Introduction

'Operational conditions (pressure and temperature) will cause expansion of the pipelines to occur. This expansion at the ends of the pipelines needs to be absorbed somehow. Usually this is accomplished with expansion spools.

The expansion spool accomodates the expansion with a 'dog-leg' with bending. The angle of the 'dog-leg' is usually 90°, and the length is designed to suit the anticipated expansions.

The design of spools is initially done by hand calculations to approximate the required size. Final design is done using finite element analysis. The finite element method allows inclusion of the required effects such as soil friction.

The axial expansion will deform the expansion spool and the associated bending will induce a lateral offset of the axis of the pipeline near the bend. Both the axial and lateral displacements should be considered when sevearl spools are in close proximity.

As bending moments are generated by the expansion, care should be taken over the positioning of flanges during design.

Short spools between structures are called 'jumpers', and are orientated horizontally or vertically.

jump

Notable Projects

Project Name
Project Number
Notes
BAOBAB
Notable due to the Pipe in Pipe nature
Greater Plutonio
Deep Water, using SAFEBUCK
Qatar Gas
KW

Large Diameter Pipe
Shallow Water
Snake Lay Solution

 

Other Projects

Project Name
Project Number Notes
EPC2B
KW 0728
Controlled Buckles on Existing Pipeline Crossings
Algeria Pipeline
KW 1071
Onshore
Deep Panuke
 

 

Codes & Standards

Company
Title
Doc Number / Date
SAFEBUCK JIP
Safe Design of Pipelines with Lateral Buckling - Design Guideline
DNV
Global Buckling of Submarine Pipelines
DNV-RP-F110
DNV
Submarine Pipeline Systems
(Strain Based Limit State)
DNV-OS-F101

 

Course Notes

Author
Title
Notes
C. Sicilia
Lateral Buckling Assessment and Mitigation Design
Trevor Gee
IBC
Pipeline Course

 

Books

Author
Title
Chapter
Mikael Braestrup
Design and Installation of Marine Pipelines
6.5

 

Papers

Author
Title
Notes
Hobbes, R. E.
In-service Buckling of Heated Pipelines, Journal of transportation Engineering, ASCE, Vol. 110, No.2, March 1984, pp. 175-189
Approximate method for determining propensity for lateral buckling
Taylor, N. and Gan, A. B
Submarine pipeline Buckling – Imperfection Studies, Jour. Of Thin-walled Structures, Vol. 4, 1986, pp 295-323
A developed version of ‘Hobbs’, including the effects of initial OOS

 

Prepared Calculations

Title / Software
Description
Owner / Athor
Hobbs / Excel
Predicts the onset of buckling
KAJW / CSG

 

Related Subjects

Expansion

 

 

Tie-In Spools

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