pdrp-8430-sp-0011_rev_f1.pdf

PARADIP REFINERY PROJECTPROJECT SPECIFICATION A

DESIGN&FABRICATION REQUIREMENTS FOR LIFTING&TAILING LUGS

PDRP-8430-SP-0011PAGE : 2 of 10REV : F1

DSN 1844

CONTENTS

SECTION SUBJECT

1.0 SCOPE................................................................................................32.0 DESIGN...............................................................................................32.1 General ...............................................................................................32.2 Tailing Lugs and Tailing Beam .........................................................42.3 Lifting Lugs ........................................................................................62.4 Lifting Trunnions ...............................................................................73.0 FABRICATION....................................................................................84.0 ALLOWABLE STRESSES..................................................................8




DSN 1844

1.0 SCOPE

This Specification covers the requirements to be considered by Vendors when designing and fabricating vessel lifting and tailing attachments.

2.0 DESIGN

2.1 General

A forty percent (40%) shock factor shall be applied to all lifting and tailing designs.

Vessel dressed weight shall be used for all calculations. All weights stated on IOCL documents shall be checked and confirmed by Vendors.

Allowable stresses are given in section 4 below.

Shell bending stresses shall be calculated and assessed against allowables, at the following locations:

• All changes in shell section thickness.

• All cone to cylinder junctions.

• Skirt to head junction, joint efficiency at this location shall be 0.55.

Base ring bending stresses be calculated and assessed against allowables.

Skirt compressive stresses imposed by the tailing lug during the lift from horizontal to vertical position, shall be calculated and assessed against allowable.

All lifting and tailing attachment welds shall be 100% non-destructively examined, using either ultrasonic (UT) or progressive magnetic particle inspection (MPI).




DSN 1844

The weld throat thickness shall be used for all calculations pertaining to welds. The fillet leg length shall not be used.

The weld throat dimension shall be no greater than the smallest plate thickness onto which the weld is placed. All welding shall be performed using an approved welding procedure.

Lifting & tailing lug, and vessel material shall have a minimum yield stress of 206 N/mm2.

Lugs on vessels designed for 700° F (370° C) or higher temperature, shall be removed after erection to the extent that no part of lifting lugs extends outside vessel insulation. If a cutting torch is used, at least 25mm clearance shall be provided between the cut and the vessel shell or head. Sharp edges resulting from cutting shall be ground smooth. Removal of lugs shall be carried out in accordance with an approved procedure.

Lifting attachments shall be designed, for a maximum of 5° out of alignment of the sling, from the true plane position.

All Vendor lifting and tailing calculations shall be submitted for review.

Lifting or tailing lugs attached by bolting shall not be used.

2.2 Tailing Lugs and Tailing Beams

Tailing lug standout from the base ring to the centreline of hole shall be sufficient to provide clearance for the shackle outside diameter.

If more than one tailing lug/beam is required, spacing between the lugs shall be sufficient to allow installation of two shackles.

For all tailing lifts greater than 100 Tonnes, the tailing lug shall protrude through the vessel skirt inside by a distance equal to the tailing beam web.




DSN 1844

Tailing lug shall be designed to suit the next largest Crosby G2130, G2140 or Green Pin shackle size to the tailing load.

Project Specification PDRP-8430-SP-022 may be used for guidance on hole and tailing lug dimensions. However Vendor shall ensure the following criteria are met:

• The tailing lug hole diameter shall be:

• 2mm to 4mm larger than the shackle pin diameter, for shackles less than 50 Tons SWL.

• 3mm to 6mm larger than the shackle pin diameter, for shackles 50 Tons SWL and above

• The minimum tailing lug thickness shall be 32mm. The maximum tailing lug thickness shall be shackle jaw width minus 13mm.

• Cheek plates shall be used to fill the throat of the shackle, and provide minimum bending load on the pin.

The following tailing lug stresses shall be calculated and assessed against allowables:

Vessel horizontal, in the plane of the hole:

• Tensile stress

• Shear Stress

• Bearing stress of pin in hole

• Vessel at angle of maximum tailing moment, in the plane at junction between lug and skirt:

• Tensile stress across the skirt.

• Shear stress across the lug at skirt.

• Bending stress in the lug at the skirt due to moment arm to centre of hole.

• Combined stress.

Tailing lug weld stresses shall be calculated and assessed against allowables.




DSN 1844

2.3 Lifting Lugs

The lugs are to be located on the vessel longitudinal centreline unless statedotherwise in the vessel data sheets.

Vendor shall address the bending and torsion loadings imposed on the shell by the lifting attachment. The top section of the vessel shell may require an increase in thickness to accommodate these loadings.

The Vendor shall analyze the shell for local loadings imposed by the lifting lugs:

• Vessel Horizontal:

Vessel shell is subject to Circumferential load PR and circumferential moment due to outstand of PR from vessel shell to centreline of lift lug.

