Regulation No. 51-03

Name:Regulation No. 51-03
Description:Noise - Sound Emissions.
Official Title:Uniform Provisions Concerning the Approval of Motor Vehicles Having a Least Four Wheels with Regard to their Sound Emissions
Country:ECE - United Nations
Date of Issue:2016-02-05
Amendment Level:03 Series, Supplement 2
Number of Pages:88
Vehicle Types:Agricultural Tractor, Bus, Car, Heavy Truck, Light Truck
Subject Categories:Noise
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Keywords:

vehicle, test, annex, gear, speed, engine, regulation, sound, paragraph, vehicles, acceleration, type, mass, maximum, target, approval, reference, point, series, ratio, amendments, conditions, reported, condition, line, manufacturer, level, power, category, measurement, decimal, place, pressure, calculations, rated, system, tested, date, exhaust, means, entry, force, axle, laden, measurements, figure, permissible, rear, measured, results

Text Extract:

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E/ECE/324
) Rev.1/Add.50/Rev.3/Amend.2
E/ECE/TRANS/505 )
April 26, 2018
STATUS OF UNITED NATIONS REGULATION
ECE 51-03
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF:
MOTOR VEHICLES HAVING AT LEAST FOUR WHEELS
WITH REGARD TO THEIR SOUND EMISSIONS
Incorporating:
02 series of amendments
Date of Entry into Force: 18.04.95
Supplement 1 to the 02 series of amendments
Date of Entry into Force: 05.05.96
Corr. 1 to the 02 series of amendments
Dated: 15.11.96
Corr. 2 to the 02 series of amendments
Dated: 11.03.98
Corr. 3 to the 02 series of amendments
Dated: 28.04.11
Supplement 2 to the 02 series of amendments
Date of Entry into Force: 07.02.99
Supplement 3 to the 02 series of amendments
Date of Entry into Force: 17.11.99
Corr. 1 to Supplement 3 to the 02 series of amendments
Dated: 07.03.01
Supplement 4 to the 02 series of amendments
Date of Entry into Force: 02.02.07
Supplement 5 to the 02 series of amendments
Date of Entry into Force: 18.06.07
Supplement 6 to the 02 series of amendments
Date of Entry into Force: 03.02.08
Supplement 7 to the 02 series of amendments
Date of Entry into Force: 30.01.11
Corr. 1 to Revision 2 of the Regulation
Dated: 14.03.12
Supplement 8 to the 02 series of amendments
Date of Entry into Force: 13.04.12
Supplement 9 to the 02 series of amendments
Date of Entry into Force: 03.11.13
Supplement 10 to the 02 series of amendments
Date of Entry into Force: 22.01.15
03 series of amendments
Date of Entry into Force: 20.01.16
Supplement 1 to the 03 series of amendments
Date of Entry into Force: 08.10.16
Supplement 2 to the 03 series of amendments
Date of Entry into Force: 10.02.18

REGULATION NO. 51
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF MOTOR VEHICLES HAVING AT
LEAST FOUR WHEELS WITH REGARD TO THEIR SOUND EMISSIONS
1. Scope
2. Definitions
3. Application for approval
4. Markings
5. Approval
6. Specifications
CONTENTS
7. Modifications and extension of approval of a vehicle type
8. Conformity of production
9. Penalties for non-conformity of production
10. Production definitively discontinued
11. Transitional provisions
12. Names and addresses of Technical Services responsible for conducting approval tests and of
Type Approval Authorities

REGULATION NO. 51
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF MOTOR VEHICLES HAVING AT
LEAST FOUR WHEELS WITH REGARD TO THEIR SOUND EMISSIONS
1. SCOPE
This Regulation contains provisions on the sound emitted by motor vehicles and applies to
vehicles of Categories M and N.
The specifications in this Regulation are intended to reproduce the sound levels which are
generated by vehicles during normal driving in urban traffic.
2. DEFINITIONS
For the purposes of this Regulation,
2.1. "Approval of a vehicle" means the approval of a vehicle type with regard to sound;
2.2. "Vehicle type" means a category of motor vehicles which do not differ in such essential
respects as:
2.2.1. For vehicles tested according to Annex 3, Paragraph 3.1.2.1.
2.2.1.1. the shape or materials of the engine compartment and its soundproofing;
2.2.1.2. The type of engine (positive or compression ignition, two- or four-stroke, reciprocating or
rotary piston), number and capacity of cylinders, number and type of carburettors or
injection system, arrangement of valves, or the type of electric motor;
2.2.1.3. Rated maximum net power and corresponding rated engine speed(s); however if the rated
maximum net power and the corresponding rated engine speed differs only due to different
engine mappings, these vehicles may be regarded as from the same type;
2.2.1.4. The Silencing System.
2.2.2. For Vehicles Tested According to Annex 3, Paragraph 3.1.2.2.:
2.2.2.1. The shape or materials of the engine compartment and its soundproofing;
2.2.2.2. The type of engine (positive or compression ignition, two- or four-stroke, reciprocating or
rotary piston), number and capacity of cylinders, type of injection system, arrangement of
valves, rated engine speed (S), or the type of electric motor;
2.2.2.3. Vehicles having the same type of engine and/or different overall gear ratios may be
regarded as vehicles of the same type;

(l)
(m)
Lifting platforms, access ramps and similar equipment in running order, not
exceeding 200mm, provided that the loading capacity of the vehicle is not
increased;
Coupling devices for motor vehicles.
2.7. "Vehicle width" means a dimension which is measured according to ISO standard 612-
1978, term No. 6.2. In addition to the provisions of that standard, when measuring the
vehicle structural width the following devices shall not be taken into account:
(a)
(b)
(c)
(d)
(e)
Customs sealing devices and their protection;
Devices for securing the tarpaulin and their protection;
Tyre failure tell-tale devices;
Protruding flexible parts of a spray-suppression system;
Lighting equipment.
2.8. "Rated Maximum Net Power, P " means the engine power expressed in kW and
measured by the method pursuant to Regulation No. 85.
2.8.1. "Total engine power" means the sum of all power from available propulsion sources.
2.9. "Rated engine speed, S" means the declared engine speed in min-1 (rpm) at which the
engine develops its rated maximum net power pursuant to Regulation No. 85 or, where the
rated maximum net power is reached at several engine speeds, the highest one of those
speeds.
2.10. "Power to Mass Ratio index (PMR)" means a numerical quantity (see Annex 3, Paragraph
3.1.2.1.1.) with no dimension used for the calculation of acceleration.
2.11. "Reference point" means one of the following points:
2.11.1. In the case of vehicles of Categories M , N and M ≤3,500kg technically permissible
maximum laden mass:
(a)
(b)
(c)
For front engine vehicles: the front end of the vehicle;
For mid-engine vehicles: the centre of the vehicle;
For rear engine vehicles: the rear end of the vehicle.
2.11.2. In the case of vehicles of Categories M >3,500kg technical permissible maximum laden
mass, M , N , N :
(a)
(b)
For front-engine vehicles, the front end of the vehicle;
For all other vehicles, the border of the engine closest to the front of the vehicle;

2.19. "Silencing system" means a complete set of components necessary for limiting the sound
produced by an engine, its intake and its exhaust (the exhaust manifold(s), the catalyst(s)
and emission after-treatment device(s) are not considered part of the silencing system;
these parts belong to the engine).
2.20. "Design family of exhaust silencing system or exhaust silencing system
components" means a group of silencing systems or components thereof in which all of
the following characteristics are the same:
(a)
(b)
(c)
(d)
(e)
(f)
The presence of net gas flow of the exhaust gases through the absorbing fibrous
material when in contact with that material;
The type of the fibres;
Where applicable, binder material specifications;
Average fibre dimensions;
Minimum bulk material packing density in kg/m³;
Maximum contact surface between the gas flow and the absorbing material.
2.21. "Exhaust silencing system of different types" means silencing systems which
significantly differ in respect of at least one of the following:
(a)
(b)
(c)
(d)
(e)
(f)
Trade names or trademarks of their components;
The characteristics of the materials constituting their components, except for the
coating of those components;
The shape or size of their components;
The operating principles of at least one of their components;
The assembly of their components;
The number of exhaust silencing systems or components.
2.22. "Replacement silencing system" means any part of the silencing system or its
components intended for use on a vehicle, other than a part of the type fitted to this vehicle
when submitted for type-approval pursuant to this Regulation.
2.23. "R-point" means R-point as defined in Paragraph 2.4. of Annex 1 to the Consolidated
Resolution on the Construction of Vehicles (R.E.3.).

