DNV-ST-F101 pipeline screening

NeqSim exposes a typed DNV-ST-F101:2021 screening kernel for early design studies. It keeps pressure containment, collapse, propagation buckling, local-buckling load interaction, fatigue, pressure cases, strength de-rating, safety class, ovality, fabrication route, and installation strain as separate, traceable checks.

This is not a conformity assessment or certification. A passing result always has status CALCULATED_REVIEW_REQUIRED. Use the licensed standard, project design basis, approved load-case method, installation analysis, fabrication records, and independent engineering verification for design approval.

Why this is separate from the legacy calculator

PipeMechanicalDesignCalculator.DNV_OS_F101 remains a legacy DNV-OS-F101 wall-thickness and buckling screen. It does not implement the current standard as a complete load-case model. PipelineMechanicalDesign.calcDesign() therefore fails closed when its string design code is DNV-ST-F101; it will not fall back to ASME B31.8 or relabel the legacy calculation.

Use DnvStF101PipelineDesignKernel directly, or call PipelineMechanicalDesign.assessDnvStF101(input, context). The kernel is also discoverable through EquipmentDesignKernelRegistry.lookup(StandardType.DNV_ST_F101).

Implemented screening checks

Check	Inputs retained explicitly	Screening method	Boundary
Operating containment	Local operating and external pressure	Differential-pressure burst resistance	Not a clause-complete pressure-zone assessment
Incidental containment	Local incidental and external pressure	Separate burst utilization	Incidental pressure is not replaced by operating pressure
System test	Test and test-external pressure	Separate containment utilization	Mill, installation, and system-test procedures remain project-controlled
Collapse	Minimum internal pressure, external pressure, ovality, fabrication factor	Elastic-plastic collapse interaction	Requires approved geometry and fabrication data
Propagation buckling	External overpressure, thickness, material and fabrication factor	Propagation-pressure screen	Arrestor design remains external
Local buckling/load interaction	Axial force, bending, torsion, pressure	Conservative normalized interaction envelope	Replace with approved clause calculation or nonlinear analysis
Fatigue	Stress-range spectrum, S-N curve, SCF, DFF	Palmgren-Miner damage	Curve/detail/environment selection remains external
Ovality	Measured/specified and allowable ovality	Independent utilization; also enters collapse	Does not replace fabrication acceptance
Installation strain	Axial, bending and accumulated plastic strain	Strain accumulation utilization	Reel-, S- and J-lay history must come from installation analysis

The characteristic wall used by the resistance screens is

\[t_{char}=t_{nom}(1-f_{tol})-t_{corr}.\]

Material strengths are multiplied by the supplied temperature/de-rating factor. Safety class and the material resistance factor reduce the calculated resistance. NeqSim does not infer these project-controlled values from operating temperature, installation method, or consequence class.

Java example

DnvStF101PipelineDesignInput input = DnvStF101PipelineDesignInput.builder()
    .safetyClass(DnvStF101PipelineDesignInput.SafetyClass.MEDIUM)
    .fabricationRoute(DnvStF101PipelineDesignInput.FabricationRoute.SEAMLESS)
    .geometry(0.508, 0.028, 0.003)
    .fabrication(0.125, 0.015, 0.030, 1.0)
    .material(450.0, 535.0, 207000.0, 0.30)
    .resistanceFactors(0.95, 1.0, 0.96, 1.15)
    .pressures(15.0, 16.5, 3.0, 0.2, 18.5, 3.0)
    .designLoads(1000.0, 1000.0, 250.0)
    .installationStrains(0.002, 0.005, 0.003, 0.025)
    .fatigueCurve(12.0, 3.0, 1.0, 3.0)
    .addFatigueBin(60.0, 100000.0)
    .addFatigueBin(80.0, 50000.0)
    .build();

EngineeringCalculationContext context = EngineeringCalculationContext.builder()
    .designCaseId("20-inch export line")
    .addStandardReference("DNV-ST-F101 2021 licensed project copy")
    .build();

EngineeringCalculationResult<DnvStF101PipelineAssessment> result =
    new DnvStF101PipelineDesignKernel().calculate(input, context);

if (result.getStatus() == EngineeringCalculationResult.Status.CALCULATED_REVIEW_REQUIRED) {
  DnvStF101LimitStateCheck governing = result.getValue().getGoverningCheck();
  logger.info("Governing screen: {} utilization {}", governing.getLimitState(),
      governing.getUtilization());
}

All units are explicit in method names or builder documentation: metres, MPa, kN, kN·m, and strain fractions. Supply zero explicitly when a reviewed load component is zero; an omitted value is a readiness blocker.

Readiness and result semantics

• Missing safety class, fabrication route, pressures, structural loads, fatigue data, ovality, or installation strain blocks execution.
• Unsupported editions and amendments block execution rather than falling back.
• A utilization above 1.0 is FAIL; it is not converted to a generic “unsafe” boolean.
• areAllScreeningChecksPassing() summarizes only implemented checks.
• engineeringApprovalRequired is always true in the result map.

Example notebook

See examples/notebooks/dnv_st_f101_pipeline_screening.ipynb for a wall-thickness sweep, safety-class comparison, ovality sensitivity, and the complete utilization table.

Sources and verification basis

• DNV-ST-F101 standard landing page identifies the 2021 edition and lifecycle scope.
• DNV Pipeline Engineering Tool user manual publicly describes the expected separation of burst, collapse, propagation, combined loading, fatigue, ovality, and installation checks. It is an independent architecture reference, not the source of a current-edition conformity claim.

Equation choices and default screening factors must be checked against the licensed project copy before use in engineering decisions.