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AS 4041-2006


Pressure piping

Specifies minimum requirements for the materials, design, fabrication, testing, inspection, reports and pre-commissioning of piping subject to internal or external pressure.
Published: 20/09/2006
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Table of contents
Cited references
Content history
Table of contents
About this publication
1 Scope and general
1.1 Scope
1.2 Responsibilities
1.3 Not allocated
1.4 Application of piping classes for service conditions
1.5 Selection of piping class
1.5.1 Basic requirements
1.5.2 Mixing classes
1.6 Alternative Standards
1.7 Definitions
1.8 Notation
1.9 Non-SI units
1.10 Referenced documents
1.11 Reports and certificates
1.11.1 Manufacturer’s data report
1.11.2 Copies
1.12 Not allocated
1.13 Not allocated
1.14 Non-metallic piping
1.15 Interpretation of Standards
1.16 New designs, materials and fabrication methods
1.17 Dimensional and mass tolerances
1.18 Alternative design of accessories
2 Materials and components
2.1 General
2.2 Qualification of materials and components
2.2.1 Materials and components complying with nominated Standards
2.2.2 Materials and components complying with Standards not nominated in this Standard
2.2.3 Alternative product form
2.2.4 Use of structural steel
2.2.5 Components, other than pipe, for which there are no Standards
2.2.6 Reclaimed components complying with a nominated Standard
2.2.7 Material and components not fully identified
2.2.8 Unidentified materials and components
2.2.9 Hydrostatic test
2.2.10 Specially tested materials
2.3 Not allocated
2.4 Properties of materials
2.4.1 General
2.4.2 Mechanical properties
2.4.3 Thermal expansion
2.4.4 Young’s modulus
2.4.5 Poisson’s ratio
2.4.6 Weldability
2.5 Identification of materials and components
2.6 Limitations on application
2.6.1 General
2.6.2 Deterioration of materials and components
2.6.3 Materials for ambient and high temperature service General Carbon and low and medium alloy steels High alloy steels Ductile iron and other iron castings Copper and copper alloys Aluminium and aluminium alloys Nickel and nickel alloys Titanium and titanium alloys
2.6.4 Fittings
2.6.5 Valves General Valve bodies Drain valves Valve trim Valve spindles Bypasses
2.6.6 Flanges
2.6.7 Bolting for flanges
2.6.8 Gaskets
2.6.9 Material for forming and bending
2.6.10 Limit of application of pipe made by the CW (BW) process
2.6.11 Limit of application of ERW AS 1074 pipe
2.7 Materials and components for corrosive service
2.8 Dissimilar materials
2.9 Backing rings and fusible inserts
2.9.1 Permanent backing rings
2.9.2 Temporary backing rings
2.9.3 Fusible inserts
2.10 Brazing materials
2.11 Materials for low temperature service
2.11.1 General
2.11.2 Selection of suitable material for low temperature service General Material Groups A1, A2 and A3 Alloy steels and non-ferrous metals (all forms excluding bolting and weld metal) Very thin steel pipes and tubes (including small heat-exchanger tubes) Cast iron Bolting materials Non-metallic materials
2.11.3 Minimum operating temperature
2.11.4 Required material design minimum temperature Lethal fluids Class 3 piping MDMT for steel groups A1, A2 and A3 MDMT for all other materials
2.11.5 Material reference thickness
2.11.6 Impact tests Where required Test method Test specimens Impact requirements Charpy test requirements for subsidiary test specimens Retests
3 Design
3.1 General
3.1.1 Basis for determining size of pipe
3.1.2 Design against failure
3.1.3 Other design methods
3.2 Design pressure
3.3 Design temperature
3.3.1 General
3.3.2 Uninsulated piping
3.3.3 Externally insulated piping
3.3.4 Internally insulated piping
3.3.5 Heated piping
3.4 Design life
3.5 Static and dynamic loads and forces
3.6 Risk analysis
3.6.1 General
3.6.2 Hazard and operability study (HAZOP)
3.6.3 Other methods
3.7 Thermal effects
3.8 Effects of movement at supports, anchors and terminals
3.9 Design pressure and temperature for piping associated with steam boilers
3.9.1 General
3.9.2 Design pressure for main steam piping
3.9.3 Design pressure for reheat piping Time-independent Time-dependent
3.9.4 Design pressure for piping for reduced pressure systems
3.9.5 Design temperature for steam piping
3.9.6 Design pressure and temperature for boiler feed water piping
3.9.7 Design pressure for blowdown and drain systems
3.9.8 Design temperature for blowdown and drain systems
3.9.9 Design conditions for safety valve discharge piping
3.10 Design criteria
3.10.1 Pressure-temperature design criteria Components having specified ratings Components not having specified ratings
