ISO/TR 14646:2007
(Main)Road vehicles — Side impact testing of child restraint systems — Review of background data and test methods, and conclusions from the ISO work as of November 2005
Road vehicles — Side impact testing of child restraint systems — Review of background data and test methods, and conclusions from the ISO work as of November 2005
ISO/TR 14646:2007 summarises the work within ISO to define a side impact test method for child restraint systems (CRS). It presents the main background data, and experiences from crash tests carried out during the process of development. Additional relevant data are also presented.
Véhicules routiers — Essais de choc latéral pour systèmes de retenue pour enfants — Revue des données de référence et des méthodes d'essai, et conclusions du travail de l'ISO jusqu'en novembre 2005
General Information
Standards Content (Sample)
TECHNICAL ISO/TR
REPORT 14646
First edition
2007-10-15
Road vehicles — Side impact testing of
child restraint systems — Review of
background data and test methods, and
conclusions from the ISO work as of
November 2005
Véhicules routiers — Essais de choc latéral pour systèmes de retenue
pour enfants — Revue des données de référence et des méthodes
d'essai, et conclusions du travail de l'ISO jusqu'en novembre 2005
Reference number
©
ISO 2007
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Accident statistics.1
3 Side impact test methods for cars.4
3.1 European side impact test methods.4
3.2 US side impact test methods .5
3.3 Japanese side impact test method.6
3.4 Australian side impact test method.6
4 Child related properties of car side impact test methods.7
4.1 Boundary conditions for a CRS side impact test procedure.7
4.2 Door intrusion depth.7
4.3 Door intrusion velocity from ECE tests .8
4.4 Door intrusion velocity in car-to-car tests.10
4.5 Struck car acceleration and velocity change .13
4.6 Deformation profiles .14
4.7 Dynamic force-deflection characteristics of door interior .15
4.8 Door window sill height and distance to door trim.16
5 Requirements for the side impact test procedure .17
5.1 Test severity.17
5.2 Validation.18
5.3 Repeatability and reproducibility.18
5.4 Field of application.18
6 Historical overview.18
7 Current side impact test procedures for child restraint systems .20
7.1 ISO/DIS 14646 / TRL test procedure .20
7.2 TNO test procedure .23
7.3 TUB test procedure .23
7.4 ADAC test procedure .23
7.5 Australian Standard AS/NZS 1754 test procedure.23
7.6 Australian CREP test procedure.23
8 Conclusions .24
Annex A (informative) ISO/DIS 14646-1.2: ISO side impact test procedure for rearward-facing child
restraint systems.25
Annex B (informative) Working draft of planned future ISO/TR 14646-2, ISO side impact test
procedure for forward facing systems.36
Annex C (informative) Voting results and comments received on ISO/DIS 14646:2003.39
Annex D (informative) Voting results and comments received on ISO/DIS 14646-1.2:2005 .45
Glossary .49
Bibliography.50
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.
In exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
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/TR 14646 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 12,
Passive safety crash protection systems.
iv © ISO 2007 – All rights reserved
Introduction
ISO/TC 22/SC 12/WG 1 has been working on the definition of a side impact test procedure for child restraint
systems. After meeting the deadline for finalisation of a third DIS version and with disapprovals (by a small
margin) of the previous two DIS votings, it was decided to finalise the current project with a Technical Report
and to restart the process of developing an international standard.
The aim of this Technical Report is to summarise the work done within ISO, and to compile additional relevant
information to form a solid base for the restarted project.
TECHNICAL REPORT ISO/TR 14646:2007(E)
Road vehicles — Side impact testing of child restraint
systems — Review of background data and test methods, and
conclusions from the ISO work as of November 2005
1 Scope
This Technical Report summarises the work within ISO to define a side impact test method for child restraint
systems (CRS). It presents the main background data, and experiences from crash tests carried out during
the process of development. Additional relevant data are also presented.
