ISO 12490:2011

INTERNATIONAL ISO
STANDARD 12490
First edition
2011-09-15
Petroleum and natural gas industries —
Mechanical integrity and sizing of
actuators and mounting kits for pipeline
valves
Industries du pétrole et du gaz naturel — Intégrité mécanique et
dimensionnement des motorisations et éléments de montage des
vannes de conduites
Reference number
©
ISO 2011
©  ISO 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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Published in Switzerland
ii © ISO 2011 – All rights reserved

Contents Page
Foreword . v
Introduction . vi
1  Scope . 1
2  Conformance . 1
2.1  Units of measurement . 1
2.2  Rounding . 1
2.3  Compliance with this International Standard . 1
3  Normative references . 2
4  Terms and definitions . 3
5  Symbols and abbreviated terms . 6
5.1  Symbols . 6
5.2  Abbreviated terms . 6
6  Actuator types and configurations . 7
6.1  General . 7
6.2  Actuator types . 7
6.3  Actuator configuration . 20
6.4  Action on loss of supply energy . 21
7  Design . 21
7.1  General . 21
7.2  Pressure-containing parts . 23
7.3  Bolting and tie rod design . 24
7.4  Mechanically loaded parts . 24
7.5  Springs and modules . 24
7.6  Mounting kit . 24
7.7  Stem extensions . 25
7.8  Lifting . 25
7.9  Handwheels and levers for manual override . 25
7.10  Locking devices . 26
7.11  Position indicators . 26
7.12  Travel stops . 26
7.13  Orientation . 26
7.14  Sealing . 26
7.15  Over-pressure protection . 26
7.16  Design documents . 26
8  Sizing . 26
8.1  Information required for actuator sizing . 26
8.2  Sizing method . 28
9  Instrumentation/regulation . 28
9.1  Torque limiting settings — Electric actuators . 28
9.2  Torque/thrust limiting controls — Pneumatic/hydraulic actuators . 29
10  Materials . 29
10.1  Material specification . 29
10.2  Service compatibility . 29
10.3  Composition limits . 29
10.4  Toughness test requirements for pressure-containing parts . 30
10.5  Bolting for pressure-containing, mechanically loaded parts and mounting kits . 31
10.6  Mechanically loaded parts . 31
10.7  Sour service .31
11  Welding .31
11.1  Welding of pressure-containing parts .31
11.2  Structural welding.31
11.3  Impact testing .32
11.4  Hardness testing .33
11.5  Repair .33
12  Quality control .33
12.1  NDE requirements.33
12.2  Measuring and test equipment .34
12.3  Qualification of inspection and test personnel .34
12.4  NDE of repairs .35
12.5  Visual inspection of castings .35
13  Testing .35
13.1  General .35
13.2  Shell test .35
13.3  Piston seal test .36
13.4  Torque/thrust test — Pneumatic/hydraulic actuators .36
13.5  Testing of electric actuators .36
13.6  Actuator functional test .37
14  Surface protection .37
15  Marking .38
16  Preparation for shipment .38
17  Documentation .39
Annex A (informative) Supplementary test requirements .40
Annex B (informative) Optional documentation .41
Annex C (informative) Purchasing guidelines .42
Annex D (normative) Record retention .45
Annex E (informative) Typical torque/thrust curves .46
Bibliography .51

iv © ISO 2011 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 12490 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries, Subcommittee SC 2, Pipeline transporation systems.

