09. January 2015 · Comments Off · Categories: API 6DSS

Other Specification in API 6DSS

6.3 Cavity relief

The manufacturer shall determine whether fluid can become trapped in the body cavity in the open and/or closed position. If fluid trapping is possible, then valves(mady by China valve supplier) shall be provided with an automatic cavity pressure relief unless otherwise specified by the purchaser. External cavity relief shall not be used.

6.4 External pressure and loads

Valves shall be designed for loads other than internal pressure and temperature (see 6.2), if specified by the purchaser. The purchaser shall specify any other construction, test, functional or accidental load combinations or external pressures which shall be accounted for in the design.

NOTEISO 13623 specifies construction, functional and accidental loads and provides examples of such loads for consideration by the purchaser.

 Valve Sizes

All valves, except for reduced-opening valves, shall be furnished in the DN sizes listed in Tables 2 to 5. Reduced-opening valves shall be furnished in the nominal sizes in accordance with Table 1.

In this International Standard, DN sizes are stated first, followed by the equivalent NPS size between parentheses.

 Except for reduced-opening valves, valve sizes shall be specified by DN or NPS.

 Reduced-opening valves with a circular opening through the obturator shall be specified by the nominal size of the end connections and the nominal size of the minimum bore of the obturator in accordance with Table 1, except that for valve sizes DN 50 (NPS 2) or smaller, the actual bore of the obturator shall be specified.

 EXAMPLE 1  A DN 400 (NPS 16) valve with a reduced 334-mm-diameter circular opening through the obturator is specified  as 400 × 350.

Reduced-opening valves (from China gate valve supplier) with a non-circular opening through the obturator and reduced-opening check valves shall be designated as reduced-bore valves and specified by the nominal size corresponding to the end connections followed by the letter “R”.

EXAMPLE 2A reduced-bore valve with DN 400 (NPS 16) end connections and a 381 × 305 mm rectangular opening through the obturator is specified as 400R.

6.6 Face-to-face and end-to-end dimensions

Face-to-face and end-to-end dimensions of valves shall be in accordance with Tables 2 to 5 for the A, B and C dimensions corresponding to Figures 1 to 7, unless otherwise agreed.

Face-to-face and end-to-end dimensions for valve sizes not specified in Tables 2 to 5 shall be in accordance with ASME B16.10. Face-to-face and end-to-end dimensions not shown in Tables 2 to 5 or in ASME B16.10 shall be established by agreement.

The length of valves having one welding end and one flanged end shall be determined by adding half the length of a flanged-end valve to half the length of a welding-end valve(from China ball valve supplier).

Tolerances on the face-to-face and end-to-end dimensions shall be ± 2 mm for valve sizes DN 250 and smaller, and ± 3 mm for valve sizes DN 300 and larger, unless otherwise agreed.

The nominal size and face-to-face or end-to-end dimensions shall be stated on the nameplate.

09. January 2015 · Comments Off · Categories: API 6DSS

Valve types and Configurations in API 6DSS

5.1 Valve types

5.1.1 Gate valves

Typical configurations for gate valves (from China valve supplier)with flanged and welding ends are shown in Figures 1 and 2.

 Gate valves shall have an obturator which moves in a plane perpendicular to the direction of flow. The direction of travel of the gate should be down for closed, but may be reverse-acting in which case the gate is up for closed.

 5.1.2 Ball valves

Typical configurations for ball valves with flanged or welding ends are shown in Figures 3, 4 and 5.

Ball valves shall have a spherical obturator which rotates on an axis perpendicular to the direction of flow, rotating clockwise to close.

5.1.3 Check valves

Typical configurations for check valves are shown in Figures 6, 7, 8 and 9.

Check valves shall have an obturator which responds automatically to block fluid in one direction.

 5.2 Valve configuration

5.2.1 Full-opening valves

Full-opening valves shall be unobstructed in the fully opened position and have an internal bore as specified in Table 1. There is no restriction on the upper limit of valve bore sizes.

Full-opening through-conduit valves shall have a circular bore in the obturator that allows a sphere with a nominal size not less than that specified in Table 1 to pass.

Welding-end valves may require a smaller bore at the welding end to mate with the pipe.

 5.2.2 Reduced-opening valves

The internal bore of reduced-opening valves shall be less than the internal bore specified in Table 1.

Design

Design codes and calculations

Pressure-containing parts including bolting shall be designed with materials specified in clause 7. The pressure-containment design and calculations shall be in accordance with an agreed pressure vessel design standard, for example ASME Section VIII Division 1 or Division 2, or BS 5500. The allowable stress values shall be consistent with the pressure vessel design standard.

 If design standards have test pressures less than 1,5 times the design pressure, then the design pressure for the body calculation shall be increased such that the hydrostatic test pressure in 10.2 can be applied.

 Valves (from China ball valve supplier) to which this International Standard is applicable should be furnished in one of the following classes:

PN 20 (Class 150)

PN 50 (Class 300)

PN 64 (Class 400)

PN 100 (Class 600)

PN 150 (Class 900)

PN 250 (Class 1500)

PN 420 (Class 2500)

Pressure classes shall be specified by the purchaser in accordance with the applicable rating tables for material groups in ASME B16.34 and the pipeline system design.

