dgs ie 003 r0 control valve

ABU DHABI OIL REFINING COMPANY DOCUMENT NUMBER: DGS-IE-003

Rev: 0 Date: March 2006

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TAKREER DESIGN GENERAL SPECIFICATION (DGS)

CONTROL VALVE

REVIEWED REV DATE DESCRIPTION BY

ENDORSED APPROVED

0 MAR 2006 Base Reference – Project 5601

DGS-IE-003



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TABLE OF CONTENTS

1.0 GENERAL ...............................................................................................................................................3 1.1 INTRODUCTION .........................................................................................................................3 1.2 PURPOSE......................................................................................................................................3 1.3 DEFINITIONS...............................................................................................................................3

2.0 CODES AND STANDARDS...................................................................................................................4 3.0 REFERENCE DOCUMENTS .................................................................................................................6 4.0 DOCUMENT PRECEDENCE ................................................................................................................7 5.0 SPECIFICATION DEVIATION/CONCESSION CONTROL ................................................................7 6.0 QUALITY ASSURANCE/CONTROL....................................................................................................7 7.0 DOCUMENTATION ...............................................................................................................................8 8.0 SUBCONTRACTORS/SUBVENDORS .................................................................................................8 9.0 HANDLING.............................................................................................................................................9 10.0 DESIGN .............................................................................................................................................9

10.1 TYPES OF CONTROL VALVES AND THEIR APPLICATION .................................................9 10.2 REQUISITIONING .....................................................................................................................14 10.3 SPECIAL DESIGNS....................................................................................................................15 10.4 BODY CONSTRUCTION AND MATERIALS..........................................................................16 10.5 VALVE TRIM AND SEAT RING ...............................................................................................20 10.6 CONTROL VALVES FOR SPECIAL APPLICATIONS.............................................................21 10.7 CONTROL VALVE ACTUATOR ...............................................................................................23 10.8 ACCESSORIES...........................................................................................................................26 10.9 BYPASS MANIFOLDS (Around Control Valves) ......................................................................32 10.10 ON/OFF VALVES AND ACTUATOR ........................................................................................33

11.0 EMERGENCY DEPRESSURIZING VALVES.....................................................................................33 12.0 PAINTING ...........................................................................................................................................33 13.0 VALVE IDENTIFICATION...................................................................................................................34 14.0 TESTS ...........................................................................................................................................35

14.1 GENERAL...................................................................................................................................35 14.2 DIMENSIONAL AND FLANGE FACE FINISH CHECK ........................................................36 14.3 HYDROSTATIC TEST................................................................................................................36 14.4 SEAT LEAKAGE TEST..............................................................................................................36 14.5 PERFORMANCE AND MECHANICAL OPERATION TEST..................................................37 14.6 CAPACITY TEST........................................................................................................................37 14.7 LOW TEMPERATURE TEST ....................................................................................................38 14.8 VACUUM TEST..........................................................................................................................38

15.0 MATERIALS INSPECTION AND CERTIFICATION .........................................................................38 16.0 DOCUMENTATION .............................................................................................................................38



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1.0 GENERAL

1.1 INTRODUCTION

This specification gives the minimum requirements for the selection and specification of control valves (and their actuators) for throttling and on-off services. This includes the requirements for the design, construction, functioning and testing of control valves.

Methods of sizing control valves are excluded from the scope of this specification and are covered by ISA Standard, S75.01.

1.2 PURPOSE

This specification establishes minimum technical requirements for Control Valves. Control valves shall be used in refinery and chemical plants for the modulation and control of fluids and vapors in piping and in vessels.

1.3 DEFINITIONS

For the purposes of this specification, the following definitions shall apply:

BLOWDOWN — Opening of a valve in order to reduce the pressure in process equipment at a controlled rate.

CAVITATION — Liquids only, occurs when the pressure in the valve body falls below the liquid vapor pressure. The bubbles thus formed implode immediately, or shortly after leaving the valve, owing to the fact that the downstream pressure of the control valve recovers to rise above the liquid vapor pressure.

CHARACTERISTICS — Control valve travel versus flow changes.

CONCESSION REQUEST — A deviation requested by the CONTRACTOR or VENDOR, usually after receiving the contract package or purchase order. Often, it refers to an authorization to use, repair, recondition, reclaim, or release materials, components or equipment already in progress or completely manufactured, but which does not meet or comply with COMPANY requirements. A CONCESSION REQUEST is subject to COMPANY/PMT approval.

CONTROL VALVE — A power operated device forming a final element in a process control system. It consists of a body subassembly containing integral means for changing the flow rate of the fluid. The body subassembly is linked to one or more actuators which respond to a signal transmitted from a controlling element.

Cv — Is defined as the quantity of water, at 60°F (15.5°C), in US gallons per minute, that will flow through the control valve at a specified travel with a pressure drop of 1 lbf/in2 (0.07 kg/cm2).

DEPRESSURIZING — Reducing the pressure in process equipment at a controlled rate in emergency conditions or for operational purposes.

EMERGENCY SHUTOFF/SHUTDOWN — Shutting off a fluid flow in an emergency condition, when required e.g. a safeguarding system.



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EQUAL PERCENTAGE CHARACTERISTICS — Is a characteristic for which equal increments of relative travel yield equal percentage changes of the relative flow coefficient.

FLOW COEFFICIENT — The flow capacity of a control valve, commonly expressed by the Cv-factor.

LINEAR CHARACTERISTICS — Is a characteristic for which equal increments of relative travel yield equal changes of the relative flow coefficient.

ON-OFF — Changing to an open, closed or predetermined state when required, for example, by a sequence control system.

P&IDs — Process and Instrumentation Diagrams.

PIPING CLASS — A collection of piping components, suitable for a defined service and design limits in a piping system. Piping classes are compiled in Project Specification DGS-PU-003.

RATED TRAVEL — The displacement of the closure member, from the closed position to the designated full opening.

SHALL — Indicates a mandatory requirement.

SHOULD — Indicates a strong recommendation.

STROKING TIME — The time required to move the valve over the full operational range in response to the command signal. For on-off commands, which includes safeguarding actions, the stroking time should be taken as the time to travel from 100% (fully open) to 0% (fully closed) valve travel or vice versa. For manipulating commands, the stroking time should be taken as the time for the valve to travel from 0% to 95% or from 100% to 5% in response to a control signal change from 0% to 100% or from 100% to 0%. Specifications for stroking time can be: minimum and/or maximum limitations; for valve opening and/or closing; for control signal changes and/or on-off safeguarding actions.

THROTTLING CONTROL — Continuously manipulating the stem/shaft of a control valve in order to obtain a desired process condition.

TSO — Tight Shutoff.

2.0 CODES AND STANDARDS

It shall be the VENDOR’S responsibility to be, or to become, knowledgeable of the requirements of the referenced Codes and Standards.

The following codes and standards shall, to the extent specified herein, form a part of this specification. The latest edition in force shall apply.

American National Standard Institute (ANSI):

ANSI/FCI 70.2 Standard for Control Valve Leakage Classification (Fluid Control Institute)



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American Petroleum Institute (API):

API 599 Specification for Steel Plug Valves

API 609 Butterfly Valves, Lug and Wafer Type. Face to Face Dimensions

API 2000 Venting of Atmospheric and Low Pressure Storage Tanks

American Society of Mechanical Engineers (ASME):

ASME/ANSI B 16.10 Flanged valve, Face to Face Dimensions

ASME/ANSI B16.34 Valves - Flanged, Threaded and Welded End

ASME Section VIII Boiler and Pressure Code, Div. I

American Society for Testing and Materials (ASTM):

ASTM G93-88 Standard Practice for Cleaning Methods for Material and Equipment Used in Oxygen Enriched Environment

International Society for Measurement and Control (ISA):

ISA 75.01 Flow Equations for Sizing of Control Valves

National Association of Corrosion Engineers (NACE):

NACE MR-01-75 Sour Service Piping Design and Materials

International Electrotechnical Commission (IEC):

IEC 60534 Industrial Process Control Valves

IEC 60534-1 Control Valve Terminology and General Considerations

IEC 60534-2-1 Flow Capacity, Sizing Equations for Incompressible Fluid Flow Under Installed Conditions (Control Valves)

IEC 60534-2-2 Flow Capacity, Sizing Equations for Compressible Fluid Flow Under Installed Conditions (Control Valves)

IEC 60534-2-3 Flow Capacity, Test Procedures (Control Valves)

IEC 60534-3-1 Face-To-Face Dimensions, for Flanged, Two-Way, Globe Type Control Valves

IEC 60534-3-2 Face-To-Face Dimensions for Flangeless Control Valves, Except Wafer Butterfly Valves

IEC 60534-4 Inspection and Routine Testing (Control Valves)



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IEC 60534-5

Marking (Control Valves)

IEC 60534-8 Noise Prediction Calculations (Control Valves)

IEC 60529 Degree Protection Provided by Enclosure (IP Code)

CENELEC:

EN 50014 General Requirements

EN 50018 Explosion Proof Protection (Ex d)

EN 50019 EN 50019 Increased Safety Protection (Ex e)

EN 50020 EN 50020 Intrinsic Safety Protection (Ex i)

International Organization for Standardization (ISO):

ISO 9001-2000 Quality Management System Requirements

ISO 9004-2000 Quality Management Guidelines for Performance Improvement System

ISO 9011 Guidelines for Quality and/or Environmental System Auditing

3.0 REFERENCE DOCUMENTS

Project Specifications:

DGS-IU-001 Instrumentation and Control

DGS-IU-009 Instrumentation for Depressuring Systems

DGS-MU-009 Equipment Noise Control

DGS-MU-013 Criticality Rating System

DGS-MU-014 Minimum Shop Inspection and Certification Requirements

DGS-MW-002 Welding, NDE and Prevention of Brittle Fracture of Piping

DGS-MW-006 Positive Material Identification (PMI) of Equipment and Piping

DGS-MX-001 Painting

DGS-PU-003 Technical Specification for Piping Systems

DGS-PU-016 Piping Material Purchase Specification



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4.0 DOCUMENT PRECEDENCE

The VENDOR shall notify the CONTRACTOR of any apparent conflict between this specification, the related data sheets, the Codes and Standards and any other specifications noted herein. Resolution and/or interpretation precedence shall be obtained from the CONTRACTOR in writing before proceeding with the design/manufacture.

