1. GENERAL
This specification defines minimum quality and technical
standards governing design, manufacturing and supply of pipeline flanges and
flange fixtures used with offshore pipelines.
This specification is to be used in conjunction with the following
documents:
·
Basis of Design
84506-60-00-2L-060
·
General Specification 84506-60-00-2L-000 Definitions
and Specification Directory
·
General Specification 84506-60-00-2L-010 Quality Assurance / Quality
Control
2. DESIGN REQUIREMENTS
The design and manufacture of the flanges
shall be in accordance with
ANSI B1.1 : Unified
Inch Screw Threads
ANSI B16.5 : Pipe
flanges and flange fittings
ANSI B18.22.1 : Plain
Washers
MSS-SP-44 : Steel
pipeline flanges
ANSI B16.20 : Ring-joint
gasket and grooves for steel pipe flanges
ASTM A-193 : Alloy-steel
and stainless steel bolting materials for high-
temperature services
ASTM A-194 : Carbon
and alloy steel nuts for bolts for high-pressure and high temperature service
ASTM A-388 :
Standard practice for liquid penetrant inspection method.
DNV OS–F101 : Submarine
Pipeline Systems 2000.
MSS-SP-75 : Specification
for high test wrought butt welding fittings
API 1104 : Welding
of Pipelines and Related Facilities
Flanges made to this
specification shall be ANSI Class.
3. FLANGE REQUIREMENTS
3.1 Weld neck flanges and blind flanges shall
be in accordance with the following:
ANSI B16.5 for flanges, NPS 2” to
NPS 24” except NPS 22”
NPS 22 will be designed by the
supplier and approved by a certifying agency.
3.2 CONTRACTOR shall design swivel ring
flanges to meet the requirements of MSS-SP-44.
CONTRACTOR shall provide fully dimensioned drawings, calculations etc.
to COMPANY, for approval, prior to fabricating any swivel ring flange.
3.3 Misalignment flange assemblies shall be
capable of connecting to an RTJ weld neck flange on one end and to linepipe
with a butt welded connection on the other end. The misalignment flange
assembly shall be of equivalent dimensions to the connecting flange.
3.4 Flanges
for tree tie-in spools shall be designed and manufactured to provide the
capability of performing an annulus test on the completed flanged joint, such
that the leak tight integrity of the joint can be demonstrated by an external
pressure testing procedure.
3.5 Prior to manufacture, CONTRACTOR shall
submit for approval by COMPANY detailed drawings, design calculations, detailed
manufacturing procedure in proper sequence and non-destructive testing
procedures.
3.6 Test specimens shall be full size and the
test temperature shall be -10oC for Export Pipeline Flanges and -39oC
for Infield Flowline Flanges. The Charpy
values for all flanges shall be compatible with the grade of linepipe material
to which they will be used. Charpy V-notch values shall be in accordance with
the minimum mean values and single specimen values given in Table 6-3 of
Section 6 of DNV OS–F101.
4. STEEL MANUFACTURING REQUIREMENTS
CEV = C + Mn + Cr + Mo + V
+ Cu + Ni
6 5 15
4.2 Material shall conform to the chemical
analysis requirements of DnV OS-F101. All compositions shall be subject to
COMPANY approval.
4.3
Chemical composition shall be
controlled within more stringent limits than the maximum values given in DnV
OS-F101. CONTRACTOR shall submit the
target value and proposed range of each chemical element to COMPANY for
approval. Agreed target values and
ranges shall be given in the approved manufacturing procedures
4.4 Flanges
shall have mechanical properties, for the material grade specified, that meet
the requirements of MSS-SP-44.
4.5 CONTRACTOR
shall furnish full documentation for material manufacturing process, testing,
inspection and documentation giving typical and maximum hardness valves of
flange(s). CONTRACTOR shall certify that all finished components do not exceed
270 Brinell hardness in the base metal and the heat affected zone.
4.6 CONTRACTOR
shall document and furnish to COMPANY a complete analysis of the finished
flanges. A complete analysis must include all elements mentioned above, as a
minimum.
5. HARDNESS REQUIREMENTS
CONTRACTOR shall certify that all finished components do
not exceed 270 HV10 in the base metal.