2 Accident statistics
The severity of injuries in side impacts depends on the seating position. It can be noticed that the severity of
injuries is much higher for children sitting on the struck side than sitting on the non-struck side. The share of
injuries on the non-struck side is comparable to frontal impacts, while the injury probability is much higher in
struck side accidents, see Figure 1.
frontal (n=1408) struck side (n=177) non-struck side (n=282)
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
overall head neck/spine/back chest/abdomen extremities
Figure 1 — Injury frequency depending on the impact direction [Arbogast, 2004]
Even when analysing all lateral impact accidents the relative number of children suffering MAIS 2+ injuries is
much higher than for other impact directions, see Figure 2.
weighted injury frequency [%]
involved children children with MAIS 2+
front side rear roll over
Figure 2 — Share of different impact directions [Langwieder, 2002]
Regarding the different body regions the risk for severe injuries decreases from the head down to the legs.
The frequently observed injuries of arms and legs are not of high severity, but may cause long term
impairments. The focus for investigations concerning improvements of CRS should be on the head, neck and
thorax, see Figure 3.
Figure 3 — Injury risk of different body regions of 68 injured children in side impacts
[Langwieder, 1996]
Looking at the development of injuries in lateral impacts from 1985 to 2001 it is obvious that the injury
probability decreased since 1985 while the risk to suffer neck injuries increased and the chest remained
unchanged, see Figures 4, 5, and 6.
2 © ISO 2007 – All rights reserved
no. of children
injury frequency of injured children [%]
Figure 4 — Injury probability of different body regions in side impact accidents between 1985 and
1990 [Otte, 2003]
Figure 5 — Injury probability of different body regions in side impact accidents between 1991 and
1996 [Otte, 2003]
[%]
[%]
Figure 6 — Injury probability of different body regions in side impact accidents between 1997 and
2001 [Otte, 2003]
The presented accident shows that side impact accidents are severe ones especially for those children sitting
at the struck side. Especially head, neck and chest need to be protected.
In a study of Swedish accident situation Jakobsson et al. [Jakobsson, 2005] did not find any moderate-severe
(AIS2+) head injuries in children using rear-facing (RF) CRS involved in lateral impact accidents, while
children using forward facing (FF) booster seats or the car belt only suffered from moderate-severe injuries
(AIS2+) in side impacts. Comparing the injury risk for RF and FF CRS in frontal and lateral impact accidents of
NASS Data (US American accident data base) of the years 1988 to 2003 Crandall et al. [Crandall, 2005]
observed a ratio of 4,32 in favour of RF seats. The ratio was felt to be larger than expected.
3 Side impact test methods for cars
The full-scale test methods have been validated against the real world accident conditions in the specific
regions. We can therefore utilise these test methods in the development of the child side impact test
procedure.
3.1 European side impact test methods
In Europe the compulsory side impact test method is described in ECE Regulation No. 95. In addition Euro-
NCAP defined a side impact test procedure, which is similar to ECE Regulation No. 95.
3.1.1 ECE Regulation No. 95
A moveable deformable barrier (MDB) strikes the test car with a velocity of 50 km/h in an angle of 90°. The
barrier has a weight of 950 kg and a width of 1 500 mm. The deformable element has a ground clearance of
300 mm. The centre line of the MDB should match with the X position of the hip point of the 95-percentile
dummy (R-point). A Euro SID dummy is positioned in the driver’s seat. No child dummies are prescribed for
ECE Regulation No. 95.
4 © ISO 2007 – All rights reserved
[%]
3.1.2 Euro-NCAP lateral test
The Euro-NCAP side impact test protocol is in most parts similar to that of ECE Regulation No. 95. The most
important differences to ECE Regulation No. 95 are that an ES2 dummy is used in the front driver’s position
and child dummies are used in the rear. The two following opportunities for the CRS installation are possible:
⎯ P1.5 on the struck side and P3 on the non struck side;
⎯ P1.5 on the middle rear seat and P3 on the struck side.
If a head protection system is available in the car, it can be tested in a pole test. The car travels with a velocity
of 29 km/h laterally into a rigid pole with a diameter of 254 mm. No child dummies are used in this test.
