Annexes K, L, M

Annexes K, L, M

General Information

Status
Published
Publication Date
06-Apr-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
27-Feb-2021
Completion Date
26-Feb-2021
Ref Project

RELATIONS

Buy Standard

Standard
ISO 10542-1:2012/Amd 1:2021 - Annexes K, L, M
English language
32 pages
sale 15% off
Preview
sale 15% off
Preview
Draft
ISO 10542-1:2012/FDAmd 1:Version 26-dec-2020 - Annexes K, L, M
English language
32 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

INTERNATIONAL ISO
STANDARD 10542-1
First edition
2012-10-01
AMENDMENT 1
2021-04
Technical systems and aids for
disabled or handicapped persons —
Wheelchair tiedown and occupant-
restraint systems —
Part 1:
Requirements and test methods for
all systems
AMENDMENT 1: Annexes K, L, M
Assistances et aides techniques pour les personnes invalides ou
handicapées — Systèmes d'attache du fauteuil roulant et de retenue
de l'occupant —
Partie 1: Exigences générales et méthodes d'essai pour tous les
systèmes
AMENDEMENT 1: Annexes K, L, M
Reference number
ISO 10542-1:2012/Amd.1:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© 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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
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 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 Technical Committee ISO/TC 173, Assistive products, Subcommittee SC

1, Wheelchairs.

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.
© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
Technical systems and aids for disabled or handicapped
persons — Wheelchair tiedown and occupant-restraint
systems —
Part 1:
Requirements and test methods for all systems
AMENDMENT 1: Annexes K, L, M
Introduction
Add the following text to the end of the third paragraph:

In addition, Annex K provides a test method and performance measures for WTORS manufacturers

who wish to test the wheelchair securement system for rear-impact conditions, and Annex M

provides a test method and performance measures for WTORS manufacturers who wish to evaluate

the rear-impact performance of vehicle-mounted, head-and-back restraints.
Add the following text to the end of the fourth paragraph:

Annex K provides a test method whereby they are exposed to a 14 g, 25 km/h rear impact sled test.

Add the following text to the end of the seventh paragraph:

Annex L provides a method for evaluating wheelchair securement systems for the situation of

wheelchair occupants restrained by a three-point belt comprised of a vehicle-anchored shoulder

belt and a wheelchair-anchored pelvic belt.
Clause 2
Add the following normative references:

ISO 16840-4:2009, Wheelchair seating — Part 4: Seating systems for use in motor vehicles

ISO 7176-19:2008/Amd 1:2015, Wheelchairs — Part 19: Wheeled mobility devices for use as seats in motor

vehicles — Amendment 1: Annex G
Clause 3
Add the following terms and definitions:
© ISO 2021 – All rights reserved 1
---------------------- Page: 4 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
3.46
foot/leg strap

length of webbing mounted forward and below the ATD knee to limit upward movement of the leg after

peak forward motion of the ATD knee has occurred

Note 1 to entry: The foot/leg strap minimizes damage to the ATD and provides for more realistic movement of the

lower extremities during frontal-impact loading by limiting extension of the knee joints and upward movement

of the ATD’s lower extremities. It does this in a manner that does not affect forward excursions of the ATD, but

slightly reduces the severity of rearward rebound of the ATD while making this rebound more controlled and

consistent between tests.
3.47
sharp edge
exposed, rigid edge with a radius of less than 2 mm
3.48
vehicle-mounted, head-and-back restraint
vehicle-anchored, head-and-back restraint

optional portion of a WTORS that is positioned behind a forward-facing occupant seated in a wheelchair

for the purpose of limiting rearward movement of the occupant’s torso, head, and neck to reduce the

risk of injury in rear-impact collisions

Note 1 to entry: A vehicle-mounted, head-and-back restraint system is an optional part of a WTORS.

5.2.1
Add the following notes to the end of the subclause:

Note 1 The performance of WTORS in frontal impacts for systems with a wheelchair-anchored pelvic belt can

be evaluated using the test method and performance criteria given in Annex L.

Note 2 The performance of WTORS in rear impacts can be evaluated using the test method and performance

criteria given in Annex K.

Note 3 The performance of a WTORS with an optional vehicle-mounted, head-and-back restraint in rear

impacts can be evaluated using the design guidelines, test method and performance criteria given in Annex M.

J.4
Replace the text with the following:
J.4 Engineering drawings for test equipment

Engineering drawings for the surrogate wheelchair (SWC), surrogate WTORS (SWTORS) and the

surrogate wheelchair base (SWCB) listed below can be obtained from:

The Biosciences Group, University of Michigan Transportation Research Institute (UMTRI), 2901

Baxter Road, Ann Arbor, MI 48109-2150 USA, Phone: (734) 763-3582, Fax: (734) 647-3330 and

downloaded from the website: http:// wc -transportation -safety .umtri .umich .edu/ wts -standards/

WC 4engineeri ngdrawings
The available drawings include

1) a surrogate wheelchair specified in Annex E and used in the frontal-impact tests of Annex A and

Annex L and in the methods for measuring belt-restraint geometry of Annex B,

2) a surrogate wheelchair base (SWCB) used in ISO 16840-4 for frontal-impact testing of wheelchair

seating systems and for rear-impact testing of vehicle-mounted, head-and-back restraints in

Annex M,
2 © ISO 2021 – All rights reserved
---------------------- Page: 5 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)

3) a surrogate WTORS with four-point strap type tiedown and three-point belt restraint with a means

to anchor the pelvic belt to the SWC and the SWCB per Annex L and Annex M, respectively, and

4) a surrogate wheelchair docking securement system, including docking securement device,

wheelchair adaptor, and front-stabilizing bracket for testing the crashworthiness of wheelchairs in

