The following are the dimensional accuracy requirements for SSAW Steel Pipes in different application scenarios in API Spec 5L standard:

Long distance onshore pipelines:

Outer diameter: When the outer diameter is ≥ 60.3mm and the wall thickness S is < 20mm, the allowable deviation is ± 0.75%; When the outer diameter is ≥ 60.3mm and the wall thickness S is ≥ 20mm, the allowable deviation is ± 1.00%.

Wall thickness: usually specified as -3% to+6% of the nominal wall thickness.

Length: Generally standard lengths such as 12m or 18m, with length deviation controlled within ± 50mm.

Ocean pipeline:

Outer diameter and wall thickness: The control range of outer diameter deviation and wall thickness deviation is usually stricter than that of onshore pipelines. For outer diameter ≥ 60.3mm, the deviation may be controlled within ± 0.5% - ± 0.7%; The wall thickness deviation is controlled at around -2% -+4%.

Ellipticity: generally controlled within 0.5% -0.8%.

Straightness: The straightness deviation usually does not exceed 0.2% per meter.

Acidic environment (including hydrogen sulfide):

Outer diameter and wall thickness: The dimensional accuracy requirements are similar to those of onshore long-distance pipelines, but a certain amount of corrosion allowance needs to be considered. When the outer diameter is ≥ 60.3mm and the wall thickness S is < 20mm, the allowable deviation of the outer diameter can be controlled within ± 0.75% - ± 0.8%; The wall thickness will increase by a certain margin during design, such as 1-2mm.

Low temperature environment:

Outer diameter and wall thickness: The deviation of outer diameter is controlled within ± 0.75%, and the deviation of wall thickness is controlled within -3% -+6%. For applications that require high low-temperature toughness, dimensional accuracy may be more strictly controlled to ensure the stability of steel pipe performance at low temperatures.

Urban gas transmission:

Outer diameter: When the outer diameter is ≥ 60.3mm, the deviation is generally controlled within ± 0.75% - ± 1%.

Wall thickness: The deviation is usually controlled within -3% -+6% to ensure the sealing and stability of pipeline connections, while meeting the requirements for urban gas pipeline laying.

Ellipticity and straightness: Ellipticity is generally controlled within 0.8% -1%, and straightness deviation does not exceed 0.3% per meter.

High pressure rich gas transportation:

Outer diameter: The allowable deviation for outer diameter is generally ± 0.75% - ± 1%. For large-diameter steel pipes, to ensure the roundness and overall structural stability of the pipeline, deviation control may be stricter.

Wall thickness: The deviation of wall thickness is controlled within -3% -+6% to ensure that the steel pipe has sufficient strength and pressure resistance in high-pressure and gas rich environments.

It should be noted that the specific dimensional accuracy requirements in different application scenarios may vary depending on the actual engineering situation, user specific requirements, and standards of different oil companies or projects, but overall they fluctuate within a certain range around the API Spec 5L standard.