EN ISO 3991:2025

SLOVENSKI STANDARD
01-januar-2026
Kmetijski stroji - Robotski sistemi za krmljenje - Varnost (ISO 3991:2025)
Agricultural machinery - Robotic feed systems - Safety (ISO 3991:2025)
Landmaschinen - Roboter-Fütterungssysteme - Sicherheit (ISO 3991:2025)
Matériel agricole - Systèmes d'alimentation robotisés - Sécurité (ISO 3991:2025)
Ta slovenski standard je istoveten z: EN ISO 3991:2025
ICS:
65.060.99 Drugi kmetijski stroji in Other agricultural machines
oprema and equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 3991
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2025
EUROPÄISCHE NORM
ICS 65.060.99
English Version
Agricultural machinery - Robotic feed systems - Safety
(ISO 3991:2025)
Matériel agricole - Systèmes d'alimentation robotisés - Landmaschinen - Roboter-Fütterungssysteme -
Sécurité (ISO 3991:2025) Sicherheit (ISO 3991:2025)
This European Standard was approved by CEN on 14 March 2025.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3991:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC amended by Directive 2009/127/EC
aimed to be covered . 4
European foreword
This document (EN ISO 3991:2025) has been prepared by Technical Committee ISO/TC 23 "Tractors
and machinery for agriculture and forestry" in collaboration with Technical Committee CEN/TC 144
“Tractors and machinery for agriculture and forestry” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2026, and conflicting national standards shall be
withdrawn at the latest by May 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 3991:2025 has been approved by CEN as EN ISO 3991:2025 without any modification.

Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC amended by Directive
2009/127/EC aimed to be covered
This European Standard has been prepared under a Commission’s standardization request “M/396
Mandate to CEN and CENELEC for Standardisation in the field of machinery" to provide one voluntary
means of conforming to essential requirements of Directive 2006/42/EC of the European Parliament
and of the Council of 17 May 2006 on machinery and amending Directive 95/16/EC (recast).
Once this standard is cited in the Official Journal of the European Union under that Directive,
compliance with the normative clauses of this standard given in Table ZA.1 confers, within the limits of
the scope of this standard, a presumption of conformity with the corresponding essential requirements
of that Directive, and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and EU Directive 200 6/42/EC
amended by Directive 2009/127/EC
The relevant Essential Requirements of Clause(s)/subclause(s) of Remarks/Notes
Directive 2006/42/EC this EN
To cover all the relevant safety requirements for
the products(s) in its scope, this standard
(providing global requirements and references to
regional requirements for a machine) has to be
applied together with one of those standards as
specified in the scope (providing European
regional requirements for a machine).
1.1.2. Principles of safety integration ---
1.1.2(a) 4, 5, 6
1.1.2(c) 4, 5, 6
1.1.2(d) 4, 5, 6
1.1.2(e) 4, 5, 6
1.1.4. Lighting 4.5.2, 7.1
1.1.5. Design of machinery to facilitate its handling 4.1, 4.6.1
1.1.6. Ergonomics 4.1, 4.4, 4.10.1, 4.10.2.3
1.1.7. Operating positions 4.2.1, 4.4, 4.10.2.3
1.1.8. Seating 4.10.2.3
1.2.1. Safety and reliability of control systems 4.1, 4.6.2.1, Annex C
1.2.2. Control devices 4.10, 7.1
1.2.3. Starting 4.6.1, 4.6.2.2.1, 4.6.2.3.1,
