ISO 16840-4:2009
(Main)Wheelchair seating — Part 4: Seating systems for use in motor vehicles
Wheelchair seating — Part 4: Seating systems for use in motor vehicles
ISO 16840-4:2009 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. ISO 16840-4:2009 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. ISO 16840-4:2009 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.
Sièges de fauteuils roulants — Partie 4: Systèmes d'assise dans les véhicules à moteurs
General Information
Standards Content (Sample)
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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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
excursion
horizontal movement of an ATD (3.4) or wheelchair during a test relative to its initial position on an impact sled
3.13
forward facing
orientation in which the wheelchair-seated occupant faces the front of the vehicle, with the reference plane
within ten degrees of the longitudinal axis of the vehicle
3.14
four-point tiedown
wheelchair tiedown that attaches to the wheelchair frame at four separate securement points and also
attaches to the vehicle at four separate anchor points
3.15
four-point strap-type tiedown
four-point tiedown (3.14) that uses four strap assemblies to secure the wheelchair in the vehicle
3.16
H-point
point located on the left and right side of the pelvic region of an ATD (3.4) that represents the approximate
location of the human hip joint centre in the side view, as specified by the ATD manufacturer
3.17
head support
postural aid to support the head of a wheelchair occupant, not designed or intended to provide head restraint
in a vehicle impact
3.18
head restraint
device intended to limit rearward excursion of the wheelchair occupant’s head in a vehicle impact
3.19
impact simulator
device for applying a programme of acceleration and deceleration modes to a section of a vehicle or simulated
vehicle structures, including instrumentation for measuring data required by this part of ISO 16840
3.20
impact sled
part of an impact simulator (3.19) on which components can be mounted for impact testing
3.21
occupant restraint
system or device intended to restrain a motor vehicle occupant during impact in order to prevent ejection, and
prevent or minimize contact with the vehicle interior components and other occupants
3.22
pelvic-belt restraint
lap-belt restraint
portion of the occupant restraint intended to limit movement of the pelvis by application of restraint forces to
the pelvis
See Figure 1.
Key
1 shoulder-belt restraint
2 pelvic-belt restraint
Figure 1 — Three-point-belt restaint comprised of a pelvic-belt restraint and a shoulder-belt restraint
that connect together near the hip of the occupant
3.23
point P
side-view projection of a point on the seating system which lies at the cross-sectional centre of a 100 mm
diameter, 200 mm long, cylinder with a maximum weight of 0,5 kg positioned with the longitudinal axis
perpendicular to the wheelchair reference plane, such that the curved surface of the cylinder is in contact with
the seat and back support surfaces
See Figure 2.
Dimensions in millimetres
Key
1 cylinder, diameter 100 mm
2 point P
a
Wheelchair reference plane.
b
Wheelchair ground plane.
Figure 2 — Seating system reference point P and wheelchair reference and ground planes
4 © ISO 2009 – All rights reserved
3.24
postural support device
component and/or belt used to support a person in a desired seated position during normal wheelchair use
NOTE Postural support devices are not designed or intended to provide occupant restraint on vehicle impact.
3.25
seat plane angle
angle of seat reference plane (3.27) with reference to a horizontal plane
NOTE Measurement method specified in ISO 7176-7.
3.26
seat support surface
component of seating system intended to support the inferior surface of the buttocks and thighs
3.27
seat reference plane
plane associated with the seat of the wheelchair, which is referenced to make measurements
NOTE Methods for determining the location of this reference plane are specified in ISO 7176-7.
3.28
seating system
seat and back support surfaces and their attachment hardware
3.29
securement points
points on the wheelchair to which wheelchair tiedowns are connected
3.30
shoulder-belt restraint
upper torso restraint
portion of the occupant restraint intended to limit movement of the upper body by application of restraining
forces to either or both clavicles
See Figure 1.
3.31
strap
length of webbing material used in a wheelchair tiedown
3.32
support surface
part of the seating system that is intended to contact the wheelchair occupant
3.33
surrogate wheelchair base
SWCB
re-usable device that conforms to the requirements of Annex B, used to simulate a wheelchair base for the
purpose of testing seating systems
3.34
three-point-belt restraint
three-point restraint
occupant restraint assembly with three anchorages comprised of both a pelvic-belt restraint and a diagonal
shoulder-belt restraint that connect together near the hip of the occupant.