The purchaser may specify intermediate design pressures and temperatures for a specific application.

Allowable operating pressures and temperatures for valves made of materials not covered by ASME B16.34 shall be determined by calculations in accordance with an agreed pressure vessel design standard, for example ASME Section VIII Division 1 or Division 2, or BS 5500.

NOTE   Non-metallic parts can limit minimum and maximum operating pressures and temperatures.

The minimum design temperature shall be 0 °C unless otherwise specified by the purchaser.

By Kevin Tsai from Relia Valve-Professional China API valve supplier, ball valve, gate valve, check valve and globe valve manufacturer.

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09. January 2015 · Comments Off · Categories: API 6DSS

Symbols and Abbreviated Terms in API 6DSS

Cv- Flow coefficient in United States Customary (USC) units

Qv- Flow coefficient in SI units

4.2 Abbreviated terms

BM- Base metal

CE- Carbon equivalent

DN- Nominal size

HAZ- Heat-affected zone

HBW- Brinell hardness

HIC- Hydrogen-induced cracking

HRC- Rockwell hardness

HV- Vickers hardness

MPD- Hydrogen-induced cracking

MT- Magnetic-particle testing

NDE- Non-destructive examination

NPS -Nominal pipe size

PN- Nominal pressure

PQR -Procedure qualification record

PT -Penetrant testing

PWHT- Post-weld heat treatment

ROV -Remote-operated vehicle

RT- Radiographic testing

SMYS- Specified minimum yield strength

SSIV- Subsea isolation valve

UT -Ultrasonic testing

VT- Visual testing

WM- Weld metal

WPS- Welding procedure specification

WQR- Welder qualification record

By Kevin from Relia Valve-China API Valve Supplier and Manufacturer 

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08. January 2015 · Comments Off · Categories: API 6DSS

Material Specification in API 6DSS

Specifications for metallic parts shall, as a minimum, be developed by the manufacturer (China valve supplier) and include the requirements for chemical properties, heat treatment, mechanical properties, testing, certification.

Metallic pressure-containing parts, except stems, shafts and gaskets, shall be of materials listed in ASME B16.34.

If materials are not listed in ASME B16.34, materials shall be selected by agreement.

All austenitic and duplex stainless steels shall be solution-treated and water-quenched.

Free-machining resulfurized or similar steels shall not be used for any purpose.

The chemical composition, mechanical properties and heat treatment and testing of complex alloys (e.g. duplex stainless steels) including welds, require special consideration and shall be subject to agreement.

Corrosion tests to demonstrate corrosion resistance of the heat, and heat-treatment batch combination, of high alloy steels used for the manufacturing of the valve should be specified by the purchaser.

 7.2 Service compatibility

All process-wetted parts, metallic and non-metallic, and lubricants shall be suitable for the commissioning fluids and service specified by the purchaser. External components shall be suitable for the subsea environment and/or be suitably protected.

Specific measures shall be taken to prevent the galling of moving and mating parts, for example by ensuring a differential hardness of 30 HBW minimum or by applying surface coating.

Non-metallic parts for valves intended for hydrocarbon gas service at pressures above PN 100 (Class 600) shall be resistant to explosive decompression. Graphite should not be used for stem packing, seals or gaskets which may be in contact with sea water.

 7.3 Forged parts

Forged pressure-containing parts shall be forged close to the finished shape and size.

7.4 Composition limits

7.4.1 Flanged end valves

The chemical composition of carbon steel parts which may be subjected to welding shall meet the following requirements unless otherwise agreed: the carbon content shall not exceed 0,25 % mass fraction; the content of both sulfur and phosphorus shall each not exceed 0,03 % mass fraction.

7.4.2 Welding end valves (China ball valve etc.)

a) The chemical composition of carbon steel for welding ends shall meet the following requirements.

1) The carbon content shall not exceed 0,21 % mass fraction in the ladle (heat) analysis or 0,23 % mass fraction in the product (check) analysis.

2) The maximum content of both sulfur and phosphorus shall not exceed 0,03 % mass fraction;

3) The carbon equivalent (CE) shall not exceed 0,43 in the ladle (heat) analysis or 0,45 in the product (check) analysis. CE shall be calculated in accordance with the following formula:

 b)The chemical composition of austenitic stainless steels for welding ends shall meet the following requirements.

1) The carbon content shall not exceed 0,03 % mass fraction, except under the conditions outlined in 2) and 3) below.

2) A carbon content of up to 0,08 % mass fraction is permissible provided the material is stabilized with niobium and the niobium content is at least ten times the mass of the carbon.

3) For steels stabilized with niobium, titanium or tantalum, the combined mass of niobium, titanium and tantalum shall be at least eight times the mass of the carbon.

c) Requirements for the chemical composition of welding ends of other materials shall be established by agreement.

