ISO 7634:2007

Road vehicles - Compressed air braking systems for towed vehicles including those with electronic braking control functions - Test procedures

ISO 7634:2007 specifies the test procedures for testing the operational performance requirements of towed vehicles of Category O (full trailers, semi-trailers, and centre-axle trailers) as defined in Annex 7 of the UN-ECE Consolidated Resolution on the Construction of Vehicles (R. E. 3). This includes vehicles fitted with compressed air braking systems (with and without an antilock braking system or an electronically controlled braking system), in accordance with the UN-ECE Regulation 13, 09 series of amendments, supplements 1 to 6. Test methods covering lock actuators are not included.

Véhicules routiers — Dispositifs de freinage à air comprimé pour véhicules remorqués, y compris ceux avec fonctions de commande de freinage électroniques — Modes opératoires d'essai

General Information

• Status: Published
• Publication Date: 30-May-2007
• ICS: 43.040.40 - Braking systems
• Technical Committee: ISO/TC 22/SC 33 - Vehicle dynamics and chassis components
• Drafting Committee: ISO/TC 22/SC 33 - Vehicle dynamics and chassis components
• Current Stage: 9093 - International Standard confirmed
• Start Date: 17-Jun-2021
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 7634:2003 - Road vehicles - Compressed-air braking systems - Test procedures
• Effective Date: 15-Apr-2008

Overview

ISO 7634:2007 - Road vehicles - Compressed air braking systems for towed vehicles including those with electronic braking control functions - Test procedures - defines standardized test procedures for evaluating the operational performance of compressed‑air braking systems fitted to Category O towed vehicles (full trailers, semi‑trailers, centre‑axle trailers). It covers trailers equipped with conventional compressed‑air systems as well as those incorporating antilock braking systems (ABS) and electronically controlled braking systems (EBS), and is aligned with UN‑ECE Regulation No. 13 (09 series of amendments). Test methods for lock actuators are excluded.

Key topics and technical requirements

• Scope of tests: Service braking, parking braking, automatic braking, spring‑brake actuator checks, and energy storage capacity.
• ABS / EBS testing: Procedures for wheel behaviour, adhesion utilization, split‑adhesion tests, peak adhesion determination, and ABS energy consumption; includes failure and warning‑signal checks.
• Fade and performance tests: Type I and Type III fade tests (vehicle and dynamometer alternatives) and procedures for transferring results between similar vehicles.
• Instrumentation & test conditions: Requirements for test site, road surface, ambient conditions, vehicle preparation, loading states (unladen/laden), towing vehicle simulation and additional instrumentation for ABS/EBS-equipped trailers.
• Safety and functional checks: Brake defect/failure warning signal checks, control failure of load‑sensing device, auxiliary equipment failure simulation.
• Documentation & reporting: Test report formats and normative references such as ISO 611, ISO 1176, ISO 3583 and ISO 7638 series.

Applications

ISO 7634:2007 is used to:

• Support type approval and regulatory compliance testing for trailers under UN‑ECE R13.
• Validate braking system designs during development and certification of trailers and braking components.
• Define laboratory and on‑road test protocols for independent testing laboratories and OEM quality assurance.
• Provide repeatable procedures for ABS/EBS performance verification, fade testing, parking brake validation, and spring‑brake functionality.
• Enable transfer of test results between similar vehicle types where appropriate, reducing redundant testing.

Who uses this standard

• Trailer and commercial vehicle manufacturers (OEMs)
• Braking system suppliers and component designers
• Vehicle homologation and certification bodies
• Independent testing laboratories and research institutes
• Fleet safety engineers and regulatory compliance teams

Related standards

• UN‑ECE Regulation No. 13 (braking requirements)
• ISO 611 (braking vocabulary), ISO 1176 (masses), ISO 3583 (pressure test connections)
• ISO 7638 series (electrical connectors for towing/towed vehicles)
• ISO/PAS 12158 (temperature measuring methods)

ISO 7634:2007 provides the practical, standardized test framework needed to ensure reliable, repeatable evaluation of compressed‑air braking systems on towed vehicles - essential for safety, compliance, and product development.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7634
Third edition
2007-06-01
Road vehicles — Compressed air braking
systems for towed vehicles including
those with electronic braking control
functions — Test procedures
Véhicules routiers — Dispositifs de freinage à air comprimé pour
véhicules remorqués, y compris ceux avec fonctions de commande de
freinage électroniques — Modes opératoires d'essai