See Figure 1.
3.35
wheelchair base
portion of the wheelchair consisting of the wheels and wheelchair frame (3.36)
3.36
wheelchair frame
portion of the wheelchair consisting of the members that make up the supporting structure
3.37
wheelchair ground plane
plane representing the surface on which the wheelchair rests
See Figure 2.
3.38
wheelchair reference plane
vertical plane in longitudinal centreline of the wheelchair
See Figure 2.
3.39
wheelchair tiedown
wheelchair securement system
device or system designed to secure a forward-facing wheelchair in place in a motor vehicle
3.40
wheelchair tiedown and occupant restraint system
WTORS
complete restraint system for wheelchair-seated occupants comprised of equipment for wheelchair tiedown
and a belt-type occupant restraint
4 Design requirements
NOTE It can be beneficial for some users to have a head restraint as a part of their seating system.
4.1 Reduction of sharp edges
Webbing shall be protected from contacting sharp corners and edges. If the edge of a rigid component of a
seating system has a radius less than 2,0 mm, it shall be covered with padding capable of absorbing energy
to reduce the likelihood of injuries to wheelchair users and other vehicle occupants during a vehicle impact.
Energy-absorbing padding should conform to the requirements of FMVSS 201 and/or ECE Regulation No. 21.
4.2 Accommodation of vehicle-anchored occupant restraints
The seating system shall be constructed in such a way that any part of the system (e.g. frame, hip or thigh
supports, etc) will not hold a lap-belt or shoulder-belt restraint away from a seated user’s pelvis or upper torso.
6 © ISO 2009 – All rights reserved
5 Performance requirements
NOTE Informative Annex C provides manufacturers with a preliminary means to evaluate the performance of their
seating system using low cost static tests. It is important to note that static testing results may not be equivalent to
dynamic test performance.
5.1 Frontal impact test
5.1.1 General
The wheelchair seating system shall be tested in accordance with Annex A using the surrogate wheelchair
base, as specified in Annex B, secured by a four-point strap-type tiedown that complies with ISO 10542-1 and
ISO 10542-2. The requirements of 5.1.2 and 5.1.3 shall be met during and after the conducted test.
5.1.2 During the frontal impact test
When tested in accordance with Annex A, the following requirements shall be met during the test.
a) The horizontal excursions of the ATD and the seating system shall not exceed the values given in Table 1.
NOTE Excursion limits are based upon prevention of occupant secondary impact with vehicle interior.
b) Except when the test has been conducted using a wheelchair base or seat-anchored pelvic-belt restraint
or a completely wheelchair base or seat-anchored occupant restraint system, the knee excursion, X ,
knee
shall exceed the point P excursion, X , as follows.
ss
X /X W 1,1
knee ss
Refer to Table 1 for definitions of X and X .
knee ss
NOTE Conformity with this requirement reduces the potential for the seating system to apply loads to the wheelchair
occupant.
c) The seating system shall not separate from the surrogate wheelchair base at any attachment point.
5.1.3 After the frontal impact test
When tested in accordance with Annex A, the following requirements shall be met at the end of the test.
a) The ATD shall be retained in the seating system in a seated posture, as determined by the ATD torso
being oriented at not more than 45° to the vertical when viewed from any direction.
NOTE The angle of the ATD torso can be estimated by aligning the edge of an inclinometer with a line drawn
connecting the centre of the ATD's shoulder and the ATD's hip.
b) The load-carrying components of seating system and attachment hardware shall not show visible
fractures or deformation that prevent it from supporting the mass of the ATD.
c) Components, fragments or accessories of the seating system with a mass greater than 0,1 kg shall not
have completely separated from the seating system.
d) Rigid seating system components that may contact the occupant shall not fragment or separate in a
manner that produces sharp edges with a radius of less than 2,0 mm.
e) The post-test height of the average of left and right ATD H-points relative to the wheelchair ground plane
shall not change by more than 20 % from the pre-test height.
