Solution & Implementation


Furmanite’s engineering team studied the damaged pipeline and realized immediately that a customized, unconventional solution was needed to repair the pipeline. First, the shear size of the platform leg and the presence of the gussets left virtually no place for a conventional leak sealing enclosure to land. Second, any conventional leak sealing solution which might be designed would require exact measurements and a high degree of technician expertise for installation. These factors, combined with zero visibility, eliminated the conventional leak sealing option.

Furmanite’s team began to cultivate the idea of an insert “sleeve” featuring a gasket system that could be energized remotely. The concept was based on a self imposed requirement that the gasket system must facilitate a fairly loose sleeve tolerance and require only general go/no-go measurements that could be taken by divers wearing gloves in the zero visibility environment. Moreover, the design team was certain that a sleeve, designed with a reasonably loose fit between itself and the existing pipe, could be installed in a zero visibility environment. Furmanite presented the concept to Unocal and agreed to tackle the job. The final scope of work included the development and manufacture of the insert sleeve, the measuring device to determine the go/no-go tolerances, and a full mock up that could be used to pressure test the sleeve and to allow diver training dockside.

The Design

After developing and manufacturing the measuring device, it was shipped to Alaska. An expert dive team then performed a dive to determine the minimum inside diameter of the pipe and any weldment areas and the length of pipe from the flange to the elbow that turns the pipe up toward the platform. Once that was accomplished, the final design for the sleeve was produced.

The final design was based on four major components: the sleeve (later named the stile); a nosepiece assembly that threads to the stile and holds the gaskets in place; a plunger assembly used to energize the gaskets; and the gaskets. Possible misalignment of the existing flange to the damaged pipe was also considered. Even a slight misalignment could potentially hamper installation and prevent the sleeve from fully and properly seating.

The stile was fabricated using a ten inch, fifteen hundred pound blind flange and a six inch pipe threaded on one end. The flange was cut to allow the pipe to be inserted and seal welded. To address the misalignment concern, each stud hole in the flange was oversized to allow a threaded coupling to be inserted and welded in place. Two inch pipe were threaded on one end and screwed into the couplings. These pipes could then be adjusted in or out to compensate for any alignment problems. Finally, six, one inch through-holes were drilled and tapped around the flange to allow the mounting of jacking bolts that would be used to engage the plunger and energize the gaskets. The photo below shows the stile complete with the alignment tubes and the jacking bolts.

As the design progressed, the compatible gasket material was identified and a search for the material was undertaken. It was soon discovered that gaskets of this size and geometry were not readily available and would require custom molding. The lead times first quoted were unacceptable and diligent pursuit of different sources by team members resulted in finding a manufacturer that could mold the material and meet time requirements.

The plunger was fabricated using another ten inch, fifteen hundred pound flange and a length of eight inch pipe bull-nosed on one end. Again, the flange was cut to allow the pipe to be inserted through it and seal welded. Likewise, each stud hole was oversized to allow the alignment pipes to pass through and the plunger to move freely along the stile. Finally, the nosepiece, which holds the various gaskets in place, was machined.

Assembly was accomplished by inserting the stile through the plunger, passing the alignment tubes through the holes in the plunger flange, installing the gaskets over the threaded end of the stile, and then threading the nosepiece onto the stile. Locking the nosepiece into position holds all the pieces in place.

The mock-up to allow the simulated installation of the assembly and pressure testing was manufactured using a ten inch section of pipe blinded at on end and welded to a ten inch flange at the other. The assembly was then mounted to I-beams and heavy plate for stability.

Mock-Up and Installation

Once the complete sleeve was manufactured, the first trial installation was attempted. Furmanite personnel were blindfolded in order to simulate the zero visibility conditions that would be encountered on site. Using the overhead crane in Furmanite’s LaPorte shop, the sleeve was lowered toward the mock-up. As the sleeve was lowered into place and alignment attempted, it became readily evident that a pinch point hazard was created when inserting the sleeve into the mock-up flange. Because of changing balance points during the procedure, even small crane movements in/out or up/down could result in considerable movement of the sleeve and the possibility of pinching the diver’s hand between the sleeve and the flange. After much discussion, the team concluded that using two, long, guiding rails could be installed on the mock-up flange and used to direct the sleeve into place. The rails were produced and proved and ultimately worked efficiently. Once situated on the guide rails, the sleeve became more stable and the diver’s hands were no longer subjected to the pinch point hazard. The photo below shows the entire sleeve assembly inserted in the mock-up and resting on the guide rails.

The second attempt saw the sleeve enter the pipe easily. The adjustment tubes were used to square the flanges and the studs were installed by the blindfolded Furmanite employees. The jacking bolts were then used to move the plunger and energize the gaskets. The mock-up was pressurized to 1.5 times the maximum operating pressure of the system and held overnight with no leaks. Subsequent runs were made to allow the development of a written installation procedure, and additional pressure tests were made and witnessed by the customer using a calibrated chart recorder to plot pressure and temperature during the tests.

