ISO 6055:2023

Industrial trucks - Overhead guards - Specification and testing

This document specifies the requirements and testing of overhead guards, operator’s leg(s)/feet protection for industrial trucks and overturning testing of industrial variable-reach trucks with operator position not protected by the boom (hereafter referred to as "trucks") requiring an overhead guard according to ISO 3691‑1 and ISO 3691‑2. This document is not applicable to rough-terrain variable-reach trucks and slewing rough-terrain variable-reach trucks.

Chariots de manutention — Protège-conducteurs — Spécifications et essais

Le présent document spécifie les exigences et les essais pour les protège-conducteurs, la protection de la jambe (des jambes)/du pied (des pieds) de l'opérateur des chariots de manutention, ainsi que les essais de retournement pour les chariots de manutention à portée variable avec le poste de l'opérateur non protégé par la flèche (ci-après désignés «chariots») exigeant un protège-conducteur conformément à l'ISO 3691-1 et à l’ISO 3691-2. Le présent document n’est pas applicable aux chariots tout-terrain à portée variable ni aux chariots tout-terrain à portée variable rotatifs.

General Information

• Status: Published
• Publication Date: 30-Mar-2023
• ICS: 53.060 - Industrial trucks
• Technical Committee: ISO/TC 110/SC 2 - Safety of powered industrial trucks
• Drafting Committee: ISO/TC 110/SC 2/WG 13 - Supporting standards
• Current Stage: 9092 - International Standard to be revised
• Start Date: 15-Apr-2025
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 182-3:2023 - Plastics - Determination of the tendency of compounds and products based on vinyl chloride homopolymers and copolymers to evolve hydrogen chloride and any other acidic products at elevated temperatures - Part 3: Conductometric method
• Effective Date: 06-Jun-2022
• Revises: ISO 6055:2004 - Industrial trucks - Overhead guards - Specification and testing
• Effective Date: 21-Apr-2018

Overview

ISO 6055:2023 - Industrial trucks - Overhead guards - Specification and testing defines safety, dimensional and test requirements for overhead guards and operator leg/foot protection on industrial trucks that require an overhead guard under ISO 3691‑1 and ISO 3691‑2. The fourth edition updates test procedures and performance requirements, adds provisions for transparent materials used in overhead guard tops, and excludes rough‑terrain variable‑reach trucks.

Key topics and technical requirements

• Scope and applicability: Applies to ride‑on trucks and variable‑reach trucks where the operator position requires an overhead guard; excludes rough‑terrain and slewing rough‑terrain variable‑reach trucks.
• Protected area: The overhead guard must extend over the operator in normal operating positions and must not extend beyond the truck’s plan outline. Controls and pedals are considered protected within a 150 mm forward projection rule.
• Openings and materials: Top openings shall not allow a sphere larger than 150 mm to pass. If transparent material (e.g., glazing) bridges larger openings, it must meet specific performance and testing criteria.
• Vertical clearances: Minimum clearances are specified for seated and standing operators (notably 903 mm from seat index point (SIP) to underside of guard for seated trucks, and 1 905 mm from standing platform).
• Testing requirements:
  • Dynamic test to assess resistance to permanent deflection (test sequence required before the impact drop).
  • Impact drop test to determine deformation under large loads.
  • Transparent material tests, operators’ leg/foot protection tests, and falling‑objects and overturning tests for certain variable‑reach trucks.
• Reduced‑height guards: Manufacturers may offer reduced clearance guards but must provide clear information on limitations (e.g., operator height) and must still meet performance requirements.

Applications and users

ISO 6055:2023 is used by:

• Forklift and industrial truck manufacturers - to design overhead guards and prove compliance.
• Test laboratories and certification bodies - to perform dynamic, drop and transparency tests.
• Safety engineers and fleet managers - to evaluate retrofit guards, select appropriate protective structures and document maintenance/inspection regimes.
• Regulatory and procurement teams - to reference required performance when specifying equipment.

Practical outcomes include improved operator protection from falling objects, standardized test procedures for product validation, and clear guidance for reduced‑height applications and transparent guard components.

Related standards

• ISO 3691‑1 / ISO 3691‑2 (industrial truck safety requirements)
• ISO 3449, ISO 3471 (falling‑object and roll‑over protective structures)
• ISO 5353 (seat index point)
• ISO 13564‑1 (visibility test methods)

