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  • AS 1271-1997

    Superseded A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.
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    Safety valves, other valves, liquid level gauges, and other fittings for boilers and unfired pressure vessels

    Available format(s):  Hardcopy, PDF 1 User, PDF 3 Users, PDF 5 Users, PDF 9 Users

    Superseded date:  30-06-2017

    Language(s):  English

    Published date:  01-01-1997

    Publisher:  Standards Australia

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    Table of Contents - (Show below) - (Hide below)

    1 - AS 1271-1997 SAFETY VALVES, OTHER VALVES, LIQUID LEVEL GAUGES AND OTHER FITTINGS FOR BOILERS AND UNFIRED PRESSURE VESSELS
    4 - PREFACE
    5 - CONTENTS
    7 - SECTION 1 SCOPE AND GENERAL
    7 - 1.1 SCOPE
    7 - 1.2 APPLICATION
    7 - 1.3 REFERENCED DOCUMENTS
    8 - 1.4 DEFINITIONS
    8 - 1.4.1 Assisted safety valve
    8 - 1.4.2 Blowdown (in relation to safety and relief valves)
    8 - 1.4.3 Built-up backpressure
    8 - 1.4.4 Certified capacity
    8 - 1.4.5 Coefficient of discharge (a)
    8 - 1.4.6 Cold differential test pressure
    9 - 1.4.7 Commencement of lift
    9 - 1.4.8 Corrosion
    9 - 1.4.9 Design pressure
    9 - 1.4.10 Direct-loaded safety valve
    9 - 1.4.11 Equivalent calculated capacity
    9 - 1.4.12 Fitting
    9 - 1.4.13 Inlet size
    9 - 1.4.14 Inspector
    9 - 1.4.15 Lift
    9 - 1.4.16 Manufacturer
    9 - 1.4.17 Nominal pressure (PN)
    9 - 1.4.18 Nominal size (DN)
    9 - 1.4.19 Overpressure (in relation to safety and relief valve)
    9 - 1.4.20 Pilot-operated safety valve
    9 - 1.4.21 Plug cock (cock)
    10 - 1.4.22 Purchaser
    10 - 1.4.23 Relief valve
    10 - 1.4.24 Relieving pressure (flow rating pressure)
    10 - 1.4.25 Re-seating (in relation to safety and relief valve)
    10 - 1.4.26 Safety valve
    10 - 1.4.27 Set pressure (in relation to safety and relief valve)
    10 - 1.4.28 Shall
    10 - 1.4.29 Should
    10 - 1.4.30 Superimposed backpressure
    10 - 1.4.31 Supplementary-loaded safety valve
    10 - 1.4.32 Theoretical flowing (discharge) capacity
    10 - 1.5 PRESSURES
    10 - 1.6 DESIGNATION
    11 - SECTION 2 GENERAL DESIGN AND CONSTRUCTION
    11 - 2.1 MATERIALS
    11 - 2.1.1 Material standards
    11 - 2.1.2 Suitability
    11 - 2.1.3 Limits of application
    11 - 2.1.4 Castings and forgings
    11 - 2.1.5 Repair of castings
    11 - 2.1.6 Impregnation of castings
    11 - 2.2 PRESSURE/TEMPERATURE DESIGN AND RATING
    11 - 2.2.1 Pressure/temperature rating
    12 - 2.2.2 Modified rating due to connections
    12 - 2.2.3 Determination of dimensions
    12 - 2.2.4 Design strength
    12 - 2.2.5 Method of calculation
    12 - 2.2.6 Proof test
    12 - 2.2.7 Local reductions
    12 - 2.3 MOUNTING AND CONNECTIONS
    12 - 2.3.1 Flanged connections
    12 - 2.3.2 Butt-welded connections
    12 - 2.3.3 Threaded connections
    12 - 2.3.4 Type of thread
    13 - 2.3.5 Socket-welded connections
    13 - 2.3.6 Other connections
    13 - 2.4 BOLTING
    13 - 2.5 DESIGN AND CONSTRUCTION
    13 - 2.5.1 Integrity of design
    13 - 2.5.2 Securing of seats
    13 - 2.5.3 Bonnet and cover joint
    14 - 2.5.4 Stems and stuffing boxes
    14 - 2.5.5 Ball valve, plug cock, or cock
    14 - 2.5.6 Moving parts
    14 - 2.6 MARKING AND DOCUMENTATION
    14 - 2.6.1 Direction of flow
    14 - 2.6.2 Direction of operation
    14 - 2.6.3 Open/shut indicators
