Overground Vertical Fuel Storage Tank Refurbishment

Client: Major oil company’s Joint Fuel Terminal in Dublin Port

Completion Date: 7/12/2011

Contract Duration: 3 weeks

Contract Value: Approx € 75,000

Description:
The 9m Litre Fuel Storage Tank is located in a major oil company’s Joint Fuel Terminal in Dublin Port. The tank was commissioned in 1950 and during a commercial audit last year a full internal and external survey was undertaken. The results of the survey showed various construction and design defects which were not in accordance with the relevant API and EN Standards for fuel storage tank construction and repair. A scope of works was prepared by an independent consulting Engineer and issued as part of an open tender process. MSI Ltd was awarded the contract to carry out the tank refurbishment works.

Works

Prior to undertaking the repair works, a sample of the existing redundant tank shell had to be retrieved and submitted for testing / analysis in order for a suitable weld procedure to be adopted. Due to distortion of tank shell at high level, a secondary stiffening ring was required. This involved erection of scaffolding around the tank shell, up to a height of 14m to facilitate safe access to the works area. The wind girder comprised of 125mm x 75mm angle rolled to the radius of the tank and welded with a continuous fillet weld on top and an intermediate weld stitch on the bottom. All joints were butt welded and mouse holes installed to allow or suitable water run off.

The existing high level alarm was relocated which involved the erection of scaffolding within the tank to facilitate the alterations to the tankside connection and a new hi-level sensor probe was installed. All tank nozzles and compensation pads, that showed low-throat thickness and weld porosity were ground out and rewelded. The tank floor was severely pitted and required preparation and welding of over thirty floor patch plates with rounded corners.  The tank floor was a cone down type and due to heavy corrosion the centre floor sump was removed and replaced. Due to the previous removal of the spiral staircase heavy corrosion was evident on the shell wall. All areas showing the lowest shell wall thickness were built up with weld metal to a suitable depth and ground flat on completion. Over thirty miscellaneous weld repairs and patch plates were installed on the self supported cone tank roof. The scope also included ancillary repair works to tank roof nozzles, vents, tank gauging supports, tank top handrails, spiral staircase steps/handrails and replacement of water draw off pipework.

All new welds were inspected using MPI and radiograph methods by an independent inspector.  100% of all welds passed the inspection. Every effort was made to ensure the works were carried out within the specified time frame and completed within budget. This included undertaking the works out of normal hours to coincide with site shipping schedules in order to expedite the works as per the client’s requirements.

Why MSI

  • Competitive Rates & Best Lifetime Cost
  • Comprehensive Safety Management System
  • All Supervisory staff have completed MSIC
  • LPS system operated company wide
  • Independent Accreditation of SMS from DNV
  • Winner of Numerous Safety Awards
  • ISO 9001:2008 Quality System
  • Excellent Track Record