Furmanite Designs Customized Expert Solution for Unocal’s Sub-Sea Platform Repairs

Blindfolded Furmanite Engineers Develop and Implement Solution Ahead of Schedule

In early October 2004, Unocal discovered damage to a pipeline riser connected to a production platform approximately 120 feet below the surface of the sea while working in the waters of the Cook Inlet in Alaska. Immediately Unocal engineers contacted Furmanite North America to obtain expert consultation and a solution. As one of the world’s leading independent natural gas and crude oil exploration and production companies, Unocal understands that offshore platform repairs can be costly and time consuming.


Unocal engineers learned about Furmanite based on previous experience with Furmanite products that have been used on other Unocal facilities in Alaska.

The problem discovered on the platform included damage to a ten inch pipeline riser which exits the leg of a production platform about two feet above the seabed. The line, used to transfer natural gas from the platform to the shore, travels down through the middle of the platform, turns and exits the two foot thick platform leg, and terminates at a flange approximately twenty inches outside the leg.

As a standard solution, Unocal would typically send divers down to install a sub-sea pipeline repair clamp. Unfortunately no “off the shelf” repair clamps were available to suit this repair and the lead time for a custom made clamp. To add to the troubles, the entire fix had to be completed in early November. Any later, winter weather and sea ice makes diving impossible.


The completed assembly was sandblasted and coated with paint specified by the customer and designed to withstand the harsh environment of the Cook Inlet. With all testing completed and a proven installation procedure in hand, the sleeve and the mock-up was shipped north on October 30, 2004 two days ahead of schedule. Furmanite’s solution including the customized design of many of the components solved many potential problems including injury to divers during the implementation phase. Ultimately, the quick turnaround and customized solution saved Unocal from a significant loss in production.

111130-Leak Sealing-Sub Sea Clamp

On-Line Leak Sealing

Our leak-sealing technology and unrivaled
on-site service help you maximize asset uptime
by sealing leaks online, onsite and under pressure. This means you keep producing the ‘product’ while we solve your leak problems.

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Process Piping System Hot Tap

Hot Tapping

At Furmanite we carry the largest and most diverse inventory of Hot Tapping equipment
in the world. We have a proven record of developing unique and custom Hot Tap solutions for the most complicated scenarios.

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Line Stopping & Plugging

Our Line Stopping services help prevent unwanted shutdowns and keep critical piping
and pipeline systems online during tie-ins, relocations, repairs, retrofits and routine maintenance.

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On-Site Machining

Our portable machining tools deliver the benefits of a fully equipped machine workshop on-site – where our clients need it most. We consistently achieve tolerances and finishes usually only achievable in a machine shop.

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111202-Self Leveling Machines

Self Leveling Machines

Furmanite’s Self Leveling Machines deliver precision on-site machining for large circular and irregular shaped surfaces. Our circular and linear machining equipment is portable and ready for global deployment.

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Composite Repair

Our range of composite repair solutions is designed to ensure the ongoing structural integrity and load-bearing capabilities of your assets, improving their longevity whilst minimizing the impact on your productivity.

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Post Weld Heat Treatment

Furmanite offers a full range of heat treatment services through a wide range of temperatures. We manufacture, own and operate the most technologically advanced heat treatment equipment available in the marketplace.

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All Services

We offer a comprehensive range of on-site
and on-line plant and pipeline maintenance services. From standard applications to highly customized solutions our goal is to help you maximize your asset up time.

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111201-Hot Tapping Machine

Hot Tapping

Furmanite has been manufacturing Hot Tapping equipment for over 50 years. Our Hot Tapping Machines ensure your critical piping systems maintain a continuous flow while installing new tie-ins and branch connections.

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111201-Line Stopping

Line Stopping & Plugging

For over 50 years Furmanite’s Line Plugging equipment has been helping clients maintain a continuous flow on critical piping systems while performing repairs, relocations, valve or pump installations and pipe modifications.

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111201-Pipeline Repair

Pipeline Repair Products

We have a wide range of Pipeline Repair
and Integrity products designed to handle emergency leak repairs in high pressure environments and improve the structural integrity and safety of your pipelines.

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111201-Silk Machine

Portable Machining Tools

Furmanite’s Silk portable and lightweight machine tools provide high tolerance solutions for a variety of problems. Renowned for their sound engineering, our Silk machines help you deliver precision onsite machining.

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Valve Products

The Wilson Snyder Switch Valve has provided proven reliability for over 80 years in Coker Switch Valve applications. Wilson Snyder Switch Valves have the lowest steam consumption in the industry.

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Health & Safety Products

We offer a wide range of proprietary Safety, Environmental and Maintenance products designed to eliminate injuries and improve pipeline safety. At Furmanite, your ongoing safety is our number one priority.

