IEC 63277-3-1:2025
(Main)Binary power generation systems - Part 3-1: Safety requirements - System with less than 500 kW in capacity
Binary power generation systems - Part 3-1: Safety requirements - System with less than 500 kW in capacity
IEC 63277-3-1:2025 describes the safety requirements of binary power generation systems based on organic Rankine cycle (ORC) with less than 500 kW in output capacity.
This document covers significant hazards, hazardous situations, and events, with the exception of those associated with environmental compatibility (installation conditions), relevant to binary power generation systems (ORC), when they are used as intended and under the conditions foreseen by the manufacturer.
Systèmes de production d'énergie binaire - Partie 3-1: Exigences de sécurité pour le système d'une capacité inférieure à 500 kW
General Information
Standards Content (Sample)
IEC 63277-3-1 ®
Edition 1.0 2025-02
INTERNATIONAL
STANDARD
Binary power generation systems –
Part 3-1: Safety requirements – System with less than 500 kW in capacity
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IEC 63277-3-1 ®
Edition 1.0 2025-02
INTERNATIONAL
STANDARD
Binary power generation systems –
Part 3-1: Safety requirements – System with less than 500 kW in capacity
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.190 ISBN 978-2-8327-0152-2
– 2 – IEC 63277-3-1:2025 © IEC 2025
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references. 8
3 Terms, definitions and abbreviated terms . 10
3.1 Terms and definitions . 10
3.2 Abbreviated terms . 12
4 Safety requirements and protective measurements . 12
4.1 General safety strategy . 12
4.2 Physical environment and operating conditions . 13
4.2.1 General requirements . 13
4.2.2 Electrical power input . 13
4.2.3 Physical environment . 13
4.2.4 Water input . 13
4.2.5 Vibrations, shocks and bumps . 13
4.2.6 Handling, transportation and storage . 13
4.3 Selection of materials . 13
4.4 Other requirements . 14
4.5 Pressure equipment and piping systems . 15
4.5.1 Pressure equipment . 15
4.5.2 Piping systems . 15
4.6 Electrical safety . 15
4.7 Control systems and protective components . 15
4.7.1 General requirements . 15
4.7.2 Control systems . 15
4.7.3 Protective components . 17
4.8 Pneumatic and hydraulic powered equipment. 18
4.9 Valves . 18
4.9.1 Shut off valves . 18
4.9.2 Safety valves . 18
4.10 Rotating equipment . 19
4.10.1 General requirements . 19
4.10.2 Motors and generators . 19
4.10.3 Expanders, turbines, and auxiliary equipment . 19
4.10.4 Pumps . 20
4.11 Enclosures . 20
4.12 Insulation . 20
4.13 Utilities . 21
4.13.1 General requirements . 21
4.13.2 Cold water supply . 21
4.13.3 Hot water or steam supply . 21
4.13.4 Electrical connections – Disconnection from the mains supply . 21
4.14 Installation and fulfilment . 22
4.14.1 Installation . 22
4.14.2 Maintenance . 22
5 Tests . 23
5.1 General requirements . 23
5.2 Strength-pressure test . 23
5.2.1 General . 23
5.2.2 Strength-pressure test . 23
5.3 Tightness test . 24
5.3.1 General . 24
5.3.2 Factory tests . 24
5.3.3 Site tests . 24
5.4 Electrical safety tests . 24
5.4.1 General . 24
5.4.2 Insulation resistance test . 24
5.4.3 Protective device test . 24
5.4.4 Comprehensive interlock test . 25
5.5 Electromagnetic compatibility (EMC) test . 25
5.6 Delivery test . 25
6 Marking, labeling and packaging . 25
6.1 General requirements . 25
6.2 Marking of binary power generation systems . 25
6.3 Marking of components . 26
6.4 Technical documentation . 26
6.4.1 General . 26
6.4.2 Installation manual . 26
6.4.3 Operating manual . 27
6.4.4 Maintenance manual . 27
Annex A (informative) Significant hazards, hazardous situations and events dealt with
in this document . 28
Bibliography . 30
Figure 1 – Typical binary power generation system . 8
Table 1 – Insulation resistance . 24
Table A.1 – Hazardous situations and events . 28
– 4 – IEC 63277-3-1:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
BINARY POWER GENERATION SYSTEMS –
Part 3-1: Safety requirements – System with
less than 500 kW in capacity
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
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Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 63277-3-1 has been prepared by IEC project committee 126: Binary power generation
systems. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
126/68/FDIS 126/74/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 63277 series, published under the general title Binary power
generation systems, can be found on the IEC website.