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 [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved

Contents Page
Foreword. v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols . 3
5 Test site conditions . 7
5.1 Test site . 7
5.2 Road surface condition. 7
5.3 Ambient conditions . 8
6 General requirements. 8
7 Recommended sequence of tests. 9
7.1 Preparation and static checks and tests. 9
7.2 Basic performance tests – unladen . 10
7.3 Antilock braking system/electronically controlled braking system (ABS/EBS) tests —
unladen . 10
7.4 Basic performance tests — Laden. 10
8 Vehicle preparation. 11
8.1 Documents and basic data . 11
8.2 Braking system condition and bedding . 11
8.3 Adjustment of braking equipment . 11
8.4 Tyre conditions . 12
8.5 Towing vehicles . 12
8.6 Instrumentation — General. 12
8.7 Provision for failure simulation. 12
8.8 Loading condition. 13
8.9 Additional vehicle to tow the combination of normal towing vehicle and test trailer . 13
8.10 Additional instrumentation for ABS equipped trailers . 13
8.11 Additional instrumentation for trailer with an electric control line . 13
9 Energy storage capacity test. 14
9.1 Test conditions . 14
9.2 Test procedure . 14
9.3 Test requirement. 14
9.4 Presentation of results. 14
10 Service braking system — Response time measurement. 14
10.1 General. 14
10.2 Towing vehicle simulator. 15
10.3 Test conditions . 15
10.4 Test procedure . 15
10.5 Presentation of results. 16
11 Automatic braking . 16
12 Brake defect and failure warning signals. 16
12.1 Antilock braking system warning signal.16
12.2 EBS warning signal check . 16
13 Tests on trailers equipped with spring brake actuators. 16
13.1 Initial conditions . 16
13.2 Energy depletion test . 17
13.3 Spring brake actuation test. 17
13.4 Auxiliary release system check. 17
14 Dynamometer tests (alternative to vehicle tests) . 17
14.1 General . 17
14.2 Alternative type I tests (fade test for trailers of categories O and O ). 17
2 3
14.3 Alternative type III tests (fade test for category O trailers). 19
15 Transfer of results of type I or type III tests to other vehicles . 21
15.1 General . 21
15.2 Presentation of results . 22
16 Control failure of load-sensing device/function — Stationary test. 23
17 Auxiliary equipment failure. 24
18 Basic performance tests — Unladen . 24
18.1 Type O test (Service braking system cold brake effectiveness). 24
19 Antilock braking system/electronically controlled braking system (ABS/EBS) tests —
Unladen . 26
19.1 Determination of adhesion utilization on high adhesion surface. 26
19.2 Determination of the peak coefficient of adhesion on the high adhesion surface . 27
19.3 Wheel behaviour . 30
19.4 Split adhesion tests . 30
19.5 Energy consumption of the antilock braking system (on a high adhesion surface). 31
19.6 Antilock braking system failure. 33
19.7 Additional tests on trailers equipped with EBS. 33
20 Basic performance tests — Laden . 34
20.1 Parking braking system tests . 34
20.2 Type O test (Service braking system cold brake effectiveness). 37
20.3 Control failure of load-sensing device/function — Road test . 37
20.4 Type I test (fade test for trailers of categories O and O ). 37
2 3
20.5 Type III test (fade test for vehicles of category O ). 40
Annex A (normative) Description of test vehicle, axle or brake . 44
Annex B (normative) Test report. 47
Annex C (informative) Figures. 50
Bibliography . 54

iv © ISO 2007 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 7634 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2, Braking
systems and equipment.
This third edition cancels and replaces the second edition (ISO 7634:2003), which has been technically
revised.
INTERNATIONAL STANDARD ISO 7634:2007(E)