ISO 7176-19 when secured by commercial docking devices, and for securing the SWCB during rear-

impact tests of vehicle-mounted, head-and-back restraints in Annex M.
Annex K
Add the following annex after Annex J.
© ISO 2021 – All rights reserved 3
---------------------- Page: 6 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
Annex K
(informative)
Test method and performance criteria for rear impact of WTORS
K.1 Rationale

The primary focus of this document is to provide design and performance criteria for WTORS used with

forward-facing occupants seated in a wheelchair during frontal-impact loading. This annex provides

a test method and performance criteria for evaluating the effectiveness of wheelchair securement

systems during rear-impact loading. The severity of the rear-impact test in this annex has been selected

to align with the acceleration/deceleration pulse and delta V in ISO 7176-19:2008/Amd 1:2015, Annex G,

which uses the rear-impact deceleration corridor of ECE R44 and a 25 km/h change in velocity. This

change in velocity represents a moderate-to-severe real-world rear impact that corresponds to an

80 percentile real-world rear-impact event based on analysis of effective barrier speed rear-impact

distributions from the US National Automotive Sampling System nationally representative crash/injury

databases.

Throughout this annex, the term test wheelchair (TWC) is used. The TWC may be the surrogate

wheelchair (SWC) specified in Annex E or it may be a specific wheelchair model (SWM) that the

securement system is designed to secure. If a wheelchair securement system is to be tested with an

SWM, the wheelchair’s response should be evaluated using the performance criteria in

ISO 7176-19:2008/Amd 1:2015, Annex G.
K.2 Principle

To simulate a typical moderate-to-severe rear-impact event to an occupied wheelchair, the TWC

is placed on the test platform of an impact sled facing rearward to the direction of sled acceleration

and/or deceleration. The TWC is loaded with an appropriate size ATD as specified in K.4 below that is

restrained by a three-point belt occupant restraint system, and the TWC is secured by the securement

system to be evaluated in rear impact. The sled is subjected to an acceleration/deceleration-time pulse

that falls within a specified corridor to achieve the required horizontal change in velocity, or delta V.

Observations and measurements are made during and after the test to determine if the securement

system effectively secured the TWC during rear-impact loading.
K.3 Test sample

Provide an unused WTORS, including all fittings, anchorages, fasteners, and instructions for installation

and use, for testing. If a WTORS is designed to use a modified original equipment manufacturer

(OEM) belt-type occupant restraint system, provide it for testing. Include documentation to indicate

any components of the WTORS that are designed to provide controlled failure or deformation under

dynamic loading.
K.4 Test equipment
K.4.1 Use an impact simulator that includes the following:

a) an impact sled with a flat, horizontal, structurally rigid platform on which the TWC can be mounted,

and to which the WTORS can be fastened;

b) a rigid structure attached to the impact sled to which the upper-torso restraint can be anchored in

the manner, and to the geometry, specified by the WTORS manufacturer;
4 © ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)

c) a means to drive the impact sled through a change in velocity of 25 km/h km/h;

d) a means to accelerate and/or decelerate the impact sled and test setup such that the processed sled

acceleration and/or deceleration-time pulse falls within the shaded area of Figure K.1,

K.4.2 If the WTORS is intended for use with all types of manual and powered wheelchairs, use the

following:
a) a SWC that conforms with the specifications of Annex E;
th th

b) a Hybrid III 50 percentile ATD (nominal mass 77 kg) or Hybrid II 50 percentile ATD (nominal

mass 74 kg).

NOTE 1 A head restraint can be added to the SWC to help limit rearward rotation of the ATD’s neck and

rearward movement of the ATD’s head. The addition of the head restraint can alter the centre of gravity of the

SWC. This is acceptable as long as the SWC without the head restraint is compliant to Annex E.

NOTE 2 Utilizing the 50 percentile ATD harmonizes this testing with that specified in Annex A.

K.4.3 If the WTORS is intended to be used only with a specific wheelchair model (SWM), use the

following:
a) the SWM it is designed for;

b) an ATD selected from ISO 7176-19:2008, Table A.1 that is representative of the upper size range of

users for which the specific make or model of wheelchair is designed to carry or other similar sized

ATD with equivalent mass, anthropomorphic shape, and mass distribution.

K.4.4 Provide a means to measure the TWC horizontal excursion specified in K.7 with a precision

of ±5 mm.

NOTE A side-view high-speed camera or video system with a minimum frame rate of 500 frames per second

is suggested.

K.4.5 Provide a means to measure 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.

Key
X time (ms)
Y deceleration (g)
Figure K.1 — Acceleration/deceleration corridor for 25 km/h rear impact

K.4.6 Provide a means to measure the horizontal velocity change (delta-V) of the impact sled during

the impact with a precision of ±0,5 km/h.
© ISO 2021 – All rights reserved 5
---------------------- Page: 8 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)

K.4.7 Make provisions to filter transducer signals using a low-pass filter in accordance with ISO 6487,

including

a) prefiltering of all transducer signals to Channel Class 1 000 (-4 dB at 1 650 Hz) prior to digitizing at

10 000 Hz, and

b) filtering of the digitized accelerometer and load-cell signals to Channel Class 60 (-4 dB at 100 Hz).

K.5 Test preparation and procedure

K.5.1 Use the following procedures to set up and run the test. The procedures for setting up the test

may be undertaken in any order.