In case of conflict, the order of precedence shall be stated in the AGREEMENT or other PROJECT documents as applicable.

5.0 SPECIFICATION DEVIATION/CONCESSION CONTROL

Any technical deviations to the Purchase Order and its attachments including, but not limited to, the Data Sheets and Narrative Specifications shall be sought by the VENDOR only through CONCESSION REQUEST format. CONCESSION REQUESTS require CONTRACTOR’S and COMPANY’S review/approval, prior to the proposed technical changes being implemented. Technical changes implemented prior to COMPANY approval are subject to rejection.

6.0 QUALITY ASSURANCE/CONTROL

The VENDOR shall have in effect at all times, a QA/QC program which clearly establishes the authority and responsibility of those responsible for the quality system. Persons performing quality functions shall have sufficient and well defined authority to enforce quality requirements that initiate, identify, recommend, and provide solutions to quality problems and verifies the effectiveness of the corrective action.

VENDOR’S proposed quality shall fully satisfy all the elements of ISO 9001 - 2000 and ISO 9004 - 2000. The quality system shall provide for the planned and systematic control of all quality-related activities performed during design.

A copy of the VENDOR’S QA/QC program shall be submitted to the CONTRACTOR with its quotation for CONTRACTOR’S review and concurrence prior to award. If VENDOR’S QA/QC program and facility, where the work is to be performed, is ISO 9001 certified, then only a copy of the VENDOR’S ISO 9001 certificate is required. In addition, if VENDOR’S facility is ISO certified, CONTRACTOR’S QA audit requirements will be waived in favor of ISO 9001 registrar audits, unless the CONTRACTOR’S trend analysis program indicates areas of concern.

The VENDOR shall identify in purchase documents to its SUBVENDORS all applicable QA/QC requirements imposed by the CONTRACTOR, and shall ensure compliance thereto. On request, VENDOR shall provide objective evidence of its QA/QC surveillance of its SUBVENDOR’S activities.

The VENDOR shall submit certified reports of production tests as soon as the tests are completed satisfactorily.

The COMPANY/CONTRACTOR reserves the right to inspect materials and workmanship at all stages of manufacture and to witness any or all tests. The VENDOR, 30 days after award, but prior to the pre-inspection meeting, shall provide the CONTRACTOR with a copy of its Manufacturing and Inspection Plan for review and inclusion of any mandatory COMPANY/CONTRACTOR witness points.



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The Criticality Rating (CR) System outlined in Project Specification DGS-MU-013 shall be used to develop the design checking levels and minimum requirements for shop inspection, testing and materials certification given in Specification DGS-MU-014.

7.0 DOCUMENTATION

The MANUFACTURER/VENDOR shall submit the type and quantity of drawings and documentation for CONTRACTORS authorization or information as listed in the individual Material Requisitions and Purchase Orders. Refer to Section 16.0 for a description of the minimum detailed design documentation that is required to be supplied by the VENDOR.

Mutual agreement on scheduled submittal of drawings and engineering data shall be an integral part of any formal Purchase Order.

Comments made by CONTRACTOR on drawing submittal shall not relieve VENDOR or SUBVENDORS of any responsibility in meeting the requirements of the specifications. Such comments shall not be construed as permission to deviate from requirements of the Purchase Order unless specific and mutual agreement is reached and confirmed in writing.

Each drawing shall be provided with a title block in the bottom right-hand corner incorporating the following information:

a. Official trade name of the VENDOR.

b. VENDOR’S drawing number.

c. Drawing title giving the description of contents whereby the drawing can be identified.

d. A symbol or letter indicating the latest issue or revision.

e. Purchase Order number and item tag numbers.

f. TAKREER Logo.

Revisions to drawing shall be identified with symbols adjacent to the alterations, a brief description in tabular form of each revision shall be given, and if applicable, the authority and date of the revision shall be listed. The term “Latest Revision” shall not be used.

8.0 SUBCONTRACTORS/SUBVENDORS

The VENDOR shall assume unit responsibility and overall guarantee for the control valves and associated equipment.

The VENDOR shall transmit all relevant Purchase Order documents including specifications to his SUBVENDORS and SUBCONTRACTORS.

It is the VENDOR'S responsibility to enforce all Purchase Order and Specification requirements on his SUBVENDORS and SUBCONTRACTORS.

The VENDOR shall submit all relevant SUBVENDOR and SUBCONTRACTOR drawings and engineering data to the CONTRACTOR.



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The VENDOR shall obtain and transmit all SUBVENDOR and SUBCONTRACTOR warranties to the CONTRACTOR/COMPANY, in addition to the system warranty.

9.0 HANDLING

Preparation for shipment shall be in accordance with the VENDOR'S standards and as noted herein. VENDOR shall be solely responsible for the adequacy of the preparation for shipment provisions with respect to materials and application, and to provide equipment at the destination in ex-works condition when handled by commercial carriers.

Adequate protection shall be provided to prevent mechanical damage and atmospheric corrosion in transit and at the jobsite.

Preparation for shipment and packing will be subject to inspection and rejection by COMPANY'S/CONTRACTOR'S inspectors. All costs occasioned by such rejection shall be to the account of the VENDOR.

After inspection and test, equipment shall be completely free of water and dry before start of preparation for shipment.

All equipment and material shall be preserved and export packed in accordance with Project Specification, DGS-MU-002, Preservation and Export Packing.

10.0 DESIGN

Control valves and accessories shall operate at a maximum ambient conditions for temperature of 58°C and humidity of 95%. Temperatures in the sun can reach 87°C.

10.1 TYPES OF CONTROL VALVES AND THEIR APPLICATION

10.1.1 General

Unless otherwise specified in the instrument data sheets or dictated by its application, the selection of a type of valve should be in the following order of preference:

a. Globe valve (linear motion) or rotary valve (eccentric plug or segmented ball)

b. Butterfly valve

c. Ball valve

d. Other types

Flanges shall be integrally cast type. No slip-on or weld-on flanges or wafer type valves shall be allowed, except as approved by the COMPANY.

Minimum flange rating shall be Class 300 for valve sizes 8 inch and under. Only 1 inch 1-1/2 inch, 2 inch, 3 inch, 4 inch, 6 inch, 8 inch, 10 inch, 12 inch, and higher sizes shall be used.

The materials and rating of a control valve shall be in accordance with the piping class. All identification and/or instruction plates on the valve, actuator and accessories shall be of stainless steel and be attached with screws or rivets.



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Cadmium plating or galvanizing shall not be used for any component of the control valve assembly or its accessories.

10.1.2 Sizing

The calculated Cv value shall be in accordance with ISA S75.01, Flow Equations for Sizing Control Valves or the selected VENDOR’S proprietary sizing program.

Control valves shall be sized for a minimum wide open capacity of 110 percent of maximum flow. The selected valve should normally be 60 to 80 percent open at normal flow. The selected valve shall be no less than 10 percent open at minimum flow, or shall be within the MANUFACTURER’S minimum throttling Cv recommendation.

Butterfly valves shall be sized for a maximum flow at 60 degree angular opening, except for a characterized vane valve (such as the “Fishtail”) which may be sized at 90 degrees angular opening. Three-way valves shall be sized to pass maximum flow through either port with minimum available pressure drop through the same port.

10.1.3 Noise

Valve noise limits and requirements are given in Project Specification DGS-MU-009, Equipment Noise Control. In general, the limit for noise generated by control valves shall be 85dBA or less, as measured at a distance of 1 meter from the valve for any flow condition.

Projected valve noise levels shall be calculated by the MANUFACTURER/ SUPPLIER per Project Specification DGS-MU-009.