Road vehicles — Compressed air braking systems for towed
vehicles including those with electronic braking control
functions — Test procedures
1 Scope
This International Standard specifies the test procedures for testing the operational performance requirements
of towed vehicles of Category O (full trailers, semi-trailers, and centre-axle trailers) as defined in Annex 7 of
the UN-ECE Consolidated Resolution on the Construction of Vehicles (R. E. 3). This includes vehicles fitted
with compressed air braking systems (with and without an antilock braking system or an electronically
controlled braking system), in accordance with UN-ECE Regulation No. 13, 09 series of amendments,
supplements 1 to 6. Test methods covering lock actuators are not included.
The values in square brackets [ ] and the values in the tables are taken from ECE Regulation No. 13 for
information.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 611, Road vehicles — Braking of automotive vehicles and their trailers — Vocabulary
ISO 1176, Road vehicles — Masses — Vocabulary and codes
ISO 3583, Road vehicles — Pressure test connection for compressed-air pneumatic braking equipment
ISO 3833, Road vehicles — Types — Terms and definitions
ISO 7638-1, Road vehicles — Connectors for the electrical connection of towing and towed vehicles — Part 1:
Connectors for braking systems and running gear of vehicles with 24 V nominal supply voltage
ISO 7638-2, Road vehicles — Connectors for the electrical connection of towing and towed vehicles — Part 2:
Connectors for braking systems and running gear of vehicles with 12 V nominal supply voltage
ISO 11992 (all parts), Road vehicles — Interchange of digital information on electrical connections between
towing and towed vehicles
ISO/PAS 12158, Road vehicles — Braking systems — Temperature measuring methods
UN-ECE Regulation No. 13, Uniform provisions concerning the approval of vehicles with regard to braking.
NOTE Regulation 13 is periodically updated through amendments and supplements, with this standard having been
prepared in accordance with the 09 series of amendments including supplements 1 to 6. When using this standard care
should be taken to ensure that changes have not subsequently occurred that effect the test methods or values given.
3 Terms and definitions
For the purposes of this International Standard, the terms and definitions given in ISO 611, ISO 1176 and
ISO 3833 and the following apply.
3.1
pneumatic (full air) braking system
braking system in which the control and energy are transmitted from the point of application to the brakes by
pneumatic transmission devices
NOTE Figures C.1 and C.2 show examples of typical full trailer and semi-trailer air braking systems.
3.2
electronic braking system
EBS
braking system in which the control is generated and processed as an electrical signal in the control
transmission
NOTE Electrical output signals control devices which produce actuation forces from stored pneumatic energy.
3.3
categories of ABS
3.3.1
Category A:
ABS system which meets all the requirements of UN-ECE Regulation No. 13, Annex 13
3.3.2
Category B:
ABS system which meets all the requirements of UN-ECE Regulation No. 13, Annex 13, except paragraph
6.3.2 (no braking rate on split-adhesion surface is prescribed)
3.4
wheel control
3.4.1
directly controlled wheel
wheel whose braking force is modulated according to data provided by at least its own sensor
3.4.2
indirectly controlled wheel
wheel whose braking force is modulated according to data provided by the sensor(s) of other wheel(s)
NOTE ABS systems with select-high control are deemed to include both directly and indirectly controlled wheels. In
systems with select-low control, all sensed wheels are deemed to be directly controlled wheels.
3.5
ABS – full cycling
state of the antilock system in which the brake force is repeatedly modulated to prevent the directly controlled
wheels from locking
NOTE Brake applications where modulation only occurs during the stop are not considered to meet this definition.
3.6
laden trailer
trailer laden so as to reach its total maximum design mass (ISO 1176 code: ISO-M07)
2 © ISO 2007 – All rights reserved

NOTE In the case of semi-trailers and centre-axle trailers being road tested, the loading may be such that the
maximum design load per axle (ISO 1176 code: ISO-M11) is reached without loading the fifth wheel for semi-trailers or the
mechanical coupling for centre-axle trailers. However, for the testing of the parking braking system (see 20.1) the loading
on the fifth wheel or mechanical coupling in the case of semi-trailer and centre-axle trailers is included.
3.7
unladen trailer
trailer at its shipping mass (ISO 1176 code: ISO-M05) minus spare wheel(s) and spare wheel carrier(s) and
other optional items, plus the mass of the required instrumentation (see 8.6, 8.10 and 8.11)
3.8
electric control line
electrical connection between an electronic braking system equipped power-driven vehicle and an electronic
braking system equipped trailer which provides the braking control function to the trailer
NOTE It comprises the electrical wiring and connector and includes the parts for data communication and the
electrical energy supply for the trailer control transmission.
4 Symbols
For the purposes of this International Standard, the symbols given in Table 1 apply.
Table 1 — Symbols
Symbol used
a
Symbols Description in ECE Reg.
Unit
No. 13
C Nm Brake camshaft input torque C
C ′ Nm Converted camshaft input torque (reference paragraph 15.2.3.4)
C Nm Threshold camshaft input torque (i.e. minimum camshaft torque C
o o
necessary to produce a measurable braking torque)
C
Nm Technically admissible camshaft input torque at a pressure in the
adm
brake actuator lower than the maximum pressure (reference
paragraph 15.2.3.3 )
C Nm Maximum technically admissible camshaft input torque C
max max
E E
m Wheelbase
E m Distance between kingpin and centre of axle or axles of semi-trailer E
R R
(or distance between drawbar coupling and centre of axle or axles of