NOTE For example, it can sometimes be more convenient to position the ATD on the TWC prior to lifting the

assembly onto the impact sled.
K.5.2 Prepare the ATD by

a) adjusting each joint in the upper and lower extremities to achieve a static resistance of 1 g as

indicated by just-noticeable movement with gravity acting on the mass of the distal body segment

or segments, and
b) placing close-fitting cotton clothing on the pelvis, thighs, and torso.
K.5.3 Preparation of the TWC
K.5.3.1 When the TWC is the SWC, prepare it as follows.

a) Inspect all frame junctions and components, and repair where there are signs of fatigue or

deformation.
b) Inspect tyres for cracks or damage and replace as needed.

c) Inflate the SWC tyres as specified in Annex E with the wheelchair unoccupied and resting on a

horizontal surface.
d) Inspect the seat plate and seat support structures and replacing if deformed.

e) Modify the frame as needed to accommodate a wheelchair securement adaptor provided by the

WTORS manufacturer, while maintaining the SWC specifications within the tolerances specified in

Annex E.

f) Install any wheelchair-securement adaptor provided by the WTORS manufacturer on the SWC per

the manufacturer’s instructions.
K.5.3.2 When the TWC is a SWM, prepare it as follows.

a) Prepare the wheelchair for use in a motor vehicle as specified by the manufacturer’s user

instructions.

b) If a range is specified for any adjustments, use the adjustment closest to the midpoint of the range

for testing. If more than one adjustment position can be considered closest to the midpoint, use the

adjustment position immediately rearward, down, outboard or more reclined from midpoint.

c) Equip the wheelchair with any required add-on components as specified by the manufacturer.

d) If a pelvic belt intended for use as an occupant restraint is provided as a component of the

wheelchair attach it to the wheelchair according to the manufacturer's instructions.

e) If the wheelchair is equipped with liquid electrolyte type batteries, replace them with the nearest

equivalent gel type or a surrogate battery. Supplemental weights, if used, ought to provide

equivalent mass distribution to the original batteries.
6 © ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)

f) Inflate any pneumatic tyres to the pressure recommended by the wheelchair manufacturer or to

the maximum sidewall pressure with the chair unoccupied and on a level surface if no specification

is given.
g) Turn the wheelchair power off, if applicable.
h) Equip the SWM with any required securement adaptors.

K.5.4 Position the TWC on the sled in the orientation appropriate for representing a rear-impact

event and with the wheelchair reference plane parallel to the direction of sled travel ±3°.

K.5.5 When the method of wheelchair securement is a four-point tiedown tested with the SWC:

a) Select anchor points that
1) are symmetrical about the wheelchair reference plane,

2) are located 1 300 mm ± 20 mm from the front anchor point to the rear anchor point,

3) have a lateral distance between rear anchor points equal to 425 mm ± 25 mm, and

4) have a lateral distance between front anchor points of 600 mm ± 25 mm.

NOTE 1 For purposes of locating the anchor points, the front-to-back location of an anchor point is

the location of the primary fastener that secures the anchorage to the test platform or, in the case of

multiple fasteners, the centroid of the combined fastener locations. The lateral location of an anchor

point is the centre of the location where the tiedown end fitting contacts the anchorage hardware

attached to the test platform.

b) Position the SWC 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 wheelchair

to the anchor point.

NOTE 2 For purposes of measuring the rear tiedown length, the anchor point is considered to be the point

at which a straight line along the length of the strap assembly intersects with the wheelchair ground plane.

c) Tension all tiedown straps to the manufacturer's specifications.

K.5.6 For wheelchair securement systems other than four-point tiedowns or for WTORS meant to be

used with an SWM:

a) Install the anchorage mechanism or mechanisms on the sled platform per the manufacturer’s

instructions.

b) If a range is given for any installation dimensions, use the midpoint of the given range, when

possible.

c) If fasteners supplied with the securement system are not compatible with the impact-sled platform,

replacement fasteners shall be supplied or specified by the manufacturer.

K.5.7 Position the ATD in the TWC sitting upright and symmetrical about the wheelchair reference

plane, with the pelvis and buttock as far back on the wheelchair seat as possible, and the elbows resting

on the TWC arm supports or with the hands resting on the ATD's thighs.
K.5.8 Install the occupant restraint system in accordance with A.5.14 to A.5.19.

K.5.9 Conduct the test using a deceleration/acceleration pulse that falls within the corridor of

Figure K.1 and that produces a sled change in velocity of 25 km/h km/h by executing the appropriate

sequence of steps to start data acquisition and activate the impact sled.
© ISO 2021 – All rights reserved 7
---------------------- Page: 10 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
K.6 Measurement procedures for operation force of clamp-type systems

K.6.1 The measurement procedures for operational forces as given in A.6 shall apply.

K.7 Performance criteria
K.7.1 General

a) When the securement system is tested with the SWC, the criteria of K.7.2 and K.7.3 should be met.

b) When the securement system is tested with a SWM, the performance criteria given in

ISO 7176-19:2008/Amd 1:2015, G.3.5.1 and G.3.5.2, as well as K.7.3 c), d) and e) should be met.

K.7.2 During the test

When tested in accordance with the procedure given in K.5 using the SWC, the horizontal excursion of

the SWC should not exceed the value given in Table K.1.
Table K.1 — Horizontal excursion limits
Measurement Excursion variable Excursion limit
point
Point P of TWC wc 200

x is the horizontal distance relative to the sled platform between the point-P target on the TWC at

time t and the point P target at the time of peak rearward wheelchair excursion.
K.7.3 After the test

When tested in accordance with the procedure given in K.5 using the SWC the following criteria should

be met at the conclusion of the test.

a) The SWC should be in an upright position on the test platform with at least three of the four wheels

in contact with the sled platform and the ATD should be in the wheelchair 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.

b) Release of the SWC from the wheelchair securement system should not require the use of tools.

c) No tiedown strap end fitting or anchorage, and no mechanical securement system component,

should have detached or separated from the TWC or test platform during the test.

d) Load carrying components of the securement system should not completely fail unless the part is

designed to tear or fail in a controlled and predictable manner as described by the manufacturer

before the test.

e) The WTORS should exhibit no sharp edges or protrusions that are contactable by the occupant and

likely to increase the risk of injury to the occupant.
K.8 Post-test measurements and calculations

Determine peak rearward excursion x to an accuracy of ±5 mm through analysis of the high-

speed video.
8 © ISO 2021 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
K.9 Test report
K.9.1 Include the following information in the test report:
a) name and address of the test institution;
b) date of test;
c) unique test number shown on each numbered page;
d) name of the product manufacturer;
e) address of manufacturer;
f) product type, product name or number;
K.9.2 The test report shall also include:
a) a reference to this annex and the test procedures of K.5;
b) a description of the type and mass of the ATD used in the test;
c) the measured or calculated value of the test velocity change;

d) a graph of the impact sled acceleration plotted against time superimposed on Figure K.1;

e) pre-test still photography of the set up;
f) post-test still photography showing test outcomes;
g) test results as specified in K.7.2 and K.7.3;

h) a statement as to whether or not the securement system met the criteria given in K.7.2 and K.7.3;

i) any other relevant observations.