Introduction
It is necessary that users of this International Standard be aware that further or differing requirements can be
needed for individual applications. This International Standard is not intended to inhibit a vendor from offering,
or the purchaser from accepting, alternative equipment or engineering solutions for the individual application.
This can be particularly applicable where there is innovative or developing technology. Where an alternative is
offered, it is the responsibility of the vendor to identify any variations from this International Standard and
provide details.
vi © ISO 2011 – All rights reserved

INTERNATIONAL STANDARD ISO 12490:2011(E)

Petroleum and natural gas industries — Mechanical integrity
and sizing of actuators and mounting kits for pipeline valves
1 Scope
This International Standard defines the requirements for mechanical integrity and sizing of actuators used on
valves manufactured under ISO 14313 and API Specification 6D.
This International Standard is applicable to all types of electric, pneumatic and hydraulic actuators, inclusive of
mounting kit, installed on pipeline valves.
This International Standard is not applicable to actuators installed on control valves, valves being used for
regulation, valves in sub-sea service, handheld powered devices, stand-alone manually operated gearboxes,
instrument tubing and associated fittings and actuator control equipment.
2 Conformance
2.1 Units of measurement
In this International Standard, data are expressed in both SI units and USC units. For a specific order item,
unless otherwise stated, only one system of units shall be used, without combining data expressed in the
other system.
For data expressed in SI units, a comma is used as the decimal separator and a space is used as the
thousands separator. For data expressed in USC units, a dot (on the line) is used as the decimal separator
and a comma is used as the thousands separator.
2.2 Rounding
Unless otherwise stated in this International Standard, to determine conformance with the specified
requirements, observed or calculated values shall be rounded to the nearest unit in the last right-hand place of
figures used in expressing the limiting value, in accordance with ISO 80000-1:2009.
2.3 Compliance with this International Standard
A quality system should be applied to assist compliance with the requirements of this International Standard.
NOTE ISO/TS 29001 gives sector-specific guidance on quality management systems.
The manufacturer shall be responsible for complying with all of the applicable requirements of this
International Standard. It shall be permissible for the purchaser to make any investigation necessary in order
to be assured of compliance by the manufacturer and to reject any material that does not comply.
3 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 4406:1999, Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid
particles
ISO 5210, Industrial valves — Multi-turn valve actuator attachments
ISO 5211, Industrial valves — Part-turn actuator attachments
ISO 9606-1, Approval testing of welders — Fusion welding — Part 1: Steels
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel — General principles
ISO 10474, Steel and steel products — Inspection documents
ISO 14313:2007, Petroleum and natural gas industries — Pipeline transportation systems — Pipeline valves
ISO 15156 (all parts), Petroleum and natural gas industries — Materials for use in H S-containing
environments in oil and gas production
ISO 15607, Specification and qualification of welding procedures for metallic materials — General rules
ISO 15609 (all parts), Specification and qualification of welding procedures for metallic materials — Welding
procedure specification
ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding
procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
ISO 80000-1:2009, Qualities and units — Part 1: General
IEC 60529, Degrees of protection provided by enclosures (IP Code)
ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, Rules for Construction of Pressure
1)
Vessels
ASME Boiler and Pressure Vessel Code, Section VIII:2004, Division 2, Alternative Rules, Rules for
Construction of Pressure Vessels
ASME Boiler and Pressure Vessel Code, Section IX, Welding and Brazing Qualifications
2)
ASNT SNT-TC-1A , Recommended Practice No. SNT-TC-1A, Non-Destructive Testing
3)
ASTM A320/A320M , Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for Low-
Temperature Service
ASTM A370, Standard Test Methods and Definitions for Mechanical Testing of Steel Products
4)
ANSI/AWS D1.1/D1.1M , Structural Welding Code — Steel

1) American Society of Mechanical Engineers International, 345 East 47th Street, New York, NY 10017-2392, USA.
2) American Society of Non-Destructive Testing, P.O. Box 28518, 1711 Arlingate Lane, Columbus, OH 43228-0518, USA.
3) ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, USA.
2 © ISO 2011 – All rights reserved

