PIPENG.COM : DNV OS F101 Submarine Pipelines : Section 5 D 200 Pipeline Wall Thickness

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1 PIPENG.COM : DNV OS F101 Submarine Pipelines : Section 5 D 200 Pipeline Wall Thickness This example should be used with the Pipeng calculators : : Pipeng DNV OS F101 subsea pipeline calculators Copyright Pipeng Ltd : : Creative Commons attribution license. Data Values tc:= SMTS:= Td:= ρf:= 730 kg m 3 ρe:= 1027 kg m 3 Zr:= m xf:= SMYS:= 150 C 25.4 m Zph:= m Zs:= 4.5 m 450 MPa 535 MPa Corrosion Allowance Fabrication Tolerance Fraction SMYS Yield Stress SMTS Tensile Stress Design Temperature Internal Fluid Density External Fluid Density Reference Elevation Highest Point On Pipeline Section LAT Minus Storm Surge Select : Line Pipe Stress Type [31] DNV Subsea Pipeline Select : Material Type [8] C Mn 450 MPa Select : Pipe Schedule Type [11] NPS DN ASME API Schedule Select : Wall Thickness Tolerance Type [6] 12.5% Tolerance Methodology Calculate the wall thickness for a subsea pipeline and riser (two separate sections) Calculate the pipeline section for the nominal pipe OD Calculate the riser section for the same ID as the pipeline section (constant ID). The pipeline is safety class medium. The riser is safety class high. The pipeline and riser are constructed from carbon manganese steel 450 MPa SMYS Elevation is measured relative to mean sea level (MSL) For internal fluid lighter than the external fluid the maximum delta pressure occurs at the highest submerged point. For the riser the highest submerged point is at the water line.

2 Derated Yield Stress And Ultimate Stress Carbon Manganese Steel Select : Material Strength Factor Type = [1] Normal Select : Temperature Derating Type = [2] Carbon Manganese Steel 13Cr SDC( td) := 0 MPa if td 50 C 0.6 td 50 C MPa if td> 50 C td< 100 C td 100 C MPa if td 100 C SDC( 100 C) = 30MPa Temperature Derating Carbon Steel αu:= 0.96 Material Strength Factor ft:= SDC( Td) ft= 50 MPa Derating Stress fy:= ( SMYS ft) αu fy= 384 MPa Derated Yield Stress fu:= ( SMTS ft) αu fu= MPa Derated Ultimate Stress fu fcb:= min fy, fcb= 384 MPa Minimum Stress 1.15 Pipeline Section Pressure For the pipeline section the maximum pressure difference occurs at the highest submerged point. Select : Local External Pressure Type = [1] Calculate Local External Pressure Select : Incidental Pressure Factor Type = [2] Minimum Factor = 1.05 Select : Local Incidental Pressure Type = [1] User Defined Design Pressure Input : User Defined Design Pressure At Reference Elevation = 14.1e6 Zl:= Zph Highest Point On Pipeline Section γinc:= 1.05 Incidental Pressure Factor Pd:= 14.1 MPa Design Pressure d:= max( 0 m, Zs d= m Water Depth Ple:= ρe g d Ple= MPa Local External Pressure Pri:= Pd γinc Pri= MPa Reference Incidental Pressure Pli:= Pri+ ρf g ( Zr Pli= MPa Local Incidental Pressure P:= Pli Ple P= MPa Local Delta Pressure