K.9.3 If the rear impact test is conducted using the SWC, it shall also include in the report:

a) the mass of the SWC;

b) a description of any modifications or adaptations fitted to the SWC for use with a securement system.

K.9.4 If the rear impact test is conducted using the SWM, the report shall follow the test report

criteria given in ISO 7176-19: 2008/Amd 1:2015, G.3.6 and also include:
a) details of any add-on components fitted to the SWM;

b) a description of any modifications or adaptations fitted to the SWM for use with a WTORS;

c) the mass of the SWM or TWC.
K.10 Labelling

In addition to the labelling requirements given in 6.1, WTORS in conformity with this annex should be

so indicated with text that conveys that the product conforms with this annex.
Annex L
Add the following annex after Annex K.
© ISO 2021 – All rights reserved 9
---------------------- Page: 12 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
Annex L
(informative)
Method for evaluating frontal-impact performance of wheelchair
securement systems for situations when occupants are using a
crash-tested three-point belt restraint system with a wheelchair-
anchored pelvic belt
L.1 Rationale

Annex A documents methods for evaluating complete WTORS in a simulated 48 km/h frontal crash test

when dynamic loads delivered to the wheelchair securement system are generated primarily by the

mass of an 85 kg surrogate wheelchair. Unless the occupant belt-restraint uses a pelvic belt designed

to anchor to the wheelchair, all of the occupant-restraint forces are transferred directly to the sled

platform and simulated vehicle sidewall structure (i.e. to the simulated vehicle components) except

for a small portion that is transferred to the securement system from interaction of the ATD with the

wheelchair seating system. However, when a passenger seated in a wheelchair is using a wheelchair-

anchored pelvic-belt restraint, which is allowed as an option to the consumer by ISO 7176-19, a

significant proportion of occupant-restraint forces are transferred to the wheelchair and then to the

wheelchair securement system, thereby imposing higher peak forces on the securement system than

are generated in a typical Annex-A test.

The additional loads on a wheelchair securement system generated by a wheelchair-anchored pelvic-

belt may be effectively dealt with in a real-world frontal crash by attaching additional rear tiedown

straps to the wheelchair secured to the vehicle by this method. Alternatively, stronger securement

systems designed to meet the additional loads from a wheelchair-anchored pelvic belt may be used to

secure the wheelchair. This Annex provides manufacturers of WTORS designed for general use with a

wide range of wheelchairs and occupants with a method for conducting a frontal-impact test of their

wheelchair securement system or complete WTORS to determine if it is dynamically strong enough to

withstand the higher loading conditions that can result from the use of a three-point belt restraint with

a wheelchair-anchored pelvic belt during a severe frontal crash.
L.2 Principle

The test equipment, test conditions, and frontal-impact procedures set forth in Annex A are used

to evaluate the dynamic strength of the wheelchair securement system, with the exception that the

test is conducted using the 85 kg surrogate wheelchair, a midsize-male crash-test dummy, and either

a commercial or surrogate three-point belt occupant restraint system with the pelvic belt anchored

to the surrogate wheelchair. Specifications for a surrogate three-point belt restraint system with

provision for anchoring the pelvic belt to a wheelchair or surrogate wheelchair are provided in Annex D

of RESNA WC -4: 2017, Section 19, and engineering drawings are available from the Biosciences Group of

the University of Michigan Transportation Research Institute (see J.4) and are illustrated in the annex.

However, other types of surrogate three-point belt restraints with SWC-anchored pelvic belts may also

be used (See note under L.4.9 h).
L.3 Test sample

Provide an unused wheelchair securement system or complete WTORS, including all fittings,

anchorages, fasteners and instructions for installation and use.
10 © ISO 2021 – All rights reserved
---------------------- Page: 13 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)
L.4 Test equipment
L.4.1 Use an impact simulator that includes the following:

a) an impact sled with a flat, horizontal, structurally rigid platform on which the SWC can be mounted,

and on which the WTORS can be installed;

b) a rigid structure attached to the rigid sled platform to which the upper anchorage of the surrogate

diagonal shoulder belt can be attached to achieve the belt-restraint geometry of Figure L.6;

c) a means to accelerate and/or decelerate the impact sled through a change in velocity of 48 km/h

km/h such that the processed sled acceleration- and/or deceleration-time pulse:
1) falls within the shaded area of Figure L.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;

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 deceleration pulse.
Key
X time (ms)
Y deceleration (g)

Figure L.1 — Acceleration/deceleration requirements for the impact test 48 km/h km/h

L.4.2 Use a surrogate wheelchair (SWC) that conforms with the specifications of Annex E.

L.4.3 Use a Hybrid III 50th percentile ATD with a nominal mass of 77,7 kg ± 1,18 kg.

L.4.4 Provide a means to measure the ATD and SWC excursions with an accuracy of ±5 mm.

NOTE A side-view high-speed camera or video system with a minimum frame rate of 500 frames per second

is suggested.
© ISO 2021 – All rights reserved 11
---------------------- Page: 14 ----------------------
ISO 10542-1:2012/Amd.1:2021(E)

L.4.5 Provide a means to measure 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.