AWS QC1, Standard for AWS Certification of Welding Inspectors
5)
EN 287-1 , Qualification test of welders — Fusion welding — Part 1: Steels
EN 473, Non-destructive testing — Qualification and certification of NDT personnel — General principles
EN 10204, Metallic products — Types of inspection documents
EN 12516-1, Industrial valves — Shell design strength — Part 1: Tabulation method for steel valve shells
EN 12516-2, Industrial valves — Shell design strength — Part 2: Calculation method for steel valve shells
EN 13445-3, Unfired pressure vessels — Part 3: Design
MSS SP-55, Quality Standard for Steel Castings for Valves, Flanges and Fittings and Other Piping
Components — Visual Method for Evaluation of Surface Irregularities
4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
4.1
actuator
electrically, pneumatically or hydraulically powered device bolted or otherwise attached to the valve for the
purpose of applying torque or thrust to open and close a valve
4.2
actuator, linear
actuator that transmits thrust to the valve for a defined linear stroke
4.3
actuator, multi-turn
actuator that transmits torque to the valve for a rotation of more than one revolution
4.4
actuator, part-turn
actuator that transmits torque to the valve for a rotation of one revolution or less
4.5
breakaway thrust
breakaway torque
maximum thrust or torque required to operate a valve at maximum pressure differential
[ISO 14313]
4.6
by agreement
agreed between the manufacturer and/or supplier and/or purchaser
4.7
coupling
driven component (drive adapter, drive tube, drive shaft) that allows transmission of torque and/or thrust from
an actuator driving component to the valve shaft/stem

4) The American Welding Society, 550 NW LeJeune Road, Miami, FL 33126, USA.
5) CEN, European Committee for Standardization, Central Secretariat, Rue de Stassart 36, B-1050 Brussels, Belgium.
4.8
cycle
continuous movement of the valve obturator from the fully closed position to the fully open position and back
to the fully closed position, or vice versa
4.9
drive train
all parts of a valve drive between the operator and the obturator, including the obturator but excluding the
operator
[ISO 14313]
4.10
intermediate support
mechanical component (bracket, spool, adapter flange) that allows the attachment between a valve and
actuator
4.11
mechanically loaded parts
actuator parts that are designed to provide the generation and/or transmission of torque or thrust
4.12
maximum allowable stem torque/thrust
MAST
maximum torque/thrust that it is permissible to apply to the valve drive train without risk of damage, as defined
by the valve manufacturer/supplier
4.13
mounting kit
components that may be comprised of combinations of the following: intermediate support, coupling, drive
key(s), dowel pin and bolting
4.14
pitch circle diameter
PCD
diameter of a circle on which a pattern of holes, either threaded or through-machined, is arranged, commonly
used for the purpose of fastening two mating components together
4.15
pressure-containing parts
parts whose failure to function as intended results in a release of contained fluid into the environment
[ISO 14313]
4.16
pressure, design
pressure defined for the design of the actuator pressure-containing parts, as defined by the actuator
manufacturer
4.17
pressure, maximum operating
maximum available pressure to supply at the actuator pressure port, as defined by the actuator
manufacturer/supplier
NOTE This is the pressure that generates the torque/thrust used to design the mounting kit.
4 © ISO 2011 – All rights reserved