3.10.2 Normal operating conditions
3.10.3 Variations in normal operating conditions
3.10.4 Design pressure for piping for reduced pressure systems
3.10.5 Design pressure for blowdown and drain systems Design pressure upstream of control or shut off valve Design pressure downstream of control or shut off valve
3.10.6 Design temperature for blowdown and drain systems Design temperature upstream of control or shut off valve Design temperature downstream of control or shut off valve
3.10.7 Vents of blowdown, drain and vent vessels Design pressure Design temperature
3.10.8 Design conditions for safety valve discharge piping Design pressure Design temperature
3.10.9 Design temperature for structural attachments
3.11 Design strength
3.11.1 Design strength for pressure-retaining components
3.11.2 Compressive stress
3.11.3 Shear stress
3.11.4 Bearing stress
3.11.5 Sustained longitudinal stress
3.11.6 Longitudinal stress due to sustained and occasional loads
3.11.7 Longitudinal design stress range General Specific materials at reduced cycles
3.11.8 Creep-fatigue interaction
3.12 Design factors
3.12.1 General
3.12.2 Weld joint factor
3.12.3 Class design factor
3.12.4 Casting quality factor
3.12.5 Weld joint strength reduction factor
3.13 Allowances
3.13.1 General
3.13.2 Manufacturing tolerances
3.13.3 Corrosion or erosion
3.13.4 Threading, grooving, or machining
3.13.5 Mechanical strength
3.14 Wall thickness of straight pipe
3.14.1 Required wall thickness
3.14.2 Nominal wall thickness
3.14.3 Pressure design wall thickness for pipe, under internal pressure
3.14.4 Wall thickness of pipe under external pressure
3.14.5 Pressure design wall thickness of cast pipe
3.15 Pipe bends
3.15.1 General
3.15.2 Continuous bends Method of manufacture Minimum thickness of bends Ovality
3.15.3 Wrinkle (or crease) bends
3.15.4 Mitre bends Application Single mitre bends Multiple mitre bends Mitre bends subject to external pressure Distance between mitre joints Continuation of thickness Branch connections to mitre bends for Class 1 and Class 2 piping Branch connections to mitre bends for Class 3 piping Attachments to mitre bends
3.15.5 Cut-and-shut (gussetted) bends
3.16 Reducers
3.17 Bifurcations, special fittings and connections
3.18 Expansion fittings and flexible hose assemblies
3.18.1 Expansion fittings
3.18.2 Flexible hose assemblies
3.19 Branch connections and openings
3.19.1 Application
3.19.2 Types of branch connections
3.19.3 Shape of opening
3.19.4 Size of branches and openings
3.19.5 Location of unreinforced branch connections
3.19.6 Material for branches and reinforcement
3.19.7 Branches or openings not requiring additional reinforcement General Fitting Coupling Reinforced fitting Small bore branch Threaded connection Socket-welded connection Gamma-ray boss and plug
3.19.8 Branch connections or openings requiring reinforcement General Notation Weld joint factor Required reinforcement area Reinforcement area Reinforcement zone Reinforcement of multiple openings Rings, pads, and saddles Gusset plates, ribs and stays Other designs Branch connections subject to external forces and moments
3.19.9 Extruded outlets General Notation Radius of external contour Required reinforcement area Reinforcement area
3.20 Welded branch connections
3.20.1 General
3.20.2 Fittings
3.20.3 Branch pipes General Limitations on use Weld preparations Backing rings
3.21 Design of closures for pipe ends and branches
3.21.1 General
3.21.2 Openings in closures
3.21.3 Threaded openings
3.21.4 Blanks
3.22 Design of other pressure-retaining components
3.23 Attachments
3.23.1 General
3.23.2 Welding of attachments General Elevated temperature piping Class 2 and Class 3 piping
3.23.3 Thickness of attachments
3.23.4 Intensity of radial loading
3.24 Piping joints
3.24.1 General
3.24.2 Welded joints Butt welds Fillet welds Socket-welded joints Welded sleeve joints Welded bell-and-spigot joints Partial penetration butt welds Stress corrosion cracking
3.24.3 Threaded joints General Leak tightness Thread types Ratings on fittings and screwed flanges Limitations Pressure test
3.24.4 Flanged joints General Flange ratings Flange facings Gaskets Bolting Threaded-boss flanges Limitations on the use of flanges to AS 2129 Welded flanges and lap joint flanges
3.24.5 Flared, flareless and compression joints
3.24.6 Caulked joints
3.24.7 Soldered joints
3.24.8 Brazed joints
3.24.9 Expansion joints
3.24.10 Proprietary and special joints
3.25 Design requirements pertaining to specific piping
3.25.1 Drainage systems of steam piping General Fall Drainage points Drain branches Drains subject to vacuum pressure Separators
