FINAL TECHNICAL SPECIFICATION NBSR-CSP-1.docx

TECHNICAL SPECIFICATION NBSR-CSP-1 for Fabrication AND installation of Carbon Steel Piping for NBSR

2. APPLICABLE DOCUMENTS (Latest version of these codes and standards are applicable)

C. American Welding Society (AWS):

1. AWS D1.1 - "Structural Welding Code - Steel"

2. AWS D10.9 - "Qualification of welding procedures and welders for piping and tubing, specification for".

3. AWS D10.11 - "Recommended practices for root pass welding of pipe without backing".

4. AWS D10.12 - "Welding low carbon steel pipe, recommended practices and procedures for".

D. Manufacturers Standardization Society (MSS):

1. MSS SP-58 - Pipe hangers and supports - Materials, Design and Manufacture

2. MSS SP-69 - Pipe hangers and supports - selection and application

3. MSS SP-89 - Pipe hangers and supports, fabrication and installation practices

3. DESIGN CRITERIA

All work must meet the design criteria of at least 80 psig and 150°F temperature.

4. GENERAL

A. All pipe and pipe fittings shall adhere to the following codes and standards: (All pipes and pipe fittings will be seamless)

ITEM CODE OR STANDARD

B. The welding of pressure piping shall meet the requirements of the American Standard code for pressure piping, ASME/ANSI B31.1, 1992 edition, Chapter V and VI.

C. The welding of structural steel including special pipe supports, anchors and guides if any (not defined as standard type of hanger components in MSS SP-58) shall meet requirements of para.127, Chapter V of ASME/ANSI B31.1, 1992 edition and AWS D1.1.

D. Welding procedure and welders qualification reports shall be submitted In accordance with AWS D10.9 to the Contracting Officer’s Representative (COR) for approval.

E. All filler metal, including consumable insert material, shall comply with the requirements of para.127.2 of ASME/ANSI B31.1, 1992 edition and/or ASME B & PV code, section IX. A filler metal not incorporated in Section IX, may be used if a procedure qualification test is first successfully made in accordance with section IX.

F. The following welding processes shall be used:

1. Shielded metal arc, inert gas shielded tungsten arc, inert gas shielded metal arc or submerged arc processes or combinations thereof, may be used as joint condition may indicate.

2. Tungsten electrodes shall conform to ASTM B297 and shall be classification EWTH - 2. Shielding gas shall be welding grade argon of 99.99 percent minimum purity.

5. FABRICATION

A. General

1. Adequate shielding against drafts and air currents shall be provided for all welding operations.

2. Welding shall not be done when the temperature of the base metal is less than 40°F. Preheating may be used to raise the base metal to this temperature.

B. Joint preparation

1. Carbon steels to be joined by welding shall have the abutting edges prepared by machining, grinding, power chipping or by flame cutting processes.

2. Specific permission of the COR shall be obtained prior to rebuilding the edges of a joint which is outside the tolerance of the code. Contractor shall submit request in writing and approval must be provided by the Contracting Officer via a modification to the order.

3. Abutting edges and immediate weld area of the sections to be joined shall be cleaned mechanically or chemically and thoroughly rinsed to a distance not less than 1/2 inch from the weld seam edge.

C. Positioning of Joints

1. Tack welds, when used, shall be kept to a minimum, but shall be adequate to maintain alignment of the adjacent joint edges throughout the welding operation. Tack welds do not constitute a final weld. The Contractor must perform final welds as appropriate.

2. Joint edges shall not be offset from proper alignment at any point by more than 20 percent of the thinner section at the joint, or 1/32 inch, whichever is less.

3. Piping to be welded shall have the abutting edges in uniform contact or at uniform spacing throughout the entire circumference of the joint.

D. Preheating

1. Welded joints in material with a nominal thickness greater than 3/4 inch shall be preheated adjacent to the welding zone to a temperature of not less than 400°F. This preheating may be performed by any method that will establish and maintain a uniform temperature during the welding operation.

E. Welding

1. Tack welds shall have complete fusion to the weld joint root. Fill passes shall be completely fused to tack weld, but cracked tack welds shall be removed before welding. Tack welds shall be made by qualified welder only.

2. When the joints to be welded are in vertical position, the direction of welding shall be upward when practicable.

3. When the weld joint requires multilayer welding, the starting and stopping points of successive layers shall be staggered. Each layer shall be no more than 1/8 inch thick, except in the case of submerged arc welding deposits. The minimum number of layers to make to piping weld shall be one layer of each 1/8 inch of wall thickness, but not less than two layers per weld joint.

4. All weld defects and all traces of slag, flux or foreign material shall be removed from preceding weld deposits before welding over them or connecting with them.

5. If water is used for cooling, all traces of moisture which might be detrimental to the weld shall be removed before welding.

6. No permanent backing ring will be allowed for the butt welding of the pipes.

F. Installation of Pipe Supports

1. Piping shall be supported per para.130 of ASME B31.1. 1992 edition and MSS SP-58, SP-69, and SP-89.

2. Pipe support locations and type shall be confirmed, in writing, with the COR prior to fabrication and installation of pipe supports.

