24. 7. 91 Official Journal of the European Communities No C 193/3 
II 
(Preparatory Acts) 
COMMISSION 
Proposal for a Council Directive amending Directive 70/157/EEC on the approximation of the 
laws of the Member States relating to the permissible sound level and the exhaust system of 
motor vehicles 
(91/C 193/03) 
COM(91) 51 final — SYN 337 
(Submitted by the Commission on 28 June 1991) 
from the Commission was based on studies and research 
concerning possible further legislative measures taking 
account simultaneously of all the main aspects of 
Community rules in the motor-vehicle sector, in 
particular those relating to safety, environmental 
protection and energy conservation; 
Whereas the protection of the public against noise 
pollution requires additional suitable measures to reduce 
still further the sound level of motor vehicles; whereas 
such measures must take account of the technological 
advances to be applied; whereas enough time must 
consequently be allowed for their implementation after 
adoption of this Directive so that the technological 
advances, at present at the prototype stage, can be 
applied to series production; whereas the limit values 
currently applicable to heavy goods vehicles took effect 
on 1 October 1989; 
Whereas achievement of a significant and effective 
reduction of such nuisances will require that the 
differences between the measuring techniques in current 
use and the actual traffic conditions be reduced to the 
maximum extent possible; whereas certain types of tech­
nology cannot yet be verified and are not yet comparable 
with those used hitherto in the type-approval procedures 
for motor vehicles; 
Whereas the current measuring conditions, and in 
particular the definition of the surface of the test track 
and certain ambient conditions during the tests, such as 
temperature, atmospheric pressure, humidity, wind speed 
and background noise require more detailed description; 
whereas those closer details will be provided as soon as 
possible by means of the procedure referred to in Article 
13 of Council Directive 70/156/EEC (5), as last 
amended by Directive 87/403/EEC (6); 
(») OJ No L 42, 23. 2. 1970, p. 1. 
(*) OJ No L 220, 8. 8. 1987, p. 44. THE COUNCIL OF THE EUROPEAN COMMUNITIES, 
Having regard to the Treaty establishing the European 
Economic Community, and in particular Article 100a 
thereof, 
Having regard to the proposal from the Commission, 
In cooperation with the European Parliament, 
Having regard to the opinion of the Economic and 
Social Committee, 
Whereas it is essential to adopt measures for gradual 
completion of the internal market by 31 December 1992; 
whereas that market will cover a region without internal 
frontiers where the free movement of persons, goods, 
services and capital will be ensured; 
Whereas Council Directive 70/157/EEC ('), as last 
amended by Directive 89/491/EEC (2), lays down limit 
values for the sound level of motor vehicles; whereas 
these limit values were reduced for the first time by 
Council Directive 77/212/EEC (3) and for the second 
time by Council Directive 84/424/EEC (4); whereas 
these reductions were particularly severe in the case of 
motor buses, motor coaches and lorries, amounting to 
approximately 10 dB (A); 
Whereas the Council, in adopting Directive 84/424/EEC 
amending Directive 70/157/EEC, had decided that the 
provisions of the Directive would later be reviewed on a 
proposal from the Commission; whereas the proposal 
(') OJ No L 42, 23. 2. 1970, p. 16. 
(2) OJ No L 238, 15. 8. 1989, p. 43. 
(3) OJ No L 66, 12. 3. 1977, p. 33. 
(4) OJ No L 238, 6. 9. 1984, p. 31. 
No C 193/4 Official Journal of the European Communities 24. 7. 91 
Whereas, of the noise pollution emanating from vehicles, 
that caused by the tyres has proved to be particularly 
severe when the vehicles' speed exceeds 60 km/h; 
whereas protecting the public effectively against noise 
pollution, particularly that caused by traffic in urban 
areas, requires that two further stages be completed; 
whereas the first stage, covered by this Directive, consists 
in giving as much additional weight as possible to the 
current requirements for each category of vehicle 
without considering the noise created by the contact 
between tyres and the road surface, since the appropriate 
criteria for evaluating that type of noise are still very 
poorly understood; whereas the second stage — in the 
light of more detailed studies and research to be carried 
out on the problems associated with and the technical 
solutions for noise created by the contact between tyres 
and the ground — will result in the establishment of 
more realistic and reproducible criteria and methods for 
determining this important type of noise pollution and 
for laying down the relevant requirements to be 
complied with; 
Whereas completion of the first stage requires that 
Annex I to Directive 70/157/EEC be amended by 
reducing the sound-level values expressed in decibels (dB 
(A)) for each category of vehicle referred to in the said 
Annex and by improving the test method for high-
powered vehicles; whereas this type of vehicle is 
increasingly being designed so as to produce a higher 
ratio between engine power and vehicle mass and the 
curve representing the torque as a function of engine 
speed has been modified to produce greater motive force 
at low engine speed; whereas these new designs conse­
quently give rise to greater use of gear ratios in urban 
traffic and have a major influence on the noise emitted 
by the mechanical parts as compared with road noise; 
whereas account has been taken of these new designs by 
modifying the measuring technique for this type of 
vehicle, due allowance having been made for the speed 
of approach to the acceleration section where the sound 
level is to be measured; 
Whereas, in view of the many different types of tyre and 
road surface already existing, it is not yet possible to 
control the sound emissions produced by the interaction 
between tyres and roadway; whereas it is consequently 
necessary to perform studies and research so as to be 
able to establish criteria to be met by tyres and define a 
specific numerical value for the type-approval of motor 
vehicles; whereas the results of such studies and research 
will enable introduction of further requirements in 
addition to measures covering noise of mechanical 
source, at a second stage; 
Whereas Member States should be allowed to advance 
the authorization for introduction of vehicles which 
satisfy the Community standards, by means of tax incentives; whereas this implies that the Council should, 
by 1 October 1995, adopt the requirements for the 
second stage, for which the Commission will present a 
proposal before 31 March 1994; 
Whereas to enable the European environment to obtain 
maximum benefit from these provisions and simulta­
neously to ensure the unity of the market, it is necessary 
to lay down stricter European standards based on total 
harmonization, 
HAS ADOPTED THIS DIRECTIVE: 
Article 1 
The Annexes to Directive 70/157/EEC are hereby 
replaced by the Annexes to this Directive. 