 7.5 Toughness test requirements

All carbon and low-alloy steels for pressure-containing parts in valves with a specified design temperature below 0 °C (32 °F) shall be impact-tested using the Charpy V-notch technique in accordance with ISO 148 or

ASTM A 370. Other materials that may be subjected to brittle fracture (e.g. duplex stainless steel, 13 % Cr steels, 17-4 Ph steel), when used at design temperatures below 0 °C, shall be impact-tested, which shall be by agreement.

 NOTE – Design standards or local requirements may specify impact testing for minimum design temperatures higher than 0 °C (32 °F) and/or increased impact test toughness values.

 A minimum of one impact test, comprising a set of three test specimens, shall be performed on a representative test bar of each heat of the material in the final heat-treated condition.

 Test specimens shall be cut from a separate or attached block taken from the same heat, reduced by forging where applicable, and heat-treated in the same heat treatment batch, including stress-relieving, as the product materials except that:

Pressure-containing parts stress-relieved at or below a previous stress-relieving or tempering temperature need not be retested; retesting is not required after stress-relieving if the measured toughness of the material before stress-relieving is three times the required toughness; the hot-work ratio for size reduction of a forging test specimen shall not exceed the hot-work ratio for size reduction of the part(s) it qualifies.

Toughness testing may be performed during the qualification of the valve manufacturing procedure provided that the material for testing is heat-treated using the same equipment as during valve production.

The impact test temperature shall be as defined in the applicable material specifications and pipeline design standard.

Impact test results for full-size specimens shall meet the requirements of Table 7.

Bolting

Bolting shall be suitable for the specified valve (China gate valve etc.) service and pressure rating.

Impact test results for bolting material shall meet the requirements of ASTM A 320. Bolting material with hardness exceeding 325 HV10 shall not be used for valve applications where hydrogen embrittlement can occur, unless otherwise agreed.

NOTE – Hydrogen-induced cracking (HIC) can occur in cathodically protected subsea pipelines.

Sour Service

Sulfide stress cracking

Materials for pressure-containing and pressure-controlling parts and bolting shall meet the requirements of NACE MR 0175 if sour service is specified.

Hydrogen-induced cracking

Process-wetted and pressure-controlling parts for valves in sour service applications and manufactured from plate shall be resistant to HIC.

Resistance shall be demonstrated by HIC testing in accordance with NACE TM 0284, per heat, per heat-treatment batch combination.

Defects shall not exceed the following limits unless otherwise agreed:

a) maximum crack sensitivity ratio (CSR) = 1,5 %;

b) maximum crack length ratio (CLR) = 15 %;

c) maximum crack thickness ratio (CTR) = 5 %;

d) maximum crack length in any one section = 5 mm.

08. January 2015 · Comments Off · Categories: API 6DSS

Quality Control Specification for Valves  in API 6DSS

9.1 General

The purchaser shall specify which NDE requirement QL1 or QL2 (see annex E) shall be performed.

 9.2 Measuring and test equipment

9.2.1 General

Equipment used to inspect, test or examine material or equipment shall be identified, controlled and calibrated at intervals specified in the valve manufacturer’s (China valve supplier) written specification.

9.2.2 Pressure-measuring devices

9.2.2.1 Type and accuracy

Test pressure-measuring devices shall be either pressure gauges or pressure transducers which are accurate within ± 2,0 % of the full-scale reading.

9.2.2.2 Gauge range

Pressure measurements shall be made between 25 % and 75 % of the full pressure range of the measuring device.

9.2.2.3 Calibration procedure

Pressure-measuring devices shall be periodically recalibrated with a master pressure-measuring device or a deadweight tester at 25 %, 50 %, 75 % and 100 % of the full pressure scale.07

9.2.3 Temperature measuring devices

Devices for measuring temperature, if required, shall be capable of indicating and recording temperature fluctuations of 3 °C (5 °F).

9.3 Qualification of inspection and test personnel

9.3.1 NDE personnel

NDE personnel shall be qualified in accordance with ISO 9712.

Personnel performing visual examinations shall have passed an annual eye examination in accordance with ISO 9712.

9.3.2 Welding inspectors

Personnel performing visual inspection of welding operations and completed welds shall be qualified and certified to the requirements of the AWS QC1, or the manufacturer’s(such as China ball valve supplier) documented training programme.

9.4  NDE

The extent, method and acceptance criteria for NDE shall be in accordance with annex E, which specifies two levels of NDE requirements (QL1 and QL2) to assist the purchaser with the selection of a set of requirements appropriate for the intended valve duty. The extent of NDE for QL2 is more stringent than for QL1. The purchaser shall specify the NDE level considering the following risk-of-failure factors: service fluid; size/pressure/temperature;location; material of construction; criticality and function.

All NDE of weldments shall be carried out in the final heat-treated condition and shall be performed in accordance with written procedures.

NDE of repair welding

After defect removal, the excavated area shall be examined by MT or PT methods prior to starting repair welding.Repair welds on pressure-containing parts shall be examined using MT or PT methods. Acceptance criteria shall be specified in documented procedures.The NDE requirements in annex E, if specified by the purchaser, shall also apply to repair welding.