    14 - 2.6.4 Data
    15 - 2.6.5 Additional marking -safety and relief valves
    15 - 2.6.6 Records and certification -safety and relief valves
    15 - 2.7 HYDROSTATIC TESTS
    15 - 2.7.1 Hydrostatic test fluid
    15 - 2.7.2 Body test
    16 - 2.7.3 Seat test
    18 - SECTION 3 SAFETY AND RELIEF VALVES
    18 - 3.1 GENERAL
    18 - 3.1.1 Scope of section
    18 - 3.1.2 Fail-safe
    18 - 3.1.3 Stem seals
    18 - 3.1.4 Locking of adjustments
    18 - 3.1.5 Drainage
    18 - 3.1.6 Freedom of operation
    18 - 3.2 SPRING LOADING
    18 - 3.2.1 Springs
    19 - 3.2.2 Range of application
    19 - 3.2.3 Prevention to alteration of set pressure
    19 - 3.3 EASING GEAR
    19 - 3.3.1 Provision of easing gear
    19 - 3.3.2 Lifting pressure
    19 - 3.4 OPERATION
    19 - 3.4.1 Smooth operation
    19 - 3.4.2 Tolerances on valve characteristics
    20 - 3.5 CAPACITY RATING, CLASSIFICATION, AND CERTIFICATION
    20 - 3.5.1 Method of rating
    20 - 3.5.2 Classification
    20 - 3.5.3 Certification
    20 - 3.5.4 Other approval
    21 - 3.6 TESTING FOR OPERATING AND FLOW CHARACTERISTICS FOR SAFETY VALVES USING STEAM, AIR, WATER, OR OTHER GASES OR LIQUIDS OF KNOWN
    21 - 3.6.1 Operating and flow characteristics to be tested
    21 - 3.6.2 Testing of valves
    21 - 3.6.3 Information to be supplied to the purchaser
    21 - 3.6.4 Coefficient of discharge
    21 - 3.6.5 Design changes
    21 - 3.6.6 Records of test
    21 - 3.7 TESTS TO DETERMINE OPERATING CHARACTERISTICS
    21 - 3.7.1 Test equipment
    22 - 3.7.2 Valves used in the test programme
    22 - 3.7.3 Test procedure
    22 - 3.8 TESTS TO DETERMINE FLOW CHARACTERISTICS
    22 - 3.8.1 Carrying out of tests
    22 - 3.8.2 Flow test equipment
    22 - 3.8.3 Valves used in the test programme
    22 - 3.8.4 Test procedure
    23 - 3.8.5 Adjustments during test
    23 - 3.8.6 Records and test results
    23 - 3.9 MEASUREMENT OF LIFT
    23 - 3.9.1 Carrying out measurement
    23 - 3.9.2 Measuring equipment
    23 - 3.9.3 Valves used in measurement programme
    23 - 3.9.4 Measurement procedure
    24 - 3.9.5 Records
    24 - 3.10 RATED DISCHARGE CAPACITY
    24 - 3.10.1 Class A valves
    24 - 3.10.2 Class B valves
    26 - 3.10.3 Pilot operation
    27 - SECTION 4 LIQUID RELIEF VALVES
    27 - 4.1 GENERAL
    27 - 4.2 RATED DISCHARGE CAPACITY
    28 - SECTION 5 LIQUID LEVEL GAUGES
    28 - 5.1 SCOPE OF SECTION
    28 - 5.2 MOUNTINGS
    28 - 5.3 GAUGE GLASSES
    28 - 5.4 DRAIN
    28 - 5.5 COCK HANDLES
    28 - 5.6 GUARDS
    28 - 5.7 SAFETY DEVICES
    28 - 5.8 CONNECTION TO PRESSURE VESSEL
    29 - SECTION 6 BLOWDOWN VALVES
    29 - 6.1 DESIGN
    29 - 6.2 OPERATION
    30 - APPENDIX A - MINIMUM THICKNESS OF SAND-CAST VALVES AND OTHER FITTINGS
    32 - APPENDIX B - PROPOSED TEST REPORT FOR SAFETY VALVE
    34 - APPENDIX C - FORM FOR CERTIFICATE-CLASS A SAFETY VALVES
    35 - APPENDIX D - FORM FOR CERTIFICATE-CLASS B SAFETY VALVES
    36 - APPENDIX E - PRESSURE/TEMPERATURE TRANSFER CURVE
    39 - APPENDIX F - DISCHARGE CAPACITY
    39 - F1 SCOPE
    39 - F2 COEFFICIENT OF DISCHARGE (a)
    39 - F3 DISCHARGE CAPACITY FOR STEAM
    42 - F4 DISCHARGE CAPACITY FOR AIR OR ANY GAS OR VAPOUR
    42 - F4.1 Critical and subcritical flow
    42 - F4.2 Equations
    45 - F4.3 Discharge capacity for incompressible fluids
    47 - APPENDIX G - DERIVATION OF COMPRESSIBILITY FACTOR
    47 - G1 SCOPE
    47 - G2 EQUATION
    49 - APPENDIX H - PNEUMATIC PRESSURE TESTING SAFETY REQUIREMENTS