The relevant Essential Requirements of Clause(s)/subclause(s) of Remarks/Notes
Directive 2006/42/EC this EN
4.12, 5.3.3
1.2.4.1. Normal stop 4.6.3, 4.10, 4.11.1, 4.11.3,
4.11.4
1.2.4.2. Operational stop 4.6.2.2.5, 4.6.2.3.5, 4.6.3, 4.7,
4.11.1, 4.11.2
1.2.4.3. Emergency stop 4.13
1.2.4.4. Assembly of machinery  Not covered
1.2.5. Selection of control or operating modes 4.10.2.1, 4.11, 7.1
1.2.6. Failure of the power supply 4.6.3, 4.11.1, 4.13
1.3.1. Risk of loss of stability 4.6.1
1.3.2. Risk of break-up during operation 4.1, 4.6.1, 4.6.3 ,4.12, 7.1
1.3.3. Risks due to falling or ejected objects 4.3, 4.6.6.1, 4.6.6.4
1.3.4. Risks due to surfaces, edges or angles 4.1, 4.6.1
1.3.6. Risks related to variations in operating Not covered
conditions
1.3.7. Risks related to moving parts 4.1, 4.2, 4.4, 4.7, 4.10.1, 4.12,
5.3.3
1.3.8. Choice of protection against risks arising from 4.1, 4.2, 4.2.1, 4.2.2, 4.3, 4.4,
moving parts 4.6.6, 4.12, 5.2, 5.3.3
1.3.9. Risks of uncontrolled movements 4.2.1, 4.4, 4.5.1, 4.6.1, 4.6.3,
4.6.6.1, 4.7, 4.11.1, 4.11.2,
4.11.4, 4.11.5, 4.13, 5.2, 5.3.3
1.4.1. General requirements 4.1, 4.6.2.1
1.4.2.1. Fixed guards 4.1, 5.3.3
1.4.2.2. Interlocking movable guards 4.4, 5.3.3
1.4.3. Special requirements for protective devices 4.6.2.1, 4.6.2.2, 4.6.2.3,
4.10.2.3, 4.12, 5.3.3
1.5.1. Electricity supply 4.9
1.5.6. Fire 4.9, 4.15
1.5.7. Explosion 4.9.2, 4.15
1.5.8. Noise Not covered
1.5.9. Vibrations 4.6.1
1.5.10. Radiation 4.1, 4.16, 7.1
1.5.11. External radiation 4.1
1.5.12. Laser radiation 4.1, 7.1
1.5.13. Emissions of hazardous materials and 4.9.1, 7.1
The relevant Essential Requirements of Clause(s)/subclause(s) of Remarks/Notes
Directive 2006/42/EC this EN
substances
1.5.14. Risk of being trapped in a machine 4.2.1
1.5.15. Risk of slipping, tripping or falling 4.4, 5.2
1.6.1. Machinery maintenance 4.6.6.1, 4.12, 5.2
1.6.2. Access to operating positions and servicing 4.10.2.3, 4.12, 5.2
points
1.6.3. Isolation of energy sources 4.12, 7.1
1.6.4. Operator intervention 4.2.1, 4.10.2.3, 4.11.2, 4.11.5,
4.12, 5.3.3
1.6.5. Cleaning of internal parts 4.12
1.7.1. Information and warnings on the machinery 7.1, 7.3
1.7.2. Warning of residual risks 7.1, 7.2, 7.3
1.7.3. Marking of machinery 7.3
1.7.4. Instructions 7.1
1.7.4.1. General principles for the drafting of 7.1
instructions
1.7.4.2. Contents of the instructions 7.1
1.7.4.2 t) spare parts  not covered
1.7.4.3. Sales literature  not covered
3.2. WORK POSITIONS 4.1, 4.10.2.3
3.2.1. Driving positions 4.1, 4.10.2.3
3.2.2. Seating 4.10.2.3
3.3.1. Control devices 4.10, 4.11, 7.1
3.3.2. Starting/moving 4.10.2.3, 4.11
3.3.3. Travelling function 4.5, 4.6.3, 4.6.6, 4.7, 4.10.2.2,
4.10.2.3, 4.11
3.3.5. Control circuit failure Not covered
3.4.1. Uncontrolled movements 4.1, 4.6.1, 4.6.6.1, 5.2
3.4.3. Roll-over and tip-over Not covered
3.4.4. Falling objects 4.3
3.4.5. Means of access 4.4
3.5.1. Batteries Not covered
3.5.2. Fire 4.9, 4.15
3.6.1. Signs, signals and warnings 4.6.4, 4.6.5, 7.3.2
The relevant Essential Requirements of Clause(s)/subclause(s) of Remarks/Notes
Directive 2006/42/EC this EN
3.6.2. Marking 5.3, 7.2, 7.3
3.6.3. Instructions 7.1
4.1.2.2. Machinery running on guide rails and rail 4.6.6.1, 4.6.6.4
tracks
4.1.2.7. Movements of loads during handling 4.5, 4.6.2
4.1.3. Fitness for purpose  Not covered
WARNING 1 Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 Other Union legislation can be applicable to the product(s) falling within the scope of
this standard.