4.18
pressure, maximum rated
maximum pressure permissible in the pressure-containing parts in their normal operating condition and which
is used to generate design torque/thrust
NOTE This is the pressure that generates the torque/thrust and is used to design the mechanically loaded parts of
the actuator.
4.19
pressure, maximum supply
maximum available pressure to supply at the actuator, as defined by the purchaser
4.20
pressure, minimum operating
minimum required pressure to supply at the actuator pressure port, as defined by the actuator
manufacturer/supplier
4.21
pressure, minimum supply
minimum available pressure to supply at the actuator, as defined by the purchaser
4.22
reduced stroke actuator
actuator with suitable travel stops that can be used to provide a movement to a predetermined position within
the actuator stroke
4.23
stall torque
maximum torque/thrust that an electric actuator develops when the motor is energised and the output drive is
locked
NOTE This is the torque used to design the mechanically loaded parts of the actuator.
4.24
stem
part that connects the obturator to the operator and which can consist of one or more components
[ISO 14313]
4.25
stroke
movement of the valve obturator from the fully closed position to the fully open position, or vice versa
4.26
supplier
manufacturer or third-party supplier of the actuator or the actuated valve assembly
4.27
temperature, maximum design
maximum temperature at which the actuator is capable of operating, as defined by the actuator manufacturer
4.28
temperature, maximum operating
maximum temperature at which the actuator is required to operate, as defined by the purchaser
NOTE Operating temperature can be influenced by ambient temperature.
4.29
temperature, minimum design
minimum temperature at which the actuator is capable of operating, as defined by the actuator manufacturer
4.30
temperature, minimum operating
minimum temperature at which the actuator is required to operate, as defined by the purchaser
NOTE Operating temperature can be influenced by ambient temperature.
4.31
torque/thrust, design
highest torque/thrust of an actuator at maximum spring force, maximum supply voltage, or maximum rated
pressure with torque/thrust-limiting or pressure-reducing protection devices de-activated, which is used to
design mechanically loaded parts
4.32
torque/thrust, maximum
highest torque/thrust of an actuator at specified voltage/pressure with torque/thrust-limiting or pressure-
reducing protection devices active, which is used for the design of the mounting kit
4.33
unless otherwise agreed
requirements of the standard shall apply, unless the manufacturer and purchaser agree on a deviation
[ISO 14313]
4.34
unless otherwise specified
requirements of the standard shall apply, unless the purchaser specifies otherwise
[ISO 14313]
4.35
voltage, maximum supply
maximum available voltage to be supplied at the actuator
NOTE This is the voltage used to design the mechanically loaded parts.
4.36
voltage, minimum supply
minimum available voltage to be supplied at the actuator
5 Symbols and abbreviated terms
5.1 Symbols
S design stress intensity
m
t thickness
5.2 Abbreviated terms
BM base metal
BPVC Boiler and Pressure Vessel Code
CE carbon equivalent
HAZ heat-affected zone
HBW Brinell hardness, tungsten ball indenter
6 © ISO 2011 – All rights reserved

HRC Rockwell C hardness
HV Vickers hardness
MT magnetic-particle testing
NDE non-destructive examination
PQR procedure qualification record
PT penetrant testing
PWHT post-weld heat treatment
RT radiographic testing
SMYS specified minimum yield strength
USC United States customary
UT ultrasonic testing
WM weld metal
WPQ welder performance qualification
WPS weld procedure specification
6 Actuator types and configurations
6.1 General
Actuators shall be part-turn, multi-turn or linear in action. Part-turn actuators shall be capable of withstanding
torsional forces. Multi-turn actuators shall be capable of withstanding torsional forces, and shall also be
capable of withstanding axial thrust if specified. Linear actuators shall be capable of withstanding axial thrust.
For reduced stroke actuators, i.e. an actuator that prevents the valve from reaching its fully open or fully
closed position, the stroke range shall be specified by the purchaser.
NOTE Some typical torque/thrust characteristics are shown in Annex E.
6.2 Actuator types
6.2.1 Electric
Typical configurations for electric actuators are shown, for illustration purposes only, in Figures 1 to 4.
Electric actuators shall be self-contained units, typically comprised of an electric motor, reduction gearing, limit
and/or torque switches, handwheel for manual override, and a motor control package, which may be integral
or external to the actuator.
Electric actuators shall be powered from either an AC or DC electrical source, which shall be specified by the
purchaser. The output of electric actuators shall be part-turn, multi-turn or linear in action.
Key
1 control board housing
2 terminal board housing
3 electric motor
4 reduction gear
5 motor shaft
6 motor housing
7 terminal block
8 local control unit
9 manual override
10 declutch lever
11 part-turn gear
12 gearbox input shaft
13 stop bolt
Figure 1 — Electric actuator, part-turn with reduction, double-acting
8 © ISO 2011 – All rights reserved

