ISO 8909-2:2021

Equipment for harvesting - Forage harvesters - Part 2: Specification of characteristics and performance

This document specifies the methods and requirements in assessing the dimensions and performance of a forage harvester, as defined in ISO 8909-1, and its functional components. It also allows comparison of forage harvester performance through comparative testing.

Matériel de récolte — Récolteuses-hacheuses-chargeuses de fourrage — Partie 2: Spécification des caractéristiques et des performances

General Information

• Status: Published
• Publication Date: 15-Apr-2021
• ICS: 65.060.50 - Harvesting equipment
• Technical Committee: ISO/TC 23/SC 7 - Equipment for harvesting and conservation
• Drafting Committee: ISO/TC 23/SC 7/WG 12 - Combine harvesters, forage and cotton harvesters
• Current Stage: 6060 - International Standard published
• Start Date: 16-Apr-2021
• Due Date: 26-Apr-2022
• Completion Date: 16-Apr-2021

Relations

• Revises: ISO 8909-2:1994 - Forage harvesters - Part 2: Specification of characteristics and performance
• Effective Date: 23-Apr-2020

Overview

ISO 8909-2:2021 - Equipment for harvesting - Forage harvesters - Part 2: Specification of characteristics and performance is an international standard designed to define the methods and requirements for assessing the dimensions and performance of forage harvesters and their functional components. This standard supports a uniform basis for testing and comparing forage harvester performance, ensuring consistency and reliability in agricultural machinery evaluation.

Developed by ISO Technical Committee TC 23, Subcommittee SC 7, ISO 8909-2:2021 builds upon the vocabulary and definitions established in ISO 8909-1 and sets clear frameworks for measurement, testing, and reporting, thereby facilitating objective comparison of forage harvesters in practical use.

Key Topics

• Forage Harvester Dimensions and Characteristics
  The standard specifies how to measure and report essential characteristics such as mass, length, width, height, spout discharge height, engine power, turning diameter, clearance diameter, and header dimensions. It requires accurate recording of tyre size, axle positions, and optional equipment impacts on dimensions.

• Performance Metrics
  Key performance indicators include crop throw distance, whole grain or maize fraction, theoretical length of cut, and cutting mechanism characteristics such as cutterbar frequency, rotor speed, and number of knives or flails. Particle size distribution in chopped crop material is also detailed using repeatable mechanical or manual sorting methods.

• Testing Requirements
  The document mandates testing procedures for self-propelled and tractor-mounted or towed forage harvesters on hard, level surfaces with specific conditions (e.g., fuel tank levels, empty crop containers). It requires documenting crop-specific data such as moisture content, row spacing, and kernel/stalk ratios to ensure standardized comparative evaluation.

• Technical Specifications for Functional Components
  Precise descriptions are provided for components like cylindrical rotors, flywheel cutterheads, flail chopping rotors, and impeller blowers. The standard lists their key characteristics including rotational frequencies, number of blades or paddles, and dimensional measurements, allowing manufacturers and users to assess machinery efficiency and suitability.

Applications

• Agricultural Machinery Testing
  ISO 8909-2:2021 is essential for laboratories and independent testing bodies that conduct performance assessments of forage harvesters, enabling objective and repeatable measurements for quality assurance.

• Manufacturer Product Development
  For equipment manufacturers, this standard guides the design and optimization of forage harvesters by providing clear performance benchmarks and specifications to meet market and safety requirements.

• Procurement and Purchasing Decisions
  Farmers, contractors, and agricultural businesses benefit from comparative data based on this standard to select forage harvesters that best match operational needs, improving efficiency in crop harvesting and processing.

• Regulatory Compliance and Certification
  Regulatory bodies and certification agencies can utilize ISO 8909-2:2021 as a reference to verify compliance of forage harvesting equipment with established safety, performance, and dimensional standards.

Related Standards

• ISO 8909-1:2021 - Equipment for harvesting - Forage harvesters - Part 1: Vocabulary
  Defines the terminology used in Part 2, ensuring clarity and consistency.

• ISO 8909-3:2021 - Equipment for harvesting - Forage harvesters - Part 3: Test methods
  Specifies the detailed test procedures for conducting performance assessments.

• ISO 500-1: Agricultural tractors - Rear-mounted PTO types and specifications
  Relevant for specifying PTO requirements of tractor-mounted forage harvesters.

• ISO 730 - Agricultural wheeled tractors - Rear-mounted three-point linkage categories
  Provides linkage category specifications for equipment mounting.

• ISO 789-3 - Agricultural tractors - Test procedures - Turning and clearance diameters
  Used for measuring turning and clearance diameters of self-propelled forage harvesters.

• ISO 5715 - Equipment for harvesting - Dimensional compatibility of forage harvesting machinery
  Covers compatibility dimensions critical for equipment integration.