6. BEVELS
6.1
Welding ends shall be beveled for welding in
accordance with sub-section 13.3 of MSS SP-75 and API 1104 unless otherwise
stipulated on Request for Quotation or Purchase Order.
6.2
The root face shall not be brought into
tolerance by filing or grinding.
6.3
The surface of the bevel shall be smooth and
free from tool marks as to permit proper inspection for laminations. In
removing any burr, care shall be taken to avoid excessive removal of metal and
the formation of an inside bevel. Excessive removal of metal shall be cause for
re-beveling.
6.4
All bevelled ends shall be inspected by an
approved non-destructive method.
6.5
The welding ends shall be machine parallel and
square to the pipe axis and shall have all burrs removed from both the inside
and the outside edges.
7. HEAT TREATMENT
Flanges shall be furnished in normalized, normalized and
tempered, or quenched and tempered condition after all forming operations are
completed. Temperature ranges specified
in COMPANY approved heat treating procedure(s) shall be measured during all
heat treatment. Thermocouples shall be
attached to representative flange parts in the batch to confirm actual metal
temperature.
8. NON-DESTRUCTIVE TESTING
8.1
Non-destructive
testing techniques and procedures, including radiography, Magnetic Particle
Inspection (MPI), and Ultrasonic Testing (UT) to be used by CONTRACTOR shall be
submitted in writing for COMPANY approval prior to starting production.
8.2
Technicians
performing nondestructive inspection shall be qualified to the requirements of
SNT-TC-1A, Level II.
8.3 Flanges
shall be one hundred percent (100%) visually inspected for surface defects and
dimensional tolerances.
8.4 Finished
flanges shall be subject to both one hundred percent (100%) MPI of the barrel
internal faces, external faces and weld bevel surfaces, and a full UT
examination in accordance with ASTM A-388.
8.5 Swivel ring flanges shall be inspected as
a single unit, including full rotation of the unit to ensure it swivels freely
without binding.
9. DIMENSIONAL TOLERANCES
Tolerances on forged flanges shall meet the requirements
of MSS-SP-44, ANSI B16.5 and the Project Drawings.
10. REPAIR OF DEFECTS
10.1.1 Repairs to defective flanges are to
be made in strict accordance with MSS-SP-44.
10.1.2
Surface defects such as slivers, sharp notches,
gouges, scores, pits and severe machining marks shall be considered injurious
defects and in need of repair.
10.1.3
Minor surface defects shall be removed by
machining or grinding provided that the section thickness is maintained within
the specified tolerances and the minimum specified wall thickness of the flange
hub is maintained.
10.1.4
The machined or ground area shall be carefully
dressed to ensure a smooth transition with surrounding surface of the forging
with no sharp notches or contours. The
machined or ground area shall be fully examined for any defects using magnetic
particle examination to ensure freedom from defects.
10.1.5
If the section/wall thickness is reduced below
the minimum specified section/wall thickness, the flange shall be rejected.
10.1.6
No repair work shall proceed without prior
COMPANY approval.
10.2 Weld Repairs
11. MARKINGS AND COATINGS
11.1 Flanges shall be identified in accordance with MSS SP-44, with
the following data stamped on the flange periphery by low stress, round-nosed
or interrupted dot die stamps:
·
Manufacturer's Name
·
ADGF Project
·
Flange Identification Number / Purchase
Order Number
·
Heat Number
·
Material Grade
·
Pressure Rating
·
Diameter and Wall Thickness
11.2 All forged
flanges shall be abrasive blasted to remove loose scale and other foreign
material after all required heat treatment has been performed, and prior to
inspection.
11.3 Forged
flanges shall be externally coated with a COMPANY approved two-pack epoxy paint
system suitable for a subsea environment in accordance with coating material
manufacturer’s recommendations Mating
faces, weld bevel area and bolt/nut contact areas shall not be epoxy coated.
11.4 Beveled
ends shall be protected against physical damage during transit. Ends shall be coated with a weldable primer
such as Deoxaluminite, or COMPANY approved equal, that can easily be removed
with solvent and that will prevent rusting of weld bevel faces for a period of
at least twelve (12) months, under exposed field conditions.
