Regulation No. 9-07

Name:Regulation No. 9-07
Description:Noise - Three-wheel Vehicles.
Official Title:Uniform Provisions Concerning the Approval of: Category L2, L4 and L5 Vehicles with Regard to Noise.
Country:ECE - United Nations
Date of Issue:2013-12-02
Amendment Level:07 Series, Supplement 2
Number of Pages:38
Vehicle Types:Motorcycle
Subject Categories:Noise
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Keywords:

vehicle, test, approval, regulation, type, exhaust, engine, system, sound, speed, surface, amendments, series, silencing, paragraph, requirements, annex, measured, noise, level, vehicles, measurements, measurement, made, date, microphone, maximum, number, force, pressure, figure, manufacturer, voids, track, entry, area, measuring, reference, conditions, granted, means, absorption, mass, fitted, content, point, mark, approved, outlet, cores

Text Extract:

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E/ECE/324
) Add.8/Rev.3/Amend.2
E/ECE/TRANS/505 )
February 22, 2017
STATUS OF UNITED NATIONS REGULATION
ECE 9-07
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF:
CATEGORY L , L AND L VEHICLES WITH REGARD TO NOISE
Incorporating:
05 series of amendments
Date of Entry into Force: 26.01.94
06 series of amendments
Date of Entry into Force: 08.03.99
Corr. 1 to the 06 series of amendments
Dated: 06.08.99
Supplement 1 to the 06 series of amendments
Date of Entry into Force: 10.10.06
07 series of amendments
Date of Entry into Force: 03.11.13
Supplement 1 to the 07 series of amendments
Date of Entry into Force: 20.01.16
Supplement 2 to the 07 series of amendments
Date of Entry into Force: 09.02.17

REGULATION No. 9-07
UNIFORM PROVISIONS CONCERNING THE APPROVAL
OF CATEGORY L , L AND L VEHICLES WITH REGARD TO NOISE
CONTENTS
REGULATION
1. Scope
2. Definitions
3. Application for approval
4. Markings
5. Approval
6. Specifications
7. Modification and extension of approval of a vehicle type or a type of exhaust or silencing system(s)
8. Conformity of production
9. Penalties for non-conformity of production
10. Production definitively discontinued
11. Transitional provisions
12. Name and addresses of Technical Services responsible for conducting approval tests, and of Type
Approval Authorities
ANNEXES
Annex 1 : Communication
Annex 2 : Arrangements of approval marks
Annex 3 : Methods and instruments for measuring the noise made by motor vehicles
Annex 4 : Specifications for the test site

2.4. Exhaust or Silencing Systems of Different Types means exhaust or silencing systems
which differ in such essential respects as:
2.4.1. that their components bear different trade names or marks;
2.4.2. that the characteristics of the materials constituting a component are different or that the
components differ in shape or size;
2.4.3. that the operating principles of at least one component are different;
2.4.4. that their components are assembled differently.
2.5. Exhaust or Silencing System Component means one of the individual constituent parts
whose assembly constitutes the exhaust or silencing system.
2.6. Kerb mass (as defined in Section 4.1.2 of ISO 6726: 1988) means the mass of the vehicle
ready for normal operation and fitted with the following equipment:
(a)
(b)
(c)
(d)
Full electrical equipment including the lighting and signalling devices supplied by the
manufacturer;
All instruments and fittings required by any legislation in respect of which a
measurement of the vehicle dry mass is being made;
Full complement of liquids to ensure the correct functioning of every part of the vehicle
and the fuel tank filled at least to 90% of the capacity specified by the manufacturer;
Auxiliary equipment usually supplied by the manufacturer in addition to that necessary
for normal operation (tool-kit, carrier(s), windscreen(s), protective equipment, etc.)
Notes:
1. In the case of a vehicle which operates on a fuel/oil mixture:
1.1. Where the fuel and oil are premixed, the word "fuel" is interpreted as including such a
pre-mixture of fuel and oil;
1.2. Where the fuel and oil are separately measured, the word "fuel" is interpreted as
including only the petrol. The "oil", in this case, is already included in subparagraph (c)
of this paragraph.
2.7. Maximum Speed means the maximum vehicle speed as defined in ISO 7117:1995.