6. QUALIFICATION OF WELDERS AND WELDING PROCEDURES

A. Welding of carbon steels shall be done only by welders or welding operators who are qualified in accordance with para.127.5 of ASME/ANSI B31.1, 1992 edition and/or ASME Boiler & Pressure Vessel Code Section IX, article III.

B. Renewal of performance qualification is required:

1. When the welder has not used specific process for a period of three months or more, or

2. When the contracting officer's representative has specific reason to question the welder's ability to make welds to the specified quality requirements.

C. Qualification of welding procedures will be per ASME Boiler & pressure vessel code section IX, article II. The Government reserves the right to question and examine the welding procedure during the RFQ phase of each task order and as deemed necessary.

D. The Contractor shall be required to submit the appropriate qualifications for each proposed welder and each welding procedure in the RFQ phase of each task order.

7. QUALITY ASSURANCE

A. General

1. Welds shall be reasonably smooth and uniform in appearance, have full fusion, and blend smoothly into the parent metal.

2. Welds shall be free of the following defects:

a. Cracks of any description in the weld or base metal.

b. Crater checks.

c. Cold laps in the deposited weld metal.

d. Overlay or weld metal on the base metal.

e. Undercutting at the edges of welds; nor shall any part of the finished face of the weld in the area of fusion of welded joints lie below the surface of the adjoining base metal.

f. Depressions in butt welds below the work piece surface on either side of the welded seam.

g. Unfilled weld craters.

h. Spaltic metal which may have been ejected from the metal arc.

B. Butt Welds

1. Welds having less than 100 percent penetration are unacceptable.

2. For butt welded joints, backing rings shall not be permitted.

3. The width of butt welds need be no wider than the top width of the original unwelded joint, but the weld shall have complete fusion with the metal at all points on the joint.

4. Reinforcement of butt welded joints shall be built up uniformly from the surface of the base metal to maximum at the center of the weld.

5. Except as limited further by the ASME Codes for pressure piping, reinforcement of butt welded joints shall not exceed the following:

a. Butt welded joints in material over 1/2 inch in thickness shall not be reinforced at the center of the weld by more than 20 percent of the thinner section joined or 3/16 inch, whichever is the least.

b. Butt welded joints in material 1/8 inch and under in thickness shall not be reinforced by more than 50 percent of the thickness of the thinner section joined.

6. For piping six inches or less in diameter, the weld metal shall not protrude locally by more than 20 percent of the thinner section joined or by 3/32 inch, whichever is least, beyond the inner surface of the pipe.

7. For piping over six inches in diameter, the weld metal shall not protrude locally by more than 1/8 inch beyond the inner surface of the pipe.

C. Fillet Welds

1. The faces of all fillet welds shall be at approximately equal angles to the sections they join.

2. Fillet welds may be slightly convex, flat or slightly concave, but in no case shall the throat of the weld be less than that for the specified weld size.

3. Fillet welds shall not have a convexity greater than the value O.1S, where S is the actual size of the fillet weld in inches.

D. Repair of Defective Welding

1. The Government shall advise the Contractor of defective welding. Defective welding shall be removed in a manner deemed satisfactory to the COR. The Contracting Officer’s approval shall be obtained prior to repair of any defects. Defects in welds shall be repaired by the same procedure used for original welds.

2. Defects shall be removed by grinding, machining or power chipping. Peening or caulking is not permitted.

3. Removal of undercutting by mechanical reduction of the base metal section adjacent to the welded seam is not permitted.

4. It is anticipated that all defects shall be repaired on-site at NIST.

8. INSPECTION AND TESTING TO BE PERFORMED BY THE CONTRACTOR:

A. Liquid Penetrant Examination: All welded joints shall be thoroughly clean from any slag or weld spatter prior to liquid penetrant examination. All welded joints shall be examined by Liquid Penetrant Examination in accordance with para.136.4.4 of ASME B31.1, 1992 edition by certified Non-Destructive Examination (NDE) personnel. The Contractor shall be responsible to ensure that NDE personnel are on-site for inspection. Fabricator shall inform the COR one week in advance to witness liquid penetrant examination, if fabrication is done at fabricator's facility.

B. Hydrostatic Testing: After successfully fabricating the piping, the pipe shall be pressure tested in accordance with para.137.2, 137.3, and 137.4 OF ASME B31.1, 1992 edition. The design pressure of the system shall be 80 psig. Therefore, piping shall be hydrostatically tested for the pressure of 120 psi. Any leaks found shall be repaired.

9. PREPARATION FOR SHIPMENT (Off-Site Repairs):

All nonflanged pipe openings larger than 2 inches shall be protected by a 3/8 inch thick plywood disc with a diameter equaling the pipe outside diameter, and sealed with at least three passes of sealing tape. Carbon steel flanges shall be sealed with metal or non-metallic disks bolted to the flange. A 1/8 inch thick rubber gasket is required for sealing. Flange faces shall be coated with grease as a rust preventive. All nonflanged pipe openings 2 inch and smaller shall be sealed by sealing tape.

Packaging and shipping of fabricated pipe spools shall meet the requirements for level D items as described in ASME standard N45.2.2. Pipe and fittings shall be adequately blocked, strapped or otherwise held in position during shipment and they should be further separated by dunnage as may be necessary to prevent damage.