【Common Issues in Haichuan Pipeline Design】--The clear height of pipelines for hazardous chemicals above the ground is less than 15 cm

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The 25th National “Safety Production Month” in 2026: Everyone should talk about safety and know how to handle emergencies; identify and address potential risks and hazards. -------------------------------------------------- During the design, installation, and inspection of pipelines, small issues that have been overlooked or not taken into consideration are often discovered. These issues are collected and organized into a series, which is being updated continuously. Everyone is welcome to actively participate in discussions. There is a compilation post on common problems in Haichuan pipeline design, which is still being updated; feel free to join the discussions: https://bbs.hcbbs.com/thread-5705828-1-1.html ------------------------------------------------------------------ Standards and regulations: Article 3.2.8 of the “Code for Design of Metal Pipelines in Petrochemical Industries” (SH3012-2011) states that pipelines laid along the ground must meet the requirements for installing valves and fittings, and the clear height between the pipeline and the ground should not be less than 0.15 meters. Risk analysis: 1. Installation and maintenance risks (most direct): The valve cannot be operated – the valve stem or handwheel is too close to the ground, making it impossible to turn the wrench or to reach in order to operate the valve. This results in failure to shut off the valve in emergency situations, leading to leaks, fires, and explosions. The flange cannot be tightened/changed: The bolts are below the ground level, making it impossible to tighten them; gaskets cannot be replaced either, resulting in a failed seal → material leakage ； Maintenance requires cutting the pipes with fire and re-welding, which increases the risk of fire hazards and leads to downtime losses. Welds cannot be inspected/repaired: The bottom welds are not visible, cannot be inspected for defects, and cannot be repaired; crack propagation leads to pipe rupture and severe leakage of the fluid. 2. Corrosion and leakage risks (most common): External corrosion is accelerated by prolonged exposure to water, contact with soil, and poor ventilation; the corrosion rate of carbon steel/low-alloy steel can increase by 2–5 times, leading to wall thinning and perforation leakage within 3–5 years. Corrosion of the flange sealing surface: Prolonged moisture and dirt accumulation on the bottom sealing surface, aging of gaskets, and failure of the seals can lead to leaks of flammable/toxic substances, resulting in poisoning, fires, and explosions. Electrochemical corrosion perforation: When pipes are in direct contact with concrete/soil, the galvanic effect leads to rapid local corrosion and perforation, resulting in sudden leaks that are difficult to predict. 3. Inspections and management of risks (hidden but fatal): Hidden defects exist – bottom corrosion, cracks, and leaks are not visible; thickness measurement and leak detection are not possible. Small defects can lead to major accidents (such as fires caused by perforations and leaks). Leaks are difficult to detect: The leaking substance (oil, flammable liquids) flows onto the ground or seeps underground; it is invisible and odorless. When it accumulates to a certain extent and comes into contact with a fire source, an explosion and a large-scale fire occur. High maintenance costs: premature corrosion leading to equipment failure, frequent repairs, downtime for emergency repairs, high repair expenses, significant production losses, and ongoing safety risks. 4. Safety and environmental risks: Fire and explosion: Leakage of flammable materials leads to leakage on the ground and vapor emission; when exposed to open flames, static electricity, or hot surfaces, this can result in fires and explosions, causing casualties, equipment damage, and shutdown of the facility. Poisoning and occupational diseases: Leakage of toxic substances (benzene, hydrogen sulfide, chlorine) → volatilization into the air; operators inhale these substances and get poisoned. Prolonged exposure → occupational diseases. Environmental pollution: Leaked substances seep into the soil and groundwater, causing soil contamination and groundwater pollution; addressing this issue is difficult, costly, and subject to severe environmental penalties.