3.2 US side impact test methods
The compulsory side impact test method in the US is defined in FMVSS 214. In addition consumer tests are
defined by US-NCAP and IIHS.
3.2.1 FMVSS 214
A crabbed barrier hits with a velocity of 54 km/h the stationary test car, see Figure 7. Because of the 27° angle
of the barrier the velocity has a component of 48 km/h in the car Y-direction and 25 km/h in car X-direction.
The X component should simulate that the struck car is moving in normal lateral accidents. The barriers face
has a width of 1 676 mm and a ground clearance of 279 mm. The “bumper part” of the deformable element
has a ground clearance of 330 mm. The mass of the trolley is 1 368 kg. US SID dummies are used at the front
and rear struck side seat. No child dummies are tested according to FMVSS 214.
Figure 7 — Impact configuration according to FMVSS 214 [NHTSA, 2003]
FMVSS 201 describes a pole test, which formed the basis for the Euro-NCAP pole test described above.
3.2.2 US-NCAP lateral test
The US-NCAP side impact test procedure is analogous to the FMVSS 214 protocol. The main difference is
that the impact speed is 5 mph higher in the NCAP test compared to FMVSS 214. This means an impact
velocity of 62 km/h representing 55 km/h in car Y direction and 30 km/h in X direction.
3.2.3 IIHS lateral test
The Insurance Institute for Highway Safety (IIHS) defined a more severe side impact procedure, which should
represent accidents with SUV.
A trolley with a mass of 1 500 kg hits the car in a purely lateral impact with a velocity of 50 km/h. The ground
clearance of the barrier face is 379 mm, while the ground clearance of the bumper element is 430 mm. The
shape of the barrier element shall comply with the front end shape of SUV’s, see Figure 8. Two SID-II
dummies are used in the front and rear seats on the vehicle struck side. No child dummies are used in the
IIHS side impact test.
Figure 8 — Test configuration in IIHS side impact test [IIHS, 2005]
3.3 Japanese side impact test method
In Japan, ECE Regulation No. 95 (see above) is used for compulsory side impact tests. J-NCAP utilises Euro-
NCAP side impact test method (see above) with some changes. The most important within this context are:
⎯ Test speed is 55 km/h;
⎯ No child dummies are prescribed.
3.4 Australian side impact test method
The compulsory side impact test for cars in Australia is defined by ADR72, which is equal to ECE Regulation
No. 95 (as described above). The Australian consumer test programme (ANCAP) follows in most parts the
protocols of Euro-NCAP (see above). However, no child dummies are tested in the rear seat.
6 © ISO 2007 – All rights reserved
4 Child related properties of car side impact test methods
4.1 Boundary conditions for a CRS side impact test procedure
In several full-scale crash tests according to regulation ECE Regulation No. 95 performed in the last ten years,
dynamic lateral intrusions of front and rear doors were measured. The sample includes super minis, family
cars, executive cars and mini multi-purpose vehicles of the model years from 1990 until 2004. Both two-door
and four-door cars are included. In the last tests the revised deformable barrier face according to
EEVC/WG 13 was used. In all test the lateral intrusion of the inner part of the doors was measured with a
string potentiometer or a cross tube positioned at the middle of the door. Intrusion velocities (4.3) were
calculated from the intrusion time history diagrams. For comparison, car-to-car test results are analysed in 4.4.
4.2 Door intrusion depth
The maximum intrusion depth of the front door varies from 180 mm to 310 mm, whereas the newer vehicles
have lower intrusions (Figure 9).
Figure 9 — Front door intrusion depth in side impact tests according to ECE Regulation No. 95
[Johannsen, 2005]
It can be seen that the maximum intrusion depth of the rear door varies from 170 mm to 280 mm, which
indicates that the intrusion depth is lower at the rear door compared with the front door (Figure 10).
Figure 10 — Rear door intrusion depth in side impact tests according to ECE Regulation No. 95
4.3 Door intrusion velocity from ECE tests
Regarding the intrusion velocity a comparable result can be observed. The intrusion velocity is again lower at
the rear door compared with the front door.
