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31/07/2014 - API 6D Twenty Fourth Edition


Specification for Pipeline and Piping Valves

API 6D Specification for Pipeline and Piping Valves, Twenty-Fourth Edition published 08/01/2014.
Below the main changes:

Processes requiring validation the following processes shall be validated, by the manufacturer, in accordance with their quality system as applicable:
–Nondestructive Examination (NDE)
–Welding
–Heat Treating
–External coating/ component plating that may impact product performance, by agreement.

- New /revised definitions added to text
Block and bleed valve single valve with at least one seating surface that, in the closed position, provides a seal against pressure from one end of the valve with the body vented.
Pressure-containing parts a part, whose failure to function as intended results in a release of contained fluid into the environment and as a minimum includes bodies, end-connections, bonnets/covers and stems.
Shaft part that supports the obturator on a check valve and does not pass through the pressure boundary.
Stem part that drives the obturator and passes through the pressure boundary.

- Valve Types and Configurations which included all the figures and end to end dimension tables have been moved to a new Annex B and Annex C.
When there is no minimum bore dimensions listed for a valve pressure class and size stated in Table 1, the size and bore shall be by agreement and the manufacture shall stamp the size and bore on the nameplate.

- Flanges shall be furnished with a raised face or ring joint face (raised face or full face). Specified dimensions, tolerances and finishes, including drilling templates, flange facing, nut-bearing surfaces, outside diameters and thickness.

- Design
Injection Points sealant fittings shall have a design pressure not less than the greater of the pipeline or piping valve rated pressure and the injection pressure.
Hand-wheel diameter shall not exceed the face-to-face or end-to-end length of the valve or 40 (1065 mm)
Travel Stops valves that do not require mechanical force to effect a seal shall be provided with travel stops, shall be provided on the valve and/or operator and they shall locate the position of the obturator in the open and closed position. The travel stops shall not affect the sealing capability of the valve. New Annex D for guidance for travel stops by valve type.
Actuator sizing and mounting kits shall be in accordance with API 6DX or ISO 12490

- Allowable Stresses
New text has been added to address the tensile stresses in drive train components, including stem extensions as well as shear stress (including torsional shear stress) and bearing stress with general notes section of ASME BPVC Section II, Part D.

- Material Specification
Specifications for metallic pressure containing and pressure controlling parts shall be issued by the manufacturer and shall address the following
• Material grade
• Melting practice
• Chemical analysis;
• Heat treatment;
• Mechanical properties (tensile)
• Certification to report all items listed in 8.1.
Other requirements of the material specifications shall be as follows, if applicable
• Carbon equivalent ;
• Charpy impacts
• Hardness;
• Testing;

- Service Compatibility
Selection of elastomeric materials for valves intended for rapid gas decompression service at pressures of class 600 and above shall address the effect of explosive decompression.
Forged Parts All forge material shall be formed using a hot-working practice and heat treatment throughout that produces a forged structure.
Composition Limits the chemical composition of carbon steel welding ends shall meet the following requirements.
• sulfur content shall not exceed 0.020% by mass.
• phosphorus content shall not exceed 0.025 % by mass.

- Materials
Charpy impact values for full-size specimens of duplex or super duplex stainless steels shall be as follows:
• average of three specimens: 33ft.lbs (45 J) minimum;
• no single specimen less than 26 ft. lbs. (35 J).
• Charpy impact test temperature shall be -50F (-46C)
• If the first set of the Charpy impact test doesn't satisfy the applicable requirements, one additional set of 3 impact tests on two additional test specimens (removed from the same test coupon with no additional heat treatment) may be performed in an effort to qualify the material. The results of each of these tests shall satisfy the applicable requirements.
Sour Service Materials for pressure-containing and pressure-controlling parts and bolting for sour service shall meet the requirements of NACE MR0175 or ISO 15156 (all parts) or MR0103 . Purchaser shall specify which standard is to be used.

- Welding
Welding consumables shall conform to the American Welding Society's or manufacturer's specifications. The manufacturer shall have a written procedure for storage and control of welding consumables. Materials of low-hydrogen type (including electrodes, wires, and fluxes) shall be stored and used as recommended by the manufacturer of the welding consumable to retain their original low- hydrogen properties.
Weld overlay or clad welding with nickel-based alloy UNS N06625 the weld overlay or clad thickness chemical composition shall meet one of the class listed below.
• Class Fe 10: Iron mass fraction 10.0% maximum or,
• Class Fe 5: Iron mass fraction 5.0% maximum, when specified by the purchaser.
Weld repair of forgings and plates shall not be performed to correct material defects, unless otherwise agreed. However, weld repair can be used to correct machining errors. The weld repair shall be in accordance with the applicable material standard, including any PWHT, if applicable.