Key
1 control board housing
2 terminal board housing
3 electric motor
4 reduction gear
5 motor shaft
6 motor housing
7 terminal block
8 local control unit
9 manual override
10 declutch lever
11 multi-turn gear
12 gearbox input shaft
Figure 2 — Electric actuator, multi-turn with reduction, double-acting
Key
1 control board housing
2 terminal board housing
3 electric motor
4 reduction gear
5 motor shaft
6 motor housing
7 terminal block
8 local control unit
9 manual override
10 declutch lever
11 linear motion shaft
12 thrust nut
Figure 3 — Electric actuator, linear with reduction, double-acting
10 © ISO 2011 – All rights reserved

Key
1 control board housing
2 terminal board housing
3 electric motor
4 reduction gear
5 motor shaft
6 motor housing
7 terminal block
8 local control unit
9 manual override
10 declutch lever
11 spring
12 spring cartridge
13 rack and pinion
Figure 4 — Electric actuator, part-turn with reduction, single-acting with spring return
6.2.2 Pneumatic
Typical configurations for pneumatic actuators are shown, for illustration purposes only, in Figures 5 to 9
and 11.
Pneumatic part-turn and multi-turn actuators shall be comprised of pneumatic cylinder(s) or another shape,
appropriate gearing and travel stops.
Pneumatic actuators should be powered by compressed air, unless otherwise specified. Minimum
compressed air cleanliness should be as given in ISO 8573-1:2010, class 5 for particle size and class 3 for
dew point. Where other compressed gases or pressurized fluids are used, the internal actuator parts and
lubricants shall be compatible.
6.2.3 Hydraulic
Typical configurations for hydraulic actuators are shown, for illustration purposes only, in Figures 5 to 8,
10 and 12 to13.
Hydraulic part-turn and multi-turn actuators shall be comprised of hydraulic cylinder(s) or another shape,
appropriate gearing and travel stops.
Hydraulic actuators shall be powered by pressurised hydraulic fluid. The hydraulic fluid shall be selected by
agreement, ensuring compatibility with internal actuator parts and lubricants.
Minimum hydraulic fluid cleanliness shall be in accordance with ISO 4406:1999, class 19/17/14, unless
otherwise agreed.
12 © ISO 2011 – All rights reserved

Key
1 housing
2 guide block
3 guide bar
4 piston rod
5 inner cap
6 outer cap
7 yoke
8 cylinder
9 piston
10 tie rod
11 travel stop
12 rack and pinion
13 pressure port
Figure 5 — Pneumatic/hydraulic actuator, part-turn, double-acting
Key
1 housing
2 guide block
3 guide bar
4 piston rod
5 inner cap
6 outer cap
7 yoke
8 cylinder
9 piston
10 tie rod
11 travel stop
12 rack and pinion
13 spring
14 pressure port
15 pressure vent
Figure 6 — Pneumatic/hydraulic actuator, part-turn, single-acting with spring return
14 © ISO 2011 – All rights reserved

Key
1 mounting flange
2 pedestal
3 coupling
4 piston rod
5 lower cap
6 upper cap
7 cylinder
8 piston
9 tie rod
10 visual position indicator rod
11 pressure port
Figure 7 — Pneumatic/hydraulic actuator, linear, double-acting
Key
1 mounting flange 8 piston
2 pedestal 9 tie rod
3 coupling 10 visual position indicator rod
4 piston rod 11 spring
5 lower cap 12 spring cartridge
6 upper cap 13 pressure port
7 cylinder 14 pressure vent
Figure 8 — Pneumatic/hydraulic actuator, linear, single-acting with spring return
16 © ISO 2011 – All rights reserved

Key
1 housing
2 rotor/shaft
3 vane
4 travel stop
5 pressure port
Figure 9 — Pneumatic actuator, vane, part-turn, double-acting

Key
1 housing
2 rotor/shaft
3 vane
4 cover
5 fixed shoe
6 base
7 pressure port
Figure 10 — Hydraulic actuator, vane, part-turn, double-acting
Key
1 housing
2 rotor/shaft
3 vane
4 spring housing
5 spring
6 travel stop
7 pressure port
8 pressure vent
Figure 11 — Pneumatic actuator, vane, part-turn, single-acting, spring return
18 © ISO 2011 – All rights reserved