5. APPROVAL
5.1. If the vehicle type submitted for approval pursuant to this Regulation meets the requirements
of Paragraphs 6. and 7. below, approval of that vehicle type shall be granted.
5.2. An approval number shall be assigned to each type approved. Its first two digits (at present
07 corresponding to the 07 series of amendments, which entered into force on
November 3, 2013) shall indicate the series of amendments incorporating the most recent
major technical amendments made to the Regulation at the time of issue of the approval. The
same Contracting Party shall not assign the same number to the same vehicle type equipped
with another type of exhaust or silencing system or to another vehicle type.
5.3. Notice of approval or of extension or refusal of approval of a vehicle type pursuant to this
Regulation shall be communicated to the Parties to the Agreement which apply this
Regulation by means of a form conforming to the model in Annex 1 to this Regulation and of
drawings of the exhaust or silencing system (supplied by the applicant for approval) in a
format not exceeding A4 (210 × 297mm), or folded to that format, and on an appropriate
scale.
5.4. There shall be affixed, conspicuously and in a readily accessible place specified on the
approval form, to every vehicle conforming to a vehicle type approved under this Regulation
an international approval mark consisting of:
5.4.1. a circle surrounding the Letter "E" followed by the distinguishing number of the country which
has granted approval ; and
5.4.2. the number of this Regulation, followed by the Letter "R", a dash and the approval number, to
the right of the circle prescribed in Paragraph 5.4.1 above.
5.5. If the vehicle conforms to a vehicle type approved, under one or more other Regulations
annexed to the 1958 Agreement, in the country which has granted approval under this
Regulation, the symbol prescribed in Paragraph 5.4.1 above need not be repeated; in such a
case the additional numbers and 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. above
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.
5.8. Annex 2 to this Regulation gives examples of arrangements of approval marks.

6.3.2. Exhaust or silencing systems with multiple, manually adjustable operating modes shall meet
all requirements in all operating modes. The reported noise levels shall be those resulting
from the mode with the highest noise levels.
6.3.3. The vehicle manufacturer shall not intentionally alter, adjust or introduce any device or
procedure solely for the purpose of fulfilling the noise emission requirements of this
Regulation, which will not be operational during typical on-road operation.
7. MODIFICATION AND EXTENSION OF APPROVAL OF A VEHICLE TYPE OR A TYPE OF
EXHAUST OR SILENCING SYSTEM(S)
7.1. Every modification of the vehicle type or of the exhaust or silencing system shall be notified to
the Type Approval Authority which approved the vehicle type. The said Authority may then
either:
7.1.1. consider that the modifications made are unlikely to have an appreciable adverse effect; or
7.1.2. require a further test report from the technical testing service.
7.2. Confirmation or refusal of approval, specifying the alterations, shall be communicated to the
Parties to the Agreement applying this Regulation in accordance with the procedure specified
in Paragraph 5.3 above.
7.3. The Type Approval Authority issuing the extension of approval shall assign a series number
for such an extension and inform thereof the other Contracting Parties to the 1958 Agreement
applying this Regulation by means of a communication form conforming to the model in
Annex 1 to this Regulation.
8. CONFORMITY OF PRODUCTION
The conformity of production procedures shall comply with those set out in the Agreement,
Appendix 2 (E/ECE/324-E/ECE/TRANS/505/Rev.2), with the following requirements:
8.1. Every vehicle bearing an approval mark as prescribed under this Regulation shall conform to
the vehicle type approved, be fitted with the exhaust or silencing system with which it was
approved and satisfy the requirements of Paragraph 6 above.
8.2. In order to verify conformity as prescribed in Paragraph 8.1 above, a vehicle, bearing the
approval mark required by this Regulation, shall be taken from the series. Production shall be
deemed to conform to the requirements of this Regulation if the levels measured using the
method described in Annex 3 do not exceed by more than 3dB(A) the value measured on
acceptance, nor by more than 1d(B)A the limits prescribed in Paragraph 6.2.1.3. above.
9. PENALTIES FOR NON-CONFORMITY OF PRODUCTION
9.1. The approval granted in respect of a vehicle type pursuant to this Regulation may be
withdrawn if the requirements laid down in Paragraph 8 above are not complied with, or if the
vehicle fails to pass the tests provided for in Paragraph 8.2 above.
9.2. If a Party to the Agreement which applies this Regulation withdraws an approval it has
previously granted, it shall forthwith so notify the other Contracting Parties applying this
Regulation by means of a communication form conforming to the model in Annex 1 to this
Regulation.