Figure 11 — Front door intrusion velocity in side impact tests according to ECE Regulation No. 95
[Johannsen, 2005]
8 © ISO 2007 – All rights reserved
intrusion depth [mm]
The intrusion velocity at the front door shows a range between 8 m/s and 13 m/s (Figure 11), while the
intrusion velocity at the rear door varies between 7 m/s and 13 m/s (Figure 12).
Figure 12 — Rear door intrusion velocity in side impact tests according to ECE Regulation No. 95
Taking into account the difficulties in positioning of the intrusion measurement device especially in smaller
cars, a mean difference in intrusion velocity between front and rear door of 10 % can be observed (Figure 13).
The difference could be caused either by vehicle design or the test procedure with the centre of impact
located more in the front.
front door rear door
10 %
car 1 car 2 car 3 car 4 car 5 car 6 average
Figure 13 — Comparison of maximum intrusion velocity for front and rear seat
v[m/s]
intrusion velocity [m/s]
4.4 Door intrusion velocity in car-to-car tests
For the development and assessment of a new European side impact test procedure several car-to-car and
MDB-to-car side impact tests were conducted on behalf of EEVC/WG13 [Ellway, 2005]. These data help to
analyse real-world side impact accidents, as passenger cars were used as the striking vehicles.
The intrusion measurement data presented below are acquired by acceleration based measurements for the
Camry tests (except the AEMDB V2 test) and the Corolla car-to-car tests. For the other tests string potentio-
meters were used. The intrusion was measured close to the position of the thoraxes of driver and rear seat
passenger but without interferences. When comparing acceleration based and string potentiometer based
intrusion measurements, Ellway came to the conclusion that the first one tends to deliver higher residual
velocity towards the end of the impact.
Figure 14 shows front door intrusion velocity of the inner door panel of an Alfa Romeo 147 running at 24 km/h
which was struck by a Toyota Corolla travelling at 48 km/h. In a second test an Alfa Romeo 147 was struck by
a Land Rover Freelander. While intrusion velocity in the Toyota test was approximately 6,5 m/s, the
Land Rover Freelander caused an intrusion velocity of more than 12 m/s.
Figure 14 — Comparison of front door intrusion velocity in car-to-car and SUV-to-car test [Ellway,
2005]
Looking at the rear door intrusion velocity of the inner panel these recorded approximately 7,5 m/s in the
Corolla test compared to 10,5 m/s in the Land Rover Freelander test, see Figure 15.
10 © ISO 2007 – All rights reserved
Figure 15 — Comparison of rear door intrusion velocity in car-to-car and SUV-to-car test [Ellway, 2005]
Tests with a Toyota Camry, an executive saloon, showed again considerable differences between car-to-car
(in this case a Ford Mondeo was used) and SUV-to-car tests. The intrusion velocities at the front door were
approximately 5 m/s for the Mondeo and 9,5 m/s for the Freelander respectively, see Figure 16. For the rear
door the intrusion velocities varied between 7 m/s (in the Ford test) and 10,5 m/s (in the Land Rover test, see
Figure 17).
Figure 16 — Comparison of front door intrusion velocity in different side impact tests with a Toyota
Camry [Ellway, 2005]
The MDB tests were carried out utilising a barrier face stiffness and geometry (increased ground clearance)
different from that of ECE Regulation No. 95. In addition the sled mass was increased to 1 500 kg. These
measures should help to represent a more realistic accident severity. The IIHS tests were in accordance to
the test procedure described in 3.2.3 above.
Figure 17 — Comparison of rear door intrusion velocity in different side impact tests with a Toyota
Camry [Ellway, 2005]
Figure 18 — Comparison of front door intrusion velocity in different side impact tests with a Toyota
Corolla [Ellway, 2005]
In the tests with a Toyota Corolla considerable differences between front and rear door are visible, see
Figure 18 and Figure 19. While the intrusion velocity in the Corolla-to-Corolla test were relatively low for the
front seat (approx. 3,5 m/s compared with 6 m/s at the rear door) this was contrary to the situation for all other
tests.