centre-axle trailer)
e Index to indicate the reference axle e
Adhesion utilization of the trailer
ε ε
ε ε value on the high adhesion surface ε
H H
ε ε value on the low adhesion surface ε
L L
F Average output thrust of one brake actuator at a pressure p
N
A A
corresponding to p = 0,65 MPa (= 6,5 bar)
m
N Converted brake actuator output thrust (to allow for difference
F′
A
between p and p ) (reference paragraph 15.2.3.4)
Ae A
F N Threshold brake actuator output thrust (i.e. minimum output thrust
AO
necessary to produce a measurable braking torque)

Table 1 (continued)
Symbol used
a
Symbols Unit Description in ECE Reg.
No. 13
F
N Maximum technically admissible brake actuator output thrust at a
Aadm
pressure in the brake actuator lower than the maximum pressure
(reference paragraph 15.2.3.3)
F
N Maximum technically admissible brake actuator output thrust
Amax
F N Braking force at the periphery of the wheel(s) (if no other indication is T
B
given)
F N Braking force resulting at the periphery of the wheel(s) for hot braking T
Ba
F N Sum of braking forces resulting at the periphery of all wheels of the T
BaR R
trailer for hot braking
F N Braking force at the periphery of the wheel(s) for heating the brake(s)
Bh
F N Sum of braking forces at the periphery of all wheels of the trailer T
BR R
F F
N Braking force of the trailer with the antilock system inoperative
bR bR
F N Braking force of the trailer with the antilock system operative F
bRAL bRAL
F N F on split adhesion surface
bRALS bRAL
F Maximum value of F F
N
bRmax bR bRmax
F N Total normal reaction of road surface on those axles of the motor F
Cd Cd
vehicle and trailer combination which are both unbraked and driven
F N Total normal static reaction of road surface on those axles of the F
Cnd Cnd
motor vehicle and trailer combination which are unbraked yet non-
driven
F N Normal dynamic reaction of road surface on the trailer axles, with the F
dyn dyn
antilock system operative
F N F on front axle of a full trailer F
fdyn dyn fdyn
F P F
N Normal static reaction of road surface on axle i
i i, i
F F on axle i of a full trailer F
N
idyn dyn idyn
F N Normal static reaction at a tractor fifth wheel on semi-trailer kingpin, or
K
at mechanical coupling of a towing vehicle on the drawbar of a centre-
axle trailer
F D
N Longitudinal force on a mechanical coupling
L
F N Total normal reaction of road surface on all wheels of the motor P F
M M, M
(towing) vehicle
F N Total normal static reaction of road surface on the unbraked, driven F
Md Md
axles of the motor (towing) vehicle
F F
N Total normal static reaction of road surface on the unbraked, non-
Mnd Mnd
driven axles of the motor (towing) vehicle
F N Total normal static reaction of road surface on all wheels of the trailer P F
R R, R
F N Normal dynamic reaction of road surface on all braked wheels of the P
Rb 2
trailer
F N Normal dynamic reaction of road surface on all wheels of a semi- F F
Rdyn idyn, Rdyn
trailer or a centre-axle trailer
4 © ISO 2007 – All rights reserved