12. NAMES AND ADDRESSES OF TECHNICAL SERVICES RESPONSIBLE FOR
CONDUCTING APPROVAL TESTS, AND OF TYPE APPROVAL AUTHORITIES
The Parties to the Agreement which apply 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 of withdrawal of approval or production
definitively discontinued, issued in other countries, are to be sent.

10. Number of gears ...........................................................................................................................
11. Gears used ...................................................................................................................................
12. Final drive ratio(s) .........................................................................................................................
13. Type and dimensions of tyres (by axle) ........................................................................................
14. Maximum permissible weight including semi-trailer (where applicable) .......................................
15. Brief description of the original exhaust system: ..........................................................................
......................................................................................................................................................
15.1. Type(s) of original exhaust system(s): .........................................................................................
15.2. Type(s) of intake system(s) (if necessary in order to observe the noise level limit): ....................
16. Load conditions of vehicles during test ........................................................................................
17. For stationary vehicle test: location and orientation of the microphone (by reference to
diagrams in Annex 3 to this Regulation - Appendix) ....................................................................
18. Sound levels:
Vehicle in motion ....................................................................................... dB(A) at steady speed
before acceleration of ......................................................................................................... (km/h)
Vehicle stationary ................................................................................ dB(A) with engine running
at ........................................................................................................................................ (min ).
19. Vehicle submitted for approval on ................................................................................................
20. Technical service responsible for conducting approval tests .......................................................
21. Date of report issued by that service ............................................................................................
22. Number of report issued by that service .......................................................................................
23. Approval granted/extended/refused/withdrawn
24. Position of approval mark on the vehicle ......................................................................................
25. Place .............................................................................................................................................
26. Date ..............................................................................................................................................
27. Signature ......................................................................................................................................

ANNEX 2
ARRANGEMENTS OF APPROVAL MARKS
MODEL A
(See Paragraph 5.4 of this Regulation)
a = 8mm min.
The above approval mark affixed to a vehicle shows that the vehicle type concerned has, with regard to
its noise emission, been approved in the Netherlands (E 4) pursuant to Regulation No. 9 under Approval
No. 072439. The approval number indicates that the approval was granted according to the requirements
of Regulation No. 9 as amended by the 07 series of amendments.
MODEL B
(See Paragraph 5.5 of this Regulation)
a = 8mm min.
The above approval mark affixed to a vehicle shows that the vehicle type concerned has been approved
in the Netherlands (E 4) pursuant to Regulations Nos. 9 and 33. The approval numbers indicate that, at
the date when the respective approvals were given, Regulation No. 9 included the 07 series of
amendments and Regulation No. 33 was still in its original form.