Symbol Unit Annex Paragraph Explanation
l
m
Annex 3
3.1.2.1.2.
length of vehicle; value to be reported and used for
calculations to a precision of 0.01m (1cm)
v
'
km/h
Annex 3
3.1.2.1.2.
vehicle velocity when reference point passes line AA'
(see 5.1. for definition of reference point); value to be
reported and used for calculations to the first decimal
place
v
'
km/h
Annex 3 3.1.2.1.2.
vehicle velocity when reference point or rear of
vehicle passes line BB' (see 5.1. for definition of
reference point); value to be reported and used for
calculations to the first decimal place
v
'
km/h
Annex 3
3.1.2.1.2.
vehicle velocity when reference point passes line PP'
(see 5.1. for definition of reference point); value to be
reported and used for calculations to the first decimal
place
a
m/s
Annex 3
3.1.2.1.2.1.
acceleration at wide-open throttle from AA' to BB';
value to be reported and used for calculations to the
second decimal place
a
m/s
Annex 3
3.1.2.1.2.1.
acceleration at wide-open throttle achieved in a
particular gear i; value to be reported and used for
calculations to the second decimal place
l
m
Annex 3
3.1.2.1.2.1.
point of depressing the accelerator before line AA';
value to be reported in full meter
a
m/s
Annex 3
3.1.2.1.2.2.
acceleration at wide-open throttle from PP' to BB';
value to be reported and used for calculations to the
second decimal place
a m/s Annex 3 3.1.2.1.2.3. target acceleration representing urban traffic
acceleration; value to be reported and used for
calculations to the second decimal place

Symbol Unit Annex Paragraph Explanation
v
km/h
Annex 3
3.1.2.2.1.2. (b)
target vehicle velocity when certain conditions are
met
v
km/h
Annex 3
3.1.2.2.1.2. (b)
target vehicle velocity when certain conditions are
met
n
1/min
Annex 3
3.1.2.2.1.2. (d)
engine rotational speed when the reference point
passes BB' when certain conditions are met
L
dB(A)
Annex 3
3.1.3.1.
vehicle sound pressure level at constant speed test
for gear i; value to be reported and used for
calculations to the first decimal place
L
dB(A)
Annex 3
3.1.3.1.
vehicle sound pressure level at constant speed test
for gear (i + 1); value to be reported and used for
calculations to the first decimal place
L
dB(A)
Annex 3
3.1.3.1.
reported vehicle sound pressure level at constant
speed test; value to be reported and used for
calculations to the first decimal place
L
dB(A)
Annex 3
3.1.3.1.
vehicle sound pressure level at wide-open-throttle
test for gear i; value to be reported and used for
calculations to the first decimal place
L
dB(A)
Annex 3
3.1.3.1.
vehicle sound pressure level at wide-open-throttle
test for gear (i + 1); ; value to be reported and used
for calculations to the first decimal place
L
dB(A)
Annex 3
3.1.3.1.
reported vehicle sound pressure level at wide-openthrottle;
value to be reported and used for calculations
to the first decimal place
L
dB(A)
Annex 3
3.1.3.1.
reported vehicle sound pressure level representing
urban operation; value to be reported mathematically
rounded to the nearest integer
a m/s Annex 7 2.3. maximum required acceleration at wide-open-throttle
κ

Annex 7
2.3.
gears to be tested under "Additional Sound Emission
Provisions" (ASEP)
n
1/min
Annex 7 2.3.
maximum test engine speed; value to be reported
and used for calculations to a precision of 10 min-1
v
km/h
Annex 7
2.3.
Target vehicle velocity for test point P1 of the
assessment method according Paragraph 2.4
v
km/h
Annex 7
2.3.
Target vehicle velocity for test point P4 of the
assessment method according Paragraph 2.4
P – Annex 7 2.4. test point(s) under ASEP
j – Annex 7 2.4. index for the test points under ASEP
v
km/h
Annex 7
2.4.
vehicle test speed at BB' for a particular ASEP test
point
a
m/s
Annex 7
2.5.
acceleration at wide-open throttle achieved in gear κ
and at test point j

Symbol Unit Annex Paragraph Explanation
v
km/h
Annex 7
5.3.
reference vehicle test speed for reference sound
assessment
n
1/min
Annex 7
5.3.
Reference vehicle test engine speed for reference
sound assessment
v
km/h
Annex 7
5.3.
reference vehicle test speed for reference sound
assessment
2.25. Modes
2.25.1. "Mode" means a distinct driver-selectable condition which does affect the sound emission
of the vehicle.
2.26. Stable Acceleration
2.26.1. "Stable acceleration" applicable when acceleration needs to be calculated is given when
the acceleration ratio between a and a is less than or equal to 1.2.
2.26.2. "Unstable acceleration" means a deviation from the stable acceleration during
acceleration.
2.26.2.1. Unstable acceleration might occur as well during the start of acceleration from low speeds
when the powertrain will react by bumping and jerking on the acceleration request.
3. APPLICATION FOR APPROVAL
3.1. The application for approval of a vehicle type with regard to sound shall be submitted by its
manufacturer or by his duly accredited representative.
3.2. It shall be accompanied by the undermentioned documents and the following particulars in
triplicate:
3.2.1. A description of the vehicle type with regard to the items mentioned in Paragraph 2.2.
above. The numbers and/or symbols identifying the engine type and the vehicle type shall
be specified;
3.2.2. A list of the components, duly identified, constituting the sound reduction system;
3.2.3. A drawing of the assembled sound reduction system and an indication of its position on the
vehicle;
3.2.4. Detailed drawings of each component to enable it to be easily located and identified, and a
specification of the materials used.
3.2.5. A technical information document including the information as outlined in Annex 1,
Appendix 2.

5.5. If the vehicle conforms to a vehicle type approved under one or more other Regulations
annexed to the Agreement, in the country which has granted approval under this
Regulation, the symbol prescribed in Paragraph 5.4.1. need not be repeated; in such a case
the regulation and approval numbers and the additional symbols of all the Regulations
under which approval has been granted in the country which has granted approval under
this Regulation shall be placed in vertical columns to the right of the symbol prescribed in
Paragraph 5.4.1.
5.6. The approval mark shall be clearly legible and be indelible.
5.7. The approval mark shall be placed close to or on the vehicle data plate affixed by the
manufacturer.
5.8. Annex 2 to this Regulation gives examples of arrangements of the approval mark.
6. SPECIFICATIONS
6.1. General Specifications
6.1.1. The vehicle, its engine and its sound reduction system shall be so designed, constructed
and assembled as to enable the vehicle, in normal use, despite the vibration to which it may
be subjected, to comply with the provisions of this Regulation.
6.1.2. The sound reduction system shall be so designed, constructed and assembled as to be able
to reasonably resist the corrosive phenomena to which it is exposed having regard to the
conditions of use of the vehicle, including regional climate differences.
6.2. Specifications Regarding Sound Levels
6.2.1. Methods of Measurement
6.2.1.1. The sound made by the vehicle type submitted for approval shall be measured by the
methods described in Annex 3 to this Regulation for the vehicle in motion and for the vehicle
when stationary; in the case of a vehicle where an internal combustion engine cannot
operate when the vehicle is stationary, the emitted sound shall only be measured in motion.
In the case of a hybrid electrical vehicle of Category M where an internal combustion
engine cannot operate when the vehicle is stationary, the emitted sound shall be measured
according to Annex 3, Paragraph 4. Vehicles having a technically maximum permissible
laden mass exceeding 2,800kg shall be subjected to an additional measurement of the
compressed air noise with the vehicle stationary in accordance with the specifications of
Annex 5, if the corresponding brake equipment is part of the vehicle.
6.2.1.2. The values measured in accordance with the provisions of Paragraph 6.2.1.1. above shall
be entered in the test report and a certificate corresponding to the model shown in Annex 1.