If the calculated noise level of a standard control valve exceeds the allowable limit, a control valve with special low-noise internals (special valve trim, i.e. drag type or equal) should be selected. If, for technical or economic reasons, low noise valves are not practical, one or more of the following acoustic containment techniques may be applied if approved by the COMPANY (Note: no other methods shall be considered):

a. Add a diffuser or silencer, as applicable

b. Add acoustic insulation

c. Use heavier wall pipe

Where noise attenuation is achieved by using valves or diffusers with small flow passages, strainers will be used to avoid plugging these passages. Low noise restriction plate(s) downstream of the control valve should be avoided and shall only be applied if approved by the COMPANY.

For control valves with calculated noise levels higher than the allowed limit, the MANUFACTURER/SUPPLIER should quote on a standard version valve and a low noise valve. Both calculated noise levels shall be stated in the quotation.

Noise prediction calculation and testing shall be in accordance with IEC 60534-8 and Project Specification DGS-MU-009, Equipment Noise Control.

Control valve operation above 100 dBA for any time period shall be avoided.



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10.1.4 Control Valve Characteristic

The required control valve characteristic may be obtained through a characterized trim or through a characterized cam in the valve positioner.

Two main characteristics are commonly applied, i.e. the linear and equal percentage.

Selection of the control valve characteristic shall be done in accordance with ISA S75.01, Flow equations for sizing of control valves.

In any of the following cases, the control valve shall have a linear characteristic:

a. Level control in gravity service

b. Compressor antisurge control

c. Split range control (when split range is obtained in the DCS or other remote electronic system, the control valve may also have an equal percentage characteristic.)

d. Where, for increasing the rangeability, two control valves are applied in parallel

e. Control valves that are only operated via a manual control station

f. Minimum flow protection for pumps

Due to the unavailability of an equal percentage characteristic for the miniature type of control valve, these types of control valves may have a linear characteristic.

On-off and emergency shutoff valves should have a quick closing or equal percentage characteristic. Other characteristics may be required, such as modified equal percentage to avoid or reduce the consequences of pressure shock in the piping systems.

Control valves for throttling service, which have an undefined trim characteristic, shall be applied with a characterizing mechanism in the valve positioner for obtaining the required valve characteristic.

10.1.5 Globe Valves

Globe valves (linear motion, rotary/eccentric plug or rotary/segmented ball) shall be used for all services except where the allowable pressure drop is so low that a globe valve would not function.

Cage guided globe valves and balanced type valves, with the exception of double seated control valves, shall not be used on services with a tendency towards coking.

Cage guided globe valves shall not be used for fluids that contain solid particles.

Throttling globe valves should not be used if a Class V or Class VI shutoff is required (as per ANSI/FCI 70.2 or IEC 60534-4), as these shutoff classes cannot be maintained over a prolonged period. If a Class V or Class VI shutoff is required, a dedicated TSO valve (i.e. ball valve) should be installed in series with the control valve. As this is an expensive solution, the requirement for these shutoff classes should be examined with care.



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An exception is made for depressurizing valves where, for safety reasons, two valves in series shall not be applied.

10.1.6 Angle Valves

Angle valves should be considered for:

a. Hydrocarbon services, having a tendency of coking

b. Cavitation service

c. Erosive services, e.g. slurries

d. Steam service with excessive noise

e. Applications where solids contaminants might settle in the body of a standard globe valve

10.1.7 Butterfly Valves

Butterfly valves shall comply with the piping class, shall be flanged or lug type, and shall be considered for the following circumstances:

a. If the required size (usually due to high flow rate with a low pressure drop) would make it economically attractive or if it is impossible to apply globe valves.

b. For corrosive services, where body lining of globe valves becomes economically unattractive.

Special butterfly valves (known as “high performance butterfly valves”) are now available. These butterfly valves can handle high temperatures, high differential pressures and can have a Class V or Class VI shutoff class.

10.1.8 Ball Valves

Ball valves shall be considered for on-off service. Unless equipped with a special trim, i.e. anti-cavitation or low-noise design, care should be taken with the selection of ball valves for high differential pressures.

Ball valves supplied with an actuator for remote on-off operation, shall comply with the piping class. The type of actuator shall be as specified by the COMPANY.

Ball valves for use in erosive (e.g. slurry) service, etc. should be equipped with a scraper type of seat construction.

Ball valves in throttling service shall not be used without the approval of the COMPANY.

Fire safe ball valves shall have solid stainless steel balls i.e. not plated.

10.1.9 Diaphragm Valves

Diaphragm valves should only be considered for on/off applications in slurry service. The use of diaphragm valves requires the approval of the COMPANY.



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10.1.10 Plug Valves

Plug valves should be considered for special applications, such as throttling control in slurry service. The use of plug valves requires the approval of the COMPANY.

Plug valves shall be in accordance with API 599, Specification for steel plug valves.

10.1.11 Gate Valves

Gate valves should only be considered for remotely-operated on/off applications. They are normally equipped with an electric actuator and do not have a fail-safe action. Typical applications are storage tank isolating valves, remote operated on/off valves on blenders and emergency shutoff services on well heads in oil and gas production facilities.

Gate valves shall be in accordance with ANSI B16.10, Flanged valve, face to face dimensions.

10.1.12 Self-Acting Regulators

10.1.12.1 Self-Acting Pressure-Reducing Regulators:

Self-acting pressure-reducing regulators shall only be applied on simple applications, such as for reducing instrument supply pressure. For gas blanketing of storage tanks, pilots shall be used for self actuated valves and regulators.

Regulators in gas blanketing service shall be installed on the blanketing inlet connection of the relevant tank.

Special attention shall be given to the application of self-acting regulators, with internal, self-relieving capability. For details of tank blanketing, refer to API 2000, Venting of atmospheric and low pressure storage tanks.

10.1.12.2 Self-Acting Back-Pressure Regulators:

Self-acting back-pressure regulators shall only be considered for clean fluids in simple applications, such as for maintaining a uniform back pressure in utility (e.g. nitrogen) distribution systems.

The application of self-acting back-pressure regulators requires the approval of the COMPANY.

10.1.12.3 Self-Acting Differential-Pressure Regulators:

Self-acting differential-pressure regulators shall only be considered for clean fluids in simple applications, such as for secured instrument air systems or for compressor bearing sealing services.

Except for secured instrument air supply systems, the application of self-acting differential-pressure regulators requires the approval of the COMPANY.

10.1.12.4 Self-Acting Temperature Regulators:

Self-acting temperature regulators shall only be considered for simple, nonsafety-critical heating applications, where utilities (e.g. instrument air or gas) are not available.

The application of self-acting temperature regulators requires the approval of the COMPANY.



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10.1.13 Three-way Globe Valves

When selecting three-way globe valves, special attention shall be paid to the Cv sizing of each flow path of the valve.

Except for instrument air dryers, the application of the three-way globe valves requires the approval of the COMPANY.

10.1.14 Solenoid Valves

Other than applications in instrument air signal lines (10.8.9), solenoid valves may only be considered for on-off control in hydraulic utility services, such as the hydraulic control systems for loading arms, remotely operated valves and wellhead control units.

10.2 REQUISITIONING

The MANUFACTURER/VENDOR shall:

a. Check the calculation of the selected Cv-value for the given data;

b. Quote/supply a Cv-value for each valve in the fully open position;

c. Complete the attachments where requested;

d. Quote for control valves meeting the requirements of the relevant requisition;

e. Inform the purchaser of any irregularities found in the relevant requisition; and

f. Perform noise prediction calculations on all valves on all given process conditions.

The MANUFACTURER/VENDOR is responsible for the design and construction of the supplied control valve(s) for service(s) and condition(s) as specified in the requisition.

If a control valve is provided with an actuator and/or accessories from another source, but supplied as part of the control valve requisition, the responsibility of the overall valve assembly (valve complete with actuator and/or accessories) shall be as indicated on the requisition.

The responsible party shall ensure that the supplied control valves (and accessories, if part of the requisition) will have a trouble free operation without any maintenance for a period of 12 months after the valves have been put into operation, with a maximum of 18 months after delivery, unless otherwise demanded by local regulations.

All accessories shall be as specified on the site VENDOR list or the project specification VENDOR list, whichever applicable.

The variety of types and sizes of control valves and supplied related materials ordered under the requisition shall be minimized.

To enable process line cleaning, butt-welding-end control valves shall be supplied with a blind bonnet flange, together with bonnet gasket(s) sufficient for three changes. The blind bonnet flange shall be of carbon steel and have the same rating as the body. Alternative methods are subject to the approval of the COMPANY.



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10.3 SPECIAL DESIGNS

10.3.1 Anti Cavitation Valves

If cavitation is still unavoidable after proper selection of the control valve and its location, then hardened trim materials (Paragraph 10.5.3) should be applied (or, for single seated valves, a change in flow direction through the valve may already be sufficient). If a change in flow direction is not feasible and/or hardened trim materials are not adequate, valves with special anti-cavitation trims should be considered.

For applications where anti-cavitation trims are not available, an angle valve or two valves in series may also be considered, if approved by the COMPANY.

The applications of restriction orifices downstream of the control valve requires the approval of the COMPANY.

