SOW-Aluminum_Mod__Repair_Template_5XXX_Series_Aluminum_FEB_2019_JFV.docx

USNS XXXX

(T-EPF X)

HULL STRUCTURE

19 MARCH 2017

HULL REPAIR

1.0 ABSTRACT

1.1 This item describes the repair of the damaged hull section in the XXXXXXX

2.0 REFERENCES/ENCLOSURES:

2.1 References:

2.1.1 NAVSEA Drawing 8443364, General Arrangement and Profile Drawings

2.1.2 NAVSEA Drawing 8442868, Material List

2.1.3 NAVSEA Drawing 8442884, Shell Expansion

2.1.4 TBD. Additional drawings as required to support repair.

2.1.5 MSC Drawing No. 803-7081122, MSC General Technical Requirements (GTR).

2.2 Enclosures:

2.2.1 Damage Map

3.0 ITEM LOCATION/DESCRIPTION

3.1 Location:

3.1.1 XX-XX-X; Description as needed.

4.0 GOVERNMENT FURNISHED EQUIPMENT/MATERIAL/SERVICES

4.1 Government Furnished Equipment (GFE): None

4.2 Government Furnished Material (GFM): None

4.3 Government Furnished Services: (GFS): None

5.0 NOTES:

5.1 The contractor and all subcontractors, regardless of tier, must consult the General Technical Requirements (GTR’s) to determine applicability to this work item. In performance of this work item, the contractor and all subcontractors, regardless of tier, must comply with the requirements of all applicable GTR's including but not limited to GTR’S 1 through 7, and 21 through 29. GTR’s are provided as reference 2.1.9.

· These requirements are provided as reference but may also be downloaded at: http://www.msc.navy.mil/instructions/pdf/m470016.pdf

5.2 The contractor and subcontractors, regardless of tier are advised to review other work items under this contract, to determine their effect on the work required by this item. Based on this review the contractor shall plan and schedule work to minimize conflicts between work items.

5.3 Services and materials not listed as Government Furnished in Part 4.0 shall be furnished by the Contractor. The Contractor shall provide all labor and material required to accomplish this work item including but not limited to Marine Chemist, staging, space certification, gas free certification, contamination containment, fire watches, removal and reinstallation of all interferences including insulation and deck coverings in way of repairs to effect a complete and finished end result.

5.4 The contractor must submit a Request for Deviation (RFD) to the MSC Representative (MSC REP) for approval for any areas that appearance, function, and strength are impaired. Upon MSC REP approval minor deviations from the drawings will be authorized if the appearance, function, and strength are not impaired.

5.5 The contractor must open, vent and furnish a Chemist to provide gas free certification for spaces requiring hot work. Gas Free chits must also be signed and approved by the ships Chief Mate or his designated representative daily until work is completed.

5.6 Prior to initiating any work on the electrical system, de-energize and tag-out all sources of electrical power to the circuits involved in accordance standard electrical safety practices and MSC Lockout Tagout Procedure. Restore electrical power upon completion of all aspects of this work item.

5.7 5XXX-SERIES ALUMINUM ALLOYS WILL BE CONSIDERED MODERATELY SENSITIZED IF ANY OF THE FOLLOWING CONDITIONS APPLY:

· Appearance of a stress corrosion crack (SCC).

· Appearance of cracking in base material due to welding.

· Testing by ASTM G67, DoS Probe or other MSC approved testing process has proven the aluminum has a mass loss greater that 20mg/cm2 and less than 60mg/cm2. (NOTE: All locations tested with values above 60mg/cm2 are NOT considered “weldable” and additional testing outside the original testing location will be required.). All testing will be vetted through MSC REP for approval.

· In-Situ testing by NSWCCD has shown aluminum to be sensitized.

· 5xxx-Series aluminum alloy that is exposed to the sun.

· 5xxx-Series aluminum alloy that is exposed to excessive heat. Excessive heat is considered heat exceeding 122 deg F (i.e areas around MPDE and SSDG exhaust outlets).