6.2.2.3. Limit values shall be increased by 2dB(A) for wheelchair accessible vehicles of Category M
constructed or converted specifically so that they accommodate one or more persons
seated in their wheelchairs when travelling on the road, and armoured vehicles, as defined
in Paragraph 2.5.2. of R.E.3.
6.2.2.4. For vehicle types of Category M having a gasoline only engine, the applicable limit value is
increased by 2dB(A).
6.2.2.5. For vehicle types of Category N having a technically permissible maximum laden mass of
less than or equal to 2.5t, the engine capacity not exceeding 660cc and the power-to-mass
ratio (PMR) calculated by using the technically permissible maximum laden mass not
exceeding 35 and a horizontal distance "d" between the front axle and the driver's seat
R-point of less than 1,100mm, the limits of the vehicle types of Category N having a
technically permissible maximum laden mass above 2.5t apply.
6.2.3. Additional Sound Emission Provisions
The Additional Sound Emission Provisions (ASEP) apply only to vehicles of Categories M
and N equipped with an internal combustion engine.
Vehicles are deemed to fulfil the requirements of Annex 7, if the vehicle manufacturer
provides technical documents to the type approval authority showing, that the difference
between maximum and minimum engine speed of the vehicles at BB' for any test condition
inside the ASEP control range defined in Paragraph 3.3. of Annex 7 to this Regulation
(including Annex 3 Conditions) does not exceed 0.15 × S. This article is intended especially
for non-lockable transmissions with variable gear ratios (CVT).
Vehicles are exempted from ASEP if one of the following conditions is fulfilled:
(a)
(b)
(c)
For vehicles of Category N , if the engine capacity does not exceed 660cc and the
power-to-mass ratio PMR calculated by using the technically permissible maximum
laden mass does not exceed 35.
For vehicles of Category N , if the payload is at least 850kg and the power-to-mass
ratio calculated by using the technically permissible maximum laden mass does not
exceed 40.
For vehicles of Category N or M derived from N if the technically permissible
maximum laden mass is greater than 2.5t and the R-point height is greater than
850mm from the ground and the power-to-mass ratio calculated by using the
technically permissible maximum laden mass does not exceed 40.
The sound emission of the vehicle under typical on-road driving conditions, which are
different from those under which the type-approval test set out in Annex 3 and Annex 7 was
carried out, shall not deviate from the test result in a significant manner.
6.2.3.1. The vehicle manufacturer shall not intentionally alter, adjust, or introduce any mechanical,
electrical, thermal, or other device or procedure solely for the purpose of fulfilling the sound
emission requirements as specified under this Regulation which is not operational during
typical on-road operation.

10. PRODUCTION DEFINITIVELY DISCONTINUED
10.1. If the holder of the approval completely ceases to manufacture a vehicle type approved in
accordance with this Regulation, he shall so inform the authority which granted the
approval. Upon receiving the relevant communication that authority shall inform thereof the
other Parties to the 1958 Agreement applying this Regulation by means of a communication
form conforming to the model in Annex 1 to this Regulation.
11. TRANSITIONAL PROVISIONS
11.1. As from the official date of entry into force of the 03 series of amendments to this
Regulation, no Contracting Party applying this Regulation shall refuse to grant or refuse to
accept type-approvals under this Regulation as amended by the 03 series of amendments.
11.2. Transitional Provisions for Phase 1 (see Paragraph 6.2.2. above)
11.2.1. As from July 1, 2016, Contracting Parties applying this Regulation shall grant type-approvals
only if the vehicle type to be approved meets the requirements of phase 1
(see Paragraph 6.2.2. above) of this Regulation as amended by the 03 series of
amendments.
As from the official date of entry into force of the 03 series of amendments, Contracting
Parties applying this Regulation shall grant type approvals to the vehicle type which meets
the requirements of phase 2 or phase 3 of this Regulation as amended by the 03 series of
amendments.
11.2.2. Contracting Parties applying this Regulation shall not refuse to grant extensions of type
approvals for existing types which have been granted according to the 02 series of
amendments to this Regulation.
11.2.3. Until June 30, 2022, no Contracting Party applying this Regulation shall refuse national or
regional type approval of a vehicle type-approved to the 02 series of amendments to this
Regulation.
11.2.4. As from July 1, 2022, Contracting Parties applying this Regulation shall not be obliged to
accept for the purpose of national or regional type approval, a vehicle type approved to the
preceding series of amendments to this Regulation.
11.2.5. Even after the date of entry into force of the 03 series of amendments to this Regulation,
Contracting Parties applying this Regulation may continue for national or regional purposes
granting type approvals and extensions of type approvals to the preceding series of
amendments to this Regulation.

11.4.4. As from July 1, 2026 for vehicle types other than N , N and M and as from July 1, 2027 for
vehicles types of Category N , N and M , Contracting Parties applying this Regulation shall
not be obliged to accept for the purpose of national or regional type approval, a vehicle type
approved to Phase 2 according to Paragraph 6.2.2. above.
11.4.5. Even after the date of entry into force of the 03 series of amendments to this Regulation,
Contracting Parties applying this Regulation may continue for national or regional purposes
granting type approvals and extensions of type approvals to Phase 1 or Phase 2 (see
Paragraph 6.2.2. above) or the preceding series of amendments to this Regulation.
11.5. Notwithstanding the transitional provisions above, Contracting Parties whose application of
this Regulation comes into force after the date of entry into force of the most recent series of
amendments are not obliged to accept type approvals which were granted in accordance
with any of the preceding series of amendments to this Regulation.
11.6. Until June 30, 2019, vehicles with a serial hybrid drive train which have a combustion engine
with no mechanical coupling to the power train are excluded from the requirements of
Paragraph 6.2.3. above.
11.7. Until June 30, 2019, Contracting Parties applying this Regulation can continue to grant
approvals using test sites which comply with the specifications of the preceding series of
amendments to this Regulation as an alternative to Annex 3, Paragraph 2.1. of this
Regulation.
11.8. Until June 30, 2022 for vehicle types of Category N or for vehicle types of Category M
derived from N the limits according to Paragraph 6.2.2. of the vehicle types of Category N
having a technically permissible maximum laden mass above 2.5t apply, if all the following
specifications are met:
(a)
(b)
(c)
(d)
(e)
Having a technically permissible maximum laden mass of less than or equal to 2.5t;
An R-point height greater or equal to 800mm from the ground;
An engine capacity exceeding 660cc but less than 1495cc;
An engine where the centre point of gravity of the engine is between 300mm and
1,500mm behind the front axle;
And having a rear axle drive.
12. NAMES AND ADDRESSES OF TECHNICAL SERVICES RESPONSIBLE FOR
CONDUCTING APPROVAL TESTS AND OF TYPE APPROVAL AUTHORITIES
The Contracting Parties to the 1958 Agreement applying this Regulation shall communicate
to the United Nations Secretariat the names and addresses of the Technical Services
responsible for conducting approval tests and of the Type Approval Authorities which grant
approval and to which forms certifying approval or extension or refusal or withdrawal of
approval, issued in other countries, are to be sent.