10.3.2 Steam Desuperheating Valves

Special control valves, with internal water injection for desuperheating purposes, may be used for high pressure steam reducing services. The make and type of steam conditioning valve is subject to the approval of the COMPANY.

10.3.3 Choke Valves

Choke valves are typically applied in oil and gas production facilities.

10.3.3.1 High Pressure Gas Choke Valves:

High pressure gas choke valves shall be able to withstand very high pressures, up to the maximum closed-in well pressure, and shall be capable of delivering the desired maximum and minimum flowrates at varying well pressures. The process fluid is wet gas, which makes the valve subject to erosion.

The following are the preferred minimum requirements for high pressure gas choke valves:

a. It should be possible to remove the internals of the valve, without disconnecting, readjusting or removing the actuator from the valve or the valve from the process line. Changing of internal parts should be possible by using only hand tools.

b. The body should be oversized, so as to limit the velocity and consequently the noise and the erosion. The additional space in the oversized valves may be combined with noise reducing inserts in the inlet and outlet of the valve.

c. The valve shall be TSO (i.e. class V or class VI in accordance with ANSI/FCI 70.2, standard for control valve leakage classification).

d. The plug and seat should be stellited.

10.3.3.2 Liquid Choke Valves:

For special applications, such as the draining of high pressure separators, a “liquid choke” valve should be considered.



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This valve shall be designed for liquids containing solid particles such as grit, sand, scale, etc.

The trim of the valve consists of two discs, one fixed in the valve body and one that can be rotated by the actuator. Each disc has one or more eccentric holes and throttling is created by rotating the upper disc in such a way that the holes partly overlap each other. A beam, provided downstream of the fixed disc, takes the major part of the pressure drop. The discs shall be lapped in order to give the valve its TSO feature. A built-in filter upstream of the rotating disc shall be fitted to protect the discs against large solid particles in the process fluid.

The following are the minimum requirements:

a. The valve shall be made up of a number of modular subassemblies, such as internals, bonnet, yoke, actuator, coupling, etc.

b. To replace any of the subassemblies, it shall not be necessary to remove the valve body from the process line.

c. The valve shall be TSO (i.e. class V or class VI in accordance with ANSI/FCI 70.2, standard for control valve leakage classification).

d. The discs and beam shall be made out of tungsten carbide.

10.4 BODY CONSTRUCTION AND MATERIALS

10.4.1 General

Control valves, other than wafer/wafer lug type butterfly valves (Paragraph 10.1.7) shall be provided with process flanges.

Split-body globe valves may only be applied with the approval of the COMPANY.

Control valve bodies shall not be fitted with bottom drain plugs. A bottom flange shall be provided for valves that require bottom access for trim removal.

Valve bonnets shall be of bolted construction with fully retained gaskets.

10.4.2 Body Size

The body size of a control valve in throttling service should have the same size as the calculated trim size, but oversized bodies may be required up to the size of the adjacent piping (e.g. to reduce the outlet velocity or to cater for future capacity increase).

Emergency shutoff valves shall be sized for the process conditions, and the pressure drop shall be kept to a minimum. If process conditions are not stated, the valve shall be line size.

The nominal sizes of control valve bodies should be selected from the following series:

• 1-inch

• 1-1/2-inch

• 2-inch



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• 4-inch

• 6-inch

• 8-inch

• 10-inch

• 12-inch and higher sizes

For application of body sizes smaller than 1-inch, use reduced size inner valve.

10.4.3 End Connection

The flange ANSI rating class shall be in accordance with the piping class unless otherwise specified.

The flange finish shall be smooth, 125-250 Ra, in accordance with Project Specification DGS-PU-003, Technical Specification for Piping Systems.

10.4.4 Face-to-Face Dimensions

The face-to-face dimensions of flanged globe-body control valves of body size 1-inch to 16-inch and ANSI rating class 150 (above 8 inch size), 300 and 600 shall be in accordance with ANSI B16-10.

The face-to-face dimensions of flangeless control valves shall be in accordance with IEC 534-3-2, face to face dimensions for flangeless control valves except wafer butterfly valves.

The face-to-face dimensions of lug and wafer type butterfly valves shall be in accordance with API 609, Butterfly Valves.

10.4.5 Materials

Carbon content of carbon and carbon-manganese steels shall not exceed 0.23%, except for forgings and castings, where this may be relaxed to 0.25%. For pressure containing components, the carbon equivalent shall not exceed 0.43%, as given by:

CE = %C + %Mn + %Cr + %Mo + %V + %Cu + %Ni 6 5 15

General material selection shall comply with Project Specification DGS-PU-003, Technical Specification for Piping Systems, for carbon steels pressure containing parts:

a. Specific approval of the COMPANY is required for use of types of steel with a specified minimum tensile strength exceeding 480N/mm2

b. No grade 70 materials shall be used

The material selection of the body (including bonnet and/or bottom flange), external bolts, studs and nuts, etc. shall be in accordance with the piping class. Valve bodies specified as 316 shall be 316L stainless steel minimum. Carbon, low alloy and stainless steel bodies shall be externally painted, per Paragraph 12.0.



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External, uninsulated bolts and nuts shall be shop coated with TAKECOAT-1000 from Takenada Seisakusho Co., Osaka, Japan, or equal. Insulated bolts shall also be coated if the service temperature is less than 200°C. All bolting installation requirements from the coating MANUFACTURER shall be followed in addition to installation requirements from other Project specifications.

Additional requirements for special applications are given in Paragraph 10.6.

10.4.5.2 Lining:

If approved by the COMPANY, internal lining may be used for protection against corrosion or erosion as an alternative to resistant base materials.

Internal lining of the fluid impact area with hardfacing may be required for:

a. Fluids containing erosive particle (slurries).

b. Ported plugs for wet gas or wet steam service with a pressure drop across the valve above 10 kg/cm2.

c. Other services if the pressure drop is above 40 kg/cm2.

Internal lining of the entire body with rubber, epoxy or other nonmetallic materials shall be considered for valves in sea water services.

10.4.5.3 Welding:

No welding is allowed on 316 stainless steel material. If welding is required in valve manufacture use 316L stainless steel.

10.4.6 Stuffing Box and Packing

10.4.6.1 General:

Packing materials should be:

a. PTFE-based for packing temperatures below 200°C

b. Graphite-based, metal-reinforced, for packing temperatures between 200°C and 600°C

Type B packing shall NOT contain asbestos.

External lubricators or grease nipples shall not apply, only where service conditions prohibit PTFE packing.

Depending upon the design of the valve, an extended bonnet may be required to keep the temperature at the stuffing box at an acceptable value for the applied packing.

An extended bonnet shall be used for temperatures below 0° and above 200°C.



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An extended bonnet may also be required if the operating differential pressure across the valve could otherwise cause freezing of the stuffing box/packing and/or ice formation on the trim. For example, this may be the case for compressor recycle (antisurge) valves.

For valves in cryogenic service that are intended for installation inside a “cold box”, an extended bonnet shall be applied for bringing the stuffing box outside the cold box. The minimum required length shall be specified on the requisition. The stuffing box shall be on top of the extended bonnet.

The stuffing box shall be provided with an adjustable, bolted gland flange and gland follower. The valve gland shall be properly adjusted by the valve MANUFACTURER. If, for technical reasons, the valves will be delivered with a loose gland, this shall be clearly indicated on the appropriate valve with a warning sign.

For valves in vacuum service, special attention should be paid to the type of stem packing/sealing facilities as well as to the stem surface finish. The packing box shall be suitable for vacuum service.

10.4.6.2 Bellows-Sealed Valves:

Bellows-sealed bonnets shall be applied for special applications involving toxic or hazardous service, or if specified by the Company.

The bellows for services which do not contain chlorides shall be of AISI 316 type stainless steel, unless otherwise specified in the requisition.

As an alternative to a bellows seal, special double packings with a leak-off connection between the sets or a special environmental packing may be applied if approved by the Company.

For bellows-sealed control valves an additional stuffing box with the appropriate packing material shall be included. For leak detection and venting purposes, the seal extension shall be provided with a screwed connection between the bellows seal and the packed gland.

Bellows-sealed bonnets shall not be applied above ANSI rating class 300 without the approval of the COMPANY.

To minimize fugitive emissions, the use of valves with a rotational spindle operation should be considered.

10.4.7 Gaskets

Body-to-bonnet and, if required, body-to-bottom flange gaskets shall be of the spiral wound type. Unless otherwise dictated by the process conditions, the gasket material shall be AISI 316 type stainless steel, graphite filled.

The filler material shall be expanded graphite with the following specifications:

a. Maximum 1% ash content

b. Maximum 50 mg/kg chloride content

c. Density range 0.7 to 1.8g/cm3

Other types of gasket require the approval of the COMPANY.



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10.4.8 Torque Figures

The torque figures for bolting the body/bonnet and body bottom connection shall be indicated in the relevant manuals by the MANUFACTURER/VENDOR.

10.5 VALVE TRIM AND SEAT RING

10.5.1 Seat Leakage and Flow Direction

Unless otherwise required, on-off and emergency shutoff valves should be specified and installed as “flow-tending-to-close”.

