🔍 Key Concepts

• Meaning of standard weight, extra strong (XS), and double extra strong (XXS) in piping specifications • Common industrial uses of plastic, copper, and steel pipe on commercial vessels and in shoreside marine facilities • Which materials are typically rated for very high pressure service

💭 Think About

• Think about which of these materials is most commonly used for high‑pressure steam, fuel, and hydraulic lines on ships • Ask yourself: In piping catalogs and marine engineering manuals, which material is usually listed with wall designations like STD, XS, and XXS? • Consider whether softer, lower‑pressure materials are normally cataloged with these same traditional weight designations, or with different rating systems (like schedule numbers or PSI ratings)

✅ Before You Answer

• Verify which material is standard for heavy‑duty, high‑pressure ship systems where wall thickness is critical • Check if all three materials are actually sold in all three of those exact wall designations, not just similar but different rating terms • Make sure you can picture a typical engine room piping diagram and identify what most of the main process lines are made of