International
Standard
ISO 3991
First edition
Agricultural machinery — Robotic
2025-03
feed systems — Safety
Matériel agricole — Systèmes d'alimentation robotisés —
Sécurité
Reference number
ISO 3991:2025(en) © ISO 2025
ISO 3991:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 3991:2025(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 3
4 Safety requirements and/or protective measures . 5
4.1 General .5
4.2 Storage of feed . .6
4.2.1 General .6
4.2.2 Feed storage devices .6
4.2.3 Feed storage area .7
4.3 Loading .7
4.4 Checking of the mixing .8
4.5 Travelling .8
4.5.1 General .8
4.5.2 Area of travelling and pathways .8
4.5.3 Safety distance along the route .8
4.6 MFU . .10
4.6.1 General .10
4.6.2 Obstacle protective system .11
4.6.3 Braking system .16
4.6.4 Audible alarm .16
4.6.5 Visual alarm . .16
4.6.6 Additional requirements for hanging MFU.17
4.7 Distributing .17
4.8 Pushing feed/Cleaning .18
4.9 Electrical safety .18
4.9.1 General .18
4.9.2 Battery charging .18
4.10 Controls .19
4.10.1 Location .19
4.10.2 Controls for operational modes .19
4.11 Operational modes . 20
4.11.1 General . 20
4.11.2 Manual mode . . 20
4.11.3 Autonomous mode . 20
4.11.4 Semi-autonomous robotic feed system . 20
4.11.5 Service mode .21
4.12 Service and maintenance .21
4.13 Emergency stop devices .21
4.14 Fire and explosion .21
4.15 Magnets and magnetic fields . 22
5 System integration . .22
5.1 General . 22
5.2 Layout design . 22
5.3 Zones. 23
5.3.1 Common zone . 23
5.3.2 Caution zone . 23
5.3.3 Restricted zone . 23
6 Verification of the safety requirements and/or protective measures .23
7 Information for use .26
7.1 Operators manual . 26

iii
ISO 3991:2025(en)
7.2 Layout . 26
7.3 Marking .27
7.3.1 General .27
7.3.2 Safety signs .27
Annex A (informative) Examples of robotic feed system .29
Annex B (informative) List of significant hazards .31
Annex C (normative) Safety functions of RFS requiring functional safety analysis .34

iv
ISO 3991:2025(en)
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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO 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, ISO 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
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 23, Tractors and machinery for agriculture
and forestry, Subcommittee SC 3, Safety and comfort, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 144, Tractors and machinery for agriculture and forestry,
in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
ISO 3991:2025(en)
Introduction
This document is a type-C standard as specified in ISO 12100:2010.
This document is of relevance, in particular, for the following stakeholder groups representing the market
players with regard to machinery safety:
— machine manufacturers (small, medium and large enterprises);
— health and safety bodies (regulators, accident prevention organizations, market surveillance, etc.)
Others can be affected by the level of machinery safety achieved with the means of the document by the
above-mentioned stakeholder groups:
— machine users/employers (small, medium and large enterprises);
— machine users/employees (e.g. trade unions, organizations for people with special needs);
— service providers, e.g. for maintenance (small, medium and large enterprises);
— consumers (in case of machinery intended for use by consumers).
The above-mentioned stakeholder groups have been given the possibility to participate at the drafting
process of this document.
The machinery concerned and the extent to which hazards, hazardous situations and events are covered are
indicated in the scope of this document.
When provisions of this type C standard are different from those which are stated in type A or B standards,
the provisions of this type C standard take precedence over the provisions of the other standards, for
machines that have been designed and built according to the provisions of this type C standard.
The purpose of this document is to establish specific design principles for semi-autonomous and autonomous
functions of robotic feed systems (RFS) agricultural machinery. The application of other type C standards
which deal with relevant significant hazards to the machinery covered in the scope of this document is
explained in Clause 4.