For throttling control applications with unbalanced valves, the direction should be “flow-tending-to-open” in order to avoid a very large unstable force in the nearly closed position. For angle valves, the direction should be “flow-tending-to-close” in order to avoid high velocity and turbulence in the valve body.

The requirements for TSO shall be properly specified on the requisition. The TSO direction (one or both directions) shall be as indicated on the relevant P&IDs and/or instrument data sheets.

Balanced-type single-seated control valves of the pilot operated type shall not be used as TSO valves.

For minimum requirements, reference is made to (Paragraph 10.14.4), Seat Leak Test.

10.5.2 Construction

10.5.2.1 Globe Valves and Angle Valves:

The trim and particularly the seat ring(s) shall be of the easy/quick replaceable type.

On butt-welded-end control valves, the entire assembly of trim and seat shall be removable from the top.

The clearances between the plug and guide bushings and, for cage type trims, the clearances between the plug and cage and guide bushings, shall be designed such that sticking cannot occur at minimum and maximum operating temperatures.

If specified by the COMPANY, the design shall also be suitable for services that can cause coking.

For trims which are not of the one-piece plug and stem type, the plug and stem construction shall be provided with a locking device to prevent accidental separation. The locking device may be either a special fluted pin, driven through a hole which is simultaneously drilled in the plug guide section and stem, or it may be of a welded construction.

The seat-ring(s) should be clamped or backed-up via a seat ring retainer. Special attention shall be paid to fixing of the seat ring in order to prevent loosening due to vibration. Adhesive compounds shall not be used for the locking of seat rings.

The connection of the valve stem to the actuator stem shall be adjustable and shall allow positive locking of the adjustment.



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If required, the valve stem part that is exposed to the surrounding atmosphere shall be completely covered by a protection bellows. This protection bellows shall be of a hydrocarbon and environment resistant material.

10.5.3 Materials

10.5.3.1 General Trim:

The control valve trim (consisting of plug, seat rings and stem) shall be corrosion resistant and of the grade specified in the requisition. Minimum requirement is 316 stainless steel.

For fluids that become corrosive when in contact with the atmosphere, i.e. sulfuric acid, suitable valve stem and trim materials shall be considered or precautions shall be taken to prevent contact with air.

Where soft (resilient) inserts are required for meeting the specified leakage rate, the inserts should be of glass-fiber-filled or graphite-filled PTFE; the selection shall be based on the suitability for the specified process conditions.

The resilient insert shall be properly clamped between metal parts and/or locked in position to prevent blowout in the closed position.

For globe valves, soft seats can deteriorate quickly and should be avoided as far as possible (Paragraph 10.1.5).

10.5.3.2 Hardened Trim:

Hardened (e.g. Stellite-coated or Colmonoy-coated) or solid Stellite closure member and seat rings shall be selected for the following applications:

a. Erosive services

b. Wet gas or steam service with a pressure drop greater than 5 kg/cm2

c. Other services in which the pressure drop is greater than 10 kg/cm2 at design conditions

NOTE: For choke valves and valves in other extremely erosive services, special materials like tungsten carbide and ceramics may be applied.

Angle valves for erosive services (e.g. choke valves) should be equipped with a chrome plated venturi seat ring, unless other materials are required for the process conditions.

10.6 CONTROL VALVES FOR SPECIAL APPLICATIONS

10.6.1 Oxygen Service

Only valves especially made for oxygen service and that have proved to be reliable in service shall be used.

Conform to ASTM GP3-88 for special cleaning (degreasing).



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Valves for oxygen service shall be clearly marked and shall be packed separately from other valves.

Valves for oxygen service shall generally have Monel bodies and trim. Other valve material shall be approved by the COMPANY.

10.6.1.1 Throttling valves may cause considerable turbulence. Therefore, in oxygen service carbon steel systems, a pipe section of 10 D length downstream of the throttling valve should be made of the material specified for higher velocities (usually the same material as the valve body). Only globe valves and needle valves (including angle and Y types) shall be used for throttling.

Control valves in oxygen service shall not have handwheels unless this is unavoidable.

10.6.1.2 Ball valves and gate valves shall be used as block valves only, but shall not be operated in the case of pressure differential. Hence they shall only be opened in the case of equal pressures on both sides of the valve or be closed if there is no oxygen flow.

An exception to the above may be made where a block valve is to be operated (closed) in the case of extreme emergency. Examples are a block valve at the entrance of a process plot, and a block valve upstream of a filter and/or measuring station.

Shutoff valves shall have monel trim.

Block valves with bodies of carbon steel shall only be used up to 10 kg/cm2.

10.6.1.3 Ball valves shall be of fire-safe design and have seals and seats of PTFE. The maximum temperature is 120°C. The volume of PTFE shall be as small as possible. Ball valves with all-metal seats can also be used above 120°C, provided the stem seal and trim seals are suitable.

Any sealant connections shall be left undrilled or be permanently plugged.

10.6.1.4 Automatic (solenoid-operated) shutoff valves shall be single-seated globe valves with trim especially ground for tight shutoff. In some cases — to be agreed upon between parties concerned — PTFE seat rings may be used when the temperature in the system is below 120°C.

10.6.1.5 All valves and instruments shall bear the warning:

“OXYGEN ! KEEP FREE FROM OIL AND GREASE!”

If lubrication would nevertheless be required, a fluorocarbon lubricant suitable for oxygen service may be used, provided this is agreed with the COMPANY.

10.6.2 Hydrofluoric Acid (HF) Service

Stress relieved Monel bellows seal shall be applied. All pressure-containing carbon steel welds shall be stress-relieved before bellows installation.

Viton shall be used as sealing/seating material.

The stem material shall be Hastelloy-C or Monel K500. All pressure-retaining steel bolting shall be ASTM A 193 B7M with ASTM A 194 2HM nuts.



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10.6.3 Sour Service

If sour service is specified in the requisition, NACE MR-01-75, Sour Service design and material shall apply to the valve (but not to the gaskets). Carbon steel flanges shall be normalized.

10.6.4 Low Temperature, Liquefied Gas and Lethal Services

Control valves in the following services:

a. Low-temperature service (below 15ºC)

b. Liquefied gas and LPG

c. Lethal service such as hydrofluoric acid (HF), chlorine and streams containing greater than 1000 ppm of H2S

Carbon steel body material shall meet A 352 LCB. See Specification DGS-MW-002, Welding, NDE and Prevention of Brittle Fracture of Piping.

10.7 CONTROL VALVE ACTUATOR

10.7.1 General

The actuator shall be suitable for instrument air, unless otherwise specified in the requisition.

The actuator shall function properly under the minimum, normal and maximum instrument air supply pressures as specified in the requisition.

The actual bench setting (spring range) shall be indicated on the valve tag plate.

Piston actuators shall be designed for a minimum instrument air pressure of 3.5 kg/cm2, unless otherwise required. Actuators requiring an instrument air supply pressure above 3.5 kg/cm2 shall not be used unless approved by the COMPANY.

Emergency shut-of valves shall be fitted with a fail-safe spring-return actuator.

The application of such actuators can be prohibitive in terms of cost, size and weight for large valves (typically over 12-inch). Under such circumstances detailed simplification proposals shall be made for the approval of the COMPANY. The proposals shall include the installed capital expenditure cost comparisons between the single-acting and double-acting actuator options, including cost implications due to piping layout and supports.

The piston-type actuator, if specified, should be of the spring-opposed diaphragm or of the spring-opposed short-stroke type.

Long-stroke springless piston actuators shall be opposed via a secured instrument air system or provided with lock-up valves to achieve the required action in the event of instrument air failure.

To prevent tampering, the rotary intermediate linkages between a butterfly valve and its actuator shall be of the integral type, enclosed in a protective metal housing.



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Cylinder actuators shall be provided with adjustable end-limit travel stops in both directions. Bolt adjustment type limit stops shall be applied with a locking facility, e.g. a locking nut, to prevent tampering. The construction shall be leak-tight, with seal gaskets.

Piston or cylinder actuators shall have O-ring sealing and shall be designed to minimize shaft and piston friction.

Actuators shall be equipped with a direct coupled adjustable travel or position indicator for local status indication. The position shall be indicated by a permanent mark on a reversible scale with the words “open and shut” at the travel limits, or by unambiguous symbols such as _V_ = open; −V − = closed.

10.7.2 Actuator Material

The material of the actuator case or housing shall be steel or other metallic material approved by the COMPANY.

Aluminum actuators shall not be used.

The yoke shall be of the open type to allow access for adjustment of the packing gland follower.

The diaphragm material shall be nylon-reinforced neoprene or Buna N rubber.

The actuator spring shall be fully enclosed in a metal housing and permanently treated to resist atmospheric corrosion, as approved by the COMPANY.

10.7.3 Actuator Force

The maximum process differential pressure for actuator sizing shall be taken to be the maximum upstream pressure, with the valve fully closed and the downstream pressure as atmospheric (unless otherwise required).