5.8 Filler material for welding that has been used on this ship class is also 5xxx-Series aluminum.

6.0 QUALITY ASSURANCE REQUIREMENTS:

6.1 All work, testing and materials shall be in accordance with the latest SOLAS regulations, ABS Rule Set, IEEE-STD-45, MIL-STD-1310(G), USCG Requirements, and to the satisfaction of and in the presence of the MSC Representative (MSC REP), ABS Surveyor, and Manufacturer’s Representatives (as required.

6.1.1 All disturbed surfaces shall be repaired utilizing approved methods maintaining the water tight, fire tight, or smoke tight integrity of the bulkheads, decks or equipment.

6.1.2 All shipboard structure, hull insulation, sheathing, etc damaged or disturbed by these modifications shall be repaired similar to the original or surrounding materials.

6.2 Welding shall be accomplished using pulse GMAW to reduce heat in way of welding.

6.2.1 All requests for deviation will require MSC REP and ABS approval prior to cutting or welding. Approval will be based on the weld procedure specification and controls.

6.2.2 GMAW short circuit transfer process shall not be used for any welding unless previously approved by MSC REP and ABS Surveyor.

6.2.3 Pulse GMAW shall be used on repairs and install where deck plate thickness is below 6mm.

6.3 The contractor shall provide material certs, welder certs, and an ABS approved, ‘reduced heat’ weld procedure specification (WPS) to the MSC REP and ABS surveyor prior to commencing work required to accomplish this work item.

6.3.1 All material, including prefabricated installations, shall be traceable to the material certifications and verified prior to installation.

6.3.2 The welding sequence shall be included in the WPS.

6.3.3 Where welding to thinner aluminum (below 6mm thick) welder certs shall clearly show welder is certified and has been tested to weld on/to plate thicknesses in question (i.e. welding 25mm plate to 3mm plate will require a weld cert, test results and procedure that shows welder is qualified to complete that work).

6.3.4 Material certified via ASTM/G67 testing may be used up to 12 months from the date of the certification without further testing. If the certification is over a year old, the aluminum must either be retested via ASTM/G67 testing or through surface preparation penetrant inspection (PT), whichever is lower in cost. Surface preparation PT will include 100 percent PT of four (4) inches from the expected weld area. The PT inspected surfaces shall be free of discontinuities such as linear indications or defects that may affect weld quality of the condition of the base material. If discontinuities exist, a condition found report (CFR) shall be submitted to the MSC REP and ABS surveyor prior to fit-up. After inspection the surfaces shall be thoroughly cleaned.

6.3.5 Material certified via ASTMB928 shall include the test results for ASTMG66 & ASTMG67. It is not sufficient to simply state the material was tested to ASTMB928 the pitting rating and mass loss per unit area shall be provided.

6.4 Ultrasonic Impact Treatment (UIT) shall be used as part of the repair process where the area is considered to be moderately sensitized.

6.4.1 UIT is not required where testing, by ASTM G67 or In-Situ DoS is completed to support this work item (WI), proves material is not moderately sensitized.

6.4.2 For the application of UIT, a process control procedure (PCP) is required and shall be pre-approved by MSC REP PRIOR to cropping or renewal of materials.

· UIT is often used to pretreat materials PRIOR to removal.

6.5 All welds and cutting, to and on, moderately sensitized plate shall meet the requirements for a reduced heat weld process as stated in this work item.

6.6 All welds and cutting, to and on, thin plate shall meet the requirements for a reduced heat weld process as stated in this work item.

6.6.1 Thin plate is considered plate below 6mm thick.

6.7 All welding requirements shall be accomplished by ABS certified welders and meet MSC REP, ship class welding details, ABS and AWS requirements. All welders shall be certified to perform the type of welding required and documentation of such shall be current. Fire watches shall be posted by the Contractor during hot work.

6.7.1 For aluminum hull:

· ABS Rules for Material and Welding (Part 2) – Aluminum and Fiber Reinforced Plastics (FRP) (latest revision).

· AWS D3.7.

6.8 Contractor shall ensure heat on new and existing materials is kept to a minimum in way of removal, installation and repair.