Future documents in this series will carry the new general title as cited above. Titles of existing
documents in this series will be updated at the time of the next edition.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 6 – IEC 63277-3-1:2025 © IEC 2025
INTRODUCTION
While the world's binary power generation systems are growing, the IEC 63277 series specifies
the performance test methods of binary power generation systems and acknowledges the fair
and standardized competition of binary power generation systems.
It is very important to ensure that the binary power generation systems will be operated safely
during the operation. Safety requirements are an important theme that should be internationally
standardized as well as the performance test methods.
By adding an objective evaluation of safety based on international standards, it is expected that
the selection criteria will become more appropriate and that it will have the effect of promoting
it worldwide.
This document addresses the safety considerations unique to binary power generation systems
and is intended to be one in a series of international standards addressing this new technology.
BINARY POWER GENERATION SYSTEMS –
Part 3-1: Safety requirement – System with
less than 500 kW in capacity
1 Scope
This part of IEC 63277 describes the safety requirements of binary power generation systems
based on organic Rankine cycle (ORC) with less than 500 kW in output capacity.
This document covers significant hazards, hazardous situations, and events, with the exception
of those associated with environmental compatibility (installation conditions), relevant to binary
power generation systems (ORC), when they are used as intended and under the conditions
foreseen by the manufacturer.
A typical binary power generation system is shown in Figure 1.
– 8 – IEC 63277-3-1:2025 © IEC 2025
a f l
Heat transport medium for Heat exchanger for evaporating Emission of heating medium
working fluid heating, the working fluid using of from the system after heat
commonly steam or hot water heating medium exchanged
b g m
Heat transport medium for The system consists from a Emission of cooling medium
working fluid cooling, turbine or expander and a from the system after heat
commonly air or water. generator, it converts thermal exchanged
energy of working fluid to
electric energy
c h n
Electrical input specified by the Heat exchanger for condensing The power produced from the
manufacturer, for controls and the working fluid using a system and provided to an
other supporting functions cooling medium external load or grid
d i o
Includes the providing of Pressurization equipment for The transmission of operational
control signals, setpoint and circulating the working fluid in state and other data collected
operation instructions as well a closed system or generated by the system
as remote access, parameter,
software, and firmware updates
e j p
Factors from the surrounding System(s) that is composed of Factors from the surrounding
impacting the binary power sensors, actuators, switches, impacting the binary power
generation system, such as and logic components that generation system, such as
earthquake, rain, wind, snow, maintain the binary power emission of noise, vibrations,
temperature, humidity, and generation system parameters polluted water and gas, and
atmospheric condition but also within the manufacturer's electromagnetic disturbance
electromagnetic disturbances specified limits including
moving to safe states
k
System(s) that adjusts the
power generated by the power
generation system for
transmitting to the outside of
boundaries, and System(s) that
distributes the power to the
load inside of boundaries
Figure 1 – Typical binary power generation system
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
IEC 60034-1, Rotating electrical machines – Part 1: Rating and performance
IEC 60079-10-1, Explosive atmospheres – Part 10-1: Classification of areas – Explosive gas
atmospheres
IEC 60079-29-1, Explosive atmospheres – Part 29-1: Gas detectors – Performance
requirements of detectors for flammable gases
IEC 60204-1, Safety of machinery – Electrical equipment of machines – Part 1: General
requirements
IEC 60335-1, Household and similar electrical appliances – Safety – Part 1: General
requirements
IEC 60417, Graphical symbols for use on equipment, available at http://www.graphical-
symbols.info/equipment
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 60730-1, Automatic electrical controls – Part 1: General requirements
IEC 60730-2-6, Automatic electrical controls – Part 2-6: Particular requirements for automatic
electrical pressure sensing controls including mechanical requirements
IEC 60730-2-9, Automatic electrical controls – Part 2-9: Particular requirements for temperature
sensing controls
IEC 60730-2-15, Automatic electrical controls – Part 2-15: Particular requirements for automatic
electrical air flow, water flow and water level sensing controls