By Kevin Tsai from Relia Valve-China API valve supplier and DIN Valve Supplier.

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08. January 2015 · Comments Off · Categories: API 6DSS

Testing Specification in API 6DSS

10.1 General

Each valve shall be tested in accordance with this clause prior to shipment. The purchaser shall specify which particular supplementary tests in annex C shall be performed, together with the frequency of testing.

Tests shall be performed in the sequence used in this clause for specifying the test requirements. Shell pressure tests shall be carried out before painting of the valves (such as China ball valve).

 Test fluids shall be fresh water which may contain a corrosion inhibitor and, by agreement, antifreeze. The chloride content of test water for austenitic and ferritic-austenitic (duplex) stainless steel body/bonnet valves shall not exceed 30 µg/g (30 ppm). Valves for gas service shall also be subjected to a gas test in accordance with C.4.

 Valves shall be tested with the obturator or seat faces free from sealant and lubricant. A light lubricant, of maximum viscosity SAE 10W, may be used to aid assembly of other components.

Tests specified with the valve half-open may also be performed with the valve fully open provided the body cavity is simultaneously filled and pressurized through a cavity connection.

Methods for monitoring pressures and/or leakage shall be provided when valve body connections are not available for direct monitoring.

An adequate stabilization period shall be allowed for all pressure tests. After stabilization, the pressure source shall be isolated from the valve.

A chart recorder shall be used for all pressure tests above 1 MPa (10 bar).

Pressure tests shall be performed in accordance with documented procedures.

Valves (from China gate valve supplier etc. shall be drained of test fluids and, where applicable, lubricated before shipment.

 10.2 Hydrostatic shell test

Perform hydrostatic shell testing on the fully assembled valve, including pipe pups if applicable, prior to painting.

Close off valve ends and place the obturator in the partially opened position during the test. The method of closing

the ends shall permit the transmission of the full-pressure force acting on the end blanks to the valve body, unless otherwise agreed. If present, remove external relief valves and plug their connections.

The test pressure shall be 1,5 or more times the pressure rating determined in accordance with 6.2 for materials at 38 °C (100 °F). The duration shall not be less than that specified in Table 8.

DN 50 to 100 ( NPS 2 to 4)  Test duration: 2h

DN 150 to 250  ( NPS 6 to 10)  Test duration: 4h

DN 300 and bigger (NPS 12 and bigger)  Test duration: 6h

 No visible leakage is permitted during the hydrostatic shell test. There shall be no variation in pressure that cannot be accounted for by temperature fluctuations.

If the pressure rating of the pipe pups is insufficient for the hydrostatic shell test pressure, then the pups shall be welded to the valve following the valve shell test and the valve and pup(s) tested at a pressure to be specified by the purchaser.

 Pressure protectors or caps shall be tested at a pressure no less than the hydrostatic shell test pressure. The test duration shall be a minimum of 2 h.

10.3 Operational/functional test

10.3.1 Manual valves

Operate each manual or ROV-operated valve, excluding check valves (made by China wafer check valve supplier), two times while subjecting to the differential pressure specified in 6.8. Operate the valve for each appropriate condition defined in 10.4. Valves requiring input forces exceeding that specified in 6.12 or that fail to seal after operation shall be rejected.

 10.3.2 Power-operated/actuated valves

 Operate power-operated/actuated valves, excluding check valves, two times while subjecting to the differential pressure specified in 6.8. Operate the valve for each appropriate condition defined in 10.4 and measure the thrust or torque. Values for thrust or torque shall not exceed the predicted manual or power values specified in 6.19.1.

 10.3.3 Check valves

Operate each check valve fitted with an operating mechanism close-open-close five times while the entire body cavity is subjected to the rated pressure listed in 6.2. Valves that fail to operate or fail to seal after cycling shall be rejected.

10.3.4 Sequence of testing

Operational/functional tests may be performed in conjunction with hydrostatic seat testing specified in 10.4. Seat sealing integrity shall be verified after all operational/functional testing.

10.4 Hydrostatic seat test

10.4.1 Preparation

Remove lubricants from seats and obturator sealing surfaces, unless otherwise agreed.

10.4.2 Test pressure and duration

The test pressure for all seat tests shall not be less than 1,1 times the pressure rating as determined in accordance with 6.2 for material at 38 °C (100 °F). The test duration shall be in accordance with Table 9.

DN 50 to 100 ( NPS 2 to 4)  Test duration: 5 minutes

DN1 50 to 150 ( NP6 and bigger)  Test duration: 15 minutes

10.4.3 Acceptance criteria

Leakage for soft-seated valves from China valve supplier shall not exceed ISO 5208 Rate A (no visible leakage). For metal-seated valves the leakage rate shall not exceed ISO 5208 Rate D, except that the leakage rate during the seat test in 10.4.4.5.2 shall not be more than two times ISO 5208 Rate D. Other leakage rates shall be by agreement. The test procedures for various types of block valves are given in 10.4.4.

10.4.4 Test procedures for block valves

10.4.4.1  Uni-directional valve

With the valve half open, completely fill the valve and its cavity with test fluid. Then close the valve and apply test pressure to the appropriate end of the valve.

