Can chemical pipelines be buried directly in the ground?
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There is currently 1 DN50 stainless steel pipe, with a chemical medium (Category A B), measuring 200 meters in length, and it needs to pass through two roads. I plan to bury it directly, but clause 7.2.4 of 50160 states that “pipes for flammable liquids should be installed overhead or along the ground; if installation in a trench is necessary, then…” It seems that at the very least it’s a groove; it isn’t specified whether it can be buried directly. I would like to ask everyone: 1. Can it be laid directly underground? 2. How is corrosion protection handled when stainless steel pipes are buried? Thank you!
1# Feifan Ruyi: Buried 200 meters underground, which is a rather deep depth. Those of us who have worked on similar projects have used asphalt-based anti-corrosion paint, covered it with glass cloth, and then wrapped it in PVC. But it’s not 12 meters long. It is best to keep it overhead or in a trench.
It is best to lay the pipes in ducts or trenches, as this makes it easier to detect leaks and facilitate repairs. If burial is necessary, anti-corrosion measures must be taken, or protective sleeves should be used; additionally, thick-walled pipes could be considered for use in such cases.
Trenches also present problems; to prevent the accumulation of oil and gas inside them, they are usually filled with sand and covered with a lid, which is then poured over. For a trench that is 200 meters long, this approach is definitely too lengthy and requires significant investment； This method seems safe, but it actually poses hidden risks—there is no guarantee of the presence of an air space for oil and gas, especially over time, in case the sand loses its integrity. I think burying it directly is the safest option, right?
Why not? The issue is that corrosion prevention must be thorough, and most importantly, there must be strategies in place for regular inspections and testing.
All these trenches we use for burial – it’s not that direct burial isn’t possible, but in any case, trench burial is much safer than direct burial
Personally, I think it can also be installed overhead or along the ground, or even buried directly! ! ! ! ! If nothing else works, opt for a trench; it’s still better to go with a shallow trench! ! ! The regulations do not prohibit direct burial either; it is mainly done to make it easier to detect any problems, for safety reasons! ! ! For reference only! ! !
It is recommended to avoid burying everything entirely; if it is not possible to use pipe racks, shallow trenches can be used. The sections that pass over roads can be buried directly underground, trying to avoid burying welds in this way. Sleeves should be used so that they can be removed easily during maintenance, without the need to dig up the road again. Personally, I believe that stainless steel pipes also corrode in soil, after all, the composition of soil is complex and it isn’t neutral soil. The common method for underground corrosion protection is as follows: apply asphalt paint for corrosion protection, then wrap with glass fiber cloth, apply more asphalt paint, and wrap with glass fiber cloth again; this process is repeated, using three layers of cloth and four layers of paint to prevent moisture ingress. It is strictly prohibited to damage the moisture barrier during construction.