12 © ISO 2007 – All rights reserved
Figure 19 — Comparison of rear door intrusion velocity in different side impact tests with a Toyota
Corolla [Ellway, 2005]
4.5 Struck car acceleration and velocity change
In addition to the intrusion of the side structure the struck car experiences a lateral acceleration.
00.000000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050 0.055 0.060 0.065 0.070 0.075 0.080 0.085 0.090 0.095 0.100
time [s]
Figure 20 — Acceleration of the struck car in ECE Regulation No. 95 tests [Nett, 2003]
acceleration [g]
-50.0 -45.0 -40.0 -35.0 -30.0 -25.0 -20.0 -15.0 -10.0 -5.0 0.0.00 5.0 10.0
Taking into account the theoretical velocity change for cars of an average weight in ECE Regulation No. 95
tests the struck car will be accelerated up to 22 km/h (Figure 20), which is in line with the derived velocity
change from the vehicle acceleration time histories shown in Figure 21.
time [s]
0.0.0000 0.01 0.01 0.02 0.02 0.03 0.03 0.04 0.04 0.05 0.05 0.06 0.06 0.07 0.07 0.08 0.08 0.09 0.09 0.10 0.10
time [s]
Figure 21 — Velocity change of the struck car in ECE Regulation No. 95 tests [Nett, 2003]
4.6 Deformation profiles
The comparison of static deformation of the struck vehicle from front to rear shows at first an increasing crush
over a distance of about 500 mm, then a more or less constant crush over a distance of about 900 mm and
then a decreasing trend (Figure 22).
Figure 22 — Static crush of different cars in ECE Regulation No. 95 tests [Johannsen, 2005]
The static crush in the EEVC/WG13 as described above show a comparable static crush as mentioned above,
see Figure 23 and Figure 24. The crush distribution across the vehicle height shows significant differences.
Again the influence of properties of the striking vehicle can be observed.
14 © ISO 2007 – All rights reserved
crush [mm]
velocity [km/h]
-50.0 -45.0 -40.0 -35.0 -30.0 -25.0 -20.0 -15.0 -10.0 -5.0 0.00.0 5.0 10.0 15.0
Row A
Figure 23 — Static crush of Alfa 147 in several side impact tests [Ellway, 2005]
Row A
Figure 24 — Static crush of Toyota Corolla in several side impact tests [Ellway, 2005]
4.7 Dynamic force-deflection characteristics of door interior
In addition to the dynamic behaviour, the geometric boundary condition of passenger cars, such as the lateral
distance between seat and side structure, the height of the window sill in relation to the CR-point, and the
stiffness of the side structure, are important.
The stiffness of the door trim, analysed in pendulum tests, showed considerable differences for different car
models and different impact locations, see Figure 25.
Figure 25 — Door trim force-deflection characteristics of different locations at different doors
[Nett, 2003]
4.8 Door window sill height and distance to door trim
Investigation of Nett [Nett, 2003] showed a lateral distance of the CRS centreline to the side structure of
300 mm and a window sill height of 500 mm.
The average window sill height with respect to the CR point is approximately 500 mm [Nett, 2003], Figure 26.
window sill right rear door
0 50 100 150 200 250 300 350 400 450
distance to CR point [mm] in x direction
Figure 26 — Height of the window sill in different cars [Nett, 2003]
16 © ISO 2007 – All rights reserved
force [N]
The CRS centreline has an average distance to the inner door trim of approximately 300 mm [Nett, 2003],
Figure 27.
minimum distance between seat centre line and door trim right rear
car type
12 345 678 9 10 11 12 13 14 15
Figure 27 — Lateral distance between CRS centreline and inner door trim [Nett, 2003]
5 Requirements for the side impact test procedure
The requirements of the ISO side impact test procedure for child restraint systems can be divided into the
sections; test severity, validation, repeatability and reproducibility, and field of application.