The requirements of this document concern designers, manufacturers and their authorized representatives
of feed systems. This document also includes information to be provided by the manufacturer to the user.

vi
International Standard ISO 3991:2025(en)
Agricultural machinery — Robotic feed systems — Safety
1 Scope
This document specifies the safety requirements and their verification for the design and construction of
robotic feed systems (RFS) (see Annex A), which distribute feed and perform at least one of the following
functions without the need of human interaction:
— storing of feed;
— loading of mobile feed unit (MFU);
— mixing;
— travelling;
— cleaning (residual feed);
— pushing feed.
Additionally, it provides the type of information, to be provided by the manufacturer, on safe working
practices (including information about residual risks).
This document is for feeding livestock (e.g. cows, sheep, pigs).
This document does not apply to:
— systems designed to be used at a fixed location and that discharge feed at a remote location (e.g. chain
conveyor feed systems, belt conveyor feed systems or liquid feed systems);
— tractors;
— systems designed for field application.
This document deals with all the significant hazards, hazardous situations and events relevant to RFS,
see Annex B, when they are used as intended and under the conditions of misuse, which are reasonably
foreseeable, by the manufacturer as listed in Clause 4, except for the hazards arising from:
— internal combustion engines of RFS;
— requirements for the connections to the main electric power supply;
— RFS with interchangeable equipment;
— emission of airborne noise.
NOTE 1 Hazards related to internal combustion engines of robotic feed systems (e.g. exhaust emissions in buildings)
will be considered in separate standards
NOTE 2 The main electric power supply is subject to national regulations or codes
NOTE 3 Sudden loud noises may cause farm animals to become startled. It is advised to consider this with the
design of the RFS.
Environmental aspects (except noise) have not been considered in this document.
This document is not applicable to feed systems manufactured before the date of its publication.

ISO 3991:2025(en)
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.
ISO 3691-4:2023, Industrial trucks — Safety requirements and verification — Part 4: Driverless industrial
trucks and their systems
ISO 4254-1:2013, Agricultural machinery — Safety — Part 1: General requirements
ISO 7010:2019, Graphical symbols — Safety colours and safety signs — Registered safety signs
ISO 7731:2003, Ergonomics — Danger signals for public and work areas — Auditory danger signals
ISO 11684:2023, Tractors, machinery for agriculture and forestry, powered lawn and garden equipment —
Safety labels — General principles
ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 13849-1:2023, Safety of machinery — Safety-related parts of control systems — Part 1: General principles
for design
ISO 13849-2:2012, Safety of machinery — Safety-related parts of control systems — Part 2: Validation
ISO 13850:2015, Safety of machinery — Emergency stop function — Principles for design
ISO 13856-2:2013, Safety of machinery — Pressure-sensitive protective devices — Part 2: General principles for
design and testing of pressure-sensitive edges and pressure-sensitive bars
ISO 13856-3:2013, Safety of machinery — Pressure-sensitive protective devices — Part 3: General principles for
design and testing of pressure-sensitive bumpers, plates, wires and similar devices
ISO 13857:2019, Safety of machinery — Safety distances to prevent hazard zones being reached by upper and
lower limbs
ISO 14119:2024, Safety of machinery — Interlocking devices associated with guards — Principles for design and
selection
ISO 14120:2015, Safety of machinery — Guards — General requirements for the design and construction of fixed
and movable guards
ISO 15817:2012, Earth-moving machinery — Safety requirements for remote operator control systems
ISO 16230-1:2015, Agricultural machinery and tractors — Safety of higher voltage electrical and electronic
components and systems — Part 1: General requirements
ISO 16231-2:2015, Self-propelled agricultural machinery — Assessment of stability — Part 2: Determination of
static stability and test procedures
ISO 18497-1:2024, Agricultural machinery and tractors — Safety of partially automated, semi-autonomous and
autonomous machinery — Part 1: Machine design principles and vocabulary
ISO 25119-1:2018/Amd 1:2020, Tractors and machinery for agriculture and forestry — Safety-related parts of