Section II
1.
Additional information (where applicable): See Addendum (Appendix 1)
2.
Technical Service responsible for carrying out the tests: ...............................................................
3.
Date of test report: ..........................................................................................................................
4.
Number of test report: .....................................................................................................................
5.
Remarks (if any): See Addendum (Appendix 1) ............................................................................
6.
Place: .............................................................................................................................................
7.
Date: ...............................................................................................................................................
8.
Signature: ........................................................................................................................................
9.
Reasons for extensions: ..................................................................................................................
Attachments:
Information package
Test report(s)

2.3.4. Sound pressure level L .............................................................................................. dB(A)
3. Remarks: ....................................................................................................................................
...................................................................................................................................................

2.1.2. For chassis with bodywork ........................................................................................................
2.1.2.1. Length: .......................................................................................................................................
2.1.2.2. Width: .........................................................................................................................................
2.2. Mass in running order
(a) Minimum and maximum for each variant: ........................................................................
(b) Mass of each version (a matrix shall be provided): .........................................................
2.3. Technically permissible maximum laden mass stated by the manufacturer:
3. POWER PLANT
3.1. Manufacturer of the engine: .......................................................................................................
3.1.1. Manufacturer's engine code (as marked on the engine, or other means of identification):
...................................................................................................................................................
3.2. Internal Combustion Engine
3.2.1. Specific Engine Information
3.2.1.1. Working principle: positive ignition/compression ignition, cycle four stroke/two stroke/rotary
3.2.1.2. Number and arrangement of cylinders: ......................................................................................
3.2.1.2.1. Firing order: ................................................................................................................................
3.2.1.3. Engine capacity: .............................................................................................................. cm3
3.2.1.4. Rated maximum net power: ................................ kW at ................................................... min
(manufacturer's declared value)

3.3.
Electric Motor
3.3.1.
Type (winding, excitation): .........................................................................................................
3.3.1.1.
Maximum hourly output: ....................................................................................................... kW
3.3.1.2.
Operating voltage: ................................................................................................................... V
3.4.
Engine or motor combination: ...................................................................................................
3.4.1.
Hybrid electric vehicle: yes/no
3.4.2.
Category of hybrid electric vehicle: off-vehicle charging/not off-vehicle charging:
3.4.3.
Operating mode switch: with/without
3.4.3.1.
Selectable modes
3.4.3.1.1.
Pure electric: yes/no
3.4.3.1.2.
Pure fuel consuming: yes/no
3.4.3.1.3.
Hybrid modes: yes/no
(if yes, short description):
3.4.4.
Electric motor (describe each type of electric motor separately)
3.4.4.1.
Make: .........................................................................................................................................
3.4.4.2.
Type: ..........................................................................................................................................
3.4.4.3.
Rated maximum net power: ................................................................................................. kW
4.
TRANSMISSION
4.1.
Type (mechanical, hydraulic, electric, etc.): ...............................................................................

7. MISCELLANEOUS
7.1. Details of any non-engine devices designed to reduce noise
(if not covered by other items): ..................................................................................................
Signed: .......................................................................................................................................
Position in company: .................................................................................................................
Date: ...........................................................................................................................................

ANNEX 3
METHODS AND INSTRUMENTS FOR MEASURING THE SOUND
MADE BY MOTOR VEHICLES
1. MEASURING INSTRUMENTS
1.1. Acoustic Measurements
The apparatus used for measuring the sound level shall be a precision sound-level meter
or equivalent measurement system meeting the requirements of Class 1 instruments
(inclusive of the recommended windscreen, if used). These requirements are described
in "IEC 61672-1:2002: Precision Sound Level Meters", second edition, of the
International Electrotechnical Commission (IEC).
Measurements shall be carried out using the "fast" response of the acoustic
measurement instrument and the "A" weighting curve also described in
"IEC 61672-1:2002". When using a system that includes a periodic monitoring of the A-
weighted sound pressure level, a reading should be made at a time interval not greater
than 30ms.
The instruments shall be maintained and calibrated in accordance to the instructions of
the instrument manufacturer.
1.2. Calibration of the Entire Acoustic Measurement System for a Measurement
Session
At the beginning and at the end of every measurement session the entire measurement
system shall be checked by means of a sound calibrator that fulfils the requirements for
sound calibrators of at least precision Class 1 according to IEC 60942:2003. Without any
further adjustment the difference between the readings of two consecutive checks shall
be less than or equal to 0.5dB(A).
If this value is exceeded, the results of the measurements obtained after the previous
satisfactory check shall be discarded.
1.3. Compliance with Requirements
Compliance of the acoustic measurement instrumentation shall be verified by the
existence of a valid certificate of compliance. These certificates shall be deemed to be
valid if certification of compliance with the standards was conducted within the previous
12 month period for the sound calibration device and within the previous 24 month period
for the instrumentation system. All compliance testing shall be conducted by a
laboratory, which is authorized to perform calibrations traceable to the appropriate
standards.

The background noise shall be measured for duration of 10s immediately before and
after a series of vehicle tests. The measurements shall be made with the same
microphones and microphone locations used during the test. The A-weighted maximum
sound pressure level shall be reported.
The background noise (including any wind noise) shall be at least 10dB(A) below the
A-weighted sound pressure level produced by the vehicle under test. If the difference
between the ambient noise and the measured sound is between 10 and 15dB(A), in
order to calculate the test results the appropriate correction shall be subtracted from the
readings on the sound-level meter, as in the following table:
Difference between ambient noise and
sound to be measured dB(A)
10 11 12 13 14 15
2.2. Vehicle
Correction dB(A) 0.5 0.4 0.3 0.2 0.1 0.0
2.2.1. The vehicle shall be representative of vehicles to be put on the market as specified by
the manufacturer in agreement with the Technical Service to fulfil the requirements of
this Regulation.
Measurements shall be made without any trailer, except in the case of non-separable
vehicles. At the request of the manufacturer, measurements may be made on vehicles
with lift axle(s) in a raised position.
Measurements shall be made on vehicles at the test mass m specified according to the
following table.
Target mass, m , is used to denote the mass that N and N vehicles should be tested
at. The actual test mass of the vehicle can be less due to limitations on vehicle and axle
loading.

2.2.2. At the applicant's request the vehicle of a Category M , M , N or N is deemed
representative of its completed type if the tests are carried out to an incomplete vehicle
not having a bodywork. In the test of an incomplete vehicle all relevant soundproofing
materials, panels and noise reduction components and systems shall be fitted on the
vehicle as designed by the manufacturer except a part of bodywork which is built in a
later stage.
No new test shall be required due to fitting of a supplement fuel tank or relocation of the
original fuel tank on condition that other parts or structures of the vehicle apparently
affecting sound emissions have not been altered.
The tyres to be used for the test shall be representative for the vehicle and shall be
selected by the vehicle manufacturer and recorded in Addendum to the Communication
form (Annex 1, Appendix 1). They shall correspond to one of the tyre sizes designated
for the vehicle as original equipment. The tyre is or will be commercially available on the
market at the same time as the vehicle. The tyres shall be inflated to the pressure
recommended by the vehicle manufacturer for the test mass of the vehicle. The tyres
shall have at least 1.6mm tread depth.
2.2.3. Before the measurements are started, the engine shall be brought to its normal operating
conditions.
2.2.4. If the vehicle is fitted with more than two-wheel drive, it shall be tested in the drive which
is intended for normal road use.
2.2.5. If the vehicle is fitted with fan(s) having an automatic actuating mechanism, this system
shall not be interfered with during the measurements.
2.2.6. If the vehicle is equipped with an exhaust system containing fibrous materials, the
exhaust system is to be conditioned before the test according to Annex 4.
2.2.7. Calculation Procedure to Determine Extra Loading of N and N Vehicles Only
2.2.7.1. Calculation of extra loading
The target mass, m , (per kW rated power) for two-axle vehicles of Category N and
N is specified in the Table in Paragraph 2.2.1: above.
m = 50 [kg/kW] × P [kW] (1)
To reach the required target mass, m , for a vehicle being tested, the unladen vehicle,
including the mass of the driver, m , shall be loaded with an extra mass, m , which
shall be placed above the rear axle as given in Formula (8):
m = m + m + m (2)
The target mass, m , shall be achieved with a tolerance of ±5%.