5.1 Test severity
The test severity is defined by sled acceleration, intrusion depth and intrusion velocity (as far as intrusion is
simulated), but also by geometrical measurements such as the panel height, distance of the CRS to the panel
etc.
Analysis of full-scale side impact tests shows that the performance of current cars has been significantly
improved during the last years. However, there are still old cars on the road and the test severity of the full-
scale test is subject to several discussions as it is felt to be too moderate. One example for higher severity
tests is the IIHS test procedure, where the mass of the barrier as well as the stiffness and shape of the barrier
face, causes a more aggressive contact with the car in comparison to ECE Regulation No. 95 and
FMVSS 214 test conditions.
Whilst there are no validated biomechanical load limits for children in side impact tests, the dummy readings
resulting from the side impact test procedure should correlate with those measured in full-scale side impact
tests.
distance to seat centre line in y direction
[mm]
Summing up the results presented in Clause 4 and the statements above, the following properties defining the
test severity apply to a majority of cars in use:
⎯ Intrusion velocity range: 7 – 10 m/s
⎯ Intrusion depth: approx. 250 mm
⎯ Sled acceleration range: 10 – 15 g
⎯ Door panel height: approx. 500 mm
⎯ Distance between door and CRS centre line: approx. 300 mm
In addition the padding specification needs to be fully defined.
5.2 Validation
For the validation of the test procedure, the test severity as well as the CRS definition according to the scope
(see below) needs to be approved. Concerning the test severity, accident statistics show that the most
important body region to protect is the head. Therefore it is necessary to put special emphasis on the
validation of head loads and the capability of child restraints to contain the head inside the CRS during the test.
5.3 Repeatability and reproducibility
The most crucial parameters with respect to repeatability and reproducibility are intrusion velocity (magnitude
and timing) and dummy and CRS installation. Based on test experience and numerical simulation, variation in
sled acceleration do not influence the dummy readings in a similar way as the parameters mentioned above.
5.4 Field of application
Besides the differences of forward facing and rear-facing the fixation of the CRS and the child can be different.
The following types can be found in today’s world markets: belt fixed CRS with integral harness for the child
(FF mainly 5-point-harness, RF mainly 3-point-harness), booster with/without backrest (CRS and child
restrained with car belt), ISOFIX connection of CRS and car with integral harness for the child. For the belted
CRS the usage of tensioning devices, which reduce the belt slack of the car belt, are becoming more popular.
The side impact test procedure has to be able to cope with all these different CRS types. In addition it is
important that all these seats are tested with comparably realistic severity.
6 Historical overview
Based on a side impact test procedure developed by TUB (Technical University of Berlin) within the EU
funded project Brite ATASED (Advanced Technologies for Automotive Seat Evaluation and Design) TUB
started testing CRS in lateral impacts. These tests were conducted in a double-sled arrangement, where the
first sled impacted the second one. This double sled approach represents the deceleration and intrusion as
recognised in car side impact accidents. In the beginning a real car door was mounted on the striking sled,
which impacted a CRS mounted on a car seat. See Figure 28.
18 © ISO 2007 – All rights reserved
Figure 28 — Double sled test set-up with car door and car seat
In a later evolution a flat panel was used to represent the door and the CRS was mounted at an ECE
Regulation No. 44 test bench. See Figure 29.
Figure 29 — Double sled test set-up with flat panel and ECE Regulation No. 44 test bench
It was then proposed by TRL (Transport Research Laboratory) to represent the intrusion with a hinged door.
The hinged door was impacted by a 100 kg pendulum mass. Because of the relatively low mass the intrusion
depth and intrusion velocity could not be reproduced in a satisfactory manner. Both depended on the CRS
fixture, CRS weight etc. However, the principle idea of the hinged door concept seemed to be a good
compromise of reproducing vehicle acceleration and intrusion.