control systems — Part 1: General principles for design and development — Amendment 1
ISO 25119-2:2019, Tractors and machinery for agriculture and forestry — Safety-related parts of control
systems — Part 2: Concept phase
ISO 25119-3:2018/Amd 1:2020, Tractors and machinery for agriculture and forestry — Safety-related parts of
control systems — Part 3: Series development, hardware and software — Amendment 1
ISO 25119-4:2018, Tractors and machinery for agriculture and forestry —Safety-related parts of control
systems — Part 4: Production, operation, modification and supporting processes

ISO 3991:2025(en)
ISO 25119-4:2018/Amd 1:2020, Tractors and machinery for agriculture and forestry —Safety-related parts of
control systems — Part 4: Production, operation, modification and supporting processes — Amendment 1
EN 703:2021, Agricultural machinery — Safety — Silage loading, mixing and/or chopping and distributing
machines
EN 1175:2020, Safety of industrial trucks — Electrical/ electronic requirements
IEC 60204-1:2016, Safety of machinery — Electrical equipment of machines — Part 1: General requirements
IEC 60825-1:2014, Safety of laser products — Part 1: Equipment classification and requirements
IEC 61000-6-2:2016, Electromagnetic compatibility (EMC) — Part 6-2: Generic standards — Immunity standard
for industrial environments
IEC 61000-6-4:2018, Electromagnetic compatibility (EMC) — Part 6-4: Generic standards — Emission standard
for industrial environments
IEC 61496-1:2020, Safety of machinery — Electro-sensitive protective equipment — Part 1: General requirements
and tests
IEC 61496-2:2020, Safety of machinery — Electro-sensitive protective equipment — Part 2: Particular
requirements for equipment using active opto-electronic protective devices
IEC 62485-6:2021, Safety requirements for secondary batteries and battery installations — Part 6: Lithium-ion
batteries for traction applications
IEC 62619:2022, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Safety
requirements for secondary lithium cells and batteries, for use in industrial applications
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18497-1:2024 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
robotic feed system
RFS
feed system, either semi-autonomous or autonomous, consisting of various machinery performing the
necessary functions to feed livestock
3.1.1
semi-autonomous robotic feed system
system comprising feed robotic device(s) (3.2.1) and any machinery, equipment, devices, or sensors
supporting the feed robotic device(s) performing its feed task
3.1.2
autonomous robotic feed system
system comprising feed robot(s) (3.2.2) and any machinery, equipment, devices, or sensors supporting the
feed robot performing its feed task
3.2
mobile feed unit
MFU
specific mobile device used to deploy the feed to the livestock, which is either a feed robotic device (3.2.1) or
a feed robot (3.2.2) as part of an RFS (3.1)

ISO 3991:2025(en)
3.2.1
feed robotic device
actuated programmable mechanism fulfilling the characteristics of feed robot but operating at a semi-
autonomous level of autonomy
EXAMPLE Hanging MFU.
3.2.2
feed robot
actuated programmable mechanism operating autonomously
3.3
operator
local or remote positioned designated person who is responsible for the movement and operation of the RFS
3.4
feed storage area
designated area where one or more different feed storage devices (3.5) are located and/or where feedstuffs
are stocked in bulk
3.5
feed storage device
stationary device for intermediate storage and processing of feedstuffs (e.g. feed bunker) as part of an RFS (3.1)
3.6
loading
transferring feedstuffs into the MFU (3.2)
3.7
loading area
designated area where the loading (3.6) is performed
3.8
service mode
mode of machine operation in which service is performed
Note 1 to entry: See ISO 4254-1:2013, 3.2 for the definition of service.
3.9
common zone
designated area open to all people which includes the autonomous operating zone of the RFS
3.10
caution zone
designated area part of a common zone (3.1) where there is an increased safety risk, e.g. due to inadequate
clearance or where a loading (3.6) takes place
3.11
restricted zone
designated and physically separated area, which contains hazardous autonomous functions of the RFS in
which only authorized persons are permitted to enter
3.12
non-contact protective system
non-contact protective equipment fitted to the MFU, having one or more detection zones that generates a
signal prior to physical contact
Note 1 to entry: Non-contact protective equipment can include different types of technologies such as optical, laser,
radar, etc.