IEC 60950-1, Information technology equipment – Safety – Part 1: General requirements
IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic safety-
related systems
IEC 61511-1, Functional safety – Safety instrumented systems for the process industry sector
– Part 1: Framework, definitions, system, hardware and application programming requirements
IEC 61557-1, Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V
DC – Equipment for testing, measuring or monitoring of protective measures – Part 1: General
requirements
IEC 61557-2, Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V
DC – Equipment for testing, measuring or monitoring of protective measures – Part 2: Insulation
resistance
IEC 62040-1, Uninterruptible power systems (UPS) – Part 1: Safety requirements
IEC 62061, Safety of machinery – Functional safety of safety-related control systems
IEC 62477-1, Safety requirements for power electronic converter systems and equipment –
Part 1: General
IEC 62477-2, Safety requirements for power electronic converter systems and equipment –
Part 2: Power electronic converters from 1 000 V AC or 1 500 V DC up to 36 kV AC or 54 kV
DC
– 10 – IEC 63277-3-1:2025 © IEC 2025
ISO 3864-2, Graphical symbols – Safety colours and safety signs – Part 2: Design principles
for product safety labels
ISO 4413, Hydraulic fluid power – General rules and safety requirements for systems and their
components
ISO 4414, Pneumatic fluid power – General rules and safety requirements for systems and their
components
ISO 7000, Graphical symbols for use on equipment, available at http://www.graphical-
symbols.info/equipment
ISO 12100, Safety of machinery – General principles for design – Risk assessment and risk
reduction
ISO 13709, Centrifugal pumps for petroleum, petrochemical and natural gas industries
ISO 13849-1, Safety of machinery – Safety-related parts of control systems – Part 1: General
principles for design
ISO 13849-2, Safety of machinery – Safety-related parts of control systems – Part 2: Validation
ISO 13850, Safety of machinery – Emergency stop function – Principles for design
ISO 14847, Rotary positive displacement pumps – Technical requirements
ISO 15649, Petroleum and natural gas industries – Piping
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1 Terms and definitions
3.1.1
binary power generation system
set of components that consists of five main components and a system in which a working fluid
having a low boiling point is heated and evaporated by hot water, and the expander is driven
by the working fluid gas to generate electricity
Note 1 to entry: The five main components are an evaporator, a condenser, a working fluid pump, an expander and
a generator.
3.1.2
working fluid
medium used within the thermodynamic cycle that receives heat from the heat source via a heat
transport medium and produces power by fluid expansion
3.1.3
heat source
component that supplies heat to drive the system
Note 1 to entry: This power generation system utilizes factory waste heat, hot spring water, geothermal heat and
solar heat as heat sources from which it extracts heat with hot water (heat transfer medium) and thereby heats the
working fluid through an evaporator to generate vapour.
3.1.4
evaporator
heat exchanger that heats and evaporates working fluid liquid by using hot water
3.1.5
condenser
heat exchanger that cools and condenses working fluid gas by using cold water or ambient air
3.1.6
working fluid pump
fluid machine that pressurize and circulate the liquid from the condenser to the evaporator
3.1.7
expander
machine that generates power by expanding a high-pressure working medium (working fluid
vapour) thereby driving a generator
Note 1 to entry: More specifically, high-pressure medium vapour taken in from the expander's inlet internally
expands and then is discharged from the outlet port as low-pressure medium vapour; this process converts fluid
energy into mechanical power.
Note 2 to entry: Generally, expanders are categorized according to their expansion mechanism into kinetic type
(centrifugal, axial, etc.) and displacement type (reciprocating, rotary, scroll, screw, etc.), and are selected depending
on operating conditions and capacity range.
3.1.8
design pressure
highest pressure that can occur under any and all operating modes, including steady state and
transient
3.1.9
electromagnetic disturbance
electromagnetic phenomenon that can degrade the performance of a device, piece of equipment
or system, or adversely affect living or inert matter
3.1.10
electrical equipment
material, fittings, devices, appliances, fixtures, apparatus and the like used as part of, or in
connection with, an electrical installation
3.1.11
emergency shutdown
control system actions (based on process parameters) taken to shutdown immediately the
binary power generation system and all its reactions, to avoid equipment damage, or personnel
hazards or both
[SOURCE: IEC 60050-485:2020, 485-19-02, modified – The words "fuel cell power system"
have been replaced with "binary power generation system".]
