Thin Walled Corrosion Resistant Steel (CRES) Pipe Leak Repair
Navy SBIR 2014.1 - Topic N141-052
NAVSEA - Mr. Dean Putnam - [email protected]
Opens: Dec 20, 2013 - Closes: Jan 22, 2014

N141-052 TITLE: Thin Walled Corrosion Resistant Steel (CRES) Pipe Leak Repair

TECHNOLOGY AREAS: Materials/Processes

ACQUISITION PROGRAM: PMS 312, In-Service Aircraft Carrier Program Office

OBJECTIVE: The objective is to develop an innovative technology that stops leakage in a thin walled CRES welded joint within Jet Propulsion Grade JP-5 fuel lines without causing further damage to the fuel line.

DESCRIPTION: Thin walled (Schedule 10) CRES 316L pipe (ref. 1) has been used in JP-5 fuel systems (ref. 2). The pipe joint design uses a belled end fitting creating an inherent crevice. The thinness of this piping may lead to poor weld quality at the welded joints which could cause additional crevices within the pipe joint. Crevices create areas for corrosion to form eventually resulting in leakage across the pipe joint. This type of pipe is currently in use and there is a need to create an easily applied repair to staunch any leak which may result from possible crevice corrosion without causing any further damage to the pipe. The welded joint repair is to be applied on In-service Aircraft Carriers while underway. In many instances, there is limited access space surrounding the pipe joint.

Pipe joint leakage failures were identified on the Aircraft Carrier, USS George H.W. Bush (CVN 77), within the first three years of service. The JP-5 fuel system installed on CVN 77 and planned for all FORD Class Carriers have over 28,000 welded joints per ship. Additional failures are expected to be identified.

Any material and/or technique developed must be safe for use in fuel piping and applicable for pipe sizes ranging from 2 to 12 inches. Joint types include couplings, tees and elbows which may be made using sockets or belled end fittings. The leakage repair for the intended pipe system must be able to tolerate contact with JP-5 fuel without contaminating the fuel, and must be able to withstand internal pressures up to 190 psi. Current state of the art pipe patches intended for damage control purposes are expensive and may not work well on thin walled piping or with JP-5 fuel. Repair techniques currently available use epoxy resins which require extensive surface preparation and curing time. In addition, due to the confined spaces on the ship, fumes from the application of epoxy resins can be hazardous and therefore require environmental protection. There is no evidence that epoxy resin pipe joint repairs being used by the Navy will last as long as the rest of the piping system or if the resin will tolerate contact with JP-5 fuel. Any repair approach should be expected to last as long as the base piping installation (~25 years). Currently, there is no available patch or industrial technique to meet this need.

The new CRES Pipe Leak Repair shall stop existing leaks, prevent future leaks, and achieve competing objectives of low installation and maintenance costs, and easy application. Any repair concept must stop an existing leak onboard an In-Service Carrier while it is underway. Ideally, any proposed repair method should not require hot work or evacuating the system.

Epoxy resin patches and welding options are already available to repair defective pipe joints. A variety of damage control for fuel lines related leak repairs exist. However, the damage control related repairs are expensive and generally do not provide a permanent repair (ref. 3). Composite materials could be used for this pipe repair application (ref.4). The bulk of research into this area is directed at large pipe repair for the petroleum or construction industry where metal sleeves are an option (ref. 5). Although this type of sleeve may not be an option for this application, the related research may be helpful. Another potential area to investigate is metal deposition which can be applied similarly to welding (ref. 6) or applied with high pressure gas (ref. 7 and 8).

PHASE I: The company will develop a concept for an inexpensive and easily applied thin walled CRES pipe leak repair that can stop an existing leak, withstand pipe pressure up to 190 psi and tolerate contact with JP-5 fuel. The concept should demonstrate how the leak repair could be applied with limited access to the pipe joint on an In-Service Aircraft Carrier while underway. The concept should also present reasonable cost estimates for the technique to stop an existing leak and prevent future leakage. Feasibility will be established by material testing and/or analytical analysis/modeling. The small business will provide a Phase II development plan that addresses technical risk reduction, and provide performance goals and key technical milestones.

PHASE II: Based on the results of Phase I and the Phase II development plan, the small business will develop a prototype for evaluation. The prototype will be evaluated to determine its capability in meeting the performance goals defined in the Phase II development plan and the Navy requirements for the thin walled CRES pipe leak repair. Repair performance will be demonstrated through prototype evaluation and modeling or analytical methods over the required range of parameters including numerous deployment cycles. Evaluation results will be used to refine the prototype into an initial design that will meet Navy requirements. The company will prepare a Phase III development plan to transition the technology for Navy use.

PHASE III: The company will be expected to support the Navy in transitioning the technology for Navy use. The company will develop a thin walled CRES pipe leak repair according to the Phase III development plan for evaluation to determine its effectiveness in an operationally relevant environment. The company will support the Navy for test and validation to certify and qualify the system for Navy use.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: If successfully demonstrated, there may be a commercial market for this thin walled pipe joint leak repair in any industry that employs thin walled CRES piping, such as petroleum production or distribution.

1. "Pipe and Tubing, Carbon, Alloy, and Stainless Steel, Seamless and Welded, Military Specification Mil-P-24691 Grade 316L", 23 September 1987,

2. "Turbine Fuel, Aviation Grades JP-4 and JP-5, Military Specification Mil-DTL-5624U", 18 September 1998,

3. Rick Carlton, "Types of Navy Patches for Damaged Pipes",,

4. Chris Alexander and Bob Francini, "Assessment Of Composite Systems Used To Repair Transmission Pipelines", International Pipeline Conference, September 25-29, 2006

5. Bill Bruce and Bill Amend, "Advantages of steel sleeves over composite materials for pipeline repair", Pipelines International, June 2011

6. Matt Boring and Randy Dull, "In-Service Weld Metal Deposition", Edison Welding Institute, 2012,

7. D. D. Hass, J. F. Groves and H. N. G. Wadley, "Reactive vapor deposition of metal oxide coatings", University of Virginia, Surface and Coatings Technology,

8. Metal Deposition, Georgia Institute of Technology, <>

KEYWORDS: Thin walled CRES; repair welded joints; welded pipe joints; stop existing leaks; pipe repair; damage control for JP-5 fuel piping; JP-5 fuel

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