6.8.1 Plasma Arc Cutting, grinding wheels and fiber cutting discs shall NOT be used for material cutting unless previously approved by MSC REP.

6.9 The contractor shall use protective enclosures to ensure a draft free environment.

6.10 The contractor shall clean and gas free affected enclosed spaces per SMS Procedure 2.1-010-ALL (Hotwork) as approved by the ship and/or MSC REP.

6.11 Recommended wire is 5183 for welding to 5083. Typical brands that are ABS approved are Lincoln, Alcotech, and Maxal. Contractor shall verify material requirement with the MSC REP and ABS prior to starting any work.

6.12 Circular saws, reciprocating saws, portable band saws, and saber saws can result in good quality cuts when cutting speeds and proper equipment are used. Cut edges shall be smooth, uniform, and free from burrs, tears, and cracks. A rough surface shall be milled, filed, deburred, or sanded to make it smooth. Plasma cutting shall not be used.

6.13 Aluminum surfaces must be thoroughly cleaned within six (6) hours of welding. Cleaning will be no less than a minimum of four (4) inches on both sides from the expected weld area prior to fit-up and welding. Cleaning shall include degreasing, then the oxide film shall be removed manually cleaned using either a carbide burr, stainless steel wire brush, aluminum oxide coated fiber wheel, or abrasive disk. Stainless steel wire brushes used for surface preparation shall be used for aluminum cleaning only. After oxide film is removed, the joint surface and adjacent base material shall be wiped clean with a rag that has been soaked in approved chemical solvent immediately prior to welding.

7.0 STATEMENT OF WORK REQUIRED

7.1 Arrangements/Outfitting:

7.1.1 The contractor shall design and make all necessary arrangements (scaffolding, safety gear, temporary accesses, install padeyes and lifting gear, rigging path, etc) to safely complete the repair called out in this work item.

7.2 Structural:

7.2.1 Contractor will provide all tools, material and labor to repair hull damage. Only ABS approved materials shall be used in the execution of this work item.

7.2.2 The contractor shall mark on the hull and provide a paper sketch of the area to be cropped and repaired using direction and recommendations called out in this work item. This sketch shall be submitted to the MSC REP and ABS for approval prior to cutting. The area will be repaired to meet the original specifications as described in this work item and references 2.1.1 thru 2.1.3.

· Shell seams shall be 300mm apart unless a request for deviation is approved by the MSC REP. To remove the heat affected zone (HAZ) created by the existing weld and were seam distances cannot be met, the cut for repair shall be 75mm beyond the existing seam.

· The contractor shall ensure recommendations called out in this work item are met unless a deviation is required and vetted through MSC REP and ABS.

· Existing weld seams shall not be used for cut and repair.

· The recommended distance between field weld seams is 100mm (4in).

· The recommended distance between seam and fillet weld is 100mm (4in).

· Where plate and T shapes or friction stir welded extruded planking is used to repair damaged area, the T’s shall be longer than the plate on both sides to allow a minimum of 200mm overlap on both sides. Joints between T’s and shell plate weld seams shall be staggered.

· Inserts shall include cut and insert plate or planking with a minimum of 75mm (3in) radius corners.

7.2.3 Contractor shall provide ABS and MSC REP with inspection checkpoints for fit-up, final welding and NDT as required by this specification and regulatory body.

7.2.4 All welds shall include non-destructive testing (NDT) upon completion and be completed to the satisfaction of the MSC REP and ABS surveyor. As a minimum, PT and UT shall be conducted on ALL shell plating welds. NDT 100% of weld seam. Structure welded to the hull perimeter shall have 20% PT testing.

· The 20% structure PT locations shall be determined based on 5X visual inspection completed in the presence of ABS and MSC REP.

· 5X visual inspection shall be completed on all of the welds that are not tested by PT and UT. Exception is given for secondary structure that is not welded to hull perimeter and does not negatively affect design strength.

· Secondary structure that is not welded to hull perimeter (i.e flat bar used to stiffen a frame panel or attachment of small electrical components) shall include NDT by visual inspection only.