3.1.12
interlock
component that prevents other operations from occurring unless certain conditions are met and
provides that proof to the related safety control device which performs the safety shutdown
– 12 – IEC 63277-3-1:2025 © IEC 2025
3.1.13
enclosure
housing affording the type and degree of protection suitable for the intended application
3.2 Abbreviated terms
EMC electromagnetic compatibility
FMEA failure mode and effects analysis
FTA fault tree analysis
ORC organic Rankine cycle
UPS uninterruptible power systems
4 Safety requirements and protective measurements
4.1 General safety strategy
The manufacturer shall perform risk assessment in written form, in accordance with ISO 12100,
to ensure the following.
a) All reasonably foreseeable hazards, hazardous situations and events, and foreseeable
misuse throughout the anticipated binary power generation system's lifetime have been
identified. Annex A lists the hazards covered in this document.
b) The risk to these hazards is estimated from a combination of the probability of occurrence
of the hazard and the projected severity.
c) The two factors which determine each one of the estimated risks (probability and severity)
have been eliminated or reduced to a level not exceeding the acceptable risk level through
the application of
1) intrinsically safe structural design and its methods, or
2) guards and protective devices provided
i) by passive control of energy release without endangering the surrounding
environment (e.g. rupture disc, discharge valve, heat shut-off device), or
ii) by active control of energy that is released through safety-related control functions.
EXAMPLE An electronic control device installed in a binary power generation system evaluates sensor
signals and implements appropriate measures with safety-related control functions.
d) For residual risks that could not be mitigated by the measures referred to in c), labels,
warnings or special training requirements shall be presented so that persons entering the
hazardous area understand the need for countermeasures.
e) For functional safety, the required severity level, performance level or grade of control
function shall be determined and designed in accordance with the following:
1) for systems covered by IEC 60204-1, IEC 61511-1, ISO 13849-1, ISO 13849-2, the
IEC 61508 series or IEC 62061 shall apply;
2) IEC 60730-1 shall apply to equipment based on IEC 60335-1 or IEC 62040-1;
3) for other systems, both the IEC 61508 series and IEC 61511-1 shall apply.
f) For failure mode and effects analysis (FMEA) and fault free analysis (FTA), the following
standards can be used as guidance:
• IEC 60812;
• SAE J1739;
• IEC 61025.
4.2 Physical environment and operating conditions
4.2.1 General requirements
The protection system of the binary power generation systems shall be designed and
constructed to perform the intended functions under the physical environment and operating
conditions specified in 4.2.2 to 4.2.6.
4.2.2 Electrical power input
Binary power generation systems shall be designed to operate correctly with the electrical
power input conditions specified in the relevant electrical product standards listed in 4.7 or
specified by the manufacturer.
4.2.3 Physical environment
The manufacturer shall define the physical environmental conditions suitable for the binary
power generation systems, considering the following:
• use indoors or outdoors;
• temperature, humidity, altitude;
• the possibility of earthquake in the area where it will be installed.
4.2.4 Water input
The manufacturer shall specify the water quality and supply the characteristics of the water
used for the binary power generation systems.
4.2.5 Vibrations, shocks and bumps
Adverse effects of vibrations, shocks and bumps (including those generated by machinery and
related equipment, and those caused by the physical environment) shall be avoided by selecting
the suitable equipment, by mounting away from the binary power generation systems or by
mounted on anti-vibration mounts. This does not include the impact of earthquake shocks which
shall be dealt with separately if the manufacturer determines that the effects of earthquakes
shall be considered (see 4.2.3).
4.2.6 Handling, transportation and storage
Binary power generation systems and its components shall be designed or packed so that they
can be safely handled and transported. They shall also, if applicable, provide a means suitable
for handling by crane or similar equipment, and be designed to be stored safely and without
damage (e.g. proper stability, special support, etc.).