L.4.6 Provide a means to filter transducer signals using a low-pass filter in accordance with ISO 6487,

including

a) prefiltering of all transducer signals to Channel Class 1 000 (-4 dB at 1 650 Hz) prior to digitizing at

10 000 Hz, and
b) filtering of the digitized accelerometer and load
...

FINAL
ISO
AMENDMENT
DRAFT
10542-1:2012
FDAM 1
ISO/TC 173/SC 1
Technical systems and aids for
Secretariat: SABS
disabled or handicapped persons —
Voting begins on:
2021-01-01 Wheelchair tiedown and occupant-
restraint systems —
Voting terminates on:
2021-02-26
Part 1:
Requirements and test methods for
all systems
AMENDMENT 1: Annexes K, L, M
Assistances et aides techniques pour les personnes invalides ou
handicapées — Systèmes d'attache du fauteuil roulant et de retenue
de l'occupant —
Partie 1: Exigences générales et méthodes d'essai pour tous les
systèmes
AMENDEMENT 1: Annexes K, L, M
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO 10542-1:2012/FDAM 1:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© 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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
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 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 Technical Committee ISO/TC 173, Assistive products, Subcommittee SC

1, Wheelchairs.

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.
© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
Technical systems and aids for disabled or handicapped
persons — Wheelchair tiedown and occupant-restraint
systems —
Part 1:
Requirements and test methods for all systems
AMENDMENT 1: Annexes K, L, M
Introduction
Add the following text to the end of the third paragraph:

In addition, Annex K provides test methods and performance measures for WTORS manufacturers

who wish to test the wheelchair securement system for rear-impact conditions, and Annex M

provides test methods and performance measures for WTORS manufacturers who wish to evaluate

the rear-impact performance of vehicle-mounted, head-and-back restraints.
Add the following text to the end of the fourth paragraph:

Annex K provides a test method whereby they are exposed to a 14 g, 25 km/h rear impact sled test.

Add the following text to the end of the seventh paragraph:

Annex L provides the method for evaluating wheelchair securement systems for the situation of

wheelchair occupants restrained by a three-point belt comprised of a vehicle-anchored shoulder

belt and a wheelchair-anchored pelvic belt.
Clause 2
Add the following normative references:

ISO 16840-4:2009, Wheelchair seating — Part 4: Seating systems for use in motor vehicles

ISO 7176-19:2008/Amd 1:2015, Wheelchairs — Part 19: Wheeled mobility devices for use as seats in motor

vehicles — Amendment 1: Annex G
Clause 3
Add the following terms and definitions:
© ISO 2021 – All rights reserved 1
---------------------- Page: 4 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
3.46
foot/leg strap

length of webbing mounted forward and below the ATD knee to limit upward movement of the leg after

peak forward motion of the ATD knee has occurred

Note 1 to entry: The foot/leg strap minimizes damage to the ATD and provides for more realistic movement of the

lower extremities during frontal-impact loading by limiting extension of the knee joints and upward movement

of the ATD’s lower extremities. It does this in a manner that does not affect forward excursions of the ATD, but

slightly reduces the severity of rearward rebound of the ATD while making this rebound more controlled and

consistent between tests.
3.47
sharp edge
exposed, rigid edge with a radius of less than 2 mm
3.48
vehicle-mounted, head-and-back restraint
vehicle-anchored, head-and-back restraint

optional portion of a WTORS that is positioned behind a forward-facing occupant seated in a wheelchair

for the purpose of limiting rearward movement of the occupant’s torso, head, and neck to reduce the

risk of injury in rear-impact collisions

Note 1 to entry: A vehicle-mounted, head-and-back restraint system is an optional part of a WTORS.

5.2.1
Add the following notes to the end of the subclause:

Note 1 The performance of WTORS in frontal impacts for systems with a wheelchair-anchored pelvic belt can

be evaluated using the test method and performance criteria given in Annex L.

Note 2 The performance of WTORS in rear impacts can be evaluated using the test method and performance

criteria given in Annex K.

Note 3 The performance of a WTORS with an optional vehicle-mounted, head-and-back restraint in rear

impacts can be evaluated using the design guidelines, test method and performance criteria given in Annex M.

J.4
Replace the text with the following:
J.4 Engineering drawings for test equipment

Engineering drawings for the surrogate wheelchair (SWC), surrogate WTORS (SWTORS) and the

surrogate wheelchair base (SWCB) listed below can be obtained from:

The Biosciences Group, University of Michigan Transportation Research Institute (UMTRI), 2901

Baxter Road, Ann Arbor, MI 48109-2150 USA, Phone: (734) 763-3582, Fax: (734) 647-3330 and

downloaded from the website: http:// wc -transportation -safety .umtri .umich .edu/ wts -standards/

WC 4engineeri ngdrawings
The available drawings include

1) a surrogate wheelchair specified in Annex E and used in the frontal-impact tests of Annex A and

Annex L and in the methods for measuring belt-restraint geometry of Annex B,

2) a surrogate wheelchair base (SWCB) used in ISO 16840-4 for frontal-impact testing of wheelchair

seating systems and for rear-impact testing of vehicle-mounted, head-and-back restraints in

Annex M,
2 © ISO 2021 – All rights reserved
---------------------- Page: 5 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)

3) a surrogate WTORS with four-point strap type tiedown and three-point belt restraint with a means

to anchor the pelvic belt to the SWC and the SWCB per Annex L and Annex M, respectively, and

4) a surrogate wheelchair docking securement system, including docking securement device,

wheelchair adaptor, and front-stabilizing bracket for testing the crashworthiness of wheelchairs in