Actuators shall be sized to provide, under minimum air supply conditions, sufficient torque or thrust to position and fully stroke the inner valve against the maximum differential pressure that may develop under the specified process and/or start-up conditions. Particular attention shall be paid to unbalanced dynamic forces on the valve plug.

For flow-tending-to-close valves the actuator shall be capable of opening the valve against the full upstream pressure, and for flow-tending-to-open valves the actuator shall be capable of closing the valve against the full-upstream pressure.

Special attention shall be paid to actuators for on/off (rotary) valves, particularly if the actuator and the valve are from a different MANUFACTURER/VENDOR.

10.7.4 Stroking Time

Unless other stroking times are indicated on the P&ID or in the requisition, the following maximum stroking times for both directions shall not be exceeded:



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Body Size Maximum stroking time

2 inch and under 10 seconds

3 inch 15 seconds

4 inch 15 seconds

6 inch 20 seconds

8 inch 25 seconds

10 inch 35 seconds

12 and up 45 seconds

The stroking times are applicable to throttling control valves, complete with valve positioner and other accessories, e.g. solenoid valves, etc.

Valves used for on/off service (e.g. ESD valves or control valves with a trip function) shall have a stroking time as indicated on the P&ID or in the requisition or instrument data sheet.

Special care shall be taken for compressor antisurge valves, with respect to the required fast stroking time, which shall be no more than one second.

Where the stroking time requirements in any one direction can not be met, a volume booster (for a modulating control valve) or a quick exhaust valve (for an ESD valve) shall be considered.

If air pressure is used to closed the valve under emergency conditions or to assist the spring force, the size of the air signal line and fittings and the air capacity of the accessories shall be suitable to ensure the specified stroking time.

The effect of stroking time on the pressure build-up in liquid filled lines (hydraulic shock or water hammer) should be checked by process engineering, this in particular for long lines and/or short stroking times.

Similarly, to prevent shock-loading of process equipment downstream of fail-closed shutoff valves, measures may be required to ensure controlled (re-) opening of these valves.

10.7.5 Actuator Color Coding

The color of the actuator shall be in accordance with the MANUFACTURER/ VENDOR’S standard unless otherwise specified in the requisition.

10.7.6 Actuators for Dampers

The actuators shall have sufficient torque to overcome the dynamic forces on the dampers or louvers, plus the friction forces in the bearings, etc.

They shall be designed to cope with fouling and distortion of the dampers. Special attention shall be paid to the prevention of damage to damper blades and linkages by full force of the actuator.

The cylinders shall be double acting and, where necessary, shall be provided with air lubricators.



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For throttling services, the dampers or louvers shall be provided with the following:

a. A cylinder actuator of suitable diameter and stroke length. The actuator shall be opposed via a secured instrument air system or provided with lock-up valves to achieve the required action on instrument air failure;

b. A valve positioner with characterizing cam and facilities for manual actuation. For small actuators a simple lever may be satisfactory, for large actuators a handwheel with gear reduction may be required to enable operation by one man. In both cases, a locking device shall be provided;

c. A weatherproof enclosure around all the above items (excluding operating handles, links, etc.);

d. Instrument air lines to actuators and positioners of dampers shall be connected via flexible hoses;

e. The connecting linkages shall have turn-buckles to allow length adjustment on site; and

f. Safety guards shall be provided.

10.7.7 Electrical Actuators

The application of electrical actuators for throttling control valves requires the approval of the COMPANY. Electrical actuators for on/off valves are outside the scope of this specification.

10.7.8 Hydraulic Actuators

The application of hydraulic actuators for throttling control valves requires the approval of the COMPANY. Hydraulic actuators for on/off valves are outside the scope of this specification.

10.7.9 Valves identified as being located in the Fire Hazardous Area, shall have their actuators protected by Fire Safe Enclosures.

10.8 ACCESSORIES

10.8.1 General

The following accessories, if required, shall be installed on the valve or on a stainless steel mounting plate on the valve:

a. Solenoid valve (except for emergency shutoff valves)

b. Lock-up valve

c. Filter regulator

d. Filter

Tubing and fittings: All accessories on valves in emergency or depressuring service shall be piped and tubed onto the control valve, by the VENDOR, with 317L SS tubing and 316 SS compression fittings.



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Installation and vibration: The control valve and its accessories shall maintain its proper operation even when subject to vibration.

Electronics: Shall be “Tropicalized” for high heat and humidity.

10.8.2 Valve Positioners

Electropneumatic valve positioners (input signal 4-20 mA) shall be applied, unless otherwise requested in the requisition for a specific application.

“Smart” control valve positioners are to be supplied as the standard valve positioners. This device shall be a two-wire, 4-20 mA, 24VDC loop-powered unit, powered from the DCS section of the plant ICS. The device shall provide self diagnostics as well as control valve diagnostics. The device shall also provide digital communication with the DCS through field proven communications protocol (HART or equivalent). This digital communication shall be easily upgradable to utilize the future international fieldbus standard once that standard is proven. Strong preference is given to systems that allow calibration, configuration and on-line diagnostics to take place in the DCS, e.g. an integrated system not a stand-alone platform. COMPANY will inform VENDOR as to the supplier of the DCS prior to any bid activity.

VENDOR shall propose only solutions that allow integration of all potential standard “Smart” devices (transmitters, basic analyzers, MOVs, etc.) Service requirements for these devices are identical to Control Valves in so far as signal and information transmission is concerned. Type information may be quite different.

The positioner output action shall be direct.

The positioner shall not be provided with a bypass valve. The positioner shall have a weatherproof enclosure with a degree of protection of at least IP 54 in accordance with IEC 60529.

The valve positioner shall have sufficient capacity in both directions for pressuring and venting the actuator to prevent response time limitations.

The MANUFACTURER/VENDOR shall specify the air consumption and the air filter requirements for the elements which are supplied with the valve.

Accessory pressure gauges, as required, graduated in the units specified on the requisition, shall be provided on the valve positioner for the air signals.

The execution of tubing between the positioner output and the actuator or accessories and the actuator shall be as follows:

a. The control valve MANUFACTURER shall determine the tubing diameter; however, with a minimum size of 6 mm OD, with larger sizes of 10 mm and 16 mm as required. The tubing shall comply with the specification as given in the requisition.

b. The compression fittings shall be of the make, type and composition as specified in the requisition. All parts of the fittings shall be made by the same MANUFACTURER. The fittings and tubing shall be installed by skilled personnel and strictly in accordance with the compression fitting MANUFACTURER/VENDOR’S instructions.



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Valve positioners having a selectable characterizing mechanism shall be properly adjusted by the valve MANUFACTURER.

The valve positioner shall be provided with an identification plate, marked with air supply pressure and input signal.

The combination of a separate electropneumatic converter and a pneumatic valve positioner should be avoided. If this is unavoidable, the output capability of the converter and the input required on the pneumatic valve positioner shall be checked in order to prevent possible instability.

10.8.3 Handwheels

Control valves, six-inch and above, except depressuring valves, shall be provided with a handwheel, when indicated on the P&IDs. When control valve has no bypass, handwheels shall be provided regardless of size.

If a handwheel is required, the following are the minimum requirements:

a. The handwheel shall be of fire safe design.

b. The handwheel shall be provided with position indicators.

c. The operating force shall not exceed 27 kg force on the rim of the handwheel.

d. The transfer from actuator operation to handwheel operation shall be possible in all stem positions.

e. The handwheel should be yoke mounted and of the nondeclutchable type.

f. The handwheel for butterfly valves shall be shaft mounted instead of yoke mount.

Except where local manual operation of low-rate operational depressuring valves is applied, depressuring valve(s) shall be supplied without a handwheel and without mounting facilities for a handwheel, i.e. brackets, threaded holes, etc. shall not be available on the valve.

10.8.4 Limit Stops

Limit stops shall be fitted only if indicated on the P&IDs.

Limit stops shall be mechanical devices mounted on the actuator, but they shall not form part of the handwheel mechanism (if provided). Bolts screwed in the body shall not be used as a limit stop.

Screwed bolt-type limit stops, e.g. on the control valve stem, adjustable over the full length of the stroke shall be applied if requested.

To prevent tampering, the limit stops shall be fitted with a locking facility, e.g. a locking nut.

The limit stops shall be adequately protected against unintentional adjustments.



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The MANUFACTURER/VENDOR shall set the limit/travel stops at the required minimum or maximum valve opening.

The application of nonmechanical limit stops requires the approval of the COMPANY.

10.8.5 Lock-Up Valves

Air lock-up valves shall be specified for the following applications:

a. All services requiring the control valve to remain in the position immediately prior to a complete failure of the instrument air supply.

b. All shutoff control valves requiring an air supply pressure higher than the guaranteed minimum instrument air pressure.

The lock-up valves shall have a bolt adjustment provided with a locking facility, e.g. a locking nut, to prevent unintentional adjustments.

A separate name plate shall be provided to indicate the range and the set values.

The lock-up valves shall be set at 0.5 kg/cm2 above the required control valve air supply pressure unless some other set value is required for a particular actuator.

The lock-up valves shall be properly adjusted by the valve MANUFACTURER.