Article 2 
1. With effect from 1 January 1993, Member States 
may not, on grounds relating to the permissible sound 
level and the exhaust systems: 
— refuse, in respect of a type of motor vehicle, to grant 
EEC type-approval, to issue the document referred to 
in the last indent of Article 10 (1) of Directive 
70/156/EEC, or to grant national type-approval, or 
— prohibit the entry into service of vehicles, 
if the sound level and the exhaust system of this type of 
vehicle or of these vehicles comply with the provisions of 
Directive 70/157/EEC as amended by this Directive. 
2. With effect from 1 October 1994, Member States: 
— may no longer grant EEC type-approval or issue the 
document referred to in the last indent of Article 
10 (1) of Directive 70/156/EEC in respect of a type 
of motor vehicle, 
— must refuse to grant national type-approval in respect 
of a type of motor vehicle, 
of which the sound level and the exhaust system do not 
comply with the requirements set out in the Annexes to 
Directive 70/157/EEC as amended by this Directive. 
24. 7. 91 Official Journal of the European Communities No C 193/5 
3. With effect from 1 October 1995, Member States 
shall prohibit the initial entry into service of vehicles of 
which the sound level and the exhaust systems do not 
comply with the requirements set out in the Annexes to 
Directive 70/157/EEC as amended by this Directive. 
Article 3 
Member States may make provision for tax incentives in 
respect of the vehicles covered by this Directive. Such 
incentives must comply with the provisions of the Treaty 
and, in addition, must meet the following conditions: 
— they must apply to all nationally-manufactured motor 
vehicles and all imported vehicles offered for sale on 
the market of a Member State and equipped with 
systems which make for early compliance with the 
requirements of this Directive that would have to be 
met in 1994, 
— they shall be terminated with effect from the 
mandatory application of the sound level values laid 
down in Article 2 (3) for new vehicles, 
— in respect of each type of vehicle, they must represent 
an amount substantially below the actual cost of the 
systems introduced to ensure compliance with the 
established values and of their installation on the 
vehicle. 
To enable the Commission to put forward its comments, 
it must be informed in good time of plans to institute or 
change tax incentives such as those referred to in the 
first paragraph of this Article. Article 4 
1. Specific details on the measuring conditions, 
including a definition of the surface of the test track, 
shall be supplied as soon as possible via the procedure 
referred to in Article 13 of Directive 70/156/EEC. 
2. Subsequent measures intended, in particular, to 
limit the noise arising from contact between tyres and 
the road surface shall be decided upon before 1 October 
1995 the Council, acting by a qualified majority on the 
basis of a proposal from the Commission, which shall 
take account of the studies and research to be performed 
on this source of noise, and will be presented before 31 
March 1994. 
Article 5 
Member States shall bring into force the laws, regu­
lations and administrative provisions necessary to comply 
with this Directive not later than 1 October 1992. They 
shall forthwith inform the Commission thereof. 
When Member States adopt these provisions, these shall 
contain a reference to this Directive or shall be accom­
panied by such reference at the time of their official 
publication. The procedure for such reference shall be 
adopted by Member States. 
Article 6 
This Directive is addressed to the Member States. 
No C 193/6 Official Journal of the European Communities 24. 7. 91 
ANNEX I 
EEC TYPE-APPROVAL IN RESPECT OF THE SOUND LEVEL OF A TYPE OF MOTOR VEHICLE 
1. DEFINITIONS 
For the purposes of this Directive: 
1.1. Type of vehicle 
means vehicles which do not differ essentially as regards the following parts: 
1.1.1. the shape or materials of the bodywork (particularly the engine compartment and its soundproofing); 
1.1.2. the length and width of the vehicle; 
1.1.3. 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 systems, arrangement of valves, rated 
maximum power and corresponding engine speed(s)); 
1.1.4. the transmission system, the gear ratio in which the test is performed and the relevant overall ratio(s); 
1.1.5. the number, type and arrangement of the exhaust systems; 
1.1.6. the number, type and arrangement of the intake systems. 