3.25.2 Vents of blowdown, drain and vent vessels
3.25.3 Instrument, control and sampling piping General Take-off connections Blowdown valve Piping Joints
3.25.4 Pressure relief valve discharge piping General Flexible bellows Reaction loads Discharge
3.25.5 Piping located below ground level General Buried piping
3.26 Not allocated
3.27 Flexibility, stress analysis and support design
3.27.1 General
3.27.2 Flexibility General Need for flexibility analysis Self and cold spring Balanced design
3.27.3 Stress analysis
3.27.4 Data for stress analysis
3.27.5 Stress limitations General Displacement stress range Sustained longitudinal stress Stress due to sustained and occasional loads Flexibility and stress intensification factors Calculation of flexural stresses
3.27.6 Reactions General Maximum reactions for a simple system Maximum reaction for complex systems Reaction limits Calculation of pipe movements
3.28 Pipe supports
3.28.1 General Design criteria Design loads Analysis Design strength Materials Threaded elements Springs
3.28.2 Pipe support spacing
3.28.3 Fixtures Anchors and guides Supports without springs other than anchors and guides Variable spring supports Constant effort supports Counterweight supports Hydraulic supports Special fixtures Sway braces and vibrational dampeners
3.28.4 Support attachments General Non-integral attachments Integral attachments
3.28.5 Load-supporting structure
3.29 Information to be supplied
3.30 Information to be supplied by the owner
4 Fabrication and installation
4.1 Scope
4.2 Fabrication
4.3 Installation
4.4 Thermal insulation
4.5 Identification
5 Welding and allied joining processes
6 Examination and testing
6.1 Scope
6.2 Responsibility
6.3 Qualification of welding procedures and welders
6.4 Non-destructive examination
6.5 Alternatives to non-destructive testing
6.5.1 Alternative to radiographic or ultrasonic examination
6.5.2 Alternative to spot non-destructive testing by use of destructive tests
6.5.3 Alternative to radiographic or ultrasonic examination by use of in-process examination Purpose Application Stage of examination Method of examination
6.6 Pressure tests
6.6.1 General
6.6.2 Types of pressure tests
6.7 Hydrostatic test
6.7.1 Application
6.7.2 Test pressure
6.7.3 Hold period
6.8 Alternatives to hydrostatic test
6.8.1 Alternative to hydrostatic test by use of pneumatic testing
6.8.2 Alternative to hydrostatic test by means of visual examination and initial service leak-test
6.8.3 Alternative to hydrostatic test by use of increased non-destructive examination and leak test General Pressure retaining welds Mechanical joints Structural attachments
6.8.4 Proof hydrostatic test
6.9 Initial service leak test
6.10 Testing pressure-limiting devices, relief valves, pressure regulators, and control equipment
6.11 Report
7 Protective systems and devices
7.1 General
7.1.1 Basic requirement
7.1.2 Protective systems
7.1.3 Design and construction
7.1.4 Safeguarding
7.2 Pressure and temperature control systems
7.3 Pressure relief systems
7.3.1 General
7.3.2 Stop valves in pressure relief systems
7.4 Corrosion protection
7.5 Fire protection
7.6 Earthing
7.7 Protection from impact
7.8 Lightning protection
7.9 Human contact protection
7.10 Noise control
7.11 Isolation protection (for interconnected piping)
7.12 Not allocated
7.13 Protection against interference
8 Quality assurance and inspection
8.1 General
8.1.1 Scope
8.1.2 Basic requirements
8.1.3 Inspectors
8.2 Review of design
8.2.1 Design verification
8.2.2 Approval of design
8.3 Material and component inspection
8.3.1 Materials and components
8.3.2 Marking
8.4 General inspection of fabrication
9 Commissioning and operation
9.1 Commissioning
9.1.1 General
9.1.2 Commissioning personnel
9.1.3 Alarm and shutdown systems
9.1.4 Pressure-limiting devices, relief valves, pressure regulators and control equipment
9.1.5 Identification
9.1.6 Support settings
9.2 Operation
9.2.1 General
9.2.2 Modifications
Appendix A
Appendix B
Appendix C
C1 General
C1.1 Scope of Appendix
C1.2 Notation
C2 Cylindrical shells with a branch not radially arranged (hillside branches)
C3 Cylindrical shells with Y-shaped branch
C3.1 Design of cylindrical shells with Y-shaped branch
C3.2 Fin reinforcement
C3.3 Assessment factor
C4 Branches in spherical shells
C4.1 General
C4.2 Spherical shells with openings
C4.3 Branch geometry constraints
C4.4 Design of spherical shells
C4.4.1 Spherical shells without openings
C4.4.2 Spherical shells with openings
C4.4.2.1 Spherical shells with a vertical branch and an additional reinforcement (see Figure C4.3(d)).