- Quality control
Calibration Intervals
• Calibration intervals shall be established for calibrations based on repeatability and degree of usage.
• Calibration intervals shall be a maximum of three (3) months until recorded calibration history can be established by the manufacturer.
• Intervals shall be shortened and may be lengthened based on review of the calibration history and determination of interval adjustments as defined in the manufacturer’s written procedure. Increments to establish longer intervals shall be limited to three (3) months maximum.
• The maximum calibration period shall not exceed one (1) calendar year.
Personnel performing visual inspections of welding operations and completed welds shall be qualified and certified as either:
• AWS QC1 or equivalent certified welding inspector or;
• AWS QC1 or equivalent senior certified welding inspector or;
• AWS QC1 or equivalent certified associated welding inspector, or;
• welding inspector certified by the manufacturer’s documented training program

- Testing
Test fluid shall be fresh water, shall contain a corrosion inhibitor. Based on the end location of the valve the test fluid shall have, antifreeze (glycol) unless otherwise agreed. The water temperature shall not be no greater than 100 F (38 C) during the testing period.
All hydrostatic and pneumatic shell tests specified shall be performed with the valve unseated and partially open and may also be performed with the valve fully open, provided the body cavity is simultaneously filled and pressurized through a cavity connection.
Supply pressure shall be isolated from the valve being tested and shall be stabilized prior to the start of pressure testing duration. The pressure measuring device shall be installed in the test apparatus in such a manner that the device continuously monitors/records the test pressure of the valve assembly. The pressure test shall be held for the minimum test durations listed in Tables 4, 5, and 6 after stabilization as determined by the manufacturer.
Minimum Duration of Seat Tests - table 6
- DN ≤ 100, NPS ≤ 4 test duration 2 minutes
- DN 150-450, NPS 6-18 test duration 5 minutes
- DN 500 and larger, 20 NPS & Larger test duration 10 minutes

- Coating
All non-corrosion-resistant valves shall be coated externally in accordance with the manufacturer’s standards, unless otherwise agreed. If external coating operations are performed by the manufacturer or their coating contractor, preventative measures shall be taken to assure that no foreign material enters the internal cavity of the valve that may impact the valve function.
Flange faces sealing surfaces, weld bevel ends and exposed stems shall not be external coated. See Annex M to provided details on where coat is not allowed.
Corrosion protection shall be provided using the manufacturer’s documented requirements for flange faces, weld bevel ends, exposed stems and internal surfaces of the valve.

- Marking
If a product or component is marked in accordance with the product specification and the API monogram is applied, and it is subsequently determined that the product fails to satisfy any applicable requirements of this specification, the nonconformance should be reported to the API Monogram Program per the Monogram Program Annex (see Annex A.6).
Each valve shall be provided with an austenitic stainless steel nameplate securely affixed and so located that it is easily accessible. The nameplate shall be attached to the valve body, however based on valve design the nameplate maybe attached the bonnet/cover or closure /end-connector at the option of the manufacture.
The marking on the body, end connector and bonnet/cover and nameplate shall be visually legible.
The body marking shall be minimum letter size shall be 0.25 in.
The nameplate minimum letter size shall be 125 in (3 mm) on valves sizes NPS 2 (DN 50) and larger. All valves NPS 1.5in (DN 38) and smaller, the nameplate letter size shall be per the manufactures standard.
On valves whose size or shape limits the body markings, they may be omitted in the following order:
a) manufacturer’s name or trademark;
b) material;
c) rating;
d) size

- Preparation for Shipment
Protective covers shall be made of wood, wood fiber, plastic or metal and shall be securely attached to the valve ends by using bolting/nuts or plastic straps or steel clips or friction-locking devices.
Protective covers made of wood or wood fiber shall be fitted with a non-porous moisture barrier between the cover and the metal flange or welding end. All flanged end and weld end protective covers installed on the valves shall be sealed using a rubberized water proof tape.
Check valves NPS 4 (DN 100) and larger shall be shipped with the disc secured or supported during transport. A warning label shall be attached to the protective cover with instructions to remove, prior to installation, material from inside the valve that secures or supports the disc.

- Documentation
Documentation provided with the valve.
As a minimum, a certificate of compliance to this standard shall be supplied by the manufacturer.
The Certificate shall identify the valves type, size, class, end connection; serial number(s) and a statement that valve (s) are in full compliance with this product specification and revision date.

- Minimum facility requirementsfor the following category of manufacturer.
- Product Design - Performed on-site, off-site and/or outsourced
- Product design validation - Performed on-site, off-site
- Material Procurement - Performed on-site, off-site or outsourced
- Receiving Verification - Performed on-site
- Machining- Performed on-site, off-site or outsourced
- In-process Inspection - Performed on-site, off-site or outsourced
- Welding - Performed on-site, off-site or outsourced
- Assembly - Performed on-site
- Verification Testing-FAT - Performed on-site
- Supplementary NDE & Testing (Annex G,H, I, O) - Performed on-site, off-site or outsourced
- Marking/ Tagging/nameplate - Performed on-site
- Painting/Coating - Performed on-site, off-site or outsourced
- Preparation for shipment - Performed on-site
- Final Inspection - Performed on-site

Api 6D Annex
- Annex A - API monogram requirements
- Annex B –Valve configurations sketches
- Annex C – Valve end-to-end dimensions
- Annex D (Informative) Guidance for travel stops by valve type
- Annex E – (Informative) supply chain management
- Annex F (Normative) Recommended Practice for Qualification of Heat-treating Equipment
- Annex G (Normative) Requirements for non-destructive examination
- Annex I (Normative) Supplementary Test Requirements
- Annex J (informative) Requirements for Extended Hydrostatic Shell Test Duration and Records Retention for Valves in Jurisdictional Pipeline Systems
- Annex K (normative) Quality Specification Level (QSL) for Pipeline Valves
- Annex L(Informative) Isolation valve features
- Annex M (Informative) External Coating for End Connections
- Annex N (informative) Supplementary Documentation Requirements
- Annex O (informative) Purchasing Guidelines

 

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