1.1.7. Notwithstanding the provisions of items 1.1.2 and 1.1.4, vehicles other than those in categories M, and Nj (') 
having the same type of engine and/or different overall gear ratios, may be regarded as vehicles of the same type. 
However, if the above differences provide for a different test method, these differences are to be considered as a 
change of type. 
1.2. Exhaust and intake systems 
1.2.1. Exhaust systems 
means a complete set of parts necessary to reduce the noise produced by the vehicle's engine exhaust. 
1.2.2. Intake systems 
means a complete set of parts necessary to reduce the noise produced by the vehicle's engine intake. 
1.2.3. For the purposes of this Directive, these systems do not include the manifolds. 
1.3. Different types of exhaust or intake system 
means systems characterized by fundamental differences, such as the following: 
1.3.1. systems bearing different trade marks or trade names; 
1.3.2. systems in which the characteristics of the materials of a component differ, or in which the components are of 
different shape or size; a change in the plating procedure (galvanization, aluminium coating, etc.) is not deemed 
to produce a difference of type; 
(') In accordance with the definition given in item 0.4 of Annex I to Directive 70/156/EEC. 
24.7.91 Official Journal of the European Communities No C 193/7 
1.3.3. systems in which the operating principles of at least one component differ; 
1.3.4. systems in which the components are combined differently. 
1.4. Component of an exhaust or an intake system 
means one of the separate components which together form the exhaust system (e.g. exhaust pipes, the silencer 
proper) or the intake system (e.g. air filter). 
1.5. Overall gear ratio 
means the number of turns made by the engine per each turn of the driving wheels. 
2. APPLICATION FOR EEC TYPE-APPROVAL 
2.1. The application for EEC type-approval in respect of the sound level of a type of motor vehicle must be submitted 
by the manufacturer of the vehicle or his authorized representative. 
2.2. It must be accompanied by the undermentioned documents in triplicate and the following information: 
2.2.1. a description of the type of vehicle with reference to the points mentioned in item 1.1. The numbers and/or 
symbols identifying the engine type and vehicle type must be indicated; 
2.2.2. a list, with appropriate identification, of the component parts of the exhaust and intake systems; 
2.2.3. a drawing of the entire exhaust system with an indication of its position on the vehicle; 
2.2.4. a detailed drawing of each component so that it can be easily located and identified, and an indication of the 
materials used. 
2.3. A vehicle representative of the type in respect of which type-approval is sought must be submitted to the technical 
service responsible for the tests by the vehicle manufacturer or his authorized representative. 
2.3.1. In the case of item 1.1.7 the single vehicle, representative of the type in question , will be selected by the technical 
service conducting approval tests, in accordance with the vehicle manufacturer, as that with the lowest mass in 
running order with the shortest length and following the specification laid down in item 5.2.2.4.3.3.1.2. 
2.4. At the request of the technical service, a specimen of the exhaust system and an engine of at least the same 
cylinder capacity and rated maximum power as that fitted to the vehicle in respect of which type-approval is 
sought must also be submitted. 
2.5. The competent authority shall verify the existence of satisfactory arrangements for ensuring effective control of 
the conformity of production before type approval is granted. 
3. MARKINGS 
3.1. The exhaust and intake system components, excluding fixing hardware and pipes, must bear: 
3.1.1. the trade mark or name of the manufacturer of the systems and their components; 
3.1.2. the manufacturer's trade description. 
3.2. These markings must be clearly legible and indelible. 
No C 193/8 Official Journal of the European Communities 24. 7. 91 
4. 
4.1. EEC TYPE-APPROVAL 
If an application within the meaning of item 2.1 is approved, the competent authority will draw up a certificate, 
corresponding to the type which appears in Annex III, to be attached to the EEC vehicle type-approval certificate. 
5. 
5.1. 
5.1.1. 
5.1.2. 
5.2. 
5.2.1. 
5.2.1.1. 
5.2.1.2. 
5.2.2. 
5.2.2.1. 
5.2.2.1.1. 
5.2.2.1.2. 
5.2.2.1.2.1. 
5.2.2.1.2.2. 
5.2.2.1.3. 
5.2.2.1.3.1. 
5.2.2.1.3.2. 
5.2.2.1.4. 
5.2.2.1.4.1. 
5.2.2.1.4.2. 
5.2.2.1.4.3. SPECIFICATIONS 
General specifications 
The vehicle, its engine and exhaust and intake systems must be designed, constructed and mounted such that, 
under normal conditions of use and notwithstanding the vibrations to which they may be subject, the vehicle 
satisfies the requirements of this Directive. 
The systems must be designed, constructed and mounted so that reasonable resistance to the corrosion phenomena 
to which they are exposed is obtained having regard to the conditions of use of the vehicle. 
Specifications relating to sound levels 
Method of measurement 
The sound emitted by the type of vehicle submitted for EEC type-approval must be measured in accordance with 
each of the two methods described in item 5.2.2.4 in the case of moving vehicles and item 5.2.3.4 in the case of 
stationary vehicles, respectively ('). 