1.5. Meteorological Instrumentation
The meteorological instrumentation used to monitor the environmental conditions during the
test shall meet the following specifications:
±1°C or less for a temperature measuring device;
±1.0m/s for a wind speed measuring device;
±5hPa for a barometric pressure measuring device;
±5% for a relative humidity measuring device.
2. CONDITIONS OF MEASUREMENT
2.1. Condition of the Vehicle
2.1.1. General Conditions
The vehicle shall be supplied as specified by the vehicle manufacturer.
Before the measurements are started, the vehicle shall be brought to its normal operating
conditions.
If the vehicle is fitted with fans with an automatic actuating mechanism, this system shall not
be interfered with during the sound measurements. For vehicles having more than one driven
wheel, only the drive provided for normal road operation may be used. If the vehicle is fitted
with a trailer or a semi-trailer, this shall be removed for the purposes of the test.
The tests shall not be carried out if the wind speed, including gusts, exceeds 5m/s during the
sound-measurement interval.
2.1.2. Test Mass of the Vehicle
Measurements shall be made on vehicles at the following test mass mt, in kg, specified as:
mt = mkerb ± 75 ± 5kg
where:
75 ± 5kg equates to mass of the driver and instrumentation
mkerb = kerb mass
2.1.3. Tyre Selection and Condition
The tyres shall be appropriate for the vehicle and shall be inflated to the pressure
recommended by the vehicle manufacturer for the test mass of the vehicle.
The tyres shall be selected by the vehicle manufacturer, and correspond to one of the tyre
sizes and types designated for the vehicle by the vehicle manufacturer. The minimum tread
depth shall be at least 80% of the full tread depth.

3. METHODS OF MEASUREMENT
3.1. Measurement of Noise of Vehicles in Motion
3.1.1. Positions for the Test
3.1.1.1. The maximum weighted sound-level (A), expressed in decibels (dB), shall be measured as
the vehicle is driven between Lines AA' and BB' (Figure 1). The measurement shall be invalid
if an abnormal discrepancy between the peak value and the general sound-level is recorded.
At least two measurements shall be made on each side of the vehicle.
Preliminary measurements may be made for adjustment purposes, but shall be disregarded.
3.1.1.2. The distance of the microphone positions from the Line CC', on the microphone Line PP',
perpendicular to the reference Line CC' on the test track (Figure 1 of Appendix to this annex),
shall be 7.5m ± 0.05m.
The microphones shall be located 1.2m ± 0.02m above the ground level. The reference
direction for free-field conditions (see IEC 61672-1:2002) shall be horizontal and directed
perpendicularly towards the path of the vehicle Line CC'.
3.1.1.3. Two Lines, AA' and BB', parallel to Line PP' and situated respectively 10m forward and 10m
rearward of that line shall be marked out on the test runway. The vehicle shall approach
Line AA' at a steady speed as specified below. The throttle shall then be fully opened as
rapidly as practicable and held in the fully-opened position until the rear of the vehicle crosses
Line BB'; the throttle shall then be closed again as rapidly as possible.
3.1.1.4. 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.
3.1.1.5. The values, rounded off to the nearest whole decibel, shall be taken from the measuring
apparatus. If the figure following the decimal point is between 0 and 4, the total is rounded
down and if between 5 and 9, it is rounded up.
Only values which are obtained from two consecutive measurements on the same side of the
vehicle, and do not differ by more than 2dB(A), shall be accepted.
The result of the measurement shall be determined in accordance with Paragraph 4 of this
annex.
3.1.2. Determination of the Steady Speed
3.1.2.1. Vehicle with no Gearbox
The vehicle shall approach Line AA' at a steady speed corresponding either, in terms of
engine speed (min ), to three-quarters of the engine speed at which the engine develops its
maximum power, or to three-quarters of the maximum engine speed permitted by the
governor, or to 50km/h, whichever is the lowest.