Vessel shell is also subject to torsional moment due to moment arm of PR from lift lug weld centroid to centre of lift lug hole.

• Vessel Vertical: Vessel is subject to Longitudinal load PV and longitudinal moment due to outstand of PV from vessel shell to centreline of lift lug.An additional longitudinal moment is imposed due to nominal side load PH multiplied by moment arm from lift lug weld centroid to centre of lift lug hole.

Lifting lug dimensions shall be in accordance with Project Specification PDRP-8430-SP-022

For lifting loads less than 17 Tonnes, lifting lugs shall be designed to suit by Vendor.

For lifting loads greater than 130Tonnes, the use of lifting trunnions is preferred.

The following lifting lug stresses shall be calculated and assessed against allowables:

• Tensile stress• Shear Stress• Bearing stress of pin hole• Bending stress at hole due to side load PH and

moment arm from brace clip.• Bending stress at hole due to circumferential load PR

and moment arm from lug weld.

Lifting Lug weld stresses shall be analysed and assessed against allowables.




DSN 1844

2.4 Lifting Trunnions

Sizing:

Trunnion outstand shall be minimised to keep shell stresses to a minimum.

Distance between keeper plates shall be 1.3 times the rope diameter, to allow for flattening during lifting.

The inside keeper plate shall be at least the thickness of the insulation away from the vessel shell.

Shell reinforcing pads shall be used where permitted by code and project standards

Design:

The quadrant above the lifting trunnion containing the lifting arc of sling, shall be checked for obstructions during lifting.

If the vessel is lifted with external piping and reboilers then the centre of gravity of the vessel and location of trunnions may be offset from the vertical centreline. In this case additional loads will be imposed onto the lifting lugs.

The following lifting trunnion stresses shall be calculated and assessed against allowables:

• Bending stress in the trunnion in the plane at shell/compensation pad and junction, ignoring any fillet weld thickness.• Maximum shear stress in the trunnion in the plane at shell/compensation pad and junction, ignoring any fillet weld thickness, using the design load divided by 50% of the trunnion cross-sectional area.• Compressive stress on the trunnion surface due to imposed radial loads by the sling.

The Vendor shall analyze the vessel shell for local loadings imposed by the lifting trunnions:

Vessel Horizontal:• Circumferential load• Radial load due to 5º angle of lifting sling.• Circumferential moment.

Vessel Vertical:• Vertical load• Radial load due to 5º angle of lifting sling.• Vertical moment.




DSN 1844

3.0 FABRICATION

3.1 In Project Specification PDRP-8430-SP-022, dimension "C" has been determined using a 2:1 semi-ellipsoidal head to allow for shackle and shackle pin to clear head and insulation by 25mm. Vendor shall check fabricated head, and revise dimension “C” to suit.

3.2 The vessel shall have a minimum thickness of 12mm at the position of lifting lug.

3.3 Portion of lifting lugs above tangent line shall be flat. Portion of lugs below tangent line shall fit curvature of shell. Shell to head seam under lifting lug shall be ground flush and fully radiographed over the entire affected length plus 102mm either side of lug, prior to welding on of lug.

3.4 The portion of shell under lifting lugs shall be 100% ultrasonically examined to confirm the absence of lamellar defects.

3.5 Lifting and tailing attachments shall not be used to tie down the vessel during shipment.

3.6 All holes shall be drilled and reamed. On no account shall flame cutting be used.

3.7 If cheek plates are used, the holes shall be drilled or reamed after completion of cheek plate to lug plate welds.

4.0 ALLOWABLE STRESSES

4.1 Shell Bending:

• Bending Stress66% Yield Stress

• Meridional Bending + Hoop Stress @ Cone Junction 100% Yield Stress• Compressive Stress

Code allowable• Tensile Stress

Code Sa




DSN 1844

4.2 Tailing lug/Tailing beam:

• Bending Stress66% Yield stress

• Compressive StressCode allowable

• Tensile StressCode Sa

• Shear Stress40% yield Stress

• Bearing Stress80% Yield Stress

• Combined Bending + Shear Stress90% Yield Stress

4.3 Lifting Lug:

• Local Membrane Stress79% Yield Stress

• Local Membrane + Bending Stress132% Yield Stress

• Bending Stress66% Yield stress

• Compressive StressCode allowable

• Tensile StressCode Sa

• Direct Shear Stress40% yield Stress

• Maximum Shear Stress50% yield Stress

• Bearing Stress80% Yield Stress

• Combined Bending + Shear Stress90% Yield Stress




DSN 1844

4.4 Lifting Trunnion:

• Bending Stress66% Yield Stress

• Maximum Shear Stress33% yield Stress

• Compressive Stress79% yield Stress

• Local Membrane Stress79% Yield Stress

• Local Membrane + Bending Stress132% Yield Stress

pdrp-8430-sp-0011_rev_f1.pdf

Documents