Vehicles having a maximum permissible mass exceeding 2 800 kg must be subjected to an additional measurement 
of the compressed air noise with the vehicle stationary in accordance with item 5.4, if corresponding brake 
equipment is part of the vehicle. 
The values measured as specified in item 5.2.1.1, above, must be recorded in the test report and in a certificate 
corresponding to the model shown in Annex III. 
Sound level of moving vehicles 
Limiting values 
The sound level measured in accordance with items 5.2.2.2 to 5.2.2.5, inclusive, of this Annex shall not exceed the 
following limits: 
Vehicle categories 
Vehicles intended for the carriage of passengers, and comprising not more than 
seats including the driver's seat 
Vehicles intended for the carriage of passengers and equipped with more than 
seats, including the driver's seat; and having a maximum permissible mass of more 
3,5 tonnes and: 
with an engine power of less than 150 kW 
with an engine power of not less than 150 kW 
Vehicles intended for the carriage of passengers and equipped with more than 
seats including the driver's seat; vehicles intended for the carriage of goods: 
with a maximum permissible mass not exceeding 2 tonnes 
with a maximum permissible mass exceeding 2 tonnes but not exceeding 3,5 tonnes 
Vehicles intended for the carriage of goods and having a maximum permissible 
exceeding 3,5 tonnes: 
with an engine power of less than 75 kW 
with an engine power of not less than 75 kW but less than 150 kW 
with an engine power of not less than 150 kW nine 
nine 
than 
nine 
mass Values expressed 
in dB (A) 
(decibels (A)) 
74 
78 
80 
76 
77 
77 
78 
80 
(') A stationary vehicle test is conducted in order to establish a reference value for the authorities which employ this method for the inspection of vehicles 
in service. 
24. 7. 91 Official Journal of the European Communities No C 193/9 
However: 
— for vehicles of categories 5.2.2.1.1 and 5.2.2.1.3, the limit values shall be increased by 1 dB (A) if they are 
equipped with a direct injection diesel engine, 
— for vehicles with a maximum permissible mass of over two tonnes designed for off-road use, the limit values 
are increased by 1 dB (A) if their engine power is less than 150 kW and 2 dB (A) if their engine power is equal 
to or greater than 150 kW. 
5.2.2.2. Measuring instruments 
5.2.2.2.1. Acoustic measurements 
The apparatus used for measuring the noise level must be a precision sound-level meter of the type described in 
Publication 179 'Precision sound level meters', second edition, of the International Electrotechnical Commission 
(IEC). Measurements must be carried out using the 'fast' response of the sound-level meter and the 'A' weighting 
curve which are also described in that publication. 
At the beginning and end of each set of measurements, the sound-level meter must be calibrated according to the 
manufacturer's instructions by means of an appropriate sound source (e.g. a pistonphone). The test must be 
considered invalid if the sound-level meter errors registered during this calibration exceed 1 dB. 
5.2.2.2.2. Speed measurements 
The engine speed and vehicle speed on the test section shall be determined with an accuracy of 3 % or better. 
5.2.2.3. Conditions of measurement 
5.2.2.3.1. Test site 
The test site must consist of a central acceleration section surrounded by a substantially flat test area. The test 
acceleration section must be level; the track surface must be dry and such that rolling noise remains low. 
The test track must be such that the conditions of a free sound field between the sound source and the 
microphone are attained to within 1 dB. This conditions shall be deemed to be met if there are no large sound-
reflecting objects such as fences, rocks, bridges or buildings within 50 m of the centre of the acceleration section. 
The surface of the site must be made of hard materials such as concrete, asphalt or any other acoustically equi­
valent material within a minimum radius of 10 m around the centre of the acceleration section and be free of 
powdery snow, tall grass, loose soil or cinders. 
There must be no obstacle which could affect the sound field within the vicinity of the microphone and no persons 
shall stand between the microphone and the sound source. The observer carrying out the measurements must so 
position himself as not to affect the readings of the measuring instrument. 
5.2.2.3.2. Meteorological conditions 
Measurements must not be made in poor atmospheric conditions. It must be ensured that the results are not 
affected by gusts of wind. 
5.2.2.3.3. Ambient noise 
For measurements, the A-weighted sound level of sound sources other than those of the vehicle to be tested and 
of wind effects must be at least 10 dB (A) below the sound level produced by the vehicle. A suitable windscreen 
may be fitted to the microphone provided that account is taken of its effect on the sensitivity and directional 
characteristics of the microphone. 
5.2.2.3.4. Condition of vehicle 
For these measurements, the vehicle must be in running order as defined in item 2.6 of Annex I to Directive 
70/156/EEC and, except in the case of vehicles which cannot be uncoupled, without trailer or semi-trailer. 
No C 193/10 Official Journal of the European Communities 24. 7. 91 
The vehicle's tyres must be of the type normally fitted to such vehicles by the manufacturer and must be inflated 
to the appropriate pressure(s) for the unladen vehicle. 
