Process materials (gases and chemicals)

Which combination of material and surface treatment is commonly used for high-purity gas piping?

  1. APVC pipe
  2. BPainted iron pipe
  3. CStainless steel (such as SUS316L) with electropolished interior surfaces
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Answer: C. Stainless steel (such as SUS316L) with electropolished interior surfaces

High-purity gas lines use corrosion-resistant stainless steel such as SUS316L, with the interior electropolished to be very smooth. Reducing surface roughness limits adsorption of moisture and impurities and particle generation.

  • A. PVC is not suited to high-purity gas piping.
  • B. Painted iron contaminates the gas and corrodes easily.
  • C. Correct. Electropolished stainless steel is used.
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