Table 1 — Horizontal excursion limits
Dimensions in millimetres
Excursion 6-year old child 10-year old Small adult Midsize and
Measurement point
variable ATD child ATD female ATD large adult ATD
Point P of seating system X 150 175 200 200
ss
ATD knee centre X 300 325 375 375
knee
ATD front of head X 450 500 550 650
headF
ATD back of head X −350 −400 −400 −450
headR
X is the forward horizontal distance relative to the sled platform between the point P target on the seating system
ss
at time t , to the point P target at the time of peak seating system excursion.
X is the horizontal distance relative to the sled platform between the ATD knee joint target at time t , to the
knee 0
knee-joint target at the time of peak knee excursion.
X is the horizontal distance relative to the sled platform between the most forward point on the ATD's head above
headF
the nose at time t , to the most forward point on the ATD's head at the time of peak head excursion.
X is the horizontal distance relative to the sled platform between the most rearward point on the ATD's head at
headR
time t , to the most rearward point on the ATD's head at the time of peak head excursion.
NOTE 1 Refer to Table A.1 for appropriate ATD selection.
NOTE 2 Positive limit values indicate forward excursions, while negative values indicate rearward excursions.
5.2 Accommodation of vehicle-anchored occupant belt restraints
The wheelchair seating system shall be tested for accommodation of vehicle-anchored occupant restraint
systems in accordance with Annex D and the resulting rating shall be reported in the product presale literature.
6 Identification, labelling, user instructions, warning and disclosure requirements
6.1 Identification and labelling
The wheelchair seating system shall be permanently marked with:
a) the manufacturer’s name;
b) the month and year of manufacture;
c) a unique serial number;
d) a statement that the seating system meets the requirements of ISO 16840-4:2008;
e) a statement that any postural support device not intended for use as occupant restraint in motor vehicle
transport may not provide occupant protection in a vehicle impact;
f) the maximum occupant mass;
g) an indication that each component of the system that functions as a postural support conforms to
requirements of ISO 16840-4:2008.
8 © ISO 2009 – All rights reserved
6.2 Pre-sale literature
The seating system manufacturer's presale literature shall include:
a) a statement that the seating system is intended only for use with wheelchair bases tested as part of a
complete wheelchair system that conforms to the performance requirements of ISO 7176-19;
b) a statement that the seating system must be used on a wheelchair base that provides securement points
that conform to the design requirements of ISO 7176-19;
c) a description of the seating system including the components that are intended for use during motor
vehicle transport;
d) a statement that the seating system is designed to be forward facing when used with a wheelchair base in
a motor vehicle;
e) a description of the WTORS to be used;
1)
f) the overall score and rating of the seating system (i.e. A, B or C) with regard to accommodating vehicle-
anchored occupant restraints, and an explanation of the different ratings based on the test methods of
Annex D.
6.3 User instructions
User instructions shall be provided with each seating system in the official languages of the countries in which
the product is marketed, and shall include:
a) a statement that the seating system meets the requirements of ISO 16840-4:2008 and that it is suitable
for use as a motor vehicle seat when used with an appropriate wheelchair base;
b) a statement describing assembly, use, maintenance and any limitations in using the seating system with
a wheelchair base in a motor vehicle;
c) in cases of custom-contoured seating systems, a statement that custom contoured seating systems may
require a qualified professional to configure and install the seating system;
d) a statement that both a pelvic-belt restraint and shoulder-belt restraint should be used.
6.4 User warnings
The seating manufacturer shall provide the following warnings in the user instructions using 12-point or larger
bold font:
a) the seating system shall only be used with wheelchair bases that were 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;
b) the seating system shall only be used for forward-facing seating in motor vehicles;
c) the seating system shall only be used as indicated in the manufacturer's instructions;
d) wheelchair-mounted trays not specifically intended to be used in transport shall:
1) be removed and secured separately in the vehicle or
2) be secured to the wheelchair but positioned away from the wheelchair-seated occupant with energy-
absorbing padding placed between the tray and the occupant;
1) A = good; B = acceptable; C = poor.
e) postural support devices that are not labelled as conforming to ISO 16840-4 may be used when in a
vehicle, but should not be relied on for occupant restraint;
f) alterations or substitutions shall not be made to the seating system structure, parts or components,
without consulting the manufacturer;
g) both pelvic-belt and shoulder-belt restraints as a part of a complete WTORS which meets ISO 10542-1
shall be used to achieve effective occupant restraint and optimum protection in a vehicle impact; the belt
restraints should be fitted to the user in accordance with WTORS manufacturers’ instructions;
h) children whose mass is less than 22 kg should be transferred from their seating system into appropriate
child restraint systems intended for use in motor vehicles.