Before the measurements are made, the engine must be brought to its normal operating condition as regards 
temperatures, settings, fuel, spark plugs, carburettor(s), etc. (as appropriate). If the vehicle is fitted with fan(s) 
having an automatic actuating mechanism, this system must not be interfered with during the measurements. 
Only the normal highway drive must be engaged in vehicles with more than two drive wheels. 
5.2.2.4. Method of measurement 
5.2.2.4.1. Nature and number of measurements 
The maximum sound level expressed in A-weighted decibels (dB (A)) 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 must be taken on each side of the vehicle. 
5.2.2.4.2. Positioning of the microphone 
The microphone must be located at a distance of 7,5 ± 0,2 m from the reference line CC (Figure 1) of the track 
and 1,2 ±0,1 m above the ground. Its axis of maximum sensitivity must be horizontal and perpendicular to the 
path of the vehicle (line CC). 
5.2.2.4.3. Conditions of operation 
5.2.2.4.3.1. General conditions 
For all measurements, the vehicle must be driven in a straight line over the acceleration section in such a way that 
the longitudinal median plane of the vehicle is as close as possible to the line CC. 
The vehicle must approach the line AA' at a steady initial road speed as specified in items 5.2.2.4.3.2 and 
5.2.2.4.3.3. When the front end of the vehicle has reached the line AA', the accelerator control shall be fully 
operated as rapidly as practicable and held in the fully opened position until the rear of the vehicle reaches the line 
BB'; the accelerator control must be released as quickly as possible. 
The trailers of articulated vehicles which cannot be uncoupled must not be taken into account as regards the 
crossing of line BB'. 
5.2.2.4.3.2. Approach speed 
The vehicle must approach the line AA' at a steady speed corresponding to the lowest of the following three 
speeds: 
— 50 km/h, 
— the speed corresponding to an engine speed equal to three-quarters of the speed, S, at which the engine 
develops its rated maximum power, in the case of vehicles of category M! and in the case of vehicles of the 
other categories having an engine power not greater than 225 kW, 
— the speed corresponding to an engine speed equal to half the speed, S, at which the engine develops its rated 
maximum power, in the case of vehicles not belonging to category Mt having an engine power greater than 
225 kW. 
However, if in the case of vehicles equipped with an automatic transmission having more than two discrete ratios 
there is a change-down to first gear during the test, the manufacturer may select either of the following test 
procedures: 
— the speed, V, of the vehicle shall be increased to a maximum of 60 km/h in order to avoid such a 
change-down, or 
24. 7. 91 Official Journal of the European Communities No C 193/11 
— the speed, V, shall remain at 50 km/h and the fuel supply to the engine shall be limited to 95 % of the supply 
necessary for full lead. This condition is considered to be satisfied: 
— in the case of a spark-ignition engine, when the angle of the throttle opening is 90 %, and 
— in the case of a compression-ignition engine, when the movement of the central rack of the injection pump 
is limited to 90 % of its travel. 
If the vehicle is equipped with an automatic transmission which has no manual override, it must be tested at 
different approach speeds, namely 30, 40, and 50 km/h, or at three-quarters of maximum road speed if this value 
is lower. The test result shall be that obtained at the speed which produces the maximum sound level. 
5.2.2.4.3.3. Choice of gear ratios (in vehicles fitted with gearboxes) 
5.2.2.4.3.3.1. Manually-operated, non-automatic gearbox 
5.2.2.4.3.3.1.1. Vehicles in categories Mx and Nj equipped with a manually operated gearbox having not more than four forward 
gear ratios must be tested in second gear. 
Vehicles in these categories equipped with a manually operated gearbox having more than four forward gear 
ratios must be tested in second and third gears successively. Only overall gear ratios intended for normal road use 
shall be considered. The arithmetic mean of the sound levels recorded for each of these two conditions shall be 
calculated. 
If during the test in second gear, the engine speed exceeds the engine speed, S, at which the engine develops its 
rated maximum power, the test shall be repeated with an approach speed and/or approach engine speed reduced 
by steps of 5 % of S until the engine speed attained, no longer exceeds S. 
However, the vehicles in category M{ having more than four forward gears and equipped with an engine 
developing a maximum power greater than 140 kW, and whose permissible maximum-power/maximum-mass ratio 
exceeds 75 kW/t, may be tested in third gear only, provided that the speed at which the rear of the vehicle passes 
the line BB' in third gear is greater than 61 km/h. 
5.2.2.4.3.3.1.2. Vehicles other than those in categories M, and N, in which the total number of forward gear ratios is x (including 
the ratios obtained by means of an auxiliary gearbox or a multiple-ratio drive axle) must be tested using, in turn, 
ratios equal to or higher than x/n (') (2). 
The test result will be that obtained from the ratio producing the maximum sound level. 
Shifting up gears from x/n shall be terminated in that gear X where the engine speed, S, at which the engine 
develops its rated maximum power is for the last time reached when passing the line BB'. 
