Definition
Wall Thickness — Wall thickness is the radial thickness of a tubular's steel body — the difference between its outside and inside radius — and it governs the pipe's tensile, collapse and burst strength as well as its inspection class as it wears.
Also known as: wall thickness, pipe wall, remaining wall
What wall thickness is
Wall thickness is how thick the steel body of a pipe is, measured radially — half the difference between the outside diameter and the inside diameter. It is the single most important dimension for strength: for a given grade, thicker wall means higher tensile, torsional, collapse and burst capacity, which is why nominal weight (and thus wall) is specified alongside OD and grade.
As drill pipe is used, internal and external wear reduce the wall. The remaining body wall, expressed as a percentage of nominal, determines the pipe’s inspection class — Premium Class, Class 2, and so on — and the derated load ratings that go with it.
Why it matters
- Strength — all body ratings scale with wall thickness.
- Wear and class — DS-1 and API RP 7G-2 define minimum remaining wall for each class.
- Measurement — ultrasonic and electromagnetic inspection quantify remaining wall along the tube.
Renting by inspection class
Rental pipe is graded by remaining wall, so its class tells you the load ratings you can rely on. We supply drill pipe and drill collars with documented wall and inspection class — contact us to match ratings to your well.