Table 1 (continued)
Symbol used
a
Symbols Unit Description in ECE Reg.
No. 13
F P
N Total normal static reaction of road surface on all unbraked wheels of
Ru 1
the trailer
F N F on rear axle of a full trailer
rdyn dyn
F N Rolling resistance of the motor (towing) vehicle: F
WM WM
0,01 F + 0,015 F
Mnd Md
g m/s² Acceleration due to gravity G, g
h m Height of drawbar (hinge point on trailer) h
D D
h m Height of fifth wheel coupling (kingpin) h h
K K, S
h m Height of centre of gravity of the trailer h
R R
k Coefficient of adhesion between tyre and road k
b
K K
Correction factor, semi-trailer laden
c c
k k-factor of one front axle k
f f
k k-factor for high adhesion surface k
H H
k k
k-factor for low adhesion surface
L L
k Peak k-factor k
peak peak
k k-factor of one rear axle k
r r
k k-factor of the trailer k
R R
I m Lever length I
P P kg Mass of the individual motor vehicle / trailer P
M, R
p bar Pressure in brake actuator(s)
A
p bar Pressure in the trailer control line p
m m
p bar Pressure in the energy reservoir(s) of the service braking system of
res
the trailer, when the control device of the service braking system is
fully applied for the first time
p′ bar Pressure in the energy reservoir(s) of the service braking system of
res
the trailer, when the control device of the service braking system has
been fully applied 9 times
p bar Pressure in the trailer supply line
s
R R
mm Dynamic tyre rolling radius
R mm Static tyre radius
s
r R
mm Normal effective radius of brake drum or disc
BD
S mm Stroke of brake actuator
A
S mm Stroke of brake actuator at which output thrust is 0,9 F s
Ap A p
S mm Automatic brake adjustment device re-adjustment stroke (at an s
re-adjust re-adjust
actuator pressure of 1 bar)
Table 1 (continued)
Symbol used
a
Symbols Unit Description in ECE Reg.
No. 13
t t
s Time interval
t Mean value of t t
s
m m
t s Minimum value of t t
min min
v km/h Vehicle speed v
v km/h Velocity of cooling air flow v
air air
v km/h Final vehicle speed at the end of braking test v
f 2
v km/h Vehicle speed at beginning of braking test v, v
s 1
z Braking rate [total braking force of vehicle divided by the normal static z
reaction of road surface (can be calculated for the whole vehicle, a
single axle or a single wheel)]
z Achieved braking rate
a
z Achieved braking rate of an axle, evaluated by calculation
aA
z z + M
Achieved braking rate of the vehicle combination
aC R
z Achieved braking rate of trailer, evaluated by calculation
aR
z Calculated braking rate of vehicle with hot brakes
BaR
z z
Braking rate of vehicle combination with the trailer only braked and
C C
the antilock system inoperative (towing vehicle engine disconnected)
z Braking rate of vehicle combination with the trailer only braked and z
CAL CAL
antilock system operative
z z on the split-adhesion surface
CALS CAL
z Maximum value of z z
Cmax C Cmax
z Braking rate resulting from F
hae Bae
z Braking rate resulting from F
he Bhe
z
Braking rate for one wheel
pW
z Hot braking rate for one wheel
paW
z Braking rate for heating the brakes of the trailer
phR
z
Trailer service braking rate
pR
z Braking rate of the trailer obtained by calculation from z
RAL CAL
z z on the high friction surface z
RALH RAL RALH
z z on the low friction surface z

RALL RAL RALL
z z on the split-surface z
RALS RAL RALS
c
z R
Total braking rate as a result of rolling resistance
r
a
In accordance with ISO 31-3:1992. Quantities and units-Part Mechanics.
b
See UN-ECE Regulation No. 13 Annex 10, diagram 4B.
c
Value is 0,01 (see UN-ECE Regulation No. 13 Annex 4, sub-clause 1.4.4.3).
6 © ISO 2007 – All rights reserved