NOTE See also E.2 c).
7 Documentation of compliance
7.1 General
The wheelchair manufacturer shall maintain documentation, including test reports, that provide evidence of
compliance to the design and performance requirements of this part of ISO 16840. This documentation shall
include the information listed in 7.2 to 7.4.
7.2 Test report
The following shall be included in the report of each test conducted in accordance with this part of ISO 16840:
a) reference to this part of ISO 16840, i.e. ISO 16840-4:2008;
b) the name and address of the test institution;
c) the date of test;
d) a unique test report number shown on each numbered page;
e) the name and address of the manufacturer;
f) product type, designation and serial number of the seating system;
g) a list of individual components and their designation, including postural supports and attachment
hardware, tested as a part of the seating system;
h) photographs of the seating system, once test set-up procedures have been completed, before testing and
after testing;
i) photographs of the seating system attachment hardware, once test set-up procedures have been
completed, before testing and after testing;
j) photographs of the side and frontal view of the test setup before and after testing;
k) a description of any postural support devices used in the test.
10 © ISO 2009 – All rights reserved
7.3 Frontal impact test
The test report for the frontal impact shall also include:
a) the measured or calculated value of the sled velocity change, ∆V, during the impact event;
b) a graph of the impact sled deceleration plotted against time and the specified acceleration/deceleration
requirements described in A.4.1 g) and Figure A.1;
c) a description and the total mass of the ATD used in the test;
d) a statement as to whether or not the seating system met the requirements of 5.1 and any other relevant
observations.
7.4 Design, labelling and literature requirements
The seating system manufacturer shall maintain statements and evidence on file as to:
a) whether the seating system meets the requirements specified in 4.1, 4.2, 5.1 and 5.2;
b) whether the seating system, its components and related literature are in accordance with the
requirements of 6.1, 6.2, 6.3 and 6.4.
Annex A
(normative)
Test method for frontal impact test
A.1 General
This annex specifies apparatus, conditions and procedures for conducting a sled impact test to simulate the
dynamic loading on complete wheelchair seating systems, including attachment hardware, during frontal
impact. A complete wheelchair seating system shall be evaluated forward facing, using a 48 km/h, 20 g frontal
impact.
A.2 Principle
The principle of this test method is to evaluate the performance of a wheelchair seating system, including
attachment hardware, occupied by an ATD, independent of a specific wheelchair frame, when subjected to
frontal impact. Test procedures specify the use of a surrogate wheelchair base (SWCB) described in Annex B
to represent a commercial wheelchair frame. Observations and measurements are made to determine
whether the seating system strength and performance are satisfactory under these test conditions.
A.3 Test sample
This comprises a complete seating system, consisting of an unused seating system, attachment hardware,
and any postural support devices typically supplied with the seating system and instructions for their
installation and use. Obtain instructions from the manufacturer for mounting attachment hardware to the
SWCB support structure. This will ensure that the SWCB seat support structure will be compatible with the
attachment hardware.
NOTE The SWCB seat support structure is replaceable so that the cross section of the members are compatible with
the seating system attachment hardware.
A.4 Test apparatus
A.4.1 An impact simulator, including the following:
a) an impact sled equipped with a flat, horizontal, structurally rigid platform on which the surrogate
wheelchair base can be mounted, and to which the wheelchair tiedown can be anchored;
b) a horizontal track or guide path to provide unidirectional movement of the sled during the impact event;
c) a means of driving the impact sled through a change in velocity of 48 km/h + 2 km/h − 0 km/h;
d) a rigid structure attached to the impact sled to which the upper anchorage of the shoulder-belt restraint
can be anchored as specified in A.5.9;
e) a wheelchair tiedown that conforms with the dynamic performance requirements specified in 6.2 of
ISO 10542-2:2001 and that secures the surrogate wheelchair base by the method specified by the
manufacturer;
12 © ISO 2009 – All rights reserved
f) a vehicle-anchored three-point-belt restraint or a wheelchair base anchored lap-belt restraint with a
vehicle anchored shoulder-belt restraint that conforms to the requirements of ISO 10542-1;
g) a means of accelerating and/or decelerating the impact sled and test set-up such that the processed sled
acceleration- and/or deceleration-time pulse:
1) falls within the shaded area of Figure A.1,
2) exceeds 20 g for a cumulative time period of at least 15 ms,
3) exceeds 15 g for a cumulative time period of at least 40 ms and
4) has a duration of at least 75 ms from t to t where t is the time at the beginning of the deceleration
o f o
and t indicates the time at the end of the deceleration pulse;
f
h) an ATD selected from Table A.1 which is representative of the upper size range of users for which the
seating system is designed;
i) a surrogate wheelchair base that complies with the specifications of Annex B.