2.2.7.2. Loading considerations if load cannot be aligned with the centre of rear axle If the centre
of gravity of the extra loading, m , cannot be aligned with the centre of the rear axle,
the test mass of the vehicle, m , shall not exceed the sum of the unladen front axle load,
m , and the unladen rear axle load, m , plus the extra loading, m ,
and the mass of the driver, m .
This means that if the actual front and rear axle loads are measured on a scale when the
extra loading, m , is placed onto the vehicle and it is aligned with the centre of the rear
axle, the test mass of the vehicle minus the mass of the driver is as given by Formula
(14):
m − m = m + m (14)
Where:
m = m (15)
If the centre of gravity of the extra loading cannot be aligned with the centre of the rear
axle, Formula (14) is still fulfilled, but
m >m (16)
because the extra loading has partly distributed its mass to the front axle. In that case, it
is not allowed to add more mass onto the rear axle to compensate for the mass moved
to the front axle.
2.2.7.3. Test mass for vehicles with more than two axles
If a vehicle with more than two axles is tested, then the test mass of this vehicle shall be
the same as the test mass for the two-axle vehicle.
If the unladen vehicle mass of a vehicle with more than two axles is greater than the test
mass for the two-axle vehicle, then this vehicle shall be tested without extra loading.
3. METHODS OF TESTING
3.1. Measurement of Sound of Vehicles in Motion
3.1.1. General conditions of test
Two lines, AA' and BB', parallel to line PP' and situated respectively 10m ± 0.05m
forward and 10 m ± 0.05 m rearward of line PP' shall be marked out on the test runway.
At least four measurements shall be made on each side of the vehicle and for each gear.
Preliminary measurements may be made for adjustment purposes, but shall be
disregarded.
The microphone shall be located at a distance of 7.5m ± 0.05m from the reference line
CC' of the track and 1.2m ± 0.02m above the ground.
The reference axis for free field conditions (see IEC 61672-1:2002) shall be horizontal
and directed perpendicularly towards the path of the vehicle line CC'.

3.1.2.1.2. Calculation of Acceleration
Acceleration calculations are applicable to M , N and M ≤3,500kg technically
permissible maximum laden mass categories only.
All accelerations are calculated using different speeds of the vehicle on the test track.
The formulae given are used for the calculation of a , a and a . The speed
either at AA' or PP' is defined as the vehicle speed when the reference point passes AA'
(v ') or PP' (v '). The speed at BB' is defined when the rear of the vehicle passes BB'
(v '). The method used for determination of the acceleration shall be indicated in the
test report.
Due to the definition of the reference point for the vehicle the length of the vehicle (l ) is
considered differently in the formula below. If the reference point is in the front of the
vehicle, then l = l , mid: l = ½ l and rear: l = 0.
At the choice of the vehicle manufacturer, front engine vehicles may use l = 5m, and
mid-engine vehicles may use l = 2.5m.
3.1.2.1.2.1. Calculation procedure for vehicles with manual transmission, automatic transmission,
adaptive transmissions and transmissions with continuous variable transmissions
(CVT's) tested with locked gear ratios:
a = ((v /3.6) - (v /3.6) ) / (2*(20+l))
a used in the determination of gear selection shall be the average of the four a
during each valid measurement run.
Pre-acceleration may be used. The point of depressing the accelerator before line AA'
shall be reported in the Addendum to the Communication form (Annex 1, Appendix 1).
3.1.2.1.2.2. Calculation procedure for vehicles with automatic transmissions, adaptive transmissions
and CVT's tested with non-locked gear ratios:
a used in the determination of gear selection shall be the average of the four
a during each valid measurement run.
If devices or measures described in Paragraph 3.1.2.1.4.2. can be used to control
transmission operation for the purpose of achieving test requirements, calculate a
using the equation:
a = ((v '/3.6) - (v '/3.6) ) / (2*(20 + l))
Pre-acceleration may be used.
If devices or measures described in Paragraph 3.1.2.1.4.2. are not used, calculate a
using the equation:
a = ((v '/3.6) - (v '/3.6) ) / (2*(10 + l))

3.1.2.1.4.1. Vehicles with manual transmission, automatic transmissions, adaptive transmissions or
CVTs tested with locked gear ratios
The following conditions for selection of gear ratios are possible:
(a)
If one specific gear ratio gives an acceleration in a tolerance band of ±5% of the
reference acceleration a , not exceeding 2.0m/s , test with that gear ratio.
(b) If none of the gear ratios give the required acceleration, then choose a gear ratio i,
with an acceleration higher and a gear ratio i+1, with an acceleration lower than
the reference acceleration. If the acceleration value in gear ratio i does not exceed
2.0m/s , use both gear ratios for the test. The weighting ratio in relation to the
reference acceleration a is calculated by:
k = (a – a )/(a – a )
(c)
(d)
(e)
If the acceleration value of gear ratio i exceeds 2.0m/s , the first gear ratio shall be
used that gives an acceleration below 2.0m/s unless gear ratio i+1 provides
acceleration less than a . In this case, two gears, i and i+1 shall be used,
including the gear i with acceleration exceeding 2.0m/s . In other cases, no other
gear shall be used. The achieved acceleration a during the test shall be used
for the calculation of the part power factor k instead of a .
If the vehicle has a transmission in which there is only one selection for the gear
ratio the acceleration test is carried out in this vehicle gear selection. The achieved
acceleration is then used for the calculation of the part power factor k instead of
a .
If rated engine speed is exceeded in a gear ratio before the vehicle passes BB' the
next higher gear shall be used. If the next higher gear results in an acceleration
below a , the vehicle test speed, v , shall be reduced by 2.5km/h and the gear
ratio selection shall proceed as specified by the options given in this Paragraph. In
no case shall the vehicle test speed be reduced below 40km/h. In this case, a gear
ratio is allowed even if a does not exceed a .
In the case of a vehicle not exempted from ASEP according to Paragraph 6.2.3., gear i
shall be tested and values reported (L
, n
v
) in order to perform tests of
Annex 7.
3.1.2.1.4.2. Vehicles with automatic transmission, adaptive transmissions and CVTs tested with
non-locked gear ratios:
The gear selector position for full automatic operation shall be used.
The acceleration value a shall be calculated as defined in Paragraph 3.1.2.1.2.2.
The test may then include a gear change to a lower range and a higher acceleration. A
gear change to a higher range and a lower acceleration is not allowed. A gear shifting to
a gear ratio which is not used in urban traffic shall be avoided.
Therefore, it is permitted to establish and use electronic or mechanical devices, including
alternate gear selector positions, to prevent a downshift to a gear ratio which is typically
not used for the specified test condition in urban traffic.

