ISO 16840-4:2009

INTERNATIONAL ISO
STANDARD 16840-4
First edition
2009-03-15
Wheelchair seating —
Part 4:
Seating systems for use in motor
vehicles
Sièges de fauteuils roulants —
Partie 4: Systèmes d'assise dans les véhicules à moteurs

Reference number
©
ISO 2009
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©  ISO 2009
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ii © ISO 2009 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Design requirements . 6
4.1 Reduction of sharp edges. 6
4.2 Accommodation of vehicle-anchored occupant restraints. 6
5 Performance requirements . 7
5.1 Frontal impact test. 7
5.2 Accommodation of vehicle-anchored occupant belt restraints . 8
6 Identification, labelling, user instructions, warning and disclosure requirements . 8
6.1 Identification and labelling . 8
6.2 Pre-sale literature. 9
6.3 User instructions . 9
6.4 User warnings . 9
7 Documentation of compliance . 10
7.1 General. 10
7.2 Test report . 10
7.3 Frontal impact test. 11
7.4 Design, labelling and literature requirements . 11
Annex A (normative) Test method for frontal impact test . 12
Annex B (normative) Specifications for the surrogate wheelchair base used for impact testing of
a seating system. 19
Annex C (informative) Wheelchair seating system — Static test method. 24
Annex D (normative) Test method for rating the seating system's accommodation of vehicle-
anchored belt restraints. 33
Annex E (informative) Recommended user instructions and user warnings . 37
Bibliography . 40

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 16840-4 was prepared by Technical Committee ISO/TC 173, Assistive products for persons with disability,
Subcommittee SC 1, Wheelchairs.
ISO 16840 consists of the following parts, under the general title Wheelchair seating:
⎯ Part 1: Vocabulary, reference axis convention and measures for body segments, posture and postural
support surfaces
⎯ Part 2: Determination of physical and mechanical characteristics of devices intended to manage tissue
integrity — Seat cushions
⎯ Part 3: Determination of static, impact and repetitive load strengths for postural support devices
⎯ Part 4: Seating systems for use in motor vehicles
iv © ISO 2009 – All rights reserved

Introduction
Transportation safety research has demonstrated that the design of the vehicle seat, the occupant restraints
and seat compartment in motor vehicles play a vital role in protecting the occupant in the event of a crash. For
some wheelchair users, it is not feasible to transfer to the seat provided by the vehicle manufacturer and they
must remain seated in their wheelchair while travelling in a vehicle. ISO 7176-19 provides a means of
evaluating the design and frontal crashworthiness performance of complete wheelchairs when used as
forward-facing seats in motor vehicles. However, it is common practice that a seating system from one
manufacturer and a wheelchair base from another manufacturer be used to form the complete wheelchair.
Wheelchair seating systems may also be intended for use on multiple models of wheelchair bases. For this
reason, there is a need to be able to evaluate the design and performance of wheelchair seating systems
independent of the commercial wheelchair bases on which they may be installed. This part of ISO 16840
provides a means of assessing frontal impact crashworthiness of seating systems without the host wheelchair
by using a surrogate wheelchair base.
Manufacturers may choose to not test customized variations of a given seating system. The manufacturer
may test a representative variation of the seating system and it is for the manufacturer to document how the
results of this test would apply to the limitations in use and instructions for use supplied with the product.
This part of ISO 16840 is intended to encourage safer motor vehicle transportation of wheelchair users by
increasing the availability of wheelchair seating systems that comply with basic principles of occupant
protection. This part of ISO 16840 should not be used to deny or limit wheelchair user access to motor vehicle
transportation.
Currently this part of ISO 16840 addresses only complete wheelchair seating systems and the test
requirements are representative of frontal impact conditions. However, future versions may address testing of
the individual components of the seating system as well as other directions of impact such as side or rear.

INTERNATIONAL STANDARD ISO 16840-4:2009(E)

Wheelchair seating —
Part 4:
Seating systems for use in motor vehicles
1 Scope
This part of ISO 16840 specifies test methods and requirements for design and performance, for instructions
and warnings and for product marking and labelling of seating systems intended to be used as a
forward-facing seat in a motor vehicle when fitted to a manual or powered wheelchair. It evaluates the frontal
crashworthiness performance of complete seating systems for occupancy by adults or children of mass equal
to or greater than 22 kg.
This part of ISO 16840 only applies to complete wheelchair seating systems including attachment hardware,
designed to be used with a wheelchair base tested as part of a wheelchair system that conforms to
ISO 7176-19 performance requirements and that has securement points for use with four-point, strap-type
tiedowns.
This part of ISO 16840 applies to seating systems designed to be used with occupant restraints that anchor
either to the vehicle, the tiedown system, the seating system or the wheelchair base.
Seating systems that are intended only for use with a specific wheelchair base should be tested to
ISO 7176-19 using the specifically intended wheelchair base.
2 Normative references
The following referenced documents are indispensable for the application 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 898-7, Mechanical properties of fasteners — Part 7: Torsional test and minimum torques for bolts and
screws with nominal diameters 1 mm to 10 mm
ISO 6487, Road vehicles — Measurement techniques in impact tests — Instrumentation
ISO 7176-19:2008, Wheelchairs — Part 19: Wheeled mobility devices for use as seats in motor vehicles
ISO 10542-1:2001, Technical systems and aids for disabled or handicapped persons — Wheelchair tiedown
and occupant-restraint systems — Part 1: Requirements and test methods for all systems
ISO 10542-2, Technical systems and aids for disabled or handicapped persons — Wheelchair tiedown and
occupant-restraint systems — Part 2: Four-point strap-type tiedown systems
FMVSS 201, Standard No. 201, Occupant protection in interior impact. (Federal Motor Vehicle Safety
Standards), 49 CFR 571.201
ECE Regulation 21, Uniform provisions concerning the approval of vehicles with regard to their interior fittings,
Revision 2, Amendment 2
ASTM E527-83 (2003), Standard Practice for Numbering Metals and Alloys (UNS)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
adult
person having a mass equal to or greater than 43 kg
3.2
anchor point
location on a vehicle interior component, floor, wall, wheelchair, or wheelchair tiedown, to which an
anchorage (3.3) is attached
3.3
anchorage
assembly of components and fittings by which loads are transferred directly from the wheelchair tiedown to
the vehicle, or from the occupant restraint to the vehicle, wheelchair, wheelchair tiedown or vehicle interior
component
3.4
anthropomorphic test device
ATD
articulated physical analogue used to represent a wheelchair occupant in a test
3.5
attachment hardware
mechanical means of attaching a seating system to the wheelchair frame
EXAMPLE Metal or plastic hooks, nuts or bolts.
3.6
back support angle
angle of the back support reference plane with reference to a vertical plane
NOTE Measurement method specified in ISO 7176-7.
3.7
back support surface
component of seating system intended to support the posterior surface of the sacral, lumbar and/or thoracic
segments of the trunk
3.8
back support reference plane
plane associated with the back support of the wheelchair, which is referenced to make measurements
NOTE Method for determining the location of this reference plane specified in ISO 7176-7.
3.9
belt
length of webbing material used as part of an occupant restraint or postural support
3.10
child
person having a mass equal to or greater than 22 kg and less than 43 kg
3.11
custom contoured
uniquely shaped to match the wheelchair occupant
2 © ISO 2009 – All rights reserved

3.12
...