4.3 Selection of materials
All materials shall be suitable for their intended use.
a) Mechanical stability with respect to strength (fatigue properties, endurance limit, creep
strength) shall be maintained under the entire range of use conditions during the service life
specified by the manufacturer.
b) The fluids used in binary power generation systems (e.g. working fluids, lubricants, cooling
water) shall not be adversely affected by chemical and physical effects, and their
environmental degradation shall be ensured.
c) Unless replacement is foreseen, the chemical and physical properties of the materials
required for operational safety shall not be affected during the planned life of the equipment.
– 14 – IEC 63277-3-1:2025 © IEC 2025
d) When selecting materials and production methods, the corrosion resistance, wear
resistance, electrical conductivity, impact strength, aging resistance, temperature change
effects, effects of combining materials (e.g. electrolytic corrosion), ultraviolet rays, and the
effects on the mechanical performance of materials shall be fully considered.
e) If the materials used to build a binary power generation system are known to be hazardous
under certain circumstances, the manufacturer shall implement the necessary measures to
fully minimize the risks that threaten the safety or health of persons and provide the
necessary information.
f) Asbestos or asbestos-containing materials shall not be used in the manufacture of binary
power generation systems. The use of lead, cadmium, mercury, hexavalent chromium,
polybrominated biphenyl, polybrominated diphenyl ether and other hazardous substances,
such as polychlorinated biphenyls, can be subject to regulatory requirements.
g) In the event of the possibility of erosion, wear, corrosion or other chemical adverse effects,
the following measures shall be taken:
1) minimize such impacts through appropriate design or appropriate protection (e.g. use of
cladding materials or surface coatings), giving due consideration to the intended and
reasonably foreseeable use;
2) make the most affected parts replaceable.
h) The maintenance manual presented in 6.4.4 describes the content and frequency of
inspection and maintenance measures necessary for continued safe use. In addition, if
necessary, criteria for parts replacement shall be indicated.
4.4 Other requirements
a) To the extent permitted by the application, accessible parts of the binary power generation
systems shall not have sharp edges, sharp angles, or rough surfaces that can cause
personal injury.
b) Binary power generation systems and peripherals to which access is expected shall be
designed and constructed to prevent people from slipping, tripping, or falling.
c) The moving parts of a binary power generation systems shall be designed, built, and
arranged to avoid hazards. If hazards persist, the moving parts shall be guarded or secured
with protective equipment to prevent all contact risks leading to accidents.
d) The components of binary power generation systems and their connections shall be
constructed in such a way that they are free from damage and wear, as they are subject to
instability and distortion, which can jeopardize safety during normal use.
e) Binary power generation systems shall be designed and built to avoid hazards from gases,
liquids, dust or vapours emitted during operation or maintenance.
f) All components shall be securely installed and firmly supported.
g) Components of a safe shutdown system whose failure could cause a hazardous event shall
be assessed in accordance with ISO 12100 for the intended use.
h) The manufacturer shall eliminate any risk of injury caused by contact with or proximity to
hot external surfaces of the enclosure, handles, grips or knobs of the binary power
generation systems.
i) Binary power generation systems shall be designed and constructed to reduce acoustic
noise to an appropriate level which can be subject to relevant regional or national noise
regulation standards.
j) If explosive, flammable or toxic fluids are contained in the pipes, precautions shall be taken
with proper design and marking.
k) The power supply system shall not exceed its rated temperature.
l) Manufacturers shall not use pollutants (e.g. dust, salt, smoke) and consider the suitability
for operation of binary power generation systems in the presence of corrosive gases.
m) Binary power generation systems shall be designed to safely contain leakage of any harmful
liquids, such as oil.
4.5 Pressure equipment and piping systems
4.5.1 Pressure equipment
The construction and labelling of pressure vessels (heat exchangers, accumulators, or similar
containers) and pressure relief mechanisms associated with pressure vessels (relief valves or
similar equipment) can be subject to regulatory requirements.
Containers such as tanks and similar containers that are not subject to applicable local or
national pressure equipment regulation standards shall be constructed of appropriate materials
in accordance with 4.3 and shall satisfy the provisions of 4.4. Such containers, and their
associated joints or fittings, shall be designed and constructed with appropriate strength with
respect to functional tightness to prevent unintentional release.
4.5.2 Piping systems
Piping and associated joints shall meet the requirements of ISO 15649. The piping systems
shall be constructed of appropriate materials in accordance with 4.3 and shall meet the
applicable requirements of 4.4.