    Abstract - (Show below) - (Hide below)

    Sets out the criteria for the design, construction and testing of safety valves, liquid relief valves, liquid level gauges, blowdown valves and other fittings for use on boilers and unfired pressure vessels and their associated piping. It does not cover the selection, operation or application of valves and fittings, as these are covered in the Standard applicable to the equipment to which the valves and fittings are to be connected. This Standard now aligns with BS 5154 in terms of valve body dimensions. This alignment will overcome the problem of differing valve body thicknesses evident in previous editions and will add to safety in the selection of correctly sized safety valves.

    Scope - (Show below) - (Hide below)

    This Standard specifies requirements for the design, construction and testing of safety valves, liquid relief valves, liquid level gauges, blowdown valve, and other fittings for use on boilers and unfired pressure vessels, and their associated piping.It does not deal with the selection, operation, or application of valves and fittings, as these are dealt with in the Standard applying to the equipment to which the valves and fittings are to be connected, e.g. AS 1210, nor does it include requirements relating to safety fittings of a class or kind that are already the subject of a relevant Standard, e.g. -(a) Bourdon tube pressure and vacuum gauges . . . . . . . . . AS 1349;(b) bursting discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AS 1358;(c) fusible plugs for boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . AS 1732; and(d) bursting discs and bursting disc devices . . . . . . . . . . . . .ISO 6718.

    General Product Information - (Show below) - (Hide below)

    Committee ME-001
    Document Type Standard
    Publisher Standards Australia
    Status Superseded
    Superseded By
    Supersedes
    Under Revision

    History - (Show below) - (Hide below)

    Under Revision see DR 02299 First published as AS B190-1964.Revised and redesignated AS 1271-1973.Second edition 1982.Third edition 1990.Fourth edition 1997. First published as AS B190-1964. Revised and redesignated AS 1271-1973. Second edition 1982. Third edition 1990. Fourth edition 1997.