ISO 7176-19 when secured by commercial docking devices, and for securing the SWCB during rear-

impact tests of vehicle-mounted, head-and-back restraints in Annex M.
Annex K
Add the following annex after Annex J.
© ISO 2021 – All rights reserved 3
---------------------- Page: 6 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
Annex K
(informative)
Test method and performance criteria for rear impact of WTORS
K.1 Rationale

The primary focus of this document is to provide design and performance criteria for WTORS used with

forward-facing occupants seated in a wheelchair during frontal-impact loading. This annex provides

a test method and performance criteria for evaluating the effectiveness of wheelchair securement

systems during rear-impact loading. The severity of the rear-impact test in this annex has been selected

to align with the acceleration/deceleration pulse and delta V in ISO 7176-19:2008/Amd 1:2015, Annex G,

which uses the rear-impact deceleration corridor of ECE R44 and a 25 km/h change in velocity. This

change in velocity represents a moderate-to-severe real-world rear impact that corresponds to an

80 percentile real-world rear-impact event based on analysis of effective barrier speed rear-impact

distributions from the US National Automotive Sampling System nationally representative crash/injury

databases.

Throughout this annex, the term test wheelchair (TWC) is used. The TWC may be the surrogate

wheelchair (SWC) specified in Annex E or it may be a specific wheelchair model (SWM) that the

securement system is designed to secure. If a wheelchair securement system is to be tested with an

SWM, the wheelchair’s response should be evaluated using the performance criteria in

ISO 7176-19:2008/Amd 1:2015, Annex G.
K.2 Principle

To simulate a typical moderate-to-severe rear-impact event to an occupied wheelchair, the TWC

is placed on the test platform of an impact sled facing rearward to the direction of sled acceleration

and/or deceleration. The TWC is loaded with an appropriate size ATD as specified in K.4 below that is

restrained by a three-point belt occupant restraint system, and the TWC is secured by the securement

system to be evaluated in rear impact. The sled is subjected to an acceleration/deceleration-time pulse

that falls within a specified corridor to achieve the required horizontal change in velocity, or delta V.

Observations and measurements are made during and after the test to determine if the securement

system effectively secured the TWC during rear-impact loading.
K.3 Test sample

Provide an unused WTORS, including all fittings, anchorages, fasteners, and instructions for installation

and use, for testing. If a WTORS is designed to use a modified original equipment manufacturer

(OEM) belt-type occupant restraint system, provide it for testing. Include documentation to indicate

any components of the WTORS that are designed to provide controlled failure or deformation under

dynamic loading.
K.4 Test equipment
K.4.1 Use an impact simulator that includes the following:

a) an impact sled with a flat, horizontal, structurally rigid platform on which the TWC can be mounted,

and to which the WTORS can be fastened;

b) a rigid structure attached to the impact sled to which the upper-torso restraint can be anchored in

the manner, and to the geometry, specified by the WTORS manufacturer;
4 © ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)

c) a means to drive the impact sled through a change in velocity of 25 km/h km/h;

d) a means to accelerate and/or decelerate the impact sled and test setup such that the processed sled

acceleration and/or deceleration-time pulse falls within the shaded area of Figure K.1,

K.4.2 If the WTORS is intended for use with all types of manual and powered wheelchairs, use the

following:
a) a SWC that conforms with the specifications of Annex E;
th th

b) a Hybrid III 50 percentile ATD (nominal mass 77 kg) or Hybrid II 50 percentile ATD (nominal

mass 74 kg).

NOTE 1 A head restraint can be added to the SWC to help limit rearward rotation of the ATD’s neck and

rearward movement of the ATD’s head. The addition of the head restraint can alter the centre of gravity of the

SWC. This is acceptable as long as the SWC without the head restraint is compliant to Annex E.

NOTE 2 Utilizing the 50 percentile ATD harmonizes this testing with that specified in Annex A.

K.4.3 If the WTORS is intended to be used only with a specific wheelchair model (SWM), use the

following:
a) the SWM it is designed for;

b) an ATD selected from ISO 7176-19:2008, Table A.1 that is representative of the upper size range of

users for which the specific make or model of wheelchair is designed to carry or other similar sized

ATD with equivalent mass, anthropomorphic shape, and mass distribution.

K.4.4 Provide a means to measure the TWC horizontal excursion specified in K.7 with a precision

of ±5 mm.

NOTE A side-view high-speed camera or video system with a minimum frame rate of 500 frames per second

is suggested.

K.4.5 Provide a means to measure 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.

Key
X time (ms)
Y deceleration (g)
Figure K.1 — Acceleration/deceleration corridor for 25 km/h rear impact

K.4.6 Provide a means to measure the horizontal velocity change (delta-V) of the impact sled during

the impact with a precision of ±0,5 km/h.
© ISO 2021 – All rights reserved 5
---------------------- Page: 8 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)

K.4.7 Make provisions to filter transducer signals using a low-pass filter in accordance with ISO 6487,

including

a) prefiltering of all transducer signals to Channel Class 1 000 (-4 dB at 1 650 Hz) prior to digitizing at

10 000 Hz, and

b) filtering of the digitized accelerometer and load-cell signals to Channel Class 60 (-4 dB at 100 Hz).

K.5 Test preparation and procedure

K.5.1 Use the following procedures to set up and run the test. The procedures for setting up the test

may be undertaken in any order.