Monitor leakage from each seat via the valve body cavity vent or drain connection, where provided. For valves without body cavity or drain connection, or downstream seated valves, monitor seat leakage at the respective downstream end of the valve (the valve end downstream of the pressurized test fluid).

10.4.4.2 Bi-directional valve

With the valve half-open, completely fill the valve and its cavity with test fluid. Then close the valve and apply test pressure successively to both ends of the valve.

Monitor seat leakage from each seat via the valve body cavity vent or drain connection, where provided. For valves without body cavity vent or drain connection, monitor seat leakage from the respective downstream end of the valve.

10.4.4.3 Twin-seat valve (such as China trunnion mounted ball valve), both seats bi-directional, test each seat in both directions.

Remove cavity relief valves, if fitted. Fill the valve and cavity with test fluid, with the valve half-open, until the test fluid overflows through the cavity relief connection.

To test for seat leakage in the direction of the cavity, close the valve. Apply the test pressure successively to each valve end to test each seat separately from the upstream side. Monitor leakage via the valve cavity pressure relief, body cavity drain or vent connection.

Thereafter, test each seat as a downstream seat. Drain both ends of the valve and fill the valve cavity with test fluid. Apply pressure while monitoring leakage through each seat at both ends of the valve.

10.4.4.4 Twin-seat valve, one seat uni-directional and one seat bi-directional

10.4.4.4.1 Uni-directional seat

With the valve half-open, fill the valve and the test cavity completely with test fluid until fluid overflows through the valve cavity vent connection. Then close the valve and open the vent valve on the test closure to allow fluid to overflow, or remove the test closure on the downstream end of the valve. Then apply the test pressure to the upstream end (uni-directional seat end) and monitor leakage from the cavity connection. If leakage is also occurring through the downstream seat, take the upstream seat leakage as the sum of the leakage measured from the cavity and the downstream connections.

10.4.4.4.2 Bi-directional seat

Repeat the test in 10.4.4.4.1 to test the bi-directional seat in its upstream-sealing direction.

 To test the bi-directional seat in its downstream-sealing direction, blank off both ends of the valve. With the valve half-open, completely fill the valve with test fluid and pressurize to the test pressure. Then close the valve and allow test fluid to overflow from a connection on the test closure fitted to the end of the valve at the bidirectional seat end (i.e. downstream of the bi-directional seat). Maintain the test pressure on the cavity connection while monitoring seat leakage of the bi-directional seat at the overflow connection on the downstream test closure.

 10.4.4.5 Double-block-and-bleed valves

 10.4.4.5.1 Single-seat test

With the valve half-open, completely fill the valve and its cavity with test fluid. Then close the valve and open the valve body vent valve to allow excess test fluid to overflow from the valve cavity test connection. Then apply the test pressure to one end of the valve and release the pressure at the other end. Repeat this test for the other valve end.

Monitor seat tightness during each test via overflow from the valve cavity connection.

10.4.4.5.2 Double-block seat test

With the valve half open, completely fill the valve and its cavity. Then close the valve and open the valve body vent valve to allow excess test fluid to overflow from the valve cavity test connection. Apply the test pressure simultaneously from both valve ends.

Monitor seat tightness via overflow through the valve cavity connection.

The tests in 10.4.4.5 may be performed in any order by the manufacturer.

10.4.4.6 Check valves (such as China cast steel check valve)

Apply the pressure in the direction of the required flow blockage.

10.4.4.7 Installation of body connections after testing

On completion of the testing, fit pressure-containing parts, such as vent or drain plugs and cavity relief valves, in accordance with documented procedures.

10.5 Cavity relief test

 10.5.1 General

If a body cavity relief test is specified by the purchaser, each valve shall be tested in the closed position. If the cavity over-pressure protection in both open and closed position is achieved by a hole in the obturator, or a hole around a seat seal, cavity testing is not required.

10.5.2 Closed position test

Fill the valve in the half-open position with water. Close the valve and allow water to overflow from the test connection at each end of the valve. Apply pressure to the valve cavity until one seat relieves the cavity pressure into the valve end, noting the pressure at which the cavity relieved. Close the test connection at this end, and continue to apply pressure to the cavity until the second seat relieves, noting the relieving pressure. Failure to relieve at a cavity pressure between 0,1 and 0,33 times the valve pressure rating as determined in accordance with 6.2 for material at 38 °C (100°F) is cause for rejection.

NOTEThe second seat relief is not possible with certain valve types (e.g. gate valves and ball valves where one seat is bi-directional).

10.6 Pneumatic seat test

10.6.1 General

The seat test in 10.4 shall be repeated at a test pressure of (550 ± 50) kPa [(5,5 ± 0,5) bar]. The test medium shall be air or nitrogen. For soft-seated valves, the leakage rate shall not exceed ISO 5208 Rate A (no visible leakage).

For metal-seated valves (such as China metal seated ball valve, the leakage rate shall not exceed ISO 5208 Rate D.