ISO 3991:2025(en)
3.13
MFU with ride-on capability
self-propelled MFU equipped with controls for manual operation by an onboard operator
3.14
continuous fixed structure
fixed objects belonging to the farm buildings restricting the path of the MFU over a long distance (e.g.
walls, fences)
Note 1 to entry: Continuous fixed structures can also be boundaries for the path of the MFU.
3.15
non-continuous fixed structure
fixed objects belonging to the farm buildings restricting the path of the MFU over a limited distance (e.g.
pillars, trusses, doorways)
4 Safety requirements and/or protective measures
4.1 General
The manufacturer's risk assessment shall account for the specific type of livestock for which the RFS is
intended to be used.
When the RFS is intended to be used for other kind of animals other than livestock, the manufacturer shall
perform an additional risk assessment for potential risks caused to this kind of animals.
Agricultural machinery (self-propelled ride-on, mounted, semi-mounted and trailed) shall conform with the
relevant portions of machine-specific safety standards [e.g. ISO 4254 (all relevant parts), EN 703:2021] and
this clause for protective or risk reduction measures of relevant significant hazards.
NOTE Portions of relevant machine-specific safety standards will not be applicable due to the potential unique
characteristics of agricultural machinery semi-autonomous and autonomous functions. For example, portions of a
safety standard that address requirements for a local operator station will not be applicable to a machine that does
not have a local operator station.
RFS shall conform with the safety requirements and/or protective/risk reduction measures of this clause.
In addition, the RFS shall be designed according to the principles of ISO 12100:2010 for relevant but not
significant hazards, which are not dealt with by this document. Significant hazards resulting of interaction
of the RFS with existing equipment on the farm (e.g. tower silo) is dealt with in Clause 5.
This applies especially for the interaction between the particular functions and parts of the RFS.
Unless otherwise specified in this document, the RFS shall conform to the requirements of ISO 13857:2019,
Tables 1, 2, 3, 4 and 6 as appropriate.
Irregularities, loss or return of power supply or failure of the control system shall not lead to hazardous
situations.
Provisions shall be taken to ensure continued safe operation of critical function(s) (e.g. opening of feed
grabber, dropping feed, MFU rolling down from slope) resulting from failure of the power supply.
Hydraulic systems, if applicable, shall be in accordance with ISO 4254-1:2013, 4.13.
Mechanical movements, whether intended or unintended (e.g. effects from acceleration/deacceleration or
lifting/holding of masses) shall not result in a situation hazardous to persons.
Performance Levels for safety related parts of control systems, shall be determined in accordance
with ISO 25119-1:2018, ISO 25119-1:2018/Amd 1:2020 and ISO 25119-2:2019 and ISO 25119-3:2018,
ISO 25119-3:2018/Amd 1:2020 and ISO 25119-4:2018, ISO 25119-4:2018/Amd 1:2020, or ISO 13849-1:2023
and ISO 13849-2:2012. See Annex C.

ISO 3991:2025(en)
RFS shall comply with the requirements of electromagnetic compatibility as specified in ISO 4254-1:2013,
4.18 or shall comply with IEC 61000-6-2:2016 for immunity and IEC 61000-6-4:2018 for emission in
industrial environments.
Laser product, if used, shall be in accordance with IEC 60825-1:2014. Laser products shall be mounted such
that they do not create any risk for the operator.
Visibility of driving positions of MFU with ride-on capability shall be in accordance with EN 703:2021, 4.3.
Exposed parts of RFS shall not have sharp corners, edges, rough surfaces, etc. which can cause injury to
persons or farm animals who can come into contact with the RFS.
4.2 Storage of feed
4.2.1 General
Access to potentially hazardous moving parts inside the feed storage area or feed storage device(s) shall be
prevented.
This requirement is deemed to be fulfilled if the measures given in 4.2.2 and 4.2.3 are applied.
4.2.2 Feed storage devices
The height of the wall(s) of the feed storage device shall have a minimum height of 1,50 m, in accordance
with ISO 13857:2019.
All walls shall be designed such that easy over climbing without additional means is prevented (e.g. by
smooth surface, no horizontal structures).
Safety distances t
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