a
Table A.1 — ATDs for seating system testing
Occupant weight range ATD Size Approximate mass of ATD
kg (lb) kg (lb)
> 18 to 27 (> 40 to 60) 6-year-old child 22,5 (50)
> 27 to 43 (> 60 to 95) 10-year-old child 35 (76)
> 43 to 57 (> 95 to 125) Small adult female 47,0 (104)
b
> 57 to 75 (> 125 to 165) Small adult female, weighted 59,0 (130)
> 75 to 136 (> 165 to 300) Midsize adult male 76,3 (170)
> 136 (> 300) Large adult male 102,0 (225)
a
The midsize male ATD shall be a Hybrid II or Hybrid III type.
The other sizes of ATDs may be Hybrid II, Hybrid III, VIP, P series or Q series types.
b
The ATD mass may be increased by attaching weighted material, such as lead sheeting, to the exterior of the ATD.
Key
X time in milliseconds
Y deceleration in g force
NOTE The acceleration/deceleration of the impact sled shall stay within the shaded area and exceed the indicated
levels for the specified continuous (unbroken arrows) and cumulative (broken arrows) time period.
Figure A.1 — Acceleration/deceleration requirements for the 48 km/h (+2 km/h − 0 km/h) ∆V impact test
A.4.2 A high speed film or video system, capable of recording at a minimum frame rate of 500 frames/sec,
to measure the ATD and SWCB horizontal excursions specified in 5.1 and Table 1 to an accuracy of ± 5 mm.
A.4.3 A means of measuring the horizontal acceleration and/or deceleration of the impact sled in the
direction of travel, at a sampling rate in accordance with ISO 6487, and with a precision of ± 0,5 g.
Impact sled accelerometers shall be calibrated once per year in conformance with ISO 6487.
A.4.4 A means of measuring the horizontal velocity change, ∆V, during the impact with a precision of
± 0,5 km/h.
A.4.5 Provision to filter analog transducer signals, using a low-pass filter in accordance with ISO 6487,
including
a) pre-filtering of all transducer signals to Channel Class 1 000 (−4 dB at 1 650 Hz) prior to digitizing at
10 000 Hz,
b) filtering of the digitized accelerometer and load-cell signals to Channel Class 60 (−4 dB at 100 Hz).
14 © ISO 2009 – All rights reserved
A.5 Test preparation and procedure
A.5.1 Set up the surrogate wheelchair base and seating system in accordance with the following.
a) Select and install the appropriate surrogate wheelchair base cross brace frame which matches the seat
system width.
b) Select and install seat rails and, where applicable, seatback posts having a cross section or cross
sections that are compatible with the attachment hardware.
NOTE For seating systems having an integral seat frame, seatback posts might not be necessary.
c) Install deformable castor elements and, where applicable, the deformable seatback post elements.
d) Fasten the seat and back support surfaces as applicable with the provided attachment hardware to the
surrogate wheelchair base seat and back structure in accordance with the manufacturer’s instructions.
e) Fasten any additional postural support devices or components to the seating system in accordance with
the manufacturer’s instructions.
f) If specific instructions are not provided by the manufacturer, tighten bolts and screws to the minimum
torque specified in ISO 898-7.
g) For seating systems having an integrated tilting frame, remove the surrogate wheelchair base seatback
post elements and mount seating system frame to surrogate wheelchair base.
h) For seating systems with independently reclining back support surfaces, adjust the back support angle to
10° relative to the vertical without the ATD seated in the wheelchair.