C4.4.2.2 Spherical shells with vertical radial branch without additional reinforcement
C4.4.2.3 Spherical shells with oblique single branch, without additional reinforcement
C4.4.2.4 Spherical shells with several branches
C4.4.2.5 Spherical shells with Y-shaped branch
C4.5 Hemispherical heads
Appendix D
Appendix E
Appendix F
Appendix G
Appendix H
Appendix I
I1 General
I2 Design strength for piping classes 1, 2A and 3
I2.1 General
I2.2 Calculation of design strength
I2.3 Notation
I2.4 Design life (see Clause 3.4)
I3 Design strength for piping Class 2P
Appendix J
J1 General
J2 Absolute pressure
J3 Friction length
J4 Example
J5 Pipe junctions
J6 Mass flow discharge of exhaust pipe
Appendix K
Appendix L
L1 General
L2 Branch connections to mitred gusseted bends
L3 Reinforcement and branch thickness
L4 Branch systems
L5 Reinforcement in accordance with paragraph L3(a)
L5.1 Branch not affected by any other branch
L5.2 A branch affected by one or more other branches
L6 Reinforcement in accordance with Paragraph L3(b) (branch reinforcement when the thickness of the main is predetermined)
L6.1 Branch not affected by any other branch
L6.2 Branch affected by one or more other branches
L7 Length of branch reinforcement
L8 Mains (See Figure L4)
Appendix M
Appendix N
Appendix O
Appendix P
Appendix Q
Q1 Methods of flexibility analysis—Simplified analysis
Q2 Cold-spring
Q3 Stresses and reactions in a piping system
Q3.1 Thermal and sustained stresses
Q3.2 Resultant stress range and stress difference
Q3.3 End reactions
Q4 Plastic strains
Appendix R
R1 General
R2 Calculation of stress levels
R2.1 General
R2.2 Maximum stress range
R2.3 Maximum hot stress
R2.4 Sustained stress
R3 Analysis calculation
R4 Stress evaluation on straight pipe and a bend
R4.1 Combined stress
R4.2 Transverse stress
R4.3 Longitudinal stress
R4.4 Torsional stress
R5 Stress evaluation of a mitre bend
R5.1 Combined stress
R5.2 Transverse stress
R5.3 Longitudinal stress
R5.4 Torsional stress
R6 Stress evaluation at a branch connection
R6.1 Combined stress
R6.2 Transverse pressure stress
R6.3 Non-directional bending stress
R6.4 Torsional stress
R7 Allowable stress criteria
R8 Requirement for flexibility analysis
R9 Basis of flexibility analysis
R10 Values of proof stress, rupture stress, and design strength
Appendix S
S1 General
S2 Identification of planes
S3 Modes of operation
S4 Bending and torsional moments
S5 Determination of moments
S6 Limits
S6.1 General
S6.2 Stress range limitation
S6.3 Hot stress limitation
S6.4 Calculation of combined stress levels at point B
S6.5 Conclusion
Appendix T
Appendix U
U1 General
U1.1 Scope
U1.2 Requirements for hydrostatic test pressure
U2 Ferritic, austenitic and ferritic-austenitic steel piping, Class 1, 2A and 3
U2.1 Steam and water piping associated with steam boilers
U2.2 For all other piping services
U3 Ferritic steel piping Class 2P
U4 Non-ferrous metals
U5 Piping and pressure vessels tested together
U6 Piping subject to external pressure
U7 Jacketed piping
U8 Examples
Appendix V
V1 General
V2 Selection of piping class
Appendix W
W1 General
W2 Assessment of risks
W3 Control of risks
W3.1 General
W3.2 Control methods—General controls
W3.3 Control methods—Engineering controls
Cited references in this standard
Copper and copper alloys — Seamless tubes for heat exchangers
Copper and copper alloys — Seamless tubes for engineering purposes
Austenitic cast iron
Malleable cast iron
Ductile cast iron
Content history
DR 05158
AS 4041-2006 Rec:2016