1. Q: How does A139 differ from API 5L line pipe?
A: While both are welded steel pipes, A139 is specifically designed for water service and is often used in municipal and industrial water projects. API 5L is designed for the transmission of oil, gas, and other hydrocarbons in the petroleum and natural gas industries, with more stringent requirements for chemical composition and fracture toughness.
2. Q: What are the limitations of A139 pipe regarding service temperature?
A: A139 is a carbon steel pipe intended for ambient temperature service. It is not designed or recommended for high-temperature pressure service (which would fall under ASTM A53 or A106) or for low-temperature service where impact toughness is critical.
3. Q: What should be inspected for on the weld seam of an A139 pipe?
A: The weld seam should be visually inspected for consistency and soundness. The standard allows for some reinforcement (weld bead) on the inside and outside of the pipe, but it must not exceed specified limits. The weld must be free from cracks, incomplete fusion, and undercut.
4. Q: Can A139 pipe be bent or fabricated in the field?
A: Yes, A139 pipe can be bent and fabricated, but it must be done carefully. Cold bending is common, but the bend radius must be controlled to avoid flattening or damaging the pipe. Field welding is also possible, but it must be performed using qualified welding procedures suitable for the pipe's chemistry.
5. Q: What information is typically marked on each length of A139 pipe?
A: Each pipe is typically stenciled or stamped with the manufacturer's name or trademark, the ASTM A139 designation, the grade (e.g., A, B, C, D), the size (NPS), the wall thickness, the heat number, and the test pressure (if hydrostatically tested). This ensures full traceability.