7.2.5 Crop out and replace shell plating as per MSC REP and ABS approved repair sketch.

7.3 Mechanical/Fluids: None

7.4 Electrical: None

7.5 Electronics: None

7.6 Preparation of Drawings:

7.6.1 Sketch will be required to clearly map areas for repair. Sketch will include cut dimensions, materials repaired and seams (existing and new). At a minimum the sketch will include all weld seams within 400mm of repair area.

7.6.2 Contractor shall provide “As-Built” drawings based on all references drawings provided and Redline drawings to capture any and all approved changes or deviations. If there are not deviations as-build drawings will not be required.

· Deviations include ALL changes to existing information as well as missing information from drawing. This would include but not be limited to missing weld call out, changing weld size, adding missing dimensions needed to install equipment, changes to bill of materials, changing design based on condition reports, etc.

7.6.3 All “As-Built” drawing submissions will consist of at least three (3) 11”x17” hard copy prints and one (1) electronic copy on CD/DVD in AutoCAD 2007 and PDF format. These submissions will be provided to the MSCREP and the MSC Tech Library.

7.6.4 “As-Built” drawings shall be provided to:

MSCREP AND MSC Tech Library 9276 3rd Ave, Bldg LP-26 Norfolk, VA 23

(NOTE: A letter shall be submitted with the drawings that contains the Contract Number, Ship Name, and Port Engineer details)

7.7 Inspection/Tests:

7.7.1 Inspection and acceptance of material and work shall be by the ABS Surveyor and MSC representative (MSC REP).

7.7.2 Shipboard Inspection:

· Nondestructive testing (NDT) shall include 5x visual inspection as well as a dye penetrate (PT) on the welds. If there is any doubt about the welds further testing and repairs will be required. Testing shall be completed to the satisfaction of the MSC REP as well as the ABS surveyor. See additional test details in the statement of work above.

· Contractor shall provide ABS and MSC REP with inspection checkpoints for fit-up, final welding and NDT as required by this specification and any regulatory specifications.

· The contractor shall contact MSC REP and local surveyor prior to any work to ensure satisfaction is achieved during this installation. The ABS surveyor and MSC REP shall be present at fit-up, testing and prior to any final welds and post weld testing

· The contractor shall furnish a hard copy or electronic report for each NDT inspection.

7.7.3 Shipboard Testing:

· Tightness test using MSC GTR No. 3 (reference 2.1.9) as guidance. Testing per MSC REP and ABS surveyor.

· The Contractor’s quality assurance plan shall be invoked for all aspects of this work item.

· Additional testing as discussed in quality assurance section might be required based on material conditions. Condition report shall be required based on material conditions.

7.8 Painting:

7.8.1 If painting is required, the Contractor and MSC REP shall conduct a joint inspection of welded areas disturbed by the installations. These areas are to be prepared and primed before final painting begins to ensure that protective measures are implemented.

7.8.2 Paint all new and disturbed surfaces on the exterior deck to match the existing in accordance with the ships class paint schedule and manufacturer's recommendations. Use reference 2.1.8 as guidance. Ensure to adequately mask off or protect all electrical/electronic cables or other surfaces not required to be painted. The surfaces shall be mechanically cleaned to SSPC-SP3 with an aluminum oxide based abrasive pad (NOTE THAT NO ABRASIVES THAT INCLUDE IRON OR COPPER MAY BE USED), cleaned to SSPC-SP1 to remove oxidation and aluminum dust created during mechanical cleaning then coated with one coat of Amercoat 240 with a Dry-Film Thickness (DFT) of 5-6 mils color OFF-WHITE and 2 coats of PSX 700SG color Haze Gray with a DFT of 5-7mils. If the area to be coated is in the walkway; PPG 886 non-Skid Additive shall be added to the final coat of PSX 700SG.

7.9 Markings:

7.9.1 Contractor to fabricate and install all applicable labels, using reference 2.1.5 as guidance.

8.0 GENERAL REQUIREMENTS: None

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