As an alternative, the Nordic European countries proposed to use a curved panel as a door, which is fixed at
the concrete block. The intrusion velocity in this approach is defined by the initial sled velocity. As the intrusion
velocity in lateral impacts is higher than the lateral velocity change of the struck car, the Nordic countries
proposed to use a suitable intrusion velocity as initial sled speed. The sled was then decelerated during the
contact with CRS and dummy to meet the intrusion depths requirement. This procedure was realised by TNO
with a flat panel.
Another proposal, coming from MPA Stuttgart, was to impact the CRS by a panel without reproducing the
vehicle movements.
7 Current side impact test procedures for child restraint systems
This clause gives a brief summary of the existing side impact test procedures for child restraint systems.
7.1 ISO/DIS 14646 / TRL test procedure
The child restraint working group of ISO (ISO/TC22/SC12/WG1) started in 1994 the development of a side
impact test procedure for child restraint systems. Most of the procedures described in Clause 6 were
proposed and discussed within the responsible task group. Finally in the end of the nineties the decision was
taken to use a derivative of the hinged door concept as proposed by TRL.
The main problem recognised with the original hinged door concept was the considerable influence of the
CRS on intrusion velocity and intrusion depth. This was mainly caused by the relatively low impactor mass.
Finally the activating method of the intruding panel was not defined in the protocol but corridors for intrusion
velocity and an intrusion depth was fixed.
Due to the proposed hinged door method it is important to define the worst-case conditions. The contact
velocity between the CRS (child dummy, respectively) and the intruding panel depends on the angular velocity
of the panel and the distance of the CRS (defined by the position of the head) to the hinge line. In order to test
rear-facing and forward facing CRS with the same test severity, it is necessary to use different hinge line
positions with respect to the CR point. Within ISO it was decided to test in worst-case conditions, which
means with the maximum intrusion close to the dummy’s head, requiring the hinge line far from the dummy’s
head.
The draft standard was subject to two subsequent DIS votes. After failing the first one, it was decided to
improve the draft standard for rear-facing CRS, while defining the details for forward facing CRS in a second
part. For the second vote only the part covering RF CRS was presented, the second part should be published
as a Technical Report. However the standard proposal was disapproved also during the second DIS vote (by
a small margin).
7.1.1 Description of the ISO test method
The drafts for Part 1 (RF CRS) and Part 2 (FF CRS) are attached to this Technical Report as Annex A and
Annex B, respectively.
The main property of the ISO/DIS 14646 test procedure is the hinged door concept where an ECE Regulation
No. 44 test bench is mounted at an angle of 90° on a sled. To avoid interactions between the intruding panel
and the test bench backrest, the latter one is displaced by 100 mm, see Figure 30.
20 © ISO 2007 – All rights reserved
Key
1 sled
2 ECE R.44 test bench
3 CRS centreline
4 travel direction
Figure 30 — General test setup in ISO/DIS 14646
The hinge line of the intruding panel is perpendicular to the seat cushion by means of an angle of 15° to the
ground. The simulated intrusion should realise an intrusion depth of 250 mm and a maximum intrusion velocity
of 9 m/s.
The panel shape was subject to several discussions within the responsible task group. After initially testing
with a flat panel, curved and shaped panels were developed and tested. The main advantage of a shaped
panel is the fact that it is possible to define a maximum intrusion, which is not the case with a flat panel.
Finally a double shaped panel according to Figure 31 was developed.
Key
1 panel hinge line
2 hinged panel
Figure 31 — Seat bench construction with panel for RF configuration of ISO/DIS 14646
During the sled deceleration the hinged door intrudes. The CRS is positioned with a distance of 300 mm of its
centreline from the hinged door. The test procedure takes into account the worst-case scenario for both, RF
and FF CRS, by positioning the hinge at the side of the feet of the child dummy. The sled deceleration is
defined by a delta-v corridor representing an overall delta-v of 25 km/h. The hinged door concept transfers the
translational into a rotational intrusion. The middle angular velocity for RF CRS of 13 rad/s corresponds to a
translational intrusion velocity at the point of the head of about 12 m/s.
The test procedure according to ISO/DIS 14646 was implemented at TRL.