12. INSPECTION AND REJECTION
12.1 CONTRACTOR
shall furnish COMPANY reasonable facilities and space, without charge, and
shall provide COMPANY with free access to all parts of all plants concerned
with forging of flanges, for COMPANY inspection and testing.
12.2 COMPANY may
inspect flanges for compliance with this specification and at all stages of the
manufacturing and delivery process. This
inspection shall in no way relieve CONTRACTOR of its responsibilities for
compliance with the specifications.
12.3 COMPANY
inspectors shall operate independently of CONTRACTOR inspectors.
12.4 Flanges
shall be rotated at the final inspection bench, where the minimum illumination
level on all surfaces shall be 350 lux.
All components shall be checked for mechanical damage, correct weld
bevel preparation and marking, and end protection.
12.5 All records
shall be fully identified with the specific materials they represent, and shall
be available for COMPANY examination at the time and place of inspection,
whether at the point of manufacture or other CONTRACTOR locations.
12.6 All
materials and material manufacturers shall be approved COMPANY prior
to the placement of orders.
13. ACCESSORIES
13.1 Ring Joint Gasket
13.1.1
Ring Type Joint (RTJ) gaskets shall meet the
requirements of ANSI B16.20 and shall utilise Anti Explosive – Decompression
(AED) sealing in the correct sizing and rating for each flange. Gasket hardness
shall be less than that of the mating flange faces.
13.1.2
Oval shaped ring joint gaskets shall be
supplied, manufactured from 316 stainless steel in the annealed condition.
13.2 Fasteners
13.2.1 Studs
Stud
bolts shall comply with ASTM A-193-B7M, hexagonal nuts shall comply with ASTM
A-194-2HM, and all shall be Teflon coated (Standcote or COMPANY approved
equal). CONTRACTOR shall determine all
required stud bolt lengths, especially for use in conjunction with hydraulic
bolt tensioning equipment.
Studs
for use on swivel ring flanges shall have 6 mm (0.25 in.) lead-in taper on each
end.
Subsea
structures shall be designed to incorporate shrouding and/or configuration that
eliminates exposure of studs to the risk of snagging or other mechanical
damage.
13.2.2 Nuts
Nuts
for studs shall conform to ASTM A 194 Grade 2H, heavy duty hexagonal-head
series, with dimensions in accordance with ANSI B1.1 Class 2B fit, 8 pitch
thread series. Maximum hardness shall be 300 Brinell.
13.2.3 Washers
Two
are required in accordance with ANSI B18.22.1 “B” Regular Series. Material
shall conform to ASTM A 325 or equivalent.
13.2.4 Coatings
All
studs, nuts and washers shall have Standcote SC-1 coating or COMPANY approved
equal.
13.2.5 Inspection and Testing
In
addition to the required tests as specified by ANSI B16.20, ASTM A 193, ASTM A
194, ASTM A 325 and STM A 153, the COMPANY shall have the right to conduct
non-destructive tests by ultrasonic inspection, magnetic particle inspection,
liquid penetrant, visual examinations and other means.
14. SHIPMENT
CONTRACTOR shall submit, for COMPANY approval, drawings
of proposed flange stacking and shipment procedures. Timber blanks or metal end bevel protectors
shall be used to protect end bevels and flange faces. Flanges shall be lifted and stacked only by
approved methods that prevent damage to the flanges and their end bevels.
15. DOCUMENTATION SUBMITTALS
15.1 CONTRACTOR shall submit to COMPANY for approval of the following
documents 30 days prior to commencement of the WORK.
·
Work Procedures
·
Steel Making / Casting Methods
·
Chemical Composition
·
CONTRACTOR Shop Drawings
·
Inspection Procedures
·
Common Repair Procedures
15.2 CONTRACTOR shall submit to COMPANY for approval, a data package
containing as a minimum:
·
Certified as Fabricated Drawings
·
Mill Certificates containing
- Ladle Analysis
(each heat)
- Product Check
Analysis (each heat)
- Certified NDT
Reports
- Certified
Mechanical Test Reports
- Certified
Mechanical Test Reports
- Equipment
calibration certificates
- Test and inspection
records
- Design Reports
15.3
All certificates shall be in the English
language and use metric units of measure.
CONTRACTOR and COMPANY shall visibly sign certificates.
15.4
Data package shall be submitted to COMANY in
both hard copy and electronic format.