1. Q: What is the difference between PSL1 and PSL2 in API 5L?
A: PSL2 has more stringent requirements than PSL1, including tighter chemistry control, higher toughness (Charpy impact testing), mandatory hydrostatic testing, and stricter non-destructive examination of welds.
2.Q: What is a common issue when welding galvanized steel pipe?
A: Zinc fumes are toxic, and the zinc coating can cause weld porosity, lack of fusion, and cracking. The zinc must be removed from the weld area before welding.
3. Q: What standard covers pipe for fire protection systems (sprinklers)?
A: ASTM A795 covers black and galvanized steel pipe for fire protection, which is essentially A53 or A135 pipe with additional requirements for threading and marking.
4. Q: What is the significance of the "S" in a grade like S355JR?
A: S355JR is a structural steel grade per EN 10219 (for hollow sections), not a pipe spec. "S" stands for "Structural Steel," 355 is the min yield strength in MPa, and JR indicates Charpy impact energy at room temperature.
5. Q: How does the strength of EN 10217-1 P235GH compare to ASTM A106 Gr. B?
A: Both are for pressure purposes. P235GH has a min yield of 235 MPa, while A106 Gr. B is 240 MPa, so they are very similar in strength.