3 Pipeline Section Wall Thickness Calculate the required nominal wall thickness for the pipeline section. Select : Pipe Diameter Type [19] 12 NPS DN mm OD Select : Safety Class Resistance Factor Type = [2] Safety Class Medium Select : Wall Thickness Calculation Type = [1] Calculate Wall Thickness OD:= m Nominal Outside Diameter αm:= 1.15 Material Resistance Factor αsc:= Safety Class Resistance Factor 2 fcb fca:= fca= MPa Allowable Stress 3 αm αsc P OD th:= th= m Pressure Design Wall Thickness 2 fca+ P tm:= th+ tc tm= m Minimum Wall Thickness tm xf := = m Wall Thickness Allowance 1 xf tn:= tm+ tn= m Nominal Wall Thickness ID:= OD 2 tn ID= m Nominal ID Pb:= Pb= MPa Burst Pressure PN:= PN= MPa Nominal Pressure Determine a suitable nominal wall thickness for the pipeline section (round up the required wall thickness). The calculated ID can be used for the ID of the riser section (constant ID) Select : Wall Thickness Schedule Type = [16] 12 NPS 12.7 mm Wall XS Select : Wall Thickness Calculation Type = [2] Wall Thickness Specified tn:= m Nominal Wall Thickness := tn xf = m Wall Thickness Allowance th:= tn tc th= m Pressure Design Wall Thickness ID:= OD 2 tn ID= m Nominal ID Pb:= Pb= MPa Burst Pressure PN:= PN= MPa Nominal Pressure P Sh:= Sh= MPa Hoop Stress 2 th Sh sos:= sos= Hoop Stress Ratio fca

4 Riser Section Pressure For the riser section the maximum pressure difference occurs at the sea surface. Select : Local External Pressure Type = [3] Local External Pressure = 0 Select : Incidental Pressure Factor Type = [2] Minimum Factor = 1.05 Select : Local Incidental Pressure Type = [1] User Defined Design Pressure Input : User Defined Design Pressure At Reference Elevation = 14.1e6 Zl:= Zs γinc:= 1.05 Pd:= d:= max( 0 m, Zs Ple:= Pri:= 14.1 MPa ρe g d Pd γinc Pli:= Pri+ ρf g ( Zr P:= Pli Ple d= 0m Ple= 0MPa Pri= MPa Pli= MPa P= MPa LAT Minus storm surge Incidental Pressure Factor Design Pressure Water Depth Local External Pressure Reference Incidental Pressure Local Incidental Pressure Local Delta Pressure

5 Riser Section Wall Thickness Calculate the minimum required nominal wall thickness for the riser section. The riser ID is set equal to the pipeline ID calculated above (constant ID pipeline) The riser wall thickness calculatin is iterated Select : Pipe Schedule Type [1] User Defined Pipe Diameter And Wall Thickness Select : Pipe Diamter Type [2] User Defined Select : Safety Class Resistance Factor Type = [3] Safety Class High Select : Wall Thickness Type = [1] Calculate Wall Thickness. αm:= 1.15 Material Resistance Factor αsc:= Safety Class Resistance Factor ID:= m Nominal Pipe ID 2 fcb fca:= fca= MPa Minimum Stress 3 αm αsc tt:= m Inital Guess tth+ tc ttn( t := ttn( = m Wall Thickness Function 1 xf P ( ID tt+ 2 ttn( tt) ) th:= root fca, tt th= m Minimum Wall Thickness 2 tt tm:= th+ tc tm= m Minimum Wall Thickness tm xf := = m Wall Thickness Allowance 1 xf tn:= th+ tc+ tn= m Nominal Wall Thickness OD:= ID+ 2 tn OD = m Nominal OD Pb:= Pb= MPa Burst Pressure PN:= PN= MPa Nominal Pressure P Sh:= Sh= MPa Hoop Stress 2 th Sh sos:= sos= 1 Hoop Stress Ratio fca

6 Riser Section : Select Wall Thickness Determine a suitable nominal wall thickness for the riser section (round up the required wall thickness). Select : Wall Thickness Schedule Type = [72] 12.7 mm Wall Select : Wall Thickness Calculation Type = [2] Wall Thickness Specified tn:= := OD:= m tn xf th:= tn tc ID+ 2 tn = m th= m OD = m Nominal Wall Thickness Wall Thickness Allowance Pressure Design Wall Thickness Nominal OD Pb:= Pb= MPa Burst Pressure PN:= P Sh:= 2 th Sh sos:= fca PN= MPa Sh= MPa sos= Nominal Pressure Hoop Stress Hoop Stress Ratio