NOTE For example, it can sometimes be more convenient to position the ATD on the TWC prior to lifting the

assembly onto the impact sled.
K.5.2 Prepare the ATD by

a) adjusting each joint in the upper and lower extremities to achieve a static resistance of 1 g as

indicated by just-noticeable movement with gravity acting on the mass of the distal body segment

or segments, and
b) placing close-fitting cotton clothing on the pelvis, thighs, and torso.
K.5.3 Preparation of the TWC
K.5.3.1 When the TWC is the SWC, prepare it as follows.

a) Inspect all frame junctions and components, and repair where there are signs of fatigue or

deformation.
b) Inspect tyres for cracks or damage and replace as needed.

c) Inflate the SWC tyres as specified in Annex E with the wheelchair unoccupied and resting on a

horizontal surface.
d) Inspect the seat plate and seat support structures and replacing if deformed.

e) Modify the frame as needed to accommodate a wheelchair securement adaptor provided by the

WTORS manufacturer, while maintaining the SWC specifications within the tolerances specified in

Annex E.

f) Install any wheelchair-securement adaptor provided by the WTORS manufacturer on the SWC per

the manufacturer’s instructions.
K.5.3.2 When the TWC is a SWM, prepare it as follows.

a) Prepare the wheelchair for use in a motor vehicle as specified by the manufacturer’s user

instructions.

b) If a range is specified for any adjustments, use the adjustment closest to the midpoint of the range

for testing. If more than one adjustment position can be considered closest to the midpoint, use the

adjustment position immediately rearward, down, outboard or more reclined from midpoint.

c) Equip the wheelchair with any required add-on components as specified by the manufacturer.

d) If a pelvic belt intended for use as an occupant restraint is provided as a component of the

wheelchair attach it to the wheelchair according to the manufacturer's instructions.

e) If the wheelchair is equipped with liquid electrolyte type batteries, replace them with the nearest

equivalent gel type or a surrogate battery. Supplemental weights, if used, ought to provide

equivalent mass distribution to the original batteries.
6 © ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)

f) Inflate any pneumatic tyres to the pressure recommended by the wheelchair manufacturer or to

the maximum sidewall pressure with the chair unoccupied and on a level surface if no specification

is given.
g) Turn the wheelchair power off, if applicable.
h) Equip the SWM with any required securement adaptors.

K.5.4 Position the TWC on the sled in the orientation appropriate for representing a rear-impact

event and with the wheelchair reference plane parallel to the direction of sled travel ±3°.

K.5.5 When the method of wheelchair securement is a four-point tiedown tested with the SWC:

a) Select anchor points that
1) are symmetrical about the wheelchair reference plane,

2) are located 1 300 mm ± 20 mm from the front anchor point to the rear anchor point,

3) have a lateral distance between rear anchor points equal to 425 mm ± 25 mm, and

4) have a lateral distance between front anchor points of 600 mm ± 25 mm.

NOTE 1 For purposes of locating the anchor points, the front-to-back location of an anchor point is

the location of the primary fastener that secures the anchorage to the test platform or, in the case of

multiple fasteners, the centroid of the combined fastener locations. The lateral location of an anchor

point is the centre of the location where the tiedown end fitting contacts the anchorage hardware

attached to the test platform.

b) Position the SWC 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 wheelchair

to the anchor point.

NOTE 2 For purposes of measuring the rear tiedown length, the anchor point is considered to be the point

at which a straight line along the length of the strap assembly intersects with the wheelchair ground plane.

c) Tension all tiedown straps to the manufacturer's specifications.

K.5.6 For wheelchair securement systems other than four-point tiedowns or for WTORS meant to be

used with an SWM:

a) Install the anchorage mechanism or mechanisms on the sled platform per the manufacturer’s

instructions.

b) If a range is given for any installation dimensions, use the midpoint of the given range, when

possible.

c) If fasteners supplied with the securement system are not compatible with the impact-sled platform,

replacement fasteners shall be supplied or specified by the manufacturer.

K.5.7 Position the ATD in the TWC sitting upright and symmetrical about the wheelchair reference

plane, with the pelvis and buttock as far back on the wheelchair seat as possible, and the elbows resting

on the TWC arm supports or with the hands resting on the ATD's thighs.
K.5.8 Install the occupant restraint system in accordance with A.5.14 to A.5.19.

K.5.9 Conduct the test using a deceleration/acceleration pulse that falls within the corridor of

Figure K.1 and that produces a sled change in velocity of 25 km/h km/h by executing the appropriate

sequence of steps to start data acquisition and activate the impact sled.
© ISO 2021 – All rights reserved 7
---------------------- Page: 10 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
K.6 Measurement procedures for operation force of clamp-type systems

K.6.1 The measurement procedures for operational forces as given in A.6 shall apply.

K.7 Performance criteria
K.7.1 General

a) When the securement system is tested with the SWC, the criteria of K.7.1 and K.7.2 should be met.

b) When the securement system is tested with a SWM, the performance criteria given in

ISO 7176-19:2008/Amd 1:2015, G.3.5.1 and G.3.5.2, as well as K.7.2 c), d) and e) should be met.

K.7.2 During the test

When tested in accordance with the procedure given in K.5 using the SWC, the horizontal excursion of

the SWC should not exceed the value given in Table K.1.
Table K.1 — Horizontal excursion limits
Measurement Excursion variable Excursion limit
point
Point P of TWC wc 200

x is the horizontal distance relative to the sled platform between the point-P target on the TWC at

time t and the point P target at the time of peak rearward wheelchair excursion.
K.7.2 After the test

When tested in accordance with the procedure given in K.5 using the SWC the following criteria should

be met at the conclusion of the test.

a) The SWC should be in an upright position on the test platform with at least three of the four wheels

in contact with the sled platform and the ATD should be in the wheelchair 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.

b) Release of the SWC from the wheelchair securement system should not require the use of tools.

c) No tiedown strap end fitting or anchorage, and no mechanical securement system component,

should have detached or separated from the TWC or test platform during the test.

d) Load carrying components of the securement system should not completely fail unless the part is

designed to tear or fail in a controlled and predictable manner as described by the manufacturer

before the test.

e) The WTORS should exhibit no sharp edges or protrusions that are contactable by the occupant and

likely to increase the risk of injury to the occupant.
K.8 Post-test measurements and calculations

Determine peak rearward excursion x to an accuracy of ±5 mm through analysis of the high-

speed video.
8 © ISO 2021 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
K.9 Test report
K.9.1 Include the following information in the test report:
a) name and address of the test institution;
b) date of test;
c) unique test number shown on each numbered page;
d) name of the product manufacturer;
e) address of manufacturer;
f) product type, product name or number;
K.9.2 The test report shall also include:
a) a reference to this annex and the test procedures of K.5;
b) a description of the type and mass of the ATD used in the test;
c) the measured or calculated value of the test velocity change;

d) a graph of the impact sled acceleration plotted against time superimposed on Figure K.1;

e) pre-test still photography of the set up;
f) post-test still photography showing test outcomes;
g) test results as specified in K.7.1 and K.7.2;

h) a statement as to whether or not the securement system met the criteria given in K.7.1 and K.7.2;

i) any other relevant observations.