3.2.3.2. Test Site
Any area not subject to major acoustic perturbations may be used as a test site. Level areas
covered with concrete, asphalt or some other hard material and are highly reflective are
suitable; surfaces consisting of earth which has been tamped down shall not be used. The
test site shall have at least the dimensions of a rectangle the sides of which shall be 3m from
the outline of the vehicle (excluding handlebars). No significant obstacle such as a person
other than the observer and the driver shall be within this rectangle.
The vehicle shall be placed within the above-mentioned rectangle in such a way that the
measuring microphone is at least one metre away from any stone edging.
3.2.3.3. Miscellaneous
Instrument readings caused by ambient or wind noise shall be at least 10dB(A) less than the
noise level to be measured. The microphone may be fitted with a suitable wind-guard
provided that its effect on microphone sensitivity is taken into account.
3.2.4. Method of Measurement
3.2.4.1. Number of Measurements
At least three measurements shall be made at each measurement point. The measurements
shall be considered valid only if the difference between the results of three consecutive
measurements is not more than 2dB(A).
3.2.4.2. Position of the Microphone (see Figure 2 of Appendix to this Annex)
The microphone shall be located at a distance of 0.5m ± 0.01m from the reference point of
the exhaust pipe defined in Figure 4 of Appendix to this Annex and at an angle of 45° ± 5° 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.
The reference point shall be the highest point satisfying the following conditions:
(a)
(b)
The reference point shall be at the end of the exhaust pipe,
The reference point shall be on the vertical plane containing the exhaust outlet centre
and the flow axis of the exhaust pipe termination.
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 90° ± 5° to the vehicle longitudinal centreline,
the microphone shall be located at the point that is the furthest from the engine.
If a vehicle has two or more exhaust outlets spaced less than 0.3m apart and connected to a
single silencer, only one measurement shall be made. The microphone shall be located
relative to the outlet the farthest from the vehicle's longitudinal centreline, or, when such outlet
does not exist, to the outlet that is highest above the ground.

4. INTERPRETATION OF RESULTS FOR VEHICLES IN MOTION
The values taken shall be rounded off to the nearest whole decibel. If the figure following the
decimal point is between 0 and 4, the total is rounded down and if between 5 and 9, it is
rounded up.
Only the values of readings obtained from two consecutive measurements made on the same
side of the vehicle and not differing by more than 2dB(A) shall be accepted.
To allow for lack of precision in the readings, the result of each measurement shall be taken
as equal to the value obtained, less 1dB(A).
If the average of the four readings does not exceed the maximum permissible level for the
category to which the tested vehicle belongs, the limit specified in Paragraph 6.2.1.3 of this
Regulation shall be deemed as being complied with. This average value shall constitute the
test result.
5. ORIGINAL EXHAUST (SILENCING) SYSTEM
5.1. Requirements for silencers containing absorbent fibrous materials.
5.1.1. Fibrous absorbent material shall be asbestos-free and may be used in the construction of
silencers only if suitable devices ensure that the fibrous absorbent material is kept in place for
the whole time that the silencer is being used and the exhaust or silencing system meets the
requirements of any one of Paragraphs 5.1.2., 5.1.3. 5.1.4. or 5.1.5. below.
5.1.2. After removal of the fibrous material, the sound-level shall conform to the requirements of
Paragraph 6.2.1.3. of this Regulation.
5.1.3. The fibrous absorbent material may not be placed in those parts of the silencer through which
the exhaust gases pass and shall conform to the following requirements:
5.1.3.1. The material shall be heated at a temperature of 650°C ± 5°C for 4h in a furnace without
reduction in the average length, diameter or bulk density of the fibre;
5.1.3.2. After heating at 650°C ± 5°C for 1h in a furnace, at least 98% of the material shall be retained
in a sieve of nominal aperture size 250μm conforming to ISO Standard 3310/1:1999 when
tested in accordance with ISO Standard 2559:2000.
5.1.3.3. The loss in weight of the material shall not exceed 10.5% after soaking for 24h at 90°C ± 5°C
in a synthetic condensate of the following composition:
1N hydrobromic acid (HBr)
1N sulphuric acid (H SO )
10ml
10ml
Distilled water to make up to 1,000ml
Note: The material must be washed in distilled water and dried for 1h at 105°C before
weighing.