Key
1 housing 7 cap
2 cylinder 8 thrust bushing
3 mounting flange 9 seal
4 coupling 10 pressure port
5 piston with helix 11 pressure vent
6 position indicator 12 helical spline
a
Axial thrust.
b
Rotary motion.
Figure 12 — Hydraulic actuator, helix, part-turn, double-acting
Key
1 housing 8 thrust bushing
2 cylinder 9 cover
3 mounting flange 10 spring cartridge
4 coupling 11 spring
5 piston with helix 12 seal
6 position indicator 13 helical spline
7 cap
a
Axial thrust.
b
Rotary motion.
Figure 13 — Hydraulic actuator, helix, part-turn, single-acting, spring return
6.3 Actuator configuration
6.3.1 Double-acting
Typical configurations for double-acting actuators are shown, for illustration purposes only, in Figures 1, 2, 3,
5, 7, 9, 10 and 12.
NOTE Double-acting actuators can be of the electric, pneumatic, or hydraulic type and can have either part-turn,
multi-turn or linear action. The design requires the application of supply energy to operate the actuator output in both
directions.
CAUTION — If supplying a double-acting actuator for fail-safe action, a suitable and appropriately
sized stored energy device is required.
20 © ISO 2011 – All rights reserved

6.3.2 Single-acting
Typical configurations for single-acting actuators are shown, for illustration purposes only, in Figures 4, 6, 8,
11 and 13.
NOTE Single-acting actuators can be of the electric, pneumatic, or hydraulic type and can have either part-turn or
linear action to operate in one direction only, with the return stroke being powered by an alternative form of stored energy.
Single-acting actuators are generally associated with fail-safe applications.
6.4 Action on loss of supply energy
Upon loss of supply energy, the valve shall be automatically driven to, or remain in, a predetermined position
as defined by the purchaser. These positions are commonly as follows:
 fail-open;
 fail-closed;
 fail-last.
7 Design
7.1 General
The actuator portion of the interface between the actuator and the valve shall be in accordance with ISO 5210
or ISO 5211 unless otherwise agreed.
If alternative dimensions are used that are outside the scope of ISO 5210 or ISO 5211, they shall follow the
design methodology and acceptance criteria of these International Standards unless otherwise agreed.
Actuators that are subjected to frequent cycling and/or rapid operation can require additional design
considerations, including fatigue analysis and impact as appropriate.
Design verification and/or validation, including a design review, shall be performed.
For pneumatic and hydraulic actuators,
a) the design pressure being used for the design of the pressure-containing parts shall be specified by the
actuator manufacturer, and
b) the maximum rated pressure shall be defined by the actuator manufacturer, and shall be less than or
equal to the design pressure and greater than or equal to the maximum operating pressure.
These actuator pressure relationships are illustrated in Figure 14. The relationships between energy (e.g.
pressure and voltage), torque/thrust, component part design and sizing are shown in Figure 15, along with
references to the corresponding subclause(s).
Figure 14 — Relationship between design, supply and rated pressures
22 © ISO 2011 – All rights reserved

