammable solid pipeline should have antistatic grounding in the following locations:
(1) Access to installations or facilities;
(2) Boundary of explosion hazardous locations;
(3) Inline pumps, filters, buffers, etc.
3. Flammable gas (liquid) pipe flange, valve connection, there should be metal jumper. When flanges are connected with more than 5 bolts, the flanges can be bridged without wires, but they must constitute electrical paths.
4. The loading and unloading site should have antistatic grounding.
Fourth, anti-inductive lightning
1. The signal lines of temperature, liquid level, etc. of flammable liquid storage tanks shall be shielded by armored cable or steel pipe. The cable sheath and steel pipe shall be connected to the tank body.
2 . The power and communication lines shall be shielded by armored cables or steel pipes. The cable sheaths and steel pipes shall be grounded and arresters shall be installed.
Fifth, grounding device
With reference to the design drawings, the construction staff and the representatives of Party A should be aware of the grounding device, record the materials, specifications, quantity, and layout of the grounding body and the grounding wire, and make detailed records.
1. The buried depth of the horizontal grounding body is not less than 0.7. The length of the vertical grounding body is 1.5-2.5m and the spacing is 5.0m. Artificial grounding bodies should be hot dip galvanized steel.
2. Static grounding lines should use hot-dip galvanized steel, round steel φ ≥ 10mm, flat steel ≥ 40 × 4mm; electrostatic grounding branch should use hot galvanized steel, round bar from φ ≥ 6mm, flat steel ≥ 12 × 4mm.
Six, grounding resistance detection
Measured in accordance with the provisions of Article 4 of the Rules for the Implementation of Lightning Protection Devices for Buildings (Structures).
1. Lightning grounding resistance ≤ 10Ω, antistatic grounding resistance ≤ 100Ω.
2. Except for the first lightning protection device's independent lightning rod being separated from other grounding devices by a distance of not less than 3m, lightning protection grounding, electrical equipment grounding, anti-static grounding, and inductive lightning grounding should share the same grounding device.
VII. Calculation of protection range The calculation can be performed indoors and the protective range of the air-termination device can be determined by using the rolling ball method.
VIII. Processing of data The readings and calculation results of the tests should be kept at a decimal number (except for the lightning protection device material model specifications), and the revision should be made according to GB817-87. After the above inspection work is completed, the checker fully checks whether the results of the original records, instruments, etc., have corresponding records, and whether the connector of the lightning protection device is restored to the state before the test.