Target conditions of Category M >3,500kg technically permissible maximum laden
mass, N :
When the reference point passes line BB', the engine speed n shall be between
70 and 74% of speed S, at which the engine develops its rated maximum net power, and
the vehicle speed shall be 35km/h ± 5km/h. Between line AA' and line BB' a stable
acceleration condition shall be ensured.
Target conditions of Category M , N :
When the reference point passes line BB', the engine speed n shall be between
85 and 89% of speed S, at which the engine develops its rated maximum net power, and
the vehicle speed shall be 35km/h ± 5km/h. Between line AA' and line BB' a stable
acceleration condition shall be ensured.
3.1.2.2.1. Gear ratio selection
It is the responsibility of the manufacturer to determine the correct manner of testing to
achieve the required conditions.
The vehicle transmission, gear, or gear ratio, shall be chosen to be able to fulfil the target
conditions according to Paragraphs 3.1.2.2.1.1. or 3.1.2.2.1.2. of Annex 3 to this
Regulation. The vehicle transmission, gear, or gear ratio may be controlled by electronic
or mechanical measures including exclusion of kick-down function.
Appendix 3, Figure 4a to Figure 4d, give gear selection criteria and test run criteria for
Categories M having a technically permissible maximum laden mass exceeding
3,500 kg, and for Category N , M and N , in a flowchart as an aid to test operation.
3.1.2.2.1.1. Manual transmission, automatic transmissions, adaptive transmissions or transmissions
with continuously variable gear ratios (CVTs) tested with locked gear ratios
Stable acceleration condition shall be ensured. The gear choice is determined by the
target conditions.
The following conditions for fulfilling the target conditions in Paragraph 3.1.2.2. of
Annex 3 to this Regulation are possible:
(a)
(b)
(c)
If one gear choice fulfils both target conditions for the rotational engine speed
n and for the vehicle speed v , test with that gear.
If more than one gear choice fulfils both target conditions for the rotational engine
speed n and for the vehicle speed v , test in gear i that gives velocity
v closest to 35km/h.
If two gear choices fulfil both target conditions for the rotational engine speed
n and for the vehicle speed v , and fulfil the following condition.
(v – v ) = (v – v )
then both gears are taken for further calculation of L .

The following conditions for fulfilling the target conditions in Paragraph 3.1.2.2. of
Annex 3 to this Regulation are possible:
(a)
(b)
If the choice of the gear selector position fulfils both target conditions for the
rotational engine speed n
and for the vehicle speed v
, test with the
gear selector in that position.
If the choice of the gear selector position fulfils the target condition for the
rotational engine speed n but not the target condition for the vehicle speed
v , change the target condition for the vehicle speed to two vehicle target
speeds as follows:
Define v as
25km/h ≤v ≤35 km/h
and
Define v as
35km/h ≤v ≤45km/h.
Conduct two tests, one with v and one with v .
Both test conditions are used for further calculation of L .
(c)
If under condition b) the target rotational engine speed n
cannot be fulfilled,
condition d) shall be chosen.
(d)
If the choice of the gear selector position cannot fulfil the target condition for the
rotational engine speed n but the target condition for the vehicle speed
v , change the target condition for the vehicle speed to two vehicle target
speeds as follows:
Define v as
25km/h ≤v ≤30km/h
and
Define v as
40km/h ≤v ≤45km/h.
Conduct two tests, one with v and one with v .
Use the test where n
is closest to the target rotational engine speed n
but
not higher than n
.
n ≤n for i = 1, 2

(c) If no rotational engine speed is available and the target vehicle speed v and
v defined as
25km/h ≤v ≤35km/h
cannot be fulfilled, it is necessary to conduct, only one test with v
where v
is
defined as
35km/h ≤v ≤45km/h
The test condition for v is taken for further calculation of L .
3.1.2.2.2. Acceleration Test
When the reference point of the vehicle reaches the line AA' the accelerator control shall
be fully depressed (without operating the automatic downshift to a lower range than
normally used in urban driving) and held fully engaged until the reference point reaches
BB' + 5m. The acceleration control unit can then be released on request of the
manufacturer.
In the case of articulated vehicles consisting of two non-separable units regarded as a
single vehicle, the semi-trailer shall be disregarded in determining when line BB' is
crossed.
3.1.3. Interpretation of Results
For vehicles of Categories M and M having a maximum authorized mass not exceeding
3,500kg, and Category N the maximum A-weighted sound pressure level indicated
during each passage of the vehicle between the two lines AA' and BB' shall be rounded
to the first significant digit after the decimal place (e.g. XX,X).
For vehicles of Category M having a maximum authorized mass exceeding 3,500kg and
Categories M , N , and N the maximum A-weighted sound pressure level indicated
during each passage of the reference point of the vehicle between line AA' and line
BB' + 5m shall be rounded, to the first significant digit after the decimal place (e.g. XX,X).
If a sound peak obviously out of character with the general sound pressure level is
observed, the measurement shall be discarded. At least four measurements for each test
condition shall be made on each side of the vehicle and for each gear ratio. Left and right
side may be measured simultaneously or sequentially. The first four valid consecutive
measurement results, within 2dB(A), allowing for the deletion of non-valid results
(see Paragraph 2.1.), shall be used for the calculation of the final result for the given side
of the vehicle. The results of each side shall be averaged separately and rounded to the
first decimal place. All further calculations to derive L shall be done separately for the
left and right vehicle side. The final value to be reported as the test result mathematically
rounded to the nearest integer shall be the higher value of the two sides.
The speed measurements at AA', BB', and PP' shall be noted and used in calculations to
the first significant digit after the decimal place.
The calculated acceleration a shall be noted to the second digit after the decimal
place.

3.2.3. Test Site - Local Conditions (see Appendix of Annex 3, Figure 2)
3.2.3.1. In the vicinity of the microphone, there shall be no obstacle that could influence the
acoustical field and no person shall remain between the microphone and the sound
source. The meter observer shall be positioned so as not to influence the meter reading.
3.2.4. Disturbance Noise and Wind Interference
Readings on the measuring instruments produced by ambient noise and wind shall be at
least 10dB(A) below the sound level to be measured. A suitable windscreen may be
fitted to the microphone provided that account is taken of its effect on the sensitivity of
the microphone (see Paragraph 1.1. of this annex).
3.2.5. Measuring Method
3.2.5.1. Nature and number of measurements
The maximum sound level expressed in A-weighted decibels (dB(A)) shall be measured
during the operating period referred to in Paragraph 3.2.5.3.2.1.
At least three measurements shall be taken at each measuring point.
3.2.5.2. Positioning and preparation of the vehicle
The vehicle shall be located in the centre part of the test area with the gear selector in
neutral position and the clutch engaged. If the design of the vehicle does not allow this,
the vehicle shall be tested in conformity with the manufacturer's prescriptions for
stationary engine testing. Before each series of measurements, the engine shall be
brought to its normal operating condition, as specified by the manufacturer.
If the vehicle is fitted with fan(s) having an automatic actuating mechanism, this system
shall not be interfered with during the sound level measurements.
The engine hood or compartment cover, if so fitted, shall be closed.
3.2.5.3. Measuring of noise in proximity to the exhaust
(see appendix of Annex 3, Figure 2)
3.2.5.3.1. Positions of the microphone
3.2.5.3.1.1. The microphone shall be located at a distance of 0.5m ± 0.01m from the reference point
of the exhaust pipe defined in Figure 2 and at an angle of 45º (±5º) to the vertical plane
containing the flow axis of the pipe termination. The microphone shall be at the height of
the reference point, but not less than 0.2m from the ground surface. The reference axis
of the microphone shall lie in a plane parallel to the ground surface and shall be directed
towards the reference point on the exhaust outlet.
If two microphone positions are possible, the location farthest laterally from the vehicle
longitudinal centreline shall be used.
If the flow axis of the exhaust outlet pipe is at 90º to the vehicle longitudinal centreline,
the microphone shall be located at the point, which is furthest from the engine.

