1. Check the Physical Integrity of the Grounding Connection
The grounding system must form a continuous, low-impedance path to conduct static electricity to the earth.
2. Check the Connection Points for Secureness
Check that the static clamp (such as a toothed clamp) is securely clamped to the exposed metal part and can penetrate the paint or rust layer to ensure reliable contact with the metal body. If there is a coating at the clamping point, a clamp with penetration capability must be used.
3. Check the Integrity of the Wire
The grounding wire should be free from breaks, aging, severe corrosion, or loose connections. It is recommended to use copper core stranded wire with a cross-sectional area ≥6mm², possessing sufficient mechanical strength and conductivity.
4. Ensure the Grounding Terminal is Dedicated
The paint can should have a dedicated grounding terminal or threaded interface. Avoid grounding through undesigned paths (such as pipe supports or water pipes) to prevent poor contact.
✅ On-site Operation Recommendation: Before each operation, perform a "visual and manual inspection" to confirm that the clamp is tight, the wire is undamaged, and the connection is secure.
2. Measuring Grounding Resistance: Resistance is a core indicator of grounding effectiveness and must be tested using professional instruments.
1. Standard Requirements:
General flammable and explosive environments: Grounding resistance ≤ 10Ω
High-risk scenarios (e.g., powder coating lines, solvent handling): Stricter requirements, ≤ 4Ω
The total resistance of the anti-static grounding system should generally not exceed 100Ω.
2. Test Method: Use a grounding resistance tester (e.g., ZC-8 model). Insert the test electrodes into the ground, connect the grounding clamp and grounding stake of the paint can, and read the resistance value. Testing should be conducted in a dry environment to avoid affecting the accuracy of the results due to rain.
3. Multi-point Testing: For large storage tanks or mobile containers, multiple grounding points should be tested to ensure that each meets the standard.
✅ Recommended Practice: Establish a regular testing system, at least quarterly, and record the data for future reference.
3. Verify the equipotential connection (bridging) of the entire system. Grounding a single device is insufficient; all related devices must form an "equipotential body."
1. Ensure proper bridging. During loading and unloading operations, paint cans, receiving containers, pumps, metal hoses, etc., should all be connected by wires to achieve potential synchronization and prevent spark discharge due to potential differences.
2. Ensure correct connection sequence. Follow the principle of "grounding before operation, disconnecting pipes before grounding":
Connect all bridging wires
Connect grounding clamps
Start operation
Close valves after operation
Let stand for 2-5 minutes (to allow static electricity to dissipate)
Disconnect material pipelines first
Remove grounding devices last.
⚠️ Special reminder: This procedure must be strictly followed when loading and unloading flammable liquids in 200L metal drums. Refer to GB 12158-2024 "General Requirements for the Prevention of Static Electricity Accidents."
4. Use monitoring equipment for dynamic protection. In high-risk scenarios, automated monitoring can be introduced to improve safety.
1. Electrostatic Disconnection Monitoring System: Monitors grounding status in real time. An alarm or interlock to stop operation immediately upon disconnection, preventing human error.
2. Nitrogen Sealing Protection (Optional): For liquids with poor conductivity (such as benzene and ketones), nitrogen gas can be introduced into the tank to create an inert atmosphere, preventing explosion even if electrostatic control fails.
