Hello Pipe Enthusiasts!
In the oil and gas industry, the quality of steel pipes is determined not only by the material but also by manufacturing process that forms them. To ensure consistency and reliable quality, American Petroleum Institute (API) has established specific clauses on Manufacturing Procedure Qualification Test (MPQT) in the API 5L, 46th edition at the time this article was written.
What is MPQT?
MPQT is a manufacturing procedure qualification test that must be conducted before mass production begins. Its purpose is to prove that production methods, such as welding, heat treatment, and fabrication, are capable of producing steel pipes that meet API specifications.
MPQT Clauses in API 5L
- B.5.1: Mandatory tests listed in the standard tables (such as Table 18 – Inspection Frequency for PSL 2 Pipe, Table H.3 – Inspection Frequency, and Table J.7 – Number, Orientation, and Location of Test Pieces per Sample for Mechanical Tests) must be performed before or at the start of production.
- B.5.2: The frequency and quantity of qualification testing are defined in the purchase order. Requalification is only allowed with purchaser approval. Prequalification data from previous production may be used if noted in the purchase order.
- B.5.3: Minimum information required for welding procedure qualification of steel pipes, including for HFW (High-Frequency Welded), SAW (Submerged Arc Welding), and COW (Continuous Weld) pipes.
- B.5.4 – B.5.6: Additional clauses cover requests for other property data (e.g., weldability), assessment of coil/plate tensile property variability, and the obligation to report any coil/plate/pipe that does not meet initial rolling practice parameters but has been requalified.
Why is MPQT Important in API?
1. Ensures consistent quality: every production batch meets API standards.
2. Reduces risk of failure in the field: especially for pipes operating under high pressure.
3. International compliance: MPQT is a requirement for certification and global acceptance.
4. Transparency: MPQT results are documented and auditable by clients and regulators.
Conclusion
MPQT in API 5L is not just a formality but a quality filter that every steel pipe manufacturer must comply with. With MPQT, the oil and gas industry can be confident that each pipe produced has undergone a manufacturing process that is tested, documented, and consistent with international standards.
Southeast Asia Pipe Industries has more than 60 years of experience in producing steel pipes and has served customers using API 5L steel pipes ranging from grade API 5L B to API 5L X70. If you require steel pipes that meet international API 5L standards, trust Southeast Asia Pipe Industries to deliver. See you again in the next #SEAPIPipeInsights article!