7.1.2 Voting results
The draft ISO standard was disapproved in both DIS votes. Numerous comments were provided for both
votes. Annex C contains the detailed voting results and comments with observations of the first vote, while
Annex D includes the voting results and comments for the second vote.
In the first vote ISO/DIS 14646 was disapproved by five countries (France, Italy, Japan, Netherlands, US). The
main reason for the disapproval was the missing validation, especially for the test set up for FF CRS.
During the second vote, again five countries disapproved the proposal. This time France, Germany, Japan,
Philippines and Sweden voted against the draft especially because of separate parts describing the test
methods for FF and RF seats, and again the missing validation, especially regarding reproducibility.
22 © ISO 2007 – All rights reserved
7.2 TNO test procedure
The TNO procedure is based on an earlier stage of the ISO/DIS 14646. The main difference to ISO is the
utilisation of a flat panel and a different padding. In principle the TNO procedure was intended to be used for
both, RF and FF CRS, in worst-case conditions, but the set up for FF worst-case has not been realised yet.
7.3 TUB test procedure
The test procedure developed by the Technical University Berlin is again based on the hinged door concept.
TUB started the development in 1999 based on the resolutions and decisions taken by ISO WG1.
The main differences with respect to ISO/DIS 14646 are different hinge line orientation, different panel shape
and different panel padding. In addition the backrest and upper belt anchorage point in FF configuration are
both moveable in the Y direction and firmly connected with the intruding panel representing the seat and b-
pillar displacement in full-scale crash tests. The lower ISOFIX anchorages are free to move in Y-direction.
The hinge line in the TUB method is vertical to the ground allowing the same hinge to be used for both test
set-ups. The single shaped panel is padded with a thicker and softer material compared to the ISO procedure.
The TUB test procedure was selected to be used for the NPACS Programme (New Programme for the
Assessment of Child Restraint Systems) at the end of 2005.
7.4 ADAC test procedure
The ADAC (Germany Motoring Club) tests take place in a body-in-white of a VW Golf [Gauss, 2002]. The
body-in-white is mounted on a sled at an angle of 80° and is equipped with a fixed door. The angle of 80°
should cause an additional head movement in frontal direction. Therefore it is more difficult to pass the head
containment criterion for FF CRS. The body in white is mounted in the same way to the sled for FF and RF
CRS. In the ADAC procedure a fixed door is used, i.e. no intrusion is simulated. The sled is decelerated from
an initial velocity of 25 km/h at a level of 15 g. The main advantage of this test procedure is that it is
considerably simpler, enabling good performance with respect to reproducibility.
7.5 Australian Standard AS/NZS 1754 test procedure
In Australia and New Zealand two different kinds of side impact tests for homologation of child seats have to
be used. One test is on a test bench, which is mounted at 90° on a sled, without any door and the second test
is with a fixed door, again at 90° angle. The first test assesses for dummy ejection in lateral impacts and has
been in the standards for over 20 years while the latter test assesses the head containment capabilities of the
CRS. For the door-less tests, selected TNO P series dummies are used for forward facing seats and boosters,
while a TARU Theresa dummy is used for infant restraints. Selected TNO P series dummies are used for the
tests in which the door is utilised. The sled is calibrated to undergo a velocity change of not less than 32 km/h,
with a deceleration of 14 – 20 g. The door used was based on research work from the Child Restraint
Evaluation Program with changes to construction of the angle on the top half of the door. This side impact
testing with the door was introduced in to the 2004 version of the standard.
7.6 Australian CREP test procedure
The consumer information testing in Australia is known as the Child Restraint Evaluation Program (CREP).
There have been three rounds conducted and published. There are two side impact tests, one at 90° and the
other at 66° (previously 45°), both with a fixed door structure in place. The test conditions are the same as
AS/NZS 1754 (see above), however there are additional assessment criteria. Selected TNO P Series
dummies are used for testing. In some instances they are modified to increase their seated height.
8 Conclusions
Accident statistics prove that side impact accidents are dangerous for children travelling at the
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...