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 6055
Fourth edition
2023-03
Industrial trucks — Overhead guards
— Specification and testing
Chariots de manutention — Protège-conducteurs — Spécifications et
essais
Reference number
© ISO 2023
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
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CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements for overhead guards on ride-on trucks . 2
4.1 General . 2
4.2 Protected area . 2
4.3 Dimensions . 3
4.4 Testing . 4
4.4.1 General . 4
4.4.2 Dynamic test . 4
4.4.3 Impact drop test . 6
4.4.4 Transparent material . 8
4.4.5 Operators' leg/foot protection test . 8
4.5 Performance requirements . 8
5 Requirements for industrial variable-reach trucks with operator position not
protected by the boom .11
5.1 General . 11
5.2 Protective structures . 11
5.3 Dimensions .12
5.4 Testing .12
5.4.1 General .12
5.4.2 Falling objects test .12
5.4.3 Overturning test .12
6 Information for maintenance .12
Bibliography .13
iii
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
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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
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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
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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 110, Industrial trucks, Subcommittee
SC 2, Safety of powered industrial trucks.
This fourth edition cancels and replaces the third edition (ISO 6055:2004), which has been technically
revised.
The main changes are as follows:
— for stand-on controlled trucks, vertical clearance has been increased, from the platform to the
underside of the overhead guard;
— requirements for rough terrain variable-reach trucks have been excluded;
— specifications and test requirements have been added for transparent material used to bridge
openings in the top of the overhead guard structure not conforming to 4.3.1;
— information for use in relation to the inspection of structure and inspection and care of transparent
material has been added.
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
INTERNATIONAL STANDARD ISO 6055:2023(E)
Industrial trucks — Overhead guards — Specification and
testing
1 Scope
This document specifies the requirements and testing of overhead guards, operator’s leg(s)/feet
protection for industrial trucks and overturning testing of industrial variable-reach trucks with
operator position not protected by the boom (hereafter referred to as "trucks") requiring an overhead
guard according to ISO 3691-1 and ISO 3691-2.
This document is not applicable to rough-terrain variable-reach trucks and slewing rough-terrain
variable-reach trucks.
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 3164, Earth-moving machinery — Laboratory evaluations of protective structures — Specifications for
deflection-limiting volume
ISO 3449, Earth-moving machinery — Falling-object protective structures — Laboratory tests and
performance requirements
ISO 3471, Earth-moving machinery — Roll-over protective structures — Laboratory tests and performance
requirements
ISO 3691-1:2011, Industrial trucks — Safety requirements and verification — Part 1: Self-propelled
industrial trucks, other than driverless trucks, variable-reach trucks and burden-carrier trucks
ISO 3691-1:2011/Amd.1:2020, Industrial trucks — Safety requirements and verification — Part 1: Self-
propelled industrial trucks, other than driverless trucks, variable-reach trucks and burden-carrier trucks
— Amendment 1
ISO 3691-2:2023, Industrial trucks — Safety requirements and verification — Part 2: Self-propelled
variable-reach trucks
ISO 5053-1, Industrial trucks — Vocabulary — Part 1: Types of industrial trucks
ISO 5353, Earth-moving machinery, and tractors and machinery for agriculture and forestry — Seat index
point
ISO 13564-1:2012, Powered industrial trucks — Test methods for verification of visibility — Part 1: Sit-on
and stand-on operator trucks and variable-reach trucks up to and including 10 t capacity
ISO 16936-1:2020, Glass in building — Forced-entry security glazing — Part 1: Test and classification by
repetitive ball drop
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5053-1, ISO 3691-1, ISO 3691-2
and ISO 5353 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
overhead guard
device fitted to the truck for the purpose of protecting the operator against falling objects
[SOURCE: ISO 3691-2:2023, 3.9]
4 Requirements for overhead guards on ride-on trucks
4.1 General
This clause applies to trucks fitted with masts and industrial variable-reach trucks where the operator
position is protected by the boom, i.e. the mast or boom prevents the truck from tipping more than a
nominal 90°.
4.2 Protected area
4.2.1 The overhead guard shall extend over the operator when in the normal operating position(s) as
defined in ISO 3691-1 and ISO 3691-2 and when the operator is operating the controls as provided by
the truck manufacturer. For overhead guards fixed to the mast, this also applies when the mast is tilted.
The overhead guard shall not extend beyond the plan view outline of the truck.
The control levers in their neutral position, the pedals in their released condition and the steering wheel
are considered protected if they do not project in the direction of the mast more than 150 mm beyond
the vertical projection of the outline of the overhead guard onto a horizontal plane; see Figure 1.
Adjustable steering wheel position for the driving mode shall be placed in the centre position. No
account is taken of the parking brake lever in its foremost position in relation to the mast.
Dimensions in millimetres
Key
1 edge of overhead guard
2 phantom view of front support
3 rear of forward structure
4 foot protection structure
Figure 1 — Satisfactory protection by the overhead guard
Any part of the operator’s leg or feet, in the normal operating position, that projects more than 150 mm
beyond the front of the overhead guard when vertically projected onto a horizontal plane shall be
protected by a structure. The test procedure for the structure is described in 4.4.5.
4.2.2 Failure of the tilting mechanism shall not directly, or indirectly, cause the operator to be in
danger because of the overhead guard.
4.3 Dimensions
4.3.1 Openings in the top of the overhead guard shall not permit a sphere larger than 150 mm
diameter to pass through the openings.
4.3.2 If transparent material (for example glass) is used to bridge openings in the top of the overhead
guard structure that do not conform to 4.3.1 the transparent material shall conform to 4.4.4.
4.3.3 For trucks on which the operator is seated, the vertical clearance from the seat index point (SIP)
in accordance with ISO 5353 to the underside of the section of the overhead guard under which the
operator’s head is located when the operator is in the normal operating position, shall not be less than
903 mm.
NOTE 1 The distance of 903 mm (SIP) provides 24 mm clearance for the 95th percentile operator (1 905 mm)
according to ISO 3411.
4.3.4 For trucks on which the operator stands, the vertical clearance, from the platform where the
operator stands to the underside of the section of the overhead guard under which the operator's head
is located when the operator is in the normal operating position, shall not be less than 1 905 mm.
4.3.5 For applications requiring a reduced height overhead guard, with a cleara
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