National foreword

This British Standard is the UK implementation of EN ISO 3991:2025. It is identical to ISO 3991:2025.

The UK participation in its preparation was entrusted to Technical Committee AGE/32, Agricultural implements and trailers.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

This publication has been prepared under a mandate given to the European Standards Organizations by the European Commission and the European Free Trade Association. It is intended to support requirements of the EU legislation detailed in the European Foreword. A European Annex, usually Annex ZA or ZZ, describes how this publication relates to that EU legislation.

For the Great Britain market (England, Scotland and Wales), if UK Government has designated this publication for conformity with UKCA marking (or similar) legislation, it may contain an additional National Annex. Where such a National Annex exists, it shows the correlation between this publication and the relevant UK legislation. If there is no National Annex of this kind, the relevant Annex ZA or ZZ in the body of the European text will indicate the relationship to UK regulation applicable in Great Britain. References to EU legislation may need to be read in accordance with the UK designation and the applicable UK law. Further information on designated standards can be found at www.bsigroup.com/standardsandregulation.

For the Northern Ireland market, UK law will continue to implement relevant EU law subject to periodic confirmation. Therefore Annex ZA/ZZ in the European text, and references to EU legislation, are still valid for this market.

UK Government is responsible for legislation. For information on legislation and policies relating to that legislation, consult the relevant pages of www.gov.uk.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 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, Czechia, 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 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.

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.

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.

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.

2 Normative references

3 Terms and definitions

4 Safety requirements and/or protective measures

4.1 General

4.2 Storage of feed

4.3 Loading

4.4 Checking of the mixing

4.5 Travelling

4.6 MFU

4.7 Distributing

4.8 Pushing feed/Cleaning

4.9 Electrical safety

4.10 Controls

4.11 Operational modes

4.12 Service and maintenance

4.13 Emergency stop devices

4.14 Fire and explosion

4.15 Magnets and magnetic fields

5 System integration

5.1 General

5.2 Layout design

5.3 Zones

6 Verification of the safety requirements and/or protective measures

7 Information for use

7.1 Operators manual

7.2 Layout

7.3 Marking

BS EN ISO 3991:2025

Agricultural machinery — Robotic feed systems — Safety

Current

Published:

30 Nov 2025