NOTE For some calculations, additional indices as listed below may be used:
⎯ subscripts etc., indicate axles no. 1, no. 2, no. 3, etc., respectively;
1, 2, 3,
⎯ I or III indicate the fade test type (type I or III test respectively);
⎯ e indicates the reference axle for the calculation of the values for the axle i;
i
⎯ or indicates a front or rear axle.
f r
5 Test site conditions
5.1 Test site
The test site should be of sufficient size, without obstacles, to provide a safe testing environment.
The test site shall have a road of sufficient length prior to the test area to enable the test speeds to be attained.
The test area should be of sufficient length to allow for poor braking performance and sufficient width to allow
for poor directional stability under braking.
5.2 Road surface condition
5.2.1 Surface
5.2.1.1 The test area shall be a dry, smooth, hard-surface free of loose material providing a peak
coefficient of adhesion (k ) of about [0,8].
peak
5.2.1.2 Additionally, for the testing of trailer(s) equipped with an antilock braking system of category A, a
surface providing a k of [0,3] or less is needed. It shall be preceded and followed by a surface according to
peak
5.2.1.1 of sufficient length on the approach side to enable the test speeds to be attained.
NOTE Until such test surfaces become generally available, tyres at the limit of wear, and higher values up to [0,4]
may be used. The actual value obtained and the type of tyres and surface shall be recorded.
For testing trailers fitted with antilock braking systems of category A, it is also necessary for a low adhesion
surface (k ) to have a high adhesion surface (k ) on at least one side to enable the split-adhesion tests to be
L H
performed. Both surfaces shall be sufficiently wide to be able to determine the peak coefficients of adhesion
separately.
The above described surfaces shall be such that k is equal to or greater than [0,5] and k divided by k is
H H L
equal to or greater than [2]. If any doubt arises that this requirement is met, it is necessary to ascertain the
peak coefficients of adhesion by using the procedure detailed in 19.2. It is always necessary to measure the
peak coefficients of adhesion when testing a trailer fitted with an antilock braking system of category A.
5.2.2 Gradient
5.2.2.1 The road surface shall be substantially level; a tolerance of ±1 % average gradient, measured
over a minimum distance of 50 m, is allowed.
5.2.2.2 Type I and type III tests may be conducted on a specified gradient or on a level road as specified
in 20.4.4 (type I) and 20.5.4 (type III).
5.2.2.3 The parking braking system/hill holding test may be conducted on an appropriate gradient or on a
level road as specified in 20.1.2.3.
5.2.3 Camber
The camber (transverse gradient) across the road surface should not exceed 2 %.
5.3 Ambient conditions
5.3.1 Wind speed
The tests must be performed, when there is no wind liable to affect the results. The wind speed however shall
not exceed an average of 5 m/s.
5.3.2 Air temperature
The air temperature shall be recorded in the test report.
6 General requirements
6.1 The general test conditions to be followed during the determination of braking performance are listed
below:
⎯ motor vehicle and trailer combination speed (as defined in paragraph 6.11);
⎯ without exceeding the maximum permissible control force/pressure;
⎯ without wheel-locking, except immediately before stopping unless specifically allowed;
⎯ without deviation of the motor vehicle and trailer combination from its course;
⎯ loading condition: unless otherwise specified, all tests should be carried out with the trailer unladen.
6.2 During all phases of the following test procedures, any unusual braking performance characteristics
and/or motor vehicle and trailer combination behaviour, e.g. course deviation or abnormal vibration, shall be
observed and reported.
6.3 Deceleration measurements used in the following test procedures, unless otherwise stated, refer to the
“mean fully developed deceleration” as defined in UN-ECE Regulation No. 13, Annex 4, paragraph 1.1.2.
6.4 Tests may be carried out under adverse conditions to avoid delays, but with due consideration for
safety. Such adverse conditions shall be reported. Any failed tests under such conditions shall be repeated
under the correct conditions, but not all tests need necessarily be repeated.
6.5 The recommended sequence of the tests is listed in Clause 7.
6.6 Re-testing in the course of carrying-out the full test procedure is to be avoided, although one or two
extra stops are unlikely to prejudice subsequent test results.
6.7 Full or partial re-tests, after a failed test or to test alternative braking system components, shall again
follow the recommended order (reference Clause 7), and with particular emphasis on the trailer preparation
and bedding-in procedures.
6.8 Control force/pressure shall be applied rapidly, but without significant overshoot, and then be
maintained constant during the stop (if not otherwise specified). The use of adjustable pressure regulating
devices is recommended.
6.9 Skilled test drivers should be used who shall familiarize themselves with the optimum trailer braking
performance without wheel-locking, except immediately before stopping, and without course deviation.
6.10 Unless otherwise stated, all braking tests shall be carried out with cold brakes, i.e. when the initial
temperature of the hottest brake measured on the disc or on the outside of the drum is lower than [+100] °C.
8 © ISO 2007 – All rights reserved