    Standards Referenced By This Book - (Show below) - (Hide below)

    AS 1732-1997 Fusible plugs for boilers
    AS/NZS 1200:1994 Pressure equipment
    AS 4041-1998 Pressure piping
    AS 3653-1993 Boilers - Safety, management, combustion and other ancillary equipment
    AS 1349-1986 Bourdon tube pressure and vacuum gauges (Reconfirmed 2018)
    AS 1210-1989 Unfired Pressure Vessels (known as the SAA Unfired Pressure Vessels Code)
    AS 1358-1989 Bursting discs and bursting disc devices - Guide to application, selection, and installation
    AS 2593-1995 Boilers - Unattended and limited attendance
    AS 2129-1994 Flanges for pipes, valves and fittings
    AS 4037-1999 Pressure equipment - Examination and testing (Reconfirmed 2016)
    AS 1722.1-1975 Pipe threads of Whitworth form Sealing pipe threads (metric units)

    Standards Referencing This Book - (Show below) - (Hide below)

    AS/NZS 1596:2002 The storage and handling of LP Gas
    AS 3873-1995 Pressure equipment - Operation and maintenance
    AS 2945(INT)-2002 Batch-type washer/disinfectors for health care facilities
    AS 3653-1993 Boilers - Safety, management, combustion and other ancillary equipment
    AS 1410-2003 Sterilizers - Steam - Pre-vacuum
    AS 2945-1987 Washer/disinfectors for hospital utensils
    AS 2192-1991 Sterilizers - Steam - Downward displacement
    AS 4037-1992 Boilers and pressure vessels - Examination and testing
    AS 2711-1993 Washer/disinfectors for respiratory apparatus
    AS/NZS 1677.2:1998 Refrigerating systems - Safety requirements for fixed applications
    AS 2593-1995 Boilers - Unattended and limited attendance
    AS 1357.2-1992 Water supply - Valves for use with unvented water heaters - Control valves
    AS 2182-1994 Sterilizers - Steam - Portable
    AS 2809.2-1999 Road tank vehicles for dangerous goods - Tankers for flammable liquids
    AS 1357.1-1992 Water supply - Valves for use with unvented water heaters - Protection valves
    AS/NZS 2022:2003 Anhydrous ammonia - Storage and handling
    AS 2514-1999 Drying cabinets for medical equipment
    AS/NZS 1200:1994 Pressure equipment
    AS 1228-1997 Pressure equipment - Boilers
    AS 2182-1998 Sterilizers - Steam - Benchtop
    AS/NZS 3788:1996 Pressure equipment - In-service inspection
    AS 4041-1992 Pressure piping
    AS 4037-1999 Pressure equipment - Examination and testing (Reconfirmed 2016)
    AS 2809.4-2001 Road tank vehicles for dangerous goods - Tankers for toxic and corrosive cargoes
    AS 3533.1-1997 Amusement rides and devices - Design and construction
    AS 3814-2002 (AG 501) Industrial and commercial gas-fired appliances
    AS/NZS 1596:1997 Storage and handling of LP Gas
    AS 2192-2002 Sterilizers - Steam - Downward-displacement
    AS 3873-2001 Pressure equipment - Operation and maintenance
    AS 2809.3-1999 Road tank vehicles for dangerous goods - Tankers for compressed liquefiable gases
    AS 1357.2-1998 Valves primarily for use in warm and hot water systems - Control valves
    AS 2593-2001 Boilers - Unattended and limited attendance
    AS 1210-1997 Pressure vessels
    AS 4774.2-2002 Work in compressed air and hyperbaric facilities - Hyperbaric oxygen facilities
    AS 3961-1991 Liquefied natural gas - Storage and handling
    AS 2885.3-2001 Pipelines - Gas and liquid petroleum - Operation and maintenance
    AS 3836-1998 Rack conveyor washers for health care facilities
    AS/NZS 3788:2001 Pressure equipment - In-service inspection
    AS 4732-2002 LP Gas fuel systems for marine engines
    AS 2971-2002 Serially produced pressure vessels
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