The valve shall be drained of test fluid prior to the start of the pneumatic seat test.

 10.6.2 Test duration

The seat test duration shall be as specified in Table 9.

By Kevin Tsai from Relia Valve-China DIN valve supplier and API valve supplier.

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07. January 2015 · Comments Off · Categories: API 6DSS

Valve Marking Specification in API 6DSS

Valves shall be marked in accordance with Table 10.

All markings on body, bonnet/cover or end connections shall be low-stress steel stamped or cast.

On valves (from China wafer valve supplier) whose size or shape limits the body markings, they may be omitted in the following order:

 size;

rating;

material;

valve manufacturer’s name or trademark.

For valves with one seat uni-directional and one seat bi-directional only, the sealing directions of both seats shall

be specified on a separate identification plate as illustrated in Figure 13. In Figure 13, one symbol indicates the

bi-directional seat and the other symbol indicates the uni-directional seat.

Figure 13 — Typical identification plate for valve with one seat uni-directional and one seat bi-directional Marking

1) Manufacturer’s name or trademark … On both body and nameplate

2) Pressure class…On both body and nameplate

3) Maximum water depth…On nameplate

4) Pressure/temperature rating…On nameplate

a) Maximum operating pressure at the maximum operating temperature

b) Maximum operating pressure at the minimum operating temperature

5) Face-to-face/end-to-end dimensions (6.6)…. On nameplate

6) Body material designation a:

Material symbol, e.g. ISO, ASME or ASTM….. On both body and nameplate. Melt identification (e.g. cast or heat number) on nameplate only.

7) Bonnet/cover material designation:

Material symbol, e.g. ISO, ASME or ASTM ……On bonnet/cover [including melt identification (e.g. heat number)

8) Trim identification b: closure members, if different from that of body……On nameplate

forged steel ball valves

9) Norminal valve size.

a)  Full-opening valves: nominal valve size

b)  Reduced-opening valves: shall be marked as specified in 6.5….. On body or nameplate or both (where practicable)

10) Ring joint groove number.. on valvee flange edge (from China ball valve supplier)

11) MYS and minimum wall thickness…..on body weld bevel ends

12) Flow direction (for check valves only)…on body of uni-directional valves only

13) Seat sealing direction…separate identification plate on valve body

14) Unique serial number…On both body and nameplate,  date of manufacture (month and year).

15) API 6DSS.. on nameplate

16) API 6DSS .. . on nameplate

a) When the body is fabricated of more than one type of steel, the end connection material governs marking.

b) MSS SP-25 gives guidance for marking.

By Kevin Tsai from Relia Valve- Professional China API Valve Supplier and  China DIN Valve Supplier

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05. January 2015 · Comments Off · Categories: API 6DSS

Storing and Shipping & Documents in API 6DSS

12 Storing and shipping

12.1 Painting

Painting requirements shall be by agreement. Non-corrosion-resistant valves shall be blast-cleaned, primed and/or painted externally in accordance with a procedure approved by the purchaser prior to shipment.

Stainless steel valves (supplied by China valve supplier etc.)shall be blast-cleaned with sand or other non-ferrous medium prior to shipment.

Flange faces, weld bevel ends, exposed stems, shafts and sealant injection fittings shall be protected during blast cleaning and shall not be painted.

12.2 Corrosion prevention

Prior to shipment, parts and equipment which have bare metallic surfaces, shall be protected with a rust preventive which will provide protection at temperatures up to 50 °C (122 °F).

12.3 Protection

Valve flanged ends and welding ends shall be blanked off to protect the gasket surfaces, welding ends and valve internals during shipment and storage. Protective covers shall be made of wood, wood fibre, plastic or metal and shall be securely attached to the valve ends by bolting, steel straps, steel clips or suitable friction-locking devices.

The design of the covers shall prevent the valves from being installed unless the covers have been removed.

 Ball and gate valves (from China gate valve etc.) shall be shipped in the fully open position, unless fitted with a fail-to-close actuator.

Check valves shall be shipped with the disc supported or secured during transit.

13 Documentation

The documentation for valves shall include

design documentation,

WPS,

PQR,

WQR,qualification records of NDE personnel, records of test equipment calibration, melt identification certificates for body, bonnet, covers and end connectors traceable to the unique valve serial number, serial number for tracing the valve bill of materials, test results (pressure, torque, thrust, etc.).

Documentation to be supplied with each valve shall include certification of conformance to this International Standard, test report (including pressure, test duration, leakage rate, ROV input torque/thrust and test medium) including test charts, painting and/or plating certification, material certification for pressure-containing and pressure-controlling parts, statement of Quality Level applied to NDE records, certificate stating the maximum allowable torque/thrust value for the drive train (China ball  valve supplier and gate valves only).

Documentation shall be provided by the manufacturer in legible, retrievable and reproducible form, and free of damage.

Documentation required by this International Standard shall be retained by the manufacturer for a minimum of five years. following the date of manufacture.

The purchaser shall specify which, if any, particular supplementary documentation requirements in annex D shall be provided.

