This guide supports procurement discussion and does not replace the approved design code, materials-engineering review or project specification. Verify the current edition of every referenced standard.
Translate the line list into a purchase requirement
Oil and gas pipe selection begins with the approved design basis: fluid, design pressure and temperature, corrosion allowance, piping class, location and applicable code. Procurement then converts those controls into an auditable product specification.
Material grade, manufacturing route, dimensions, ends, heat treatment, supplementary requirements and inspection should agree across the datasheet, BOQ and purchase order.
- Identify sweet, sour, wet, dry, multiphase and chemical-injection services correctly.
- State whether seamless, welded or a qualified alternative is permitted.
- List project specifications and approved manufacturer requirements.
- Define coating, marking and preservation for the logistics route.
Material and inspection decisions
Carbon steel, stainless steel, duplex, super duplex and nickel alloys each have application windows. Selection requires corrosion and mechanical review—not a supplier assumption.
Inspection may include document review, visual and dimensional examination, NDT, hydrostatic testing, PMI and project-specific supplementary testing. Hold and witness points must be agreed before manufacture or release.
Oil and gas pipe RFQ checklist
| Control | Required information | Why it matters |
|---|---|---|
| Service | Fluid, H2S/CO2 where applicable, chlorides, temperature, pressure | Material and corrosion review |
| Product | Grade, standard, PSL/class, construction route | Manufacturing and acceptance |
| Dimensions | NPS/OD, schedule/wall, length, ends | Fit and design basis |
| Inspection | NDT, tests, ITP, third party | Verification and timing |
| Delivery | Coating, caps, bundles, marks, destination | Preservation and traceability |
Common buyer questions.
Does API 5L cover all refinery piping?+
No. API 5L addresses line pipe; refinery and process piping may use other product standards under the project piping specification.
When should sour-service requirements be stated?+
At enquiry stage, whenever the approved design basis invokes the applicable sour-service standard or project requirement.
Can a supplier choose corrosion allowance?+
No. Corrosion allowance is an engineering-design input that should be provided in the approved specification.
Standards and technical sources.
Links are provided for source context. Always use the edition required by the contract and approved project documents.
American Petroleum Institute — API Specification 5L, 47th edition announcementASME B36.10 — Welded and Seamless Wrought Steel Pipe