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111201-Smart Shim

Chocking Prevention

Furmanite’s SmartShim™ is a truly effective and state-of-the-art conductor analysis and chocking solution that will ensure your offshore production site remains productive, powerful and profitable.

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111201-Valve Products

All Products

Furmanite has been a trusted resource for sophisticated engineering products for over
75 years. From Hot Tapping to Line Stopping, we have a wide range of products to meet your pipeline repair and maintenance needs.

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Furmanite is a world leader in the provision of on site services to clients in the mining, petro-chemical, off shore, oil & gas, powergen, marine, pulp & paper and general engineering industries globally.

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Case Study: BAE Systems Airbus

To overcome the need to remove the plateaux (part of the wing) to be milled flat for a precise fit, as well as avoiding the risk of distortion when re-fitted to the aircraft.

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Case Study: Esso Fawley Refinery

Esso’s unit 1 boiler at Fawley was shutdown for repair. The unit 2 boiler had developed a superheater tube leak. The challenge was to carry out a repair, the alternative was a shutdown of the major processing units.

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Case Study: Major Operator

The customer wanted to modify their petrochemical plant – but they didn’t want to shutdown.

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Case Study: North Cormorant Platform

The original configuration of pipe-work on the North Cormorant platform of the Otter over Eider project, did not lend itself to the increased flow.

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Case Study: Nuclear Electric

Accurate and reliable valve testing was required in quick time as part of the pre-commissioning process.

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Case Study: Shell Expro Gannet Platform

When Shell United Kingdom Exploration and Production (Expro) introduced a new Induced Gas Floatation Unit (IGFU) onto their Gannet platform they had planned to finalise the installation during a 30-hour shutdown.

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Furmanite - Innovative since 1920

Leak Sealing process developed leak-sealing-developed_thumb 01/01/1920

Furmanite Leak-Sealing process is Developed The under pressure Leak Sealing process is developed by Eugene Clay Furman at the Newport …

First DIY Leak-Sealing Kit old-furmanite-leak-sealing-equipment 01/01/1924

First DIY Leak-Sealing Kit The first do-it-yourself Leak Sealing kits were developed and marketed by Clay Furman and while they …

Long Standing Relationships Sales-Brochure-1926_thumb 01/01/1926

Long Standing Relationships US customer reference list that includes individual war ships in the US Navy, US steel companies and …

1st Patent is filed in 1927 furmanite-patents1 01/01/1927

1st Patent is filed in 1927 The Furmanite patent for the leak sealing process filed in 1927 was the first …

Furmanite moves Overseas Liverpool-Exibition_thumb 06/01/1927

Furmanite moves Overseas First overseas agents appointed to market the leak Sealing kits including in the United Kingdom and Euro…

Costs of a steam leak Sales-Brochure-1926-pg-8_thumb 06/01/1928

Price List from 1926 Table detailing costs of allowing a steam leak based on $4 per ton for “Long coal”. …

Furmanite is thinking global furmanite-the-skys-the-limit_thumb 01/01/1929

Furmanite is thinking global A brief history of the United Kingdom Company written by A W Forsyth (OBE) in September 1973 …

Technology Development leak-sealing-diagram 11/22/1934

Technology Development Furmanite Expands Engineering on Leak Sealing Technology. Photographs taken from a 1934 sales brochure together with schematics of …

Growing Furmanite purchase-letter_thumb 05/01/1960

Growing Furmanite Letter from the Chairman of Furmanite Engineering based in Birkenhead, England to his lawyer requesting information on a …

New Direction New-Technology_thumb 01/01/1966

New Direction Alan Forsyth, acting as a consultant to Furmanite Engineering (1929) advised the Board to move from selling low …

Never compromise on the high quality Company-History-July-1979_thumb 07/01/1979

Never to compromise on the high quality A brief history of the United Kingdom Furmanite organisation written by Joyce Hainsworth, the …

Best in the business were called NASA---Discovery-Team_thumb 09/01/1988

Best in the business were called Furmanite successfully seals nitrous oxide leakage on the Space Shuttle “Discovery” pre launch September …

Start of Modern Furmanite company-overview 11/22/1991

Start of Modern Furmanite The common shares of Furmanite were acquired by Kaneb Inc on 24th January 1991. Furmanite remains …

Acquisition-GSG Division Acquisition-GSG-Division_thumb 01/13/2006

Acquisition of Flow-Serve GSG Division Furmanite as part of Xanser Corporation acquired the General Services Group (GSG) of Flow-Serve corporation …

Corporate Name Change Corporate-Name-Change_thumb 01/13/2007

Corporate Name Change Xanser Corporation (NYSE:XNR) changed the company’s name to Furmanite Corporation, and the company’s shares were traded on …

Acquisition of SLM Acquisition-of-SLM_thumb 04/13/2011

Furmanite Corporation Acquires Self Leveling Machining Technology Furmanite expanded  its global on-site machining capabilities through the acquisition of Self Leveling …


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