In the case of vehicles having different overall gear ratios (including a different number of gears) the representa-
tivity of the type by the test vehicle is determined as follows: 
— if the highest sound level is obtained between the ratios x/n and X the vehicle selected shall be deemed 
representative of its type, 
— if the highest sound level is obtained at ratio x/n the vehicle selected shall be deemed representative of its type 
only for those vehicles which have a lower overall gear ratio at x/n, 
— if the highest sound level is obtained at ratio X the vehicle selected shall be deemed representative of its type 
only for those vehicles which have a higher overall gear ratio at X. 
5.2.2.4.3.3.2. Automatic transmission equipped with manual override 
The test shall be conducted with the selector in a position recommended by the manufacturer for 'normal' driving. 
External downshifts (e.g. kick down) shall be put out of operation. 
(') Where: n = 2 for vehicles having an engine power not greater than 225 kW; 
n = 3 for vehicles having an engine power greater than 225 kW. 
(2) If x/n does not correspond to a whole number, the nearest higher ratio must be used. 
No C 193/12 Official Journal of the European Communities 24. 7. 91 
5.2.2.5. Interpretation of results 
5.2.2.5.1. To take account of inaccuracies in the measuring instruments, the result obtained from each measurement shall be 
determined by deducting 1 dB (A) from the meter reading. 
5.2.2.5.2. The measurements shall be considered valid if the difference between two consecutive measurements on the same 
side of the vehicle does not exceed 2 dB (A). 
5.2.2.5.3. The highest sound level measured shall constitute the test result. Should the result exceed the maximum 
permissible sound level for the category of vehicle tested by 1 dB (A), two further measurements shall be made. 
Three of the four measurements thus obtained must fall within the prescribed limits. 
5.2.3. Sound level of the stationary vehicle 
5.2.3.1. Sound level in the vicinity of vehicles 
In order to facilitate subsequent checks on vehicles in use, the sound level must be measured close to the exhaust 
system outlet in accordance with the following requirements and the measurement results entered in the test report 
drawn up for the purpose of issuing the certificate referred to in Annex III. 
5.2.3.2. Measuring instruments 
5.2.3.2.1. Acoustic measurements 
A precision sound-level meter as defined in item 5.2.2.2.1 must be used for the measurements. 
5.2.3.2.2. Measurement of engine speed 
The engine speed shall be determined by means of a tachometer having an accuracy of 3 °/o or better. The 
tachometer must be a separate one from the one of the vehicle. 
5.2.3.3. Conditions of measurement 
5.2.3.3.1. Test site (Figure 2) 
Any area not subject to significant acoustic disturbance may be used as a test site. Flat surfaces which are covered 
in concrete, asphalt or any other hard surfacing and possess a high degree of reflectivity are particularly suitable; 
surfaces consisting of earth which has been tamped down must not be used. 
The test site must be in the form of a rectangle, the sides of which are at least 3 m from the sides of the vehicle. 
This rectangle must not contain any significant obstacles, e.g. an individual other than the observer and the driver. 
The vehicle must be positioned within the abovementioned rectangle so that the microphone is at least 1 m from 
any kerbstone. 
5.2.3.3.2. Meteorological conditions 
Measurements must not be made in poor atmospheric conditions. It must be ensured that the results are not 
affected by gusts of wind. 
5.2.3.3.3. Ambient noise 
Readings on the measuring instruments produced by ambient noise and wind must be at least 10 dB (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. 
5.2.3.3.4. Condition of the vehicle 
The vehicle engine must be brought to normal running temperature before measurements commence. 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. 
During measurements, the gear lever must be in the neutral position. 
24. 7. 91 Official Journal of the European Communities No C 193/13 
5.2.3.4. Method of measurement 
5.2.3.4.1. Nature and number of measurements 
The maximum sound level expressed in A-weighted decibels (dB (A)) must be measured during the operating 
period referred to in item 5.2.3.4.3. 
At least three measurements must be taken at each measuring point. 
5.2.3.4.2. Position of the microphone (Figure 2) 
The microphone must be located level with the exhaust outlet or 0,2 m above the test-track surface, whichever is 
the higher. The microphone diaphragm must face the exhaust outlet at a distance of 0,5 m from the latter. The 
axis of maximum sensitivity of the microphone must be parallel to the track surface at an angle of 45° ± 10° to 
the vertical plane defined by the direction in which the exhaust gases are emitted. 
The microphone must be positioned to the side of this vertical plane which gives the greatest possible distance 
between the microphone and the vehicle contour. 
If the exhaust system has several outlets, the centres of which are not more than 0,3 m apart, and which are 
connected to the same silencer, the microphone must face the outlet closest to the vehicle contour or the outlet 
which is the highest above the track surface. In all other cases separate measurements must be taken at each of 
them, the highest figure recorded being taken as the test value. 
In the case of vehicles fitted with a vertical exhaust outlet (e.g. commercial vehicles), the microphone must be 
positioned at the level of the exhaust outlet, facing upwards with its axis vertical. It must be positioned at a 
distance of 0,5 m from the side of the vehicle closest to the exhaust outlet. 