By Kevin Tsai from Relia Valve- Professional China API Valve Supplier and China DIN Valve Supplier

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 Annex A in API 6DSS - Purchasing Guidelines

A.1 General

This annex provides guidelines to assist the purchaser with valve selection and specification.

 A.2 Field testing

Pressures during the testing of installed valves should not exceed the pressure rating of the valve by more than 50 % when testing with the valve (from China ball valve supplier) partially open or by more than 10 % of the pressure rating when testing against a closed valve.

 A.3 Pigging

The purchaser should examine the valve design for compatibility with pigging operations when ordering valves for use in pipelines requiring pigging.

NOTE 1  Reduced-bore valves may not be suitable for pigging operations.

 NOTE 2A valve in which the drive member or the obturator obstructs the bore in the otherwise fully open position (e.g. dual- plate check valves) is not piggable. Certain full-opening valves with pockets may allow bypass of fluid around a short pig or sphere.

A.4 Valve operator compatibility

The design of the complete valve and actuator/operator unit should be the responsibility of the valve manufacturer.

This is to ensure the following:

compatibility of the mechanical interface between the valve (China wafer check valve etc.) and the actuator/operator; matching of the actuator/operator output to the valve force/torque (including any factor of safety required or specified by the purchaser); functional testing of the combined valve and actuator/operator assembly.

A.5 Valve data sheet

The valve data sheet in this annex should be used to assist with the specification of valves for ordering.

 Specification requirements

Materials of construction

Location and function

Nominal size

Maximum water depth

Maximum operating pressure

Maximum field test pressure (see A.2)

Pressure class

Design temperature

Maximum service temperature

Minimum service temperature

Liquid or gas service

Flow medium composition

Special flow requirements: blowdown, solids, pigs, etc.

Corrosive conditions

 Valve

Type: Gate Valve, Ball Valve(such as China trunnion ball valve), Check Valve

Full-round opening required?

Minimum bore

End connections

Upstream pipe: OD____ID___Material ___

Pipe pup length

Flanged end? Yes_________No______

               Plain raised face or ring joint

               If ring joint, flat or raised face?

Size and pressure class, as per ASME B16.5 or MSS SP-44 or ASME B16.47, Series A

Ring gasket or other gasket type and size

Note: Gaskets are not furnished as a part of the valve.

Welding end? Yes___No___

Attach specifications for welding end configuration.

Special flanges and mechanical joints?

Downstream pipe: OD_____ID_____Material

Pipe pup length _____________________________

Flanged end? Yes___________No______________

               Plain raised face or ring joint?

               If ring joint, flat or raised face?

Size and pressure class, as per ASME B16.5______ or MSS SP-44_________or ASME B16.47, Series A ___________

Ring gasket or other gasket type and size

Note: Gaskets are not furnished as a part of the valve

Welding end? Yes___________No______________

Attach specifications for welding end configuration.

Special flanges and mechanical joints?

Length: Any special requirements for end-to-end or face-to-face dimension?

Valve operation

Is valve (from China valve supplier) actuated? If so, state manual or ROV operated

Is gearbox with handwheel required? If so, give details_____

For a handwheel on a horizontal shaft, the distance from the centreline of the valve opening to the handwheel: ___ mm

Or, for a handwheel on a vertical shaft, the distance from the centreline of the valve opening to the centre of the rim of the handwheel ___ mm

Wrench required?

Locking device required?___ Type ____

ROV interface required?Type___Class_____Horizontal___Vertical ___

By Kevin Tsai from Relia Valve- Professional China API Valve Supplier and China DIN Valve Supplier

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Annex G  in API 6DSS - API Regional Annex

G.1 Technical Modifications to ISO 14723

The API Subcommittee 6, that voted to adopt ISO 14723 as American National Standard 6DSS, determined that the following modifications were necessary.

These technical deviations have been noted with an arrow ( ) adjacent to the clause, table, figure, etc. that has

been modified. Errata items identified in the original ISO standard are also included in this Annex and have been noted in the text with an arrow ( ) adjacent to the clause, table, figure, etc. that contained the error.

Modifications to ISO 14723 made during its adoption as an American National Standard:

Clause /Subclause   Modification

 1    Replace “ball, check and gate valves” with “ball, check, gate and plug valves”

 2   Replace reference document “NACE MR0175” with “NACE MR0175/ISO 15156 (all parts), Petroleum and natural gas industries – Materials for use in H2S-containing environments in oil and gas production”

Add reference document “ASNT Recommended Practice SNT-TC-1A, Personnel qualifications and certification in non destructive testing”

3.10   Replace text as follows: “valve  with an unobstructed opening, not smaller than the internal bore of the end connections.”

4.2    Replace Abbreviations as follows:

HBWBrinell hardness (with tungsten ball)

HRCRockwell “C” scale hardness”

Replace “WQR” with “WPQ Welder performance qualification”

 5.1   Add, after 5.1.3:

“5.1.4 Plug valves (from China valve supplier)

Typical configurations for plug valves with flanged and welding ends are shown in Figure 14 (see page 66).

Plug valves shall have a cylindrical or conical obturator which rotates about an axis perpendicular to the direction of flow.”