6.11 The speed of the motor vehicle and trailer combination before actuating the braking system control shall
be stabilized at a level not less than 98 % of the prescribed speed for the test in question unless there is any
other overriding requirement.
6.12 If the semi-trailer, centre-axle trailer or full trailer is equipped with a load-sensing device/function, the
tests relating to the failure of its control as detailed in 16 and 20.3 are deemed to be equivalent and the
manufacturer may choose which test is to be carried out.
6.13 The pressure p in the trailer supply line at the start of each test, shall be [7] bar and the trailer control
s
line pressure p at each full service brake application shall not exceed [6,5] bar.
m
The energy depletion test of Clause 9 has special extended limits of: p = [8,5] bar and p = [7,5] bar.
s m
6.14 To enable the brake response time to be measured, a simulator(s) representing a standard towing
vehicle is required (reference Clause 10). A pneumatic control line simulator is required for all trailers together
with an electric/pneumatic simulator if the trailer is also equipped with an electric control line. (At the present
time, UN-ECE Regulation No. 13 does not allow trailers with only an electric control line.)
7 Recommended sequence of tests
7.1 Preparation and static checks and tests
See Table 2.
Table 2 — Preparation and static checks and tests
Reference to this
Reference to
No. Test Status International
ECE R 13.09
Standard
1 Vehicle preparation (documents, — 8 § 1 - 4, 5.1.1.4, A2,
instrumentation, bedding, etc.) A17, A18
2 Capacity of energy storage devices static 9 A7 § 1.3
3 Response time static 10 A6 § 3.1 - 3.5
5 Automatic braking static 11 5.2.1.18.4.2,
A4 § 3.3
6 Brake defect and failure warning static 12 5.2.1.29.2,
signals
A13 § 4.1, 4.1.1,
4.1.2, A17 § 4.2.2.2
7 Spring brake system static 13 A8 § 2.4, 2.5
8 Dynamometer test - type I 14.2 A11-App2
9 Dynamometer test - type III 14.3 A11-App2
10 Transfer of type I and type III test 15 A11
results to other trailers
11 Load-sensing device/function control static 16 A10 § 1.1,
failure
A10 § 6
12 Auxiliary equipment failure static 17 5.2.2.14
7.2 Basic performance tests – unladen
See Table 3.
Table 3 — Basic performance tests — Unladen
Reference to this
Reference to
No. Test Status International
ECE R 13.09
Standard
1 Type O test Motor veh./trailer 18 A4 § 1.4.4

7.3 Antilock braking system/electronically controlled braking system (ABS/EBS) tests —
unladen
See Table 4.
Table 4 — Antilock braking system/electronically controlled braking system (ABS/EBS) tests —
Unladen
Reference to
Reference to
No. Test Status this International
ECE R 13.09
Standard
1 Adhesion utilization on high adhesion Motor veh./trailer 19.1 A13 § 6.2
2 Determination of k peak Motor veh./trailer 19.2 A13-App.2 § 2
L
3 Wheel behaviour test Motor veh./trailer 19.3 A13 § 6.3.1,
A13 § 6.3.3
4 Split adhesion test Motor veh./trailer 19.4 A13 § 6.3.2
5 Energy consumption Motor veh./trailer 19.5 A13 § 6.1
6 Antilock braking system failure static 19.6 A13 § 4.3
7 Additional tests with EBS Motor veh./trailer 19.7 5.1.3.4, 5.2.2.15.2,
5.2.2.19
7.4 Basic performance tests — Laden
See Table 5.
Table 5 — Basic performance tests — Laden
Reference to this
Reference to
No. Test Status International
ECE R 13.09
Standard
1 Parking braking system test static 20.1 A 4 § 3.2
2 Type O test Motor veh./trailer 20.2 A 4 § 1.4.4
3 Load-sensing device/function control Motor veh./trailer 20.3 A10 § 1.1,
failure
A10 § 6
4 Type I test (fade test) Motor veh./trailer 20.4 A 4 § 1.5.2 - 4
5 Type III test (fade test) Motor veh./trailer 20.5 A 4 § 1.7
10 © ISO 2007 – All rights reserved