Where the design of the vehicle is such that the microphone cannot be located as shown in Figure 2 because of the 
presence of obstacles which form part of the vehicle (e.g. spare wheel, fuel tank, battery compartment), a drawing 
clearly indicating the position for the microphone must be made when the measurement is conducted. As far as 
possible, the microphone must be more than 0,5 m from the nearest obstacle, and its axis of maximum sensitivity 
must face the exhaust outlet from the position least concealed by the above mentioned obstacles. 
5.2.3.4.3. Conditions of engine operation 
Engine speed must be stabilized at three-quarters of the speed (S) at which the engine develops rated maximum 
power. 
When constant engine speed is reached, the throttle must be rapidly returned to the idling position. The sound 
level must be measured over an operating period comprising brief maintenance of constant engine speed and the 
entire deceleration period, the maximum sound-level meter reading being taken as the test result. 
5.2.3.5. Results (test report) 
5.2.3.5.1. The test report drawn up for the purpose of issuing the certificate referred to in Annex III shall indicate all 
relevant data, particularly those used in measuring the sound of the stationary vehicle. 
5.2.3.5.2. Readings, rounded off to the nearest decibel, shall be taken from the measuring instrument. 
Only those values obtained from three consecutive measurements which do not differ by more than 2 dB (A) 
respectively will be taken into consideration. 
5.2.3.5.3. The highest of these three values shall constitute the test results. 
5.3. Exhaust systems containing fibrous materials 
5.3.1. Fibrous materials shall not be used in the construction of silencers unless suitable measures are undertaken at the 
design or production stages to ensure that the efficiency required to comply with the limits imposed in item 5.2.2.1 
is achieved on the road. Such a silencer shall be considered to be efficient on the road if the exhaust gases are not 
in contact with the fibrous materials or if the silencer of the prototype vehicle tested in accordance with the 
requirements of items 5.2.2 and 5.2.3 has been put into a normal state for road use before the sound-level 
measurements are taken. This can be achieved by using one of the three tests described in items 5.3.1.1, 5.3.1.2 
and 5.3.1.3, below, or by removing the fibrous materials from the silencer. 
NoC 193/14 Official Journal of the European Communities 24. 7. 91 
5.3.1.1. Continuous road operation for 10 000 km 
5.3.1.1.1. About half this operation shall consist of town driving and the other half of long-distance runs at high speed; 
continuous road operation can be replaced by a corresponding test-track programme. 
5.3.1.1.2. The two speed regimes must be alternated on several occasions. 
5.3.1.1.3. The complete test programme must include a minimum of 10 breaks of at least three-hours duration in order to 
reproduce the effects of cooling and any condensation which may occur. 
5.3.1.2. Conditioning on a test bench 
5.3.1.2.1. Using standard parts and observing the vehicle manufacturer's instructions, the silencer must be fitted to the 
engine, which is coupled to a dynamometer. 
5.3.1.2.2. The test must be conducted in six six-hour periods with a break of at least 12 hours between each period in order 
to reproduce the effect of cooling any condensation which may occur. 
5.3.1.2.3. During each six-hour period, the engine shall be run under the following conditions in turn: 
1. five minutes at idling speed; 
2. one-hour sequence under 'A load at 3A of rated maximum speed (S); 
3. one-hour sequence under Vi load at 3A of rated maximum speed (S); 
4. 10-minute sequence under full load at 3A of rated maximum speed (S); 
5. 15-minute sequence under Vi load at rated maximum speed (S); 
6. 30-minute sequence under VA load at rated maximum speed (S). 
Total duration of the six sequences: three hours. 
Each period must comprise two sets of the six abovementioned sequences. 
5.3.1.2.4. During the test, the silencer must not be cooled by a forced draught simulating normal airflow around the vehicle. 
Nevertheless, at the request of the manufacturer, the silencer may be cooled in order not to exceed the 
temperature recorded at its inlet when the vehicle is running at maximum speed. 
5.3.1.3. Conditioning by pulsation 
5.3.1.3.1. The exhaust system or components thereof must be fitted to the vehicle referred to in item 2.3 or the engine 
referred to in item 2.4. In the former case the vehicle must be mounted on a roller dynamometer. In the second 
case, the engine must be mounted on a dynamometer. 
The test apparatus, a detailed diagram of which is shown in Figure 3, must be fitted at the outlet of the exhaust 
system. Any other apparatus providing equivalent results is acceptable. 
5.3.1.3.2. The test apparatus must be adjusted in such a way that the exhaust-gas flow is alternately interrupted and 
re-established by the quick-action valve for 2 500 cycles. 
5.3.1.3.3. The valve must open when the exhaust-gas back pressure, measured at least 100 mm downstream of the intake 
flange, reaches a value of between 0,35 and 0,40 bar. It must close when this pressure does not differ by more 
than 10 % from its stabilized value with the valve open. 
24. 7. 91 Official Journal of the European Communities No C 193/15 
5.3.1.3.4. The time-delay switch shall be set for the duration of gas exhaust resulting from the provisions laid down in item 
5.3.1.3.3 above. 
5.3.1.3.5. Engine speed must be 75 % of the speed (S) at which the engine develops maximum power. 
5.3.1.3.6. The power indicated by the dynamometer must be 50 % of the full-throttle power measured at 75 % of engine 
speed (S). 