NOTE Back support angle measurement method specified in ISO 7176-7.
i) For seating systems with independently adjustable seat support surface angles, adjust the seat plane
angle to a maximum incline angle of 10° relative to the horizontal without the ATD seated in the
wheelchair.
NOTE Seat plane angle measurement method specified in ISO 7176-7.
j) For seating systems having an integrated tilting frame, adjust the seat plane angle to a maximum of 30°,
relative to the horizontal, without the ATD in the wheelchair or a position selected by the manufacturer.
NOTE Seat plane angle measurement method specified in ISO 7176-7.
k) Adjust the horizontal and vertical footrest extension bars to accommodate the selected ATD.
l) Record the pre-test settings, including seatback support surface angle relative to vertical and seat support
surface angle relative to horizontal, of the seating system components. Any adjustable seating
components shall be set to manufacturer’s recommended position or the mid-position of recommended
range.
A.5.2 Set up the high-speed film or video system (A.4.2) to record a lateral view of the test sled platform,
surrogate wheelchair base with seating system and ATD during the impact event and during ATD rebound.
A.5.3 Position the SWCB with seating system facing forward on the sled platform with wheelchair reference
plane parallel to the direction of sled travel.
A.5.4 Install the wheelchair tiedown anchorages on the sled platform, selecting anchor points for four-point
tiedowns that:
a) are symmetric about the intended wheelchair reference plane;
b) are located 1 300 mm ± 20 mm from the front anchor point to the rear anchor point;
c) have a lateral distance between rear anchor points equal to the lateral distance between rear securement
points of the test wheelchair base, ± 25 mm;
d) have a lateral distance between front anchor points of 508 mm to 660 mm, as is appropriate to the test
wheelchair base.
A.5.5 Using the lower rear securement point of the SWCB, secure the SWCB with four-point tiedowns to
achieve lengths of the rear tiedown strap assemblies of 495 mm to 533 mm, measured from the interface of
the tiedown end fitting and the securement point on the SWCB to the anchor point.
NOTE The upper rear securement point of the SWCB may be used to evaluate wheelchair seating system
performance under differing rear securement conditions but is not required by this part of ISO 16840.
A.5.6 Tension any tiedown straps to the manufacturer's specifications, making sure that the SWCB
reference plane remains aligned within ± 3° of the direction of sled travel.
A.5.7 Position the ATD selected from Table A.1 in the seating system sitting upright and symmetrically
positioned about the wheelchair reference plane, with the pelvis and elbows as close to the seatback of the
surrogate wheelchair base or seating system as possible.
A.5.8 Install the pelvic-belt restraint. For vehicle-anchored or SWCB-anchored pelvic-belt restraints, select
anchor points within the recommended zones as specified in Figure 5 of ISO 10542-1:2001. For seating
system-anchored pelvic-belt restraints, utilize anchor points provided on the seating system.
A.5.9 Install the shoulder-belt restraint anchorage and/or guide on a rigid structure at the point marked by a
bold X in Figure A.2 for a mid-sized male; to achieve belt restraint, fit across the ATD's shoulder and chest as
shown. For tests involving other sizes of ATDs, adjust the anchor point location accordingly to give a good fit
to the ATD chest whilst maintaining the angles shown for a mid-sized male ATD in Figure A.2.
A.5.10 Adjust the tension in the pelvic-belt restraint as follows.
a) If an emergency locking or auto-locking retractor is provided, adjust the pelvic-belt restraint for minimum
slack over the ATD’s pelvis.
b) If no emergency-locking or auto-locking retractor is provided, remove all belt restraint slack and adjust the
tension of the pelvic-belt restraint to a snug fit over the pelvis.
A.5.11 Adjust the tension in the shoulder-belt restraint as follows.
a) If an emergency locking or auto-locking retractor is provided, adjust the shoulder-belt restraint for
minimum slack over the ATD’s chest.
b) If no emergency-locking or auto-locking retractor is provided, remove all shoulder-belt restraint slack and
adjust the tension of the shoulder-belt restraint to a snug fit with a 75 mm × 75 mm × 75 mm block placed
between the shoulder-belt restraint and ATD sternum. Remove the block before conducting the test.
16 © ISO 2009 – All rights reserved
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