5.1.4.2.7. Any drainage holes shall be closed off during the test.
5.1.4.2.8. The entire test shall be completed within 48h. If necessary, a cooling period shall be allowed
after each hour.
5.1.4.3. Conditioning on a test bench
5.1.4.3.1. The exhaust system shall be fitted to an engine representative of the type fitted to the vehicle
for which the system is designed, and mounted on a test bench.
5.1.4.3.2. Conditioning shall consist of the specified number of test-bench cycles for the category of
vehicle for which the exhaust system was designed. The number of cycles for each vehicle
category shall be:
Category of vehicle according to
cylinder capacity in cm
Number of
cycles
1.
≤250
2.
>250
3.
>500
≤500
6
9
12
5.1.4.3.3. Each test-bench cycle shall be followed by a break of at least 6h in order to reproduce the
effects of cooling and condensation.
5.1.4.3.4. Each test-bench cycle shall consist of six phases. The engine conditions for, and the duration
of, each phase shall be:
Phase Conditions Duration of phase
Engines of less
than 250cm
Engines of 250cm
or more
1
2
3
4
5
6
Idling
25% load at 75% of S
50% load at 75% of S
100% load at 75% of S
50% load at 100% of S
25% load at 100% of S
(min.)
6
40
40
30
12
22
(min.)
6
50
50
10
12
22
Total time 2h 30mins 2h 30mins
5.1.4.3.5. During this conditioning procedure, at the request of the manufacturer, the engine and the
silencer may be cooled in order that the temperature recorded at a point not more than
100mm from the exhaust gas outlet does not exceed that measured when the vehicle is
running at 110km/h or 75% of S in top gear. The engine and/or vehicle speeds shall be
determined to within ±3%.
5.1.5. Exhaust gases are not in contact with fibrous materials and fibrous materials are not under
the influence of pressure variations.

ANNEX 3 - APPENDIX
Figure 1
Positions for Testing the Vehicle in Motion

Figure 3
Test Apparatus for Conditioning by Pulsation
1. Inlet flange or sleeve for connection to the rear of the test exhaust system.
2. Hand-operated regulating valve.
3. Compensating reservoir with a maximum capacity of 40 1 and a filling time of not less than 1s.
4. Pressure switch with an operating range of 5kPa to 250kPa.
5. Time delay switch.
6. Pulse counter.
7. Quick-acting valve, such as exhaust brake valve 60mm in diameter, operated by a pneumatic
cylinder with an output of 120N at 400kPa. The response time, both opening and closing, shall not
exceed 0.5s.
8. Exhaust gas evacuation.
9. Flexible pipe.
10. Pressure gauge.

ANNEX 4
SPECIFICATIONS FOR THE TEST SITE
1. INTRODUCTION
This Annex describes the specifications relating to the physical characteristics and the laying of
the test track. These specifications based on a special standard describe the required
physical characteristics as well as the test methods for these characteristics.
2. REQUIRED CHARACTERISTICS OF THE SURFACE
A surface is considered to conform to this Standard provided that the texture and voids content
or sound absorption coefficient have been measured and found to fulfil all the requirements of
Paragraphs 2.1. to 2.4. below and provided that the design requirements (Paragraph 3.2.
below) have been met.
2.1. Residual Voids Content
The residual voids content, V , of the test track paving mixture shall not exceed 8%. For the
measurement procedure, see Paragraph 4.1. below.
2.2. Sound Absorption Coefficient
If the surface fails to conform to the residual voids content requirement, the surface is
acceptable only if its sound absorption coefficient, α ≤ 0.10. For the measurement procedure,
see Paragraph 4.2. below. The requirements of Paragraphs 2.1. above and this Paragraph are
met also if only sound absorption has been measured and found to be α ≤ 0.10.
Note: The most relevant characteristic is the sound absorption, although the residual voids
content is more familiar among road constructors. However, sound absorption needs to be
measured only if the surface fails to comply with the voids requirement. This is because the
latter is connected with relatively large uncertainties in terms of both measurements and
relevance and some surfaces therefore may be rejected erroneously on the basis of the voids
measurement only.
2.3. Texture Depth
The texture depth (TD) measured according to the volumetric method (see Paragraph 4.3.
below) shall be:
TD ≥ 0.4mm

