Hydraulic Pipe Spool for L&T Defence Testing Equipment

Mumbai

2019

Larsen & Toubro (L&T), one of India’s leading engineering and technology companies, required a high-pressure hydraulic pipe spool for specialised defence testing equipment.

The project presented a unique installation challenge. The spool had to pass through a fixed sealing bulkhead, where the opening was approximately the same diameter as the outside diameter of the pipe.

A conventional fixed flange arrangement would not have allowed the pipe to pass through the bulkhead. The project therefore required a piping solution where the flanges could be assembled after the pipe had been positioned through the bulkhead.

Tube-Mac’s Retain Ring Flange System provided the required flexibility because the flange assembly can be installed onto or removed from the pipe without requiring the flange to be permanently welded to the pipe.

Cenergy Offshore, in partnership with Tube-Mac Piping Technologies (TMI), provided the engineering and pre-fabricated spool solution.

Scope of Work

The primary challenge was the installation arrangement through the fixed sealing bulkhead.

The requirement was for a 6-inch high-pressure pipe spool, but the bulkhead opening was only approximately equal to the pipe’s outside diameter.

This meant that a conventional welded flange could not simply be installed on the pipe before the spool was passed through the bulkhead.

The solution needed to allow:

  • The pipe to pass through the restricted bulkhead opening
  • Flanges to be assembled after the pipe was positioned
  • Reliable sealing at the high-pressure connection
  • Accurate dimensional control
  • Complete material traceability
  • Independent third-party inspection and pressure testing

The pipe spool also had to withstand a pressure of 290 bar (4,205 PSI).

Execution

Tube-Mac’s Retain Ring Flange System was selected for the application.

Unlike a conventional permanently attached flange arrangement, the Retain Ring Flange System allowed the flange components to be assembled onto or detached from the pipe as required.

This made it possible to pass the pipe through the restricted bulkhead opening first and complete the flange assembly afterward.

The solution therefore addressed the specific installation constraint without requiring the bulkhead opening to be enlarged.

Design & Engineering

Based on L&T’s requirements, Cenergy Offshore/TMI developed the spool design for customer approval.

The engineering process considered:

  • Pipe size and wall thickness
  • High-pressure operating requirements
  • Flange configuration
  • Bulkhead installation constraints
  • Dimensional requirements
  • Material specifications
  • Pressure testing requirements

The final spool was designed around the Retain Ring Flange System so that it could meet the installation requirement while maintaining the required pressure integrity.

Pre-Fabrication

The pipe spool was pre-fabricated at the Tube-Mac Piping Technologies (TMI) facility in Canada according to the approved drawing.

The spool was manufactured using 6-inch SCHXXS SS316L pipe and incorporated the Tube-Mac Retain Ring Flange System.

Following fabrication, the spool underwent a thorough cleaning and flushing process before being presented for inspection.

Pre-fabrication in a controlled facility allowed the spool to be manufactured, cleaned and tested before being released for shipment to the customer.

Third-Party Inspection

Because the spool was intended for a specialised high-pressure testing application, the completed assembly was subject to third-party inspection by DNV.

A detailed Quality Control Plan (QCP) was prepared by Cenergy Offshore/TMI and submitted for customer approval.

The inspection programme included:

  • Dimensional inspection of the pipe, flanges and completed assembly
  • Review of Material Test Certificates (MTCs)
  • Verification of material traceability for the pipe, flanges, fasteners, seal retainers and associated components
  • Hydrostatic pressure testing of the pipe assembly

The spool was cleared by the DNV surveyor following successful completion of the required inspections and testing.

The required Inspection Release Note and Inspection Clearance Slip were subsequently issued.

Pressure Testing

The completed pipe spool was hydrostatically tested to verify its pressure integrity.

The system was designed for a working pressure of 290 bar (4,205 PSI).

The pressure test was witnessed as part of the DNV third-party inspection programme, providing independent verification of the completed assembly.

The spool successfully completed the required inspection and testing programme before release.

Project Outcome

Cenergy Offshore and Tube-Mac successfully delivered a 6-inch SCHXXS SS316L high-pressure pipe spool for L&T’s defence testing equipment application.

The key installation challenge — passing the pipe through a fixed sealing bulkhead with an opening approximately equal to the pipe’s outside diameter — was addressed through the use of the Tube-Mac Retain Ring Flange System.

The ability to assemble and detach the flange components from the pipe provided the flexibility required for this specialised installation arrangement.

The completed spool was manufactured in Canada, cleaned, inspected and hydrostatically tested before shipment. The entire assembly successfully passed the DNV third-party inspection, including dimensional checks, material traceability verification and pressure testing.

Key Project Highlights

  • High-pressure hydraulic pipe spool for L&T Defence Testing Equipment
  • 6-inch SCHXXS SS316L pipe
  • Working pressure of 290 bar / 4,205 PSI
  • Tube-Mac Retain Ring Flange System
  • Solution for installation through a restricted fixed bulkhead
  • Flange assembly possible after passing the pipe through the bulkhead
  • Pre-fabricated at TMI’s facility in Canada
  • Controlled cleaning and flushing before inspection
  • DNV third-party inspection
  • Dimensional inspection and verification
  • Material Test Certificate and traceability review
  • Hydrostatic pressure testing
  • Inspection Release Note and Inspection Clearance Slip issued

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