 After Figure 9   Add Figure 14 (Page 66)

6.2  Replace the 5th clause, page 20 with: “Allowable operating pressures and temperatures for valves made of materials not covered by ASME B16.34 shall be determined by calculations in accordance with an agreed valve or pressure vessel design standard.”

EXAMPLE ASME Section VIII, Division 1 or Division 2 or BS 5500

 6.5  Add “and Table 11 (on pages 67 – 70)” at the end of the first sentence

6.6  Add “and Table 11” after each occurrence of “Tables 2 to 5”

After Table 5   Add Table 11 (Pages 67 – 70)

6.17   Replace with the following: “Valves of size DN 200 (NPS 8) and larger shall be provided with lifting points, unless otherwise agreed. The manufacturer shall verify suitability of the lifting points and recommend the lifting procedure. Each lifting point shall have a safe working load at least equal to the valve weight and be so marked.

Large valve enterprises

If the valve manufacturer (such as China wafer check valve manufacturer) is responsible for the supply of the valve and operator assembly the valve manufacturer shall verify the suitability of the lifting points for the complete assembly.

 If the purchaser is responsible for the supply of the operator assembly, the purchaser shall provide adequate information to enable the manufacturer to verify the suitability of the lifting points for the complete assembly.

 Local requirements may specify special design, manufacturing, testing and certification of lifting points.”

6.18  Add the following to end of the third clause. “and appropriate sealing arrangement”

6.19.1  Replace last sentence of 1st clause to read as follows: “Factors greater than two times may be used by agreement.”

6.19.2  Add after the 40% of SMYS for shear stresses:

“50% of SMYS for torsional shear stress in solid round bar.”

6.22  Delete last clause entirely. “Soft-seated valves”

6.23  Replace the 2nd sentence with “If a hyperbaric testing is required to demonstrate suitability, testing shall be in accordance C.6.).”

7.1  Replace “chemical properties” with “chemical composition”

7.3  Replace entire text as follows: “Each forging shall be hot worked and heat treated sufficiently to produce uniform grain size and mechanical properties in the finished product.”

7.6  Replace entire clause as follows:

“Bolting shall be suitable for the specified valve service and pressure rating.”

Bolting material with a hardness exceeding HRC 34 (HBW 320) shall not be used for valve applications where hydrogen embrittlement can occur, unless otherwise agreed. Bolting materials which may contact sour process fluids shall meet the requirements of NACE MR 0175/ ISO 15156.

Note: Hydrogen embrittlement can occur in pipelines with cathodic protection.”

7.7.1  Replace text to read as follows:

“…meet the requirements of NACE MR 0175/ ISO 15156…”

Add the following at end of clause. “NOTE The purchaser should provide the partial pressure of H2S, chlorides, PH and temperature as a minimum.”

8.3 Replace text to read as follows:

“Hardness testing shall be carried out for the qualification of procedures for welding on pressure-containing and pressure-controlling parts in valves required to meet NACE MR 0175/ ISO 15156.

Hardness surveys shall be performed in accordance with NACE MR 0175/ ISO 15156.

Note For existing qualification other hardness measurements methods are acceptable by agreement.”

9.2.2.3  Delete “100 %” from this clause.

9.3.1  Replace text to read as follows:

“NDE personnel shall be qualified in accordance with ASNT Recommended Practice SNT-TC-1A per the requirements of the ASNT Central Certification Program or ISO 9712.

Personnel performing visual examinations shall have passed an annual eye examination in accordance with ASNT Recommended Practice SNT-TC-1A per the requirements of the ASNT Central Certification Program or ISO 9712.”

10.3.1  Replace title as follows: “Manual/ROV valves”

Table 10  Replace “nameplate” in second sentence of Item 6, Location, with “body”

13  Replace “WQR” with “WPQ”

Annex A, Valve data sheet, Other requirements

 Replace “NACE MR0175” with “NACE MR0715/ISO 15156” Add “If yes, provide the

partial pressure of H2S, chlorides, PH and temperature as a minimum.”

Annex C.6

Replace title and text as follows:

“C.6 Hyperbaric qualification testing

A minimum of one valve (such as China ball valve supplier) of each type, size and pressure class shall be subject to a hyperbaric test at a minimum pressure equal to 1.1 times the design water depth, in accordance with written procedures. The agreed test method should simulate the valves operational requirements, except for check valves, and should include both static and functional tests as appropriate,. The use of test fixtures is also allowed, by agreement,

when circumstances dictate, for example, when large assemblies make full testing impractical or when specific seal arrangements are involved.” (also delete existing NOTE)

 Annex E, Table E.1

Replace “VT1” and “MT2 or PT2” in Column QL1, “Cast,” Part “Stem or Shaft,” with “N/A”

Replace “VT1,” “UT1,” “MT1 or PT1” and “MT2 or PT2” in Column QL2, “Cast,” Part “Stem or Shaft,” with “N/A”

By Kevin Tsai from Relia Valve- Professional China API Valve Supplier and China DIN Valve Supplier

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