Conclusion

ISO 8909-2:2021 is a critical international standard that supports consistent assessment of forage harvester dimensions and performance. It facilitates improved machinery design, informed purchasing, and rigorous testing protocols, promoting efficiency and reliability in forage harvesting operations worldwide. Adopting this standard ensures that stakeholders can reliably compare equipment capabilities, enhance productivity, and maintain safety within agricultural harvesting environments.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8909-2
Second edition
2021-04
Equipment for harvesting — Forage
harvesters —
Part 2:
Specification of characteristics and
performance
Matériel de récolte — Récolteuses-hacheuses-chargeuses de
fourage —
Partie 2: Spécification des caractéristiques et des performances
Reference number
©
ISO 2021
© ISO 2021
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Forage harvester assessment requirements . 1
4.1 General . 1
4.2 Forage harvester characteristics . 2
4.3 Performance . 5
Foreword
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bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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committee has been established has the right to be represented on that committee. International
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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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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 ISO/Technical Committee TC 23, Tractors and machinery for agriculture
and forestry, Subcommittee SC 7, Equipment for harvesting and conservation.
This second edition cancels and replaces the first edition (ISO 8909-2:1994), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— updates to normative references;
— precision of description of forage harvester characteristics.
A list of all parts in the ISO 8909 series can be found on the ISO website.
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.
iv © ISO 2021 – All rights reserved

INTERNATIONAL STANDARD ISO 8909-2:2021(E)
Equipment for harvesting — Forage harvesters —
Part 2:
Specification of characteristics and performance
1 Scope
This document specifies the methods and requirements in assessing the dimensions and performance
of a forage harvester, as defined in ISO 8909-1, and its functional components. It also allows comparison
of forage harvester performance through comparative testing.
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 500-1, Agricultural tractors — Rear-mounted power take-off types 1, 2, 3 and 4 — Part 1: General
specifications, safety requirements, dimensions for master shield and clearance zone
ISO 730, Agricultural wheeled tractors — Rear-mounted three-point linkage — Categories  1N, 1, 2N, 2, 3N,
3, 4N and 4
ISO 789-3, Agricultural tractors — Test procedures — Part 3: Turning and clearance diameters
ISO 5715, Equipment for harvesting — Dimensional compatibility of forage harvesting machinery
ISO 8909-1:2021, Equipment for harvesting — Forage harvesters — Part 1: Vocabulary
ISO 8909-3:2021, Equipment for harvesting — Forage harvesters — Part 3: Test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 8909-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Forage harvester assessment requirements
4.1 General
4.1.1 All dimensions and performance, defined in ISO 8909-1:2021, Clauses 5 and 7, and relating to
forage harvesters and their components, shall be assessed in accordance with their definition and any
requirements in this document.
4.1.2 The dimensions of hubs, wheels and tyres, and the positions of axles shall be recorded on the test
report in ISO 8909-3:2021, Clause 7. Tyres shall be inflated to the service pressure recommended by the
forage harvester manufacturer.
4.1.3 For dimensional measurements, the forage harvester shall be placed on a hard, level surface.
4.1.4 lf a self-propelled forage harvester has a crop container, it shall be empty.
4.1.5 The following data shall be recorded with the forage harvester performance specifications on the
test report in ISO 8909-3:2021, Clause 7:
a) type of header used;
b) moisture content of the crop, expressed on the wet basis (mass of water in 100 g of unprocessed
sample);
c) the average width and height between adjacent rows of crop collected and the average distance
between adjacent rows, in metres to the nearest tenth. For crops planted in rows such as corn or
sorghum, the row spacing (see ISO 8909-1:2021, 6.5) and the kernel/stalk ratio or grain stalk ratio
(see ISO 8909-1:2021, 6.6);
d) other relevant crop characteristics, as defined in ISO 8909-3:2021, Clause 6;
e) theoretical length of cut (see ISO 8909-1:2021, 5.24);
f) length distribution of particles in the chopped crop, determined using known mechanical separation
means, capable of repetition or manual sorting, recorded in terms of average geometrical length
and geometrical deviation, in accordance with ISO 8909-3;
g) if necessary, means of particle size reduction used (see ISO 8909-1:2021, 4.6 to 4.9).
4.2 Forage harvester characteristics
4.2.1 The mass (see ISO 8909-1:2021, 5.1) of a self-propelled forage harvester shall be determined
with a full fuel tank and a mass of 75 kg simulating the driver. If the transport mass is also to be indicated,
the fuel tank shall contain fuel not exceeding 10 % of its capacity.
If the complete machine includes certain optional equipment which influences its total mass, and/or
elements such as tyre weights for self-propelled forage harvesters, these sha
...