8 Vehicle preparation
8.1 Documents and basic data
NOTE The control of the data as per the definitions in 3.3 is also an integral part of the vehicle preparation.
The vehicle shall be verified based upon the documentation as follows:
a) Main technical data according to Annex 2 of UN-ECE Regulation No. 13;
b) Piping diagram, layout and list of the elements of the braking system;
c) Braking system performance calculation according to Annex 10 of UN-ECE Regulation No. 13, including:
⎯ compatibility diagrams: the relationship between p (also digital equivalent if applicable) and braking
m
rate z ; for vehicles with an antilock braking system, this is only required to cover the laden state;
pR
⎯ adhesion utilization curves (only for full trailers without an antilock braking system);
⎯ for semi-trailers with K less than [0,8] evidence that z is at least [0,45];
C pR
⎯ for full trailers and centre-axle trailers evidence that z is at least [0,5];
pR
d) Documentation according to Annex 18 of UN-ECE Regulation No. 13, if the vehicle is equipped with EBS.
This documentation includes an explanation of design provisions guaranteeing compliance with all
relevant parts of UN-ECE Regulation 13 (paragraph 5.2.2 and the appropriate sub-paragraphs) which
deal with the special requirements for brake force compensation and for EBS. This documentation may
also indicate the worst case failures for EBS.
e) Report/approval of electromagnetic compatibility (EMC) (in accordance with UN-ECE Regulation No. 10,
02 series of amendments) if the vehicle is equipped with an ABS or EBS.
f) Report that the vehicle has been satisfactorily tested to the method described in Annex 17 of UN-ECE
Regulation No. 13, if the vehicle is equipped with an electric control line.
8.2 Braking system condition and bedding
8.2.1 The braking system components shall be new, or capable of functioning as if new, and within the
vehicle manufacturer’s specifications.
It is recommended to measure individual brake forces on a roller test bench prior to the braking performance
tests.
8.2.2 The brake linings shall be bedded. Until a uniform procedure is established, the bedding of the service
and parking brake linings should be carried out according to the manufacturer’s recommendations.
The brake linings may be regarded as bedded if at least 80 % of their surface contacts with the brake drums
or discs. Neither glazed nor burned or damaged surfaces are acceptable.
8.3 Adjustment of braking equipment
Adjustable brake components shall be set according to the vehicle manufacturer’s recommendations.
Re-adjustment of the brakes, including automatically adjusted brakes, in accordance with the vehicle
manufacturer’s recommendations, may be made prior to each specific test.
8.4 Tyre conditions
8.4.1 The tyres shall be inflated to the vehicle manufacturer’s recommended pressure levels.
8.4.2 It is recommended that the tyre tread wear should not exceed 50 % of the new condition, and that
totally new tyres are not used.
8.5 Towing vehicles
8.5.1 Vehicle choice
To carry out the road tests, a towing vehicle is needed. The ratio of the mass of this towing vehicle to the
mass of the full trailer, semi-trailer, or centre-axle trailer to be tested should be as small as practical. In
addition, the braking rate of this towing vehicle, in relation to the pressure p in the trailer control line, shall
m
comply with the requirements of UN-ECE Regulation 13, Annex 10, paragraph 3.1.3.
8.5.2 Towing vehicle preparation
The towing vehicle shall be prepared such that, when coupled to the test vehicle, it is possible to brake the
test vehicle alone or to brake both vehicles and measure the longitudinal force F on the mechanical coupling.
L
8.6 Instrumentation — General
The towing vehicle and trailer shall be prepared for testing by the addition of the following instruments and/or
calibration of existing standard instruments, as required:
⎯ control force gauge for measuring the force required to apply the parking braking system;
⎯ coupling force measurement system. Required for types I and III road tests, and if tests according to
paragraph 18.1.1.2 are carried out, and should include an information display for the benefit of test
personnel;
⎯ decelerometer;
⎯ speed measuring device or calibrated speedometer. (For ABS equipped trailers, refer to paragraph 8.10);
⎯ brake temperature indicating system (see ISO/PAS 12158 for recommendations on brake temperature
measurement methods);
⎯ response time measurement system, in conjunction with a towing vehicle air system simulator (see
Figures C.3 and C.4);
⎯ line pressure gauges and pressure transducers to measure and record, where necessary, reservoir,
control line and actuator pressures;
⎯ pressure test connections complying with ISO 3583, for checking the setting of load-sensing devices, the
capacity of the energy storage devices (see Clause 9) and the response time (see Clause 10).
Other instruments may be useful in providing accurate data, but care shall be exercised to ensure that
instruments added to the standard vehicle braking equipment do not significantly affect the braking system
performance.
8.7 Provision for failure simulation
8.7.1 The vehicle shall be equipped with the necessary added devices, piping and wiring as agreed with the
vehicle manufacturer to provide the required failure simulations.
12 © ISO 2007 – All rights reserved

Such added devices, piping and wiring shall not interact with the standard vehicle braking equipment such as
to significantly affect the intact system performance or introduce side-effects in the failed case.
8.7.2 In the pneumatic part of the braking system, a failure should correspond to an uncoupled pipe.
8.7.3 In the electric part of the braking system, a failure should generally correspond to a disconnection, but
a short circuit or a ground connection may be specified by the manufacturer in certain instances. This may be
done by using prepared components or sections of wiring.
8.7.4 Fault conditions should be removed a
...