For control valves with a valve positioner, the lock-up valve shall be installed between the positioner output and the actuator. If lock-up valves are applied on valves operated by a solenoid valve, this solenoid valve shall be installed between the lock-up valve and the actuator.

10.8.6 Limit Switches

“Open” and/or “closed” limit switches shall be fitted only if indicated on the P&IDs.

Limit switches shall be of the proximity type. The proximitor(s) and initiator should be mounted inside a box for mechanical protection. The flying leads of the proximitor(s) shall terminate in an attached junction box. Alternatively, the protection box and the junction box may be combined into one box.

If not armored, the flying leads shall be protected by a flexible conduit.

If applied, the external linkage between the actuator stem or the rotary spindle and the initiator shall be protected against unintentional damage.

Proximity type switches shall:

a. be inductive type; and

b. have a 4 mm sensitivity gap.

The mounting instructions supplied by the limit switch MANUFACTURER shall be applied by the valve MANUFACTURER. The limit switches shall be properly adjusted by the valve MANUFACTURER.



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Proximity type limit switches shall be adjustable and autonomous to their function, e.g. one switch for the “fully open” position and a separate switch for the “fully closed” position.

The combination of proximitor and proximitor circuit shall be of the fail safe execution.

The method of mounting the limit switch on the control valve shall be subject to the approval of the COMPANY.

10.8.7 Secured Instrument Air Buffer Vessels

Secured instrument air shall be applied for springless actuators in order to drive the control valve to a safe position in the event of an air failure.

The secured instrument air supply shall maintain sufficient air pressure in the buffer vessel to allow for at least three full valve strokes within 30 minutes. Unless otherwise specified in the requisition, the capacity of the secured instrument or air buffer vessel shall be sized for a minimum instrument air supply pressure of 4.2 kg/cm2.

Vessels shall be designed as per ASME Section VIII, Division I, with ASME “U” stamp.

10.8.8 Air Lubricators

When required, air lubricators shall be of the oil-mist type and the oil flow shall be externally adjustable. The oil buffer capacity shall be sufficient for continuous operation for one month.

In addition, the lubricator shall have facilities for oil refilling under pressure, shall have oil level indication and shall be suitable for installing on a mounting plate.

Where air lubricators are applied for valves operated by a solenoid valve, the lubricator shall be installed upstream of the solenoid valve.

Air lubricators shall be considered for pneumatic long-stroke cylinder actuators.

Spherical glass (bowl type) air lubricators shall not be used.

10.8.9 Solenoid Valves

Solenoid valves shall be fitted in air lines to the control valve only if specified in the P&IDs.

The solenoid valves shall be 316 SS (painted) and shall be provided with a disc and/or seat of resilient material to give a TSO feature. They should be suitable for installing on a mounting plate. The air passages in the solenoid valves shall be large enough to achieve the opening or closing time of the valve as stated in the requisition. If this would lead to unrealistically large passages and consequently high power consumption of the solenoid valve, consideration should be given to the use of quick exhaust valves.

The capability of the solenoid valve (e.g. capacity, pressure rating) shall be checked against the instrument air requirement of the particular actuator.

The minimum port size in the solenoid valve shall be stated by the solenoid valve MANUFACTURER and this shall be taken into account for the stroking time calculations.



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Solenoid valves shall have Bug Screens on exhaust ports.

For long-stroke large-volume pneumatic cylinder actuators, consideration should be given to the use of pneumatically operated solenoid valves which can handle the required air capacity of the particular actuator. Pneumatically operated ‘primary’ solenoid valves shall be activated via a ‘secondary’ solenoid valve which should be electrically operated.

Solenoid valves with flying leads shall be provided with a junction box for termination of the leads.

The junction box shall be compatible with the electrical hazardous area classification of the solenoid valve. To prevent high voltage induction, solenoid valves operating on direct current shall be provided with a shunting diode.

The electrical rating of electrical solenoids shall be as specified on the Solenoid Valve or Control Valve Data Sheet.

For emergency shutoff valves, the solenoid valve shall be installed directly on the valve actuator.

For control valves with a valve positioner, the solenoid valve shall be installed between the positioner output and the actuator.

Solenoid valves should be direct-operated. The application of pilot-operated solenoid valves requires the approval of the COMPANY.

For valves that will be active, i.e. operate for long periods, consideration should be given to the use of silencers.

10.8.10 Filter Regulators

If specified, separate air filter regulators shall be installed in the instrument air supply lines to the actuator and/or positioner or individual instruments, in order to regulate the instrument air supply pressure. The make of filter regulator shall be as specified in the requisition.

The air filter regulators shall be of the reducing-relief valve type, with drainage facility and bolt adjustment provided with a locking facility, e.g. a locking nut, to prevent tampering.

The air filter cartridges shall be of the rigid structure type to resist channeling, rupturing, shrinkage or distortion and shall have a maximum mesh size of 40 µm.

The capability, e.g. output capacity and required spring range, of the filter-regulator shall be checked against the instrument air requirement of the particular positioner and/or actuator or pneumatic instrument.

Filter regulators shall be 316 SS (painted) with plastic case pressure indicator and overpressure protection. Automatic water draining shall be used.

Glass (bowl-type) filter regulators shall not be used.



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10.8.11 Filters

Air filters may be considered instead of air filter regulators in instrument air supply lines to long-stroke cylinder actuators that can withstand the maximum air pressure.

If applied, the air filter shall be provided with a manual drainage facility and a filter cartridge of the rigid structure type, to resist channeling, rupturing, shrinkage or distortion, having a maximum mesh size of 40 µm Glass (bowl type) filters shall not be used.

10.8.12 Quick Exhaust Valves

Quick exhaust valves may be provided for all services which require the control valve to open or close faster than specified in Paragraph 10.7.4, Stroking Time.

Pilot-operated, quick-exhaust valves shall not be used.

The minimum port size in the quick exhaust valve shall be verified and taken into account for stroking time calculation.

Quick exhaust valves shall have Bug Screens.

Quick exhaust valves shall be fitted directly to the port of the actuator.

10.8.13 Volume Boosters

Volume boosters shall be provided if needed to achieve the stroking times specified in the requisition. Volume boosters for pneumatic actuators shall be of the high capacity type with fast throttling facilities to control the required capacity.

10.8.14 Restrictors

If a requirement for slow opening and/or slow closing of a valve exists, this should be achieved within the DCS or other remote electronic system. The use of mechanical instrument air restrictors should be avoided.

If its use is unavoidable, then the mechanical flow restrictor shall be provided with a lockable, variable restriction adjustment facility. The direction(s) of restricted flow shall be indicated by a permanent mark on the body. The capacity of the flow restrictor shall be sized (and tested) for a normal air supply pressure.

If an air flow restrictor is applied on a control valve equipped with a solenoid valve, care shall be taken with the location of the restrictor in relation to the solenoid valve. The restrictor shall only affect the required slow-opening or slow-closing of the control valve and shall not influence the other (unrestricted) valve movement.

10.9 BYPASS MANIFOLDS (Around Control Valves)

Complete block and bypass manifolds shall be used in applications, stated below. The bypass valve can be a globe or a gate valve, but in either case the valve must have good solid design so the plug or gate does not vibrate or move while in a fixed throttle position. Bypass valves are usually globe valves in sizes up to and including four-inch. Larger sizes can be gate valves. See Bypass Valves, (d), below.



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Bypass manifold, valves and handwheels will be based on the following conditions:

a. Use a control valve without a bypass manifold when the service is intermittent or can be closed off without shutting down the process. Also, there must be block valves in the line, plus drains so the control valve can be removed.

b. Use control valves with handwheels for large valves where block and bypass valves are expensive. The line must have the capability to be blocked-in and drained in case the control valve must be removed. A handwheel only protects against a faulty operator. It will not act as a bypass if the trim fails.

c. Use on systems that are extremely corrosive.

d. Bypass valves shall have Cv values equal to or greater than control valve Cv. Use globe valves for four-inches and smaller, use ball valves in plugging service, gate valves for six-inches and larger. For control valve six-inches and larger use gate bypass valves one size smaller than the control valve size.

10.10 ON/OFF VALVES AND ACTUATOR

10.10.1 General

Valves shall generally be ball type and comply with Project Specification DGS-PU-016, Piping Material Purchase Specification.

10.10.2 Actuators

The following actuators shall be selected:

a. Quarter turn rotating actuators, single acting, piston type, spring return

b. Quarter turn, double acting piston type

c. Electric actuators, with inching facility, position indication, etc., in a two-wire system

Auxiliary fluid shall be instrument air/gas.

Reservoir shall be designed as per ASME Section VIII, Division 1, with ASME ‘U’ stamp.

11.0 EMERGENCY DEPRESSURIZING VALVES

Emergency depressurizing valves are outside the scope of this specification and are covered in Project Specification DGS-IU-009, Instrumentation for Depressuring Systems.

12.0 PAINTING

Surfaces to be painted or coated shall be dry and free from burrs, weld spatters, flux, dust, grease, oil and other foreign matter before any paint is applied. See Project Specification DGS-MX-001, Painting.