3. TEST SURFACE DESIGN
3.1. Area
When designing the test track layout it is important to ensure that, as a minimum requirement,
the area traversed by the vehicles running through the test strip is covered with the specified
test material with suitable margins for safe and practical driving. This will require the width of
the track to be at least 3m and the length of the track to extend beyond Lines AA and BB by at
least 10m at either end. Figure 1 shows a plan of a suitable test site and indicates the minimum
area which shall be machine laid and machine compacted with the specified test surface
material. According to Annex 3, Paragraph 3.1.1.1., measurements have to be made on each
side of the vehicle. This can be done either by measuring with two microphone locations (one
on each side of the track) and driving in one direction, or measuring with a microphone only on
one side of the track but driving the vehicle in two directions. If the former method is used, then
there are no surface requirements on that side of the track where there is no microphone.
Figure 1
Minimum Requirement for Test Surface Area.
The Shaded Part is called "Test Area".

Figure 2
Grading Curve of the Aggregate in the
Asphaltic Mix with Tolerances
In addition to the above, the following recommendations are given:
(a) The sand fraction (0.063mm < square mesh sieve size < 2mm) shall include no more than 55%
natural sand and at least 45% crushed sand;
(b)
(c)
(d)
(e)
(f)
The base and sub-base shall ensure a good stability and evenness, according to best road
construction practice;
The chippings shall be crushed (100% crushed faces) and of a material with a high resistance
to crushing;
The chippings used in the mix shall be washed;
No extra chippings shall be added onto the surface;
The binder hardness expressed as PEN value shall be 40-60, 60-80 or even 80-100 depending
on the climatic conditions of the country. The rule is that as hard a binder as possible shall be
used, provided this is consistent with common practice;

4.2. Sound Absorption Coefficient
The sound absorption coefficient (normal incidence) shall be measured by the impedance tube
method using the procedure specified in ISO/DIS 10 534: "Acoustics - Determination of sound
absorption coefficient and impedance by a tube method".
Regarding test specimens, the same requirements shall be followed as regarding the residual
voids content (see Paragraph 4.1. above).
The sound absorption shall be measured in the range between 400Hz and 800Hz and in the
range between 800Hz and 1,600Hz (at least at the centre frequencies of third octave bands)
and the maximum values shall be identified for both of these frequency ranges.
Then these values, for all test cores, shall be averaged to constitute the final result.
4.3. Volumetric Macrotexture Measurement
For the purpose of this standard, texture depth measurements shall be made on at least
10 positions evenly spaced along the wheel tracks of the test strip and the average value taken
to compare with the specified minimum texture depth. For the description of the procedure see
Standard ISO 10844:1994.
5. STABILITY IN TIME AND MAINTENANCE
5.1. Age Influence
In common with any other surfaces, it is expected that the tyre/road noise level measured on
the test surface may increase slightly during the first 6-12 months after construction.
The surface will achieve its required characteristics not earlier than four weeks after
construction.
The stability over time is determined mainly by the polishing and compaction by vehicles driving
on the surface. It shall be periodically checked as stated in Paragraph 2.5. above.
5.2. Maintenance of the Surface
Loose debris or dust which could significantly reduce the effective texture depth shall be
removed from the surface. In countries with winter climates, salt is sometimes used for
de-icing. Salt may alter the surface temporarily or even permanently in such a way as to
increase noise, and is therefore not recommended.
5.3. Repaving the Test Area
If it is necessary to repave the test track, it is usually unnecessary to repave more than the test
strip (of 3m width in Figure 1) where vehicles are driving, provided the test area outside the
strip met the requirement of residual voids content or sound absorption when it was measured.

Noise - Three-wheel Vehicles.