Det Norske Veritas (DNV) - CAESAR II - Help

This code is entitled "Rules for Submarine Pipeline Systems." The Allowable Stress Design (ASD) provisions of the code are implemented here, rather than the limit state requirements.

Calculate the Stress Intensification Factors (SIFs), flexibility factors, or section moduli using DNV

DNV does not provide any guidance on calculating SIFs, flexibility factors, or section moduli. An informal poll of DNV experts and users was taken and the decision was made to use the B31.1 Power Code. Make all stress calculations using the corroded wall thickness.

Calculate the expansion load case using DNV

There is no provision for a code check for the expansion load case, so no expansion cases are generated under this code.

Calculate the operating, sustained, or occasional load cases using DNV

Treat the operating, sustained, or occasional load cases identically. For these load cases, you must perform three stress calculations with different allowable limits. The stress calculation causing the highest percent of allowable is reported in the stress report, along with its specific allowable. These stress checks are:

Where:

Sh = (Pi – Pe) (D – t) / 2t

Pi = Internal Pressure

Pe = External Pressure

D = Outer Diameter

t = Wall Thickness

ns = Hoop Stress Yielding Usage Factor; see Tables C1 and C2 of the DNV Code

SMYS = Specified Minimum Yield Strength at Operating Temperature

nu = Hoop Stress Bursting Usage Factor; see Tables C1 and C2 of the DNV Code

SMTS = Specified Minimum Tensile Strength at Operating Temperature

SL = Maximum Longitudinal Stress

n = Equivalent Stress Usage Factor; see Table C4 of the DNV Code

Se = [Sh2 + SL2 - ShSL + 3t2]1/2

t = Torsional Stress

Calculate reducers using DNV

DNV does not mention reducers for SIF calculations.