K.9.3 If the rear impact test is conducted using the SWC, it shall also include in the report:

a) the mass of the SWC;

b) a description of any modifications or adaptations fitted to the SWC for use with a securement system.

K.9.4 If the rear impact test is conducted using the SWM, the report shall follow the test report

criteria given in ISO 7176-19: 2008/Amd 1:2015, G.3.6 and also include:
a) details of any add-on components fitted to the SWM;

b) a description of any modifications or adaptations fitted to the SWM for use with a WTORS;

c) the mass of the SWM or TWC.
K.10 Labelling

In addition to the labelling requirements given in 6.1, WTORS in conformity with this annex should be

so indicated with text that conveys that the product conforms with this annex.
Annex L
Add the following annex after Annex K.
© ISO 2021 – All rights reserved 9
---------------------- Page: 12 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
Annex L
(informative)
Method for evaluating frontal-impact performance of wheelchair
securement systems for situations when occupants are using a
crash-tested three-point belt restraint system with a wheelchair-
anchored pelvic belt
L.1 Rationale

Annex A documents methods for evaluating complete WTORS in a simulated 48 km/h frontal crash test

when dynamic loads delivered to the wheelchair securement system are generated primarily by the

mass of an 85 kg surrogate wheelchair. Unless the occupant belt-restraint uses a pelvic belt designed

to anchor to the wheelchair, all of the occupant-restraint forces are transferred directly to the sled

platform and simulated vehicle sidewall structure (i.e. to the simulated vehicle components) except

for a small portion that is transferred to the securement system from interaction of the ATD with the

wheelchair seating system. However, when a passenger seated in a wheelchair is using a wheelchair-

anchored pelvic-belt restraint, which is allowed as an option to the consumer by ISO 7176-19, a

significant proportion of occupant-restraint forces are transferred to the wheelchair and then to the

wheelchair securement system, thereby imposing higher peak forces on the securement system than

are generated in a typical Annex-A test.

The additional loads on a wheelchair securement system generated by a wheelchair-anchored pelvic-

belt may be effectively dealt with in a real-world frontal crash by attaching additional rear tiedown

straps to the wheelchair secured to the vehicle by this method. Alternatively, stronger securement

systems designed to meet the additional loads from a wheelchair-anchored pelvic belt may be used to

secure the wheelchair. This Annex provides manufacturers of WTORS designed for general use with a

wide range of wheelchairs and occupants with a method for conducting a frontal-impact test of their

wheelchair securement system or complete WTORS to determine if it is dynamically strong enough to

withstand the higher loading conditions that can result from the use of a three-point belt restraint with

a wheelchair-anchored pelvic belt during a severe frontal crash.
L.2 Principle

The test equipment, test conditions, and frontal-impact procedures set forth in Annex A are used

to evaluate the dynamic strength of the wheelchair securement system, with the exception that the

test is conducted using the 85 kg surrogate wheelchair, a midsize-male crash-test dummy, and either

a commercial or surrogate three-point belt occupant restraint system with the pelvic belt anchored

to the surrogate wheelchair. Specifications for a surrogate three-point belt restraint system with

provision for anchoring the pelvic belt to a wheelchair or surrogate wheelchair are provided in Annex D

of RESNA WC -4: 2017, Section 19, and engineering drawings are available from the Biosciences Group of

the University of Michigan Transportation Research Institute (see J.4) and are illustrated in the annex.

However, other types of surrogate three-point belt restraints with SWC-anchored pelvic belts may also

be used (See note under L.4.9 h).
L.3 Test sample

Provide an unused wheelchair securement system or complete WTORS, including all fittings,

anchorages, fasteners and instructions for installation and use.
10 © ISO 2021 – All rights reserved
---------------------- Page: 13 ----------------------
ISO 10542-1:2012/FDAM 1:2021(E)
L.4 Test equipment
L.4.1 Use an impact simulator that includes the following:

a) an impact sled with a flat, horizontal, structurally rigid platform on which the SWC can be mounted,

and on which the WTORS can be installed;

b) a rigid structure attached to the rigid sled platform to which the upper anchorage of the surrogate

diagonal shoulder belt can be attached to achieve the belt-restraint geometry of Figure L.6;

c) a means to accelerate and/or decelerate the impact sled through a change in velocity of 48 km/h

km/h such that the processed sled acceleration- and/or deceleration-time pulse:
1) falls within the shaded area of Figure L.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;

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 deceleration pulse.
Key
X time (ms)
Y deceleration (g)

Figure L.1 — Acceleration/deceleration requirements for the impact test 48 km/h km/h

L.4.2 Use a surrogate wheelchair (SWC) that conforms with the specifications of Annex E.

L.4.3 Use a Hybrid III 50th percentile ATD with a nominal mass of 77,7 kg ± 1,18 kg.

L.4.4 Provide a means to measure the ATD and SWC excursions with an accuracy of ±5 mm.

NOTE A side-view high-speed camera or video system with a minimum frame rate of 500 frames per second

is suggested.
© ISO 2021 – All rights reserved 11
---------------------- Page:
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.