3.2.5.3.2.3. Test Validation
3.2.6. Results
The measurement shall be regarded as valid if the test engine speed does not deviate
from the target engine speed by more than ±3% for at least 1s.
At least three measurements for each test position shall be made. The maximum
A-weighted sound pressure level indicated during each of the three measurements shall
be recorded. The first three valid consecutive measurement results, within 2dB(A),
allowing for the deletion of non-valid results (see Paragraph 2.1. except the
specifications of the test site), shall be used for the determination of the final result for
the given measurement position. The maximum sound level, for all measurement
positions, and of the three measurement results, constitutes the final result.
4. Sound from the hybrid vehicle of Categories M in motion, where an internal combustion
engine cannot operate when the vehicle is stationary (data reported to facilitate testing of
the vehicle in use).
4.1. In order to facilitate in-use compliance test of hybrid vehicles – where an internal
combustion engine cannot operate when the vehicle is stationary –, the following
information relating to the sound-pressure level measurements carried out in accordance
with Paragraph 3.1. of Annex 3 for the motor vehicles in motion is referred to as in-use
compliance reference data:
(a)
(b)
Gear (i) or, for vehicles tested with non-locked gear ratios, the position of the gear
selector chosen for the test;
Position of the operating switch during measurement of the sound pressure level
L (if switch is fitted);
(c) The pre-acceleration length lPA in m;
(d)
The average vehicle speed in km/h at the beginning of the full throttle acceleration
for tests in gear (i); and
(e) The sound pressure level L in dB(A) of the wide-open-throttle tests in gear (i),
defined as the maximum of the two values resulting from averaging the individual
measurement results at each microphone position separately.
4.2. The in-use compliance reference data shall be entered in the type approval certificate as
specified in Paragraph 2.3. of the Addendum to the Communication form (Annex 1,
Appendix 1).

Figure 2
Reference Point for Measurement of Sound Emitted by Stationary Vehicles

Figure 3a
Flowchart for Vehicles Tested According to Paragraph 3.1.2.1. of Annex 3 to this Regulation –
L Computation

Figure 3c
Flowchart for Vehicles Tested According to Paragraph 3.1.2.1. of Annex 3 to this Regulation –
Gear Selection Using Locked Gear Part 2

Figure 3e
Flowchart for Vehicles Tested According to Paragraph 3.1.2.1. of Annex 3 to this Regulation –
Gear Selection Using Non-locked Gears

Figure 4b
Flowchart for Vehicles Tested According to Paragraph 3.1.2.2. of Annex 3 to this Regulation –
Test in Non-locked Gears PART 1

Figure 4d
Flowchart for Vehicles Tested According to Paragraph 3.1.2.2. of Annex 3 to this Regulation –
Test for No- combustion Engine Speed Available

ANNEX 4
EXHAUST SILENCING SYSTEMS CONTAINING ACOUSTICALLY ABSORBING
FIBROUS MATERIALS
1. GENERAL
Sound absorbing fibrous materials may be used in silencing systems or components thereof
only if
(a)
(b)
The exhaust gas is not in contact with the fibrous materials; or if
The silencing system or components thereof are of the same design family as
systems or components for which it has been proven, in the course of type approval
process in accordance with the requirements of this regulation for another vehicletype,
that they are not subject to deterioration.
Unless one of these conditions is fulfilled, the complete silencing system or components
thereof shall be submitted to a conventional conditioning using one of three installations and
procedures described below.
1.1. Continuous road operation for 10,000km
1.1.1. 50 ± 20% of this operation shall consist of urban driving and the remaining operation shall
be long-distance runs at high speed; continuous road operation may be replaced by a
corresponding test-track programme.
1.1.2. The two speed regimes shall be alternated at least twice.
1.1.3. The complete test programme shall include a minimum of 10 breaks of at least 3h duration
in order to reproduce the effects of cooling and any condensation which may occur.
1.2. Conditioning on a Test Bench
1.2.1. Using standard parts and observing the vehicle manufacturer's instructions, the silencing
system or components thereof shall be fitted to the vehicle referred to in Paragraph 3.3. of
this Regulation or the engine referred to in Paragraph 3.4. of this Regulation. In the former
case the vehicle shall be mounted on a roller dynamometer. In the second case, the engine
shall be coupled to a dynamometer.
1.2.2. The test shall be conducted in six 6h periods with a break of at least 12h between each
period in order to reproduce the effects of cooling any condensation which may occur.

1.3.7. Any drain holes shall be closed off during the test.
1.3.8. The entire test shall be completed within 48h.
If necessary, one cooling period will be observed after each hour.

ANNEX 5
COMPRESSED AIR NOISE
1. METHOD OF MEASUREMENT
The measurement is performed at microphone positions 2 and 6 according to Figure 1, with
the vehicle stationary. The highest A-weighted sound level is registered during venting the
pressure regulator and during ventilating after the use of both the service and parking
brakes.
The noise during venting the pressure regulator is measured with the engine at idling speed.
The ventilating noise is registered while operating the service and parking brakes; before
each measurement, the air-compressor unit has to be brought up to the highest permissible
operating pressure, and then the engine switched off.
2. EVALUATION OF THE RESULTS
For all microphone positions two measurements are taken. In order to compensate for
inaccuracies of the measuring equipment, the meter reading is reduced by 1dB(A), and the
reduced value is taken as the result of measurement. The results are taken as valid if the
difference between the measurements at one microphone position does not exceed 2dB(A).
The highest value measured is taken as the result. If this value exceeds the sound limit by
1dB(A), two additional measurements are to be taken at the corresponding microphone
position.
In this case, three out of the four results of measurement obtained at this position have to
comply with the sound limit.
3. LIMITING VALUE
The sound level shall not exceed the limit of 72dB(A).

ANNEX 6
CHECKS ON CONFORMITY OF PRODUCTION
1. GENERAL
These requirements are consistent with the test for checking conformity of production (COP)
according to Paragraph 8. of this Regulation.
2. TESTING PROCEDURE
The test site and measuring instruments shall be those as described in Annex 3.
2.1. The vehicle(s) under test shall be subjected to the test for measurement of sound of vehicle
in motion as described in Paragraph 3.1. of Annex 3.
2.2. Compressed Air Noise
Vehicles having maximum mass exceeding 2,800kg and equipped with compressed air
systems shall be subjected to an additional test for measurement of the compressed air
noise as described in Paragraph 1. of Annex 5.
2.3. Additional Sound Emission Provisions (ASEP)
The vehicle manufacturer shall assess the compliance with ASEP by an appropriate
evaluation (for example, but not limited to, part checks) or may perform the test described in
Annex 7.
3. SAMPLING AND EVALUATION OF THE RESULTS
One vehicle shall be chosen and subjected to the tests set out in Point 2. If the sound level
of the vehicle tested does not exceed by more than 1dB(A) the limit value prescribed in
Annex 3, and, where appropriate, Paragraph 3. of Annex 5, the vehicle type shall be
considered to conform to the requirements of this Regulation.
If one of the test results does not fulfil the COP requirements of this annex and of
Paragraph 8. of the main body of this Regulation two more vehicles of the same type shall
be tested pursuant to Paragraph 2. above.
If the test results for the second and the third vehicle fulfil the COP requirements of this
annex and of Paragraph 8. of the main body of this Regulation, the vehicle is considered in
compliance with regard to the COP.
If one of the test results of the second or third vehicle does not fulfil the COP requirements
of this annex and of Paragraph 8. of the main body of this Regulation the vehicle type shall
be considered not to conform to the requirements of this Regulation and the manufacturer
shall take the necessary measures to re-establish the conformity.

