QX/T 399-2017 in English

This standard systematically stipulates the technical requirements for lightning protection throughout the entire water supply system, from the water treatment plant to the pumping station, and innovatively associates and grades the lightning protection zone with the size of the city and the size of the water plant. Key points include:

• Lightning protection classification standards for three types of buildings (based on lightning strike frequency and city size)
• Mandatory requirements for underground laying of medium and high voltage systems
• Construction of M-type equipotential bonding network for electronic systems
• Special protection plans for special places (chlorination room/liquid oxygen station)

Chlorination/ammonia dosing system

Liquid oxygen station

When the wall thickness of the storage tank is ≥4mm, the lightning rod can be omitted, but the following must be met:

• The distance between grounding points is ≤30m
• The impulse grounding resistance is ≤30Ω
• The oxygen pipe flange jumper resistance is <0.03Ω

Design stage

1. Determine the lightning protection category of the building according to Appendix A
2. Electronic systems shall preferably adopt M_m type equipotential bonding network
3. Long-distance signal lines shall adopt double shielding or wear steel pipes

Construction stage

• The cross-sectional area of the SPD connecting line is ≥1.2mm²
• Equipotential bonding transition resistance ≤ 0.2Ω
• Grounding of both ends of the metal sheath of the armored cable

Inspection and maintenance

Inspection before the thunderstorm season each year, focusing on the following:

• Grounding resistance value (according to the minimum required value)
• SPD degradation indication status
• Shield line conductivity