4.6 Electrical safety
Electrical systems shall meet the requirements of the relevant electrical product standards:
– IEC 60204-1 (e.g. large industrial);
– IEC 62477-1 and IEC 62477-2 (e.g. UPS, power electronic converter system).
Voltages above 600 V limit are permissible when separately evaluated in accordance with
standards appropriate to the higher voltage. The selection of appropriate standards shall be
presented in the technical specifications.
4.7 Control systems and protective components
4.7.1 General requirements
Control systems shall be designed in accordance with ISO 13849-1 and validated in accordance
with ISO 13849-2.
a) The risk assessment as specified in 4.1 shall provide the basis for setting the protection
parameters of the safety circuit.
b) Binary power generation systems shall be designed so that a single failure of a component
does not result in a cascading hazardous condition. Means to prevent cascading failures
include, but are not limited to
1) protection devices for binary power generation systems (such as interlocks, trip
devices),
2) protective interlocks for electrical circuits,
3) use of proven technologies and components, and
4) partial or complete redundancy, diversification.
In the event of a failure, the evaluation of the measures necessary to avoid or control it shall
be indicated in the criteria set out in 4.1.
4.7.2 Control systems
4.7.2.1 General requirements
Automatic electrical and electronic controls in power generation facilities shall be designed and
constructed to be safe and reliable and shall include operation systems such as remote/local
and manned/unmanned.
– 16 – IEC 63277-3-1:2025 © IEC 2025
Manual controls shall be clearly marked and designed to prevent inadvertent adjustment or
activation.
In particular, 4.7.2.2 to 4.7.2.5 apply.
4.7.2.2 Start
The start of operation should only be possible if all safety devices are installed and functioning.
Appropriate interlocks shall be provided to ensure proper startup procedures.
For automated systems functioning in automatic mode, restart after shutdown shall be possible
only after safety conditions have been met. Binary power generation systems shall be able to
be safely restarted by intentionally activating a controller provided for that purpose.
This requirement does not apply to normal sequencing restarts of binary power generation
systems.
4.7.2.3 Shutdown
4.7.2.3.1 General
As determined by the risk assessment set out in 4.1, the functional requirements of binary power
generation systems shall include the following shutdown functions.
• Emergency shutdown
Emergency shutdown is to provide the working fluid or stop the circulation of the working fluid
as a result of detecting the failure of the operation or failure of the limiter or the internal failure
of the system.
• Normal shutdown
Normal shutdown is used to stop the supply of the heating medium or the circulation of the
working fluid depending on the result of the command of the control unit.
After shutdown, the system returns to the startup position.
4.7.2.3.2 Emergency shutdown
4.7.2.3.2.1 General
The emergency stop function shall be incorporated as part of the binary power generation
systems to avoid an imminent crisis that cannot be controlled by control equipment alone.
These features include the following:
a) shutdown of the dangerous situation without creating further danger;
b) triggering or allowing triggers for specific safeguard actions as necessary;
c) taking precedence over all other features;
d) preventing the reset feature from initiating a reboot;
e) a reboot lockout function so that the new start command takes effect during normal operation
only after the restart lockout has been intentionally reset.
4.7.2.3.2.2 Emergency shutdown
If deemed necessary in the risk assessment in 4.1, a manual emergency shutdown device shall
be clearly identifiable, visible and readily accessible in accordance with ISO 13849-1 and
ISO 13850.
4.7.2.3.2.3 Control functions in the event of control systems failure
If there is a failure of the control system logic or a failure or damage to the control equipment
itself, the following shall apply.
a) After receiving a shutdown order, a power generation facility shall not be prevented from
shutdown.
b) Automatic or manual shutdown of moving parts shall not be disturbed.
c) The protective device shall be in a completely valid state.
d) Power generation facilities shall not be restarted unexpectedly.
If a protective device or interlock causes a safety shutdown of the power generation equipment,
the condition shall be notified to the logic of the control system.
Resetting the shutdown function shall not initiate a hazardous condition. Control or monitoring
systems that can operate safely in hazardous situations shall remain energized to provide
facility information.
4.7.2.3.3 Normal shutdown
Even in an unforeseen situation, if the situation can be safely controlled or does not pose an
imminent danger, the system can be restored to a normal state by normal shutdown operation.
4.7.2.4 Complex installations
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