NOTE The numbers in brackets refer to the corresponding subclause.
Figure 15 — Relationship between energy, torque/thrust and actuator design and sizing
7.2 Pressure-containing parts
Pressure-containing parts, such as the cylinder heads and cylinder, shall be designed in accordance with one
of the following:
 ASME BPVC Section VIII, Division 1 or Division 2;
 EN 12516-1, EN 12516-2 or EN 13445-3;
 other internationally recognized design codes or standards by agreement.
The use of proprietary design methodology, calculations, acceptance criteria and satisfactory documented
previous experience including validation testing shall be by agreement.
NOTE Associated fittings and actuator control equipment are not within the scope of this International Standard.
7.3 Bolting and tie rod design
Bolting and tie rod design for pressure-containing parts shall be in accordance with the selected design code
(see 7.2), unless otherwise agreed.
7.4 Mechanically loaded parts
Mechanically loaded parts shall be designed to accommodate the maximum anticipated in-service load,
including design torque/thrust, and shall take into account the following:
 torque/thrust generated at maximum rated pressure, for pneumatic/hydraulic actuators;
 torque/thrust generated by maximum compressed spring force, for spring return actuators;
 torque/thrust at maximum supply voltage;
 torque/thrust at stall condition, for electric actuators.
Mechanically loaded parts shall be designed in accordance with a documented methodology, including
acceptance criteria. Acceptance criteria shall include analysis of stress, strain (and fatigue where applicable)
encountered during operation at maximum torque/thrust output. Alternatively, acceptance criteria may be
satisfactory documented previous experience including validation testing.
7.5 Springs and modules
The spring(s) on spring return actuators shall be designed in accordance with internationally recognized
design codes or standards. If no equations exist for the spring type, a proprietary equation may be used
provided it has been validated by cycle testing.
NOTE An example of an internationally recognized design code or standard is EN 13906.
A qualification test shall be performed on all spring(s) by full-load cycling a minimum of five times followed by
load testing to validate the actuator spring design data. Additionally, a sample of each production batch of
springs shall be subjected to the same test to verify the performance.
The manufacturer shall provide procedures for the safe removal of the spring/spring module.
7.6 Mounting kit
7.6.1 Design basis shall be either stress-based or based on satisfactory documented previous experience
including validation testing.
The mounting kit shall be designed to transfer all of the loads from the actuator to the valve and to react to
them, including loads of 1,1 or more times the maximum torque/thrust output, and it shall take into account the
following:
 torque/thrust generated at maximum operating pressure or as limited by relief valve or other pressure-
limiting device, for pneumatic/hydraulic actuators;
 torque/thrust generated by maximum compressed spring force, for spring return actuators;
 torque/thrust at stall condition or 100 % torque/thrust switch setting, for electric actuators.
The maximum torque/thrust output shall be less than or equal to the design torque/thrust.
24 © ISO 2011 – All rights reserved

Tensile stresses in mounting kit components shall not exceed 67 % of SMYS when delivering 1,1 or more
times the maximum torque/thrust output. Shear, torsion and bearing stresses shall not exceed the limits
specified in ASME BPVC Section VIII:2004, Division 2, Part AD-132, except that design stress intensity values,
S , shall be 67 % of SMYS.
m
A strength efficiency factor of 0,75 shall be used for fillet welds, unless otherwise agreed. For additional
welding requirements, see 11.1.
7.6.2 For all mounting kits, attention shall be paid to deflection and strain. Adherence to these allowable
stress limits alone might not result in a functionally acceptable design for the actuated valve assembly.
NOTE Ensuring that the valve (e.g. bolting) is capable of transferring all of the loads from the actuator to the valve
and of reacting to them, including loads of 1,1 or more times the maximum torque/thrust output, is the responsibility of the
valve manufacturer.
Bolting in mounting kits shall not be subjected to shear forces, unless otherwise agreed.
The mounting kit design and manufacturing tolerance shall ensure the following:
 parallelism of the intermediate support mounting faces;
 concentricity of the PCD of the bolting of the intermediate support;
 alignment of the PCD, valve stem, coupling and the actuator drive.
7.6.3 The mounting kit design shall also consider the following:
 installed orientation of the valve and actuator;
NOTE Valves installed with horizontal stems can require additional support, e.g. spigots, to ensure accurate
alignment of valve and actuator during removal and refitting in field service.
 external loading from environmental effects (e.g. wind, snow, seismic activity);
 blast loading, if specified;
 frequency of cycling and speed of operation.
7.7 Stem extensions
Stem extensions shall be designed in accordance with ISO 14313:2007, 7.20.2.
7.8 Lifting
For actuators heavier than 25 kg, lifting points shall be identified, for the purpose of lifting the actuator alone
during installation or maintenance, unless otherwise agreed.
The supplier of the actuated valve assembly shall identify the lifting points for the complete a
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