2.3. Control Range
The ASEP requirements apply to every gear ratio κ that leads to test results within the
control range as defined below.
Vehicle speed V : v ≥20km/h
Vehicle acceleration a a ≤5.0m/s
Engine speed n n ≤2.0 * PMR * S or
n ≤0.9 * S, whichever is the lowest
Vehicle speed V :
If the vehicle, in the lowest valid gear does not achieve the maximum engine speed n
below 70km/h, increase the vehicle speed in that gear to reach the maximum speed
n , but not beyond 80km/h.
For any other gear, the maximum vehicle speed is 70km/h.
For vehicles tested in non-locked transmission conditions, the maximum vehicle speed is
80km/h.
Gears κ ≤gear i as determined in Annex 3
Transmission conditions:
Annex 3 gear selection
Annex 7 gear selection
Locked Gear ,
gear ,…
Non-locked
Non-locked
2.4. Target Conditions
The sound emission shall be measured in each valid gear ratio at the four test points as
specified below. For all test points the boundary conditions as specified in Paragraph 2.3.
shall be met.
The gear ratio is valid if all four points and the anchor point meet the specifications of
Paragraph 2.3. above. Any gear ratio for which this criteria is not fulfilled is invalid and not
analysed further.
The first test point P is defined by using an entry speed v
of 20km/h ≤v
<20km/h +
3km/h.
For P , if a stable acceleration condition cannot be achieved according to 2.26.2.1. in the
definition section of this Regulation, the speed v shall be increased in steps of 5km/h
until a stable acceleration is reached.

2.5.2. Measurements reading:
Per test point, one single run is carried out.
For every separate test run, the following parameters shall be determined and noted:
The maximum A-weighted sound pressure level of both sides of the vehicle, indicated
during each passage of the vehicle between the two lines AA' and BB', shall be
mathematically rounded to the first decimal place (L ). If a sound peak obviously out of
character with the general sound pressure level is observed, the measurement shall be
discarded. Left and right side may be measured simultaneously or separately. For further
processing, the higher sound pressure level of both sides shall be used.
The vehicle speed readings at AA', PP' and BB' shall be rounded and reported with the first
significant digit after the decimal place. (v ; v ; v )
If applicable, the engine speed readings at BB' shall be reported as a full integer value
(n ).
2.5.3. The calculated acceleration shall be determined in accordance to the formula in
Paragraph 3.1.2.1.2. of Annex 3 and reported to the second digit after the decimal place
(a ).
3. ANALYSIS METHOD 1: SLOPE-ASSESSMENT
3.1. Determination of the Anchor Point
The anchor point is the same for each gear ratio κ falling under the control range according
to Paragraph 2.3. The parameters for the anchor point are taken from the acceleration test
of Annex 3 as follows:
L is the higher sound pressure level of L of left and right side of gear ratio i;
n is the average of n , of the 4 runs of gear ratio i reported from Annex 3;
3.2 Slope of the Regression Line for Each Gear Ratio κ
The sound measurements shall be evaluated as function of engine speed according to
Paragraph 3.2.1.
3.2.1. Calculation of the Slope of the Regression Line for Each Gear Ratio κ
The linear regression line is calculated using the anchor point and the four correlated
additional measurements with the results for engine speeds and sound levels as reported
under 2.5.2. of this Annex.
Slope
=

( n − n)( L − L)
∑ ( n − n)
(in dB(A)/1,000min )
1
1
With L = ∑L
and n = ∑n
;
5
5
where n = engine speed measured at line BB'

4. ANALYSIS METHOD 2: L ASSESSMENT
4.1. General
This evaluation procedure is an alternative selected by the vehicle manufacturer to the
procedure described in Paragraph 3. of this Annex and is applicable for all vehicle
technologies. It is the responsibility of the vehicle manufacturer to determine the correct
manner of testing. Unless otherwise specified, all testing and calculation shall be as
specified in Annex 3 to this Regulation.
The measurement method is defined in Paragraph 2. Each testing point shall be evaluated
individually.
4.2. Calculation of ∆L
4.2.1. Data-processing
From any L
as measured according to this annex, ∆L
shall be calculated as
follows:
(a) Calculate a using acceleration calculation from Paragraph 3.1.2.1.2.1. or
3.1.2.1.2.2. of Annex 3 to this Regulation, as applicable;
(b) Determine the vehicle speed (v ) at BB during the L test;
(c) Calculate k as follows:
k = 1 - (a /a )
Test results where a are less than a shall be disregarded.
(d) Calculate L as follows:
L = L - k * (L - L )
For further calculation, use the L from Annex 3 to this Regulation without
rounding, including the digit after the decimal (xx.x).
(e) Calculate L to normalize the speed from v to 50km/h as follows:
L = L - (0.15 * (V - 50))
(f) Calculate the deviation ∆L relative to L as follows:
4.2.2. Specifications
∆ = L - L
Compliance with limits:
∆L shall be less than or equal to 3.0dB(A) + limit value - L .

5.3. Data-processing for Simulation Assessment
5.3.1. Determination of Reference Engine Speed n
The reference engine speed, n , shall be calculated using the gear ratio of gear α at
the reference speed of v = 61km/h.
5.3.2. Calculation of L
L = L + Slope * (n - n )/1,000
5.4. Specifications
For vehicles of Category M , L shall be less than or equal to 76dB(A).
For vehicles of Category M fitted with a manual transmission having more than four forward
gears and equipped with an engine developing a rated maximum net power greater than
140kW (according to Regulation No. 85) and having a maximum-power/maximum-mass
ratio greater than 75, L shall be less than or equal to 79dB(A).
For vehicles of Category M fitted with an automatic transmission having more than four
forward gears and equipped with an engine developing a rated maximum net power greater
than 140kW (according to Regulation No. 85) and having a maximum-power/maximum-mass
ratio greater than 75, L shall be less than or equal to 78dB(A).
For vehicles of Category N with a technically permissible maximum laden mass below
2,000kg, L shall be less than or equal to 78dB(A).
For vehicles of Category N with a technically permissible maximum laden mass above
2,000kg and below 3,500kg, L shall be less than or equal to 79dB(A).
For vehicles of Category M and N equipped with a compression-ignition and direct
injection internal combustion engine, the sound level shall be increased by 1dB(A).
For vehicles of Category M and N designed for off-road use and with a technically
permissible maximum laden mass above 2t, the sound level shall be increased by 1dB(A) if
they are equipped with an engine having a rated maximum net power of less than 150kW
(according to Regulation No. 85) or by 2dB(A) if they are equipped with an engine having a
rate maximum net power of 150kW (according to Regulation No. 85) or higher.

ANNEX 7 – APPENDIX 1
STATEMENT OF COMPLIANCE WITH THE ADDITIONAL
SOUND EMISSION PROVISIONS
(Maximum format: A4 (210 × 297mm))
...................... (Name of manufacturer) attests that vehicles of this type ..................... (type with regard to
its sound emission pursuant to Regulation No. 51) comply with the requirements of Paragraph 6.2.3. of
UN Regulation No. 51.
...................... (Name of manufacturer) makes this statement in good faith, after having performed an
appropriate evaluation of the sound emission performance of the vehicles.
Date: ...............................................................................................................................................................
Name of authorized representative: ...............................................................................................................
Signature of authorized representative:

Figure 2
Flowchart for the Vehicle Sound Assessment
According to Annex 7, Paragraph 5. "Reference Sound Assessment"

Noise - Sound Emissions.