All carbon steel, low/intermediate alloy and stainless steel parts of the control valve, in contact with the atmosphere shall be blast cleaned per Project Specification DGS-MX-001, Painting.



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A two-component, chemical-resistant paint system shall then be applied.

The finish color of the final finish shall be according to the Color Code given in Project Specification DGS-MX-001, Painting, unless otherwise specified in the requisition.

The valve stem or spindle and gasket-contact surface of flanges shall not be painted, but shall be protected against corrosion with a suitable protective fluid.

13.0 VALVE IDENTIFICATION

The control valve shall be provided with a permanently attached stainless steel identification plate. At minimum the following information shall be clearly stamped on the plate:

a. MANUFACTURER’S name or trade mark;

b. MANUFACTURER’S model/type number (valve and actuator);

c. MANUFACTURER’S serial number;

d. Body pressure rating;

e. Size (body and trim);

f. Material (body and trim);

g. Type of plug (characteristic);

h. Installed Cv value;

i. Bench setting/spring range;

j. Action on air supply and/or signal failure; and

k. Limit stop setting in % travel and between brackets, the related Cv value.

In addition, each control valve shall be provided with a stainless steel tag plate which shall be fixed to the control valve with a stainless steel wire. This plate shall be marked with the CONTRACTOR’S tag number as stated in the requisition.

Control valve body flanges, etc. shall be marked in accordance with the applicable design code.

The direction of flow, the valve body rating, the body material and, where applicable, the TSO direction(s) shall be clearly indicated by a permanent mark cast in or stamped on the valve body, not painted.

Three-way globe valves shall clearly indicate the fixed open port by a permanent mark “COMMON” stamped on the flange.

The control valve tag number shall be stamped on the valve body or flange if the identification plate is attached to the actuator.



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Control valves for oxygen services shall be tagged:

“SUITABLE FOR OXYGEN SERVICE”

Control valves for HF service shall be tagged:

“SUITABLE FOR HF ACID SERVICE”

Warning plates, if required, shall be fixed by screws or rivets.

Text,where applicable, shall be white letters on a red background and stating, as appropriate, either:

“WARNING — TRIM SIZE AFFECTS RELIEF VALVE CAPACITY”

or

“WARNING — TRIM SIZE AFFECTS FIRING OF FURNACE”

14.0 TESTS

14.1 GENERAL

All control valves (together with their accessories, if part of the supply) shall be subjected to the following checks and tests, as a minimum:

a. Dimensional check;

b. Hydrostatic test; and

c. Performance and mechanical operation test.

The following tests shall be executed on the number of control valves specified in the requisition:

a. Seat leakage test;

b. Capacity test;

c. Low-temperature or cryogenic test;

d. Helium test; and

e. Vacuum test.

NOTE: If the number of valves tested is less than the total number of valves in the order, the above sampling will be adopted to determine batch compliance. Nevertheless, all valves supplied shall meet all requirements of this specification.

The test results shall be made available to the purchaser as part of the package of final certified document and drawings.



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14.2 DIMENSIONAL AND FLANGE FACE FINISH CHECK

The face-to-face dimensions of flanged globe-body control valves shall be as given in the relevant standard ANSI B16.10.

All dimensions (including overall height) shall be as shown on the MANUFACTURER’S/VENDOR’S drawings.

The flange face finish shall be checked in accordance with SPE 77/301, in Project Specification DGS-PU-016. Gasket contact surface finish, “smooth,” 125-250 Ra, or as specified.

14.3 HYDROSTATIC TEST

Control valves shall be hydrostatically tested in accordance with the standards specified for the particular type of valve. Valves shall be drained immediately after testing.

The water quality shall be clean potable water of a natural pH value, clear and free of sulfides. Water containing up to 200 mg/kg chlorides, temperature not to exceed 50ºC, may be used for the pressure test. See Project Specification DGS-PU-004, General Piping — Process and Utility Field Pressure Testing.

The duration of the hydrostatic test shall be as follows:

Valve size: Test Duration:

< 2-inch 1 minute

3-inch up to and including 8-inch 2 minutes

> 10-inch 3 minutes

14.4 SEAT LEAKAGE TEST

The seat leakage test shall be in accordance with ANSI/FCI 70.2 and IEC-60534.4, Standard for control valve leakage.

The seat leakage test procedures shall be executed for all control valves of Class V or VI. Unless otherwise specified, the leakage rate of a single-seated control valve shall not exceed the limits of Class III. For a double-seated control valve, the leakage rate shall not exceed the limits of Class II.

IEC-60534-4, Test Procedure #1 should be used for “flow-tending-to-open” control valves, whereas Test Procedure #2 should be used for “flow-tending-to-close” control valves.

For each control valve, in the shutoff position, the MANUFACTURER/VENDOR shall perform a leakage calculation at the test conditions (as defined in the test procedure) and at operating conditions with the specified fluid.

The control valve shall be tested under the thrust or torque applied by the actuator, with the signal pressure that will be available to close the valve, e.g. 0.2 kg/cm2 or 0.2 to 1.0 kg/cm2 bench setting as required.



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For each valve tested, the MANUFACTURER/VENDOR will state the following data:

a. Flow direction;

b. Test medium;

c. Test differential pressure;

d. Duration of test;

e. Seat leakage flow rate measured;

f. Allowable seat leakage flow rate; and

g. Seat leakage class (if applicable).

14.5 PERFORMANCE AND MECHANICAL OPERATION TEST

The control valve shall be completely assembled and fitted with all accessories such as positioner, solenoid valve(s), etc. The packing box shall be correctly packed to the tightness as needed for the hydrostatic test (if necessary, packing shall be renewed after testing).

The performance and mechanical test shall include a hysteresis test, a dead band test and a stroking time test.

For definitions and test procedures refer to IEC 60534-1 and 60534-4, control valve terminology, inspection and testing.

The actuating medium for the tests shall be clean, dry air or nitrogen.

The Hysteresis Test shall consist of measuring the valve stem position for the following sequence of input signals: 50%, 75%, 100%, 75%, 50%, 25%, 0%, 25% and 50%. Hysteresis shall not exceed 0.5% of maximum valve stroke.

The Dead Band Test is expressed in percentage of the input span and shall be measured at 5%, 50% and 95% of the input span. The maximum dead band found shall not exceed 1% of rated input signal.

For each valve, if not otherwise specified in the requisition, the stroking time at the specified air pressures shall comply with Paragraph 10.7.4.

Testing shall be performed under atmospheric conditions (at zero differential pressure and ambient temperature) and with the minimum specified air supply pressure.

The above test results should be recorded on an X-Y recorder.

If the control valve is equipped with a handwheel, the fully open and closed position of the valve shall be achieved with handwheel operation, taking over from actuator starting at mid-position.

If the control valve is equipped with limit switches, they shall be checked for functional operation with a proximity tester.

14.6 CAPACITY TEST

If specified in the requisition, the actual Cv value shall be demonstrated by a test in accordance with IEC 60534-2-3, Flow capacity, test procedures (control valves).



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14.7 LOW TEMPERATURE TEST

A low temperature or a cryogenic test shall be made on selected control valves used in low temperature service (down to -50°C) or in cryogenic service (below -50°C).

Requirements, materials, procedures and testing for the low temperature test, shall be in accordance with SPE 77/306, in Project Specification DGS-PU-016, acceptance test, low temperature/cryogenic service.

14.8 VACUUM TEST

A vacuum test shall be made on selected control valves, as indicated by the COMPANY. This test shall be in accordance with SPE 77/307, in Project Specification DGS-PU-016, acceptance test for values in high vacuum service.

15.0 MATERIALS INSPECTION AND CERTIFICATION

Material inspection and certification requirements shall be in accordance with Project Specification DGS-MU-014 and Type “B” certificate (EN 10204, 3.1B), original or red stamped copies verified by COMPANY approved inspectors.

PMI (Positive Material Identification) requirements for alloy pressure containing equipment shall be in accordance with Project Specification DGS-MW-006, PMI of Equipment and Piping.

Welding certificates and NDE (Nondestructive examination) requirements shall be in accordance with Project Specification DGS-MW-002, Welding, NDE and Prevention of Brittle Fracture of Piping.

16.0 DOCUMENTATION

The MANUFACTURER/VENDOR shall submit the documents with the following quotations:

a. Calculations of control valve capacity, noise calculation, leakage Cv, details of selected actuator, details of secured instrument air vessel;

b. Dimensions and construction drawings of the control valve, including accessories and air lines; and

c. Construction drawings of the buffer vessel (if supplied).

The test results from the factory test shall be made available to the purchaser as part of a package of final certified documents and drawings.

At a later stage, the MANUFACTURER/VENDOR shall complete a spare parts list and interchangeability record for all equipment supplied.

Unless otherwise specified by the COMPANY, only the minimum necessary quantity of documentation shall be provided. For example, on an order for multiple valves of the same type a separate operating and instruction manual is not required for each valve.

dgs ie 003 r0 control valve

Documents

control valve page

control valve actuator

types of control valves

valve trim

rev date description

document precedence

special applications

reference documents