5.3.1.3.7. Any drainholes must be closed off during the test. 
5.3.1.3.8. The entire test must be completed within 48 hours. y 
If necessary, one cooling period will be observed after each hour. 
5.3.2. If the provisions of Article 8 (3) of Directive 70/156/EEC concerning EEC type-approval are to be applied, the 
test method set out in item 5.3.1.2 above must be employed. 
5.4. Compressed air noise 
5.4.1. Method of measurement 
The measurement is performed at microphone positions 2 and 6 according to Figure 4, with the vehicle stationary. 
The highest A-weighted noise levels are 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. 
5.4.2. 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 1 dB (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 2 dB (A). 
The highest value measured is taken as the test result. If this value exceeds the noise limit by 1 dB (A), two 
additional measurements are to be taken at the corresponding microphone position. In this case three out of the 
four results of measurement have to comply with the noise limit. 
5.4.3. Limiting value 
The sound level shall not exceed the limit of 72 dB (A). 
6. EXTENSION OF EEC TYPE-APPROVAL 
6.1. Vehicle types modified to run on unleaded petrol 
6.1.1. Approval of a vehicle type modified and/or adjusted solely for the purpose of making it capable of running on 
unleaded petrol, as specified in Directive 85/210/EEC, shall be extended when the manufacturer certifies, subject 
to the approval of the authority granting type approval, that the sound level for the modified vehicle shall not 
exceed the limiting values specified in item 5.2.2.1. 
6.2. Vehicle types modified for any other purpose 
6.2.1. Approval of a vehicle type may be extended to vehicle types differing with regard to the characteristics listed in 
Annex III if the authority granting type approval considers that the modifications made are not likely to have any 
substantial adverse effect on the sound level of the vehicle. 
No C 193/16 Official Journal of the European Communities 24. 7. 91 
7. CONFORMITY OF PRODUCTION 
7.1. Every vehicle manufactured following the requirements of this Directive shall conform to the vehicle type 
approved, and satisfy the requirements of item 5. 
7.2. In order to verify that the requirements of item 7.1 are met, suitable controls of the production shall be carried 
out. 
7.3. The holder of the approval shall in particular: 
7.3.1. ensure existence of procedures for the effective control of the quality of products; 
7.3.2. have access to the control equipment necessary for checking the conformity of each approved type; 
7.3.3. ensure that data of test results are recorded and that annexed documents shall remain available for a period to be 
determined in accordance with the administrative service; 
7.3.4. analyse the results of .each type of test, in order to verify and ensure the stability of the product characteristics 
making allowance for variation of an industrial production; 
7.3.5. ensure that for each type of product at least the tests prescribed in Annex V, point I, are carried out; 
7.3.6. ensure that any sampling or test pieces giving evidence of non-conformity with the type of test considered shall 
give rise to another sampling and another test. All the necessary steps shall be taken to re-establish the conformity 
of the corresponding production. 
7.4. The competent authority which has granted type-approval may at any time verify the conformity control method 
applicable to each production unit. 
7.4.1. In every inspection the test books and production survey records shall be presented to the visiting inspector. 
7.4.2. The inspector may take samples at random which will be tested in the manufacturer's laboratory. The minimum 
number of samples may be determined according to the results of the manufacturer's own verification. 
7.4.3. When the quality level appears unsatisfactory or when it seems necessary to verify the validity of the tests carried 
out in application of item 7.4.2 the Inspector shall select samples to be sent to the technical service which has 
conducted the type approval tests. 
7.4.4. The competent authority may carry out any test prescribed in Annex I. 
7.4.5. The normal frequency of inspections by the competent authority shall be one every two years. If unsatisfactory 
results are recorded during one of these visits, the competent authority shall ensure that all necessary steps are 
taken to re-establish the conformity of production as rapidly as possible. 
24 7 91 Official Journal of the European Communities No C 193/17 
Figure I 
Microphone positions for the measurement of a moving vehicle 
10m ,, c 
0-7,5 m v 
Microphone 7,5 m -0 
Microphone 
10m 
T C u 
;ee-
Li-
No C 193/18 Official Journal of the European Communities 24 7. 91 
Figure 2 
Test site and microphone positions for the measurement of a stationary vehicle 
All distances are given in metres 
24. 7. 91 Official Journal of the European Communities No C 193/19 
Figure 3 
Test apparatus for conditioning by pulsation 
© 
© 
® 
© 
© 
© 
© 
© 
© Inlet flange or sleeve for connection to the rear of the test exhaust system. 
Hand-operated regulating valve. 
Compensating reservoir having a capacity of 35 to 40 litres. 
Pressure switch with an operating range of 0,05 to 2,5 bar. 
Time delay switch. 
Impulse counter. 
Quick response valve, such as exhaust brake valve 60 mm in diameter, operated by a pneumatic 
cylinder with an output of 120 N at 4 bar. The response time, both when opening and closing, must 
not exceed 0,5 seconds. 
Exhaust gas evacuation. 
Flexible pipe. 
Pressure gauge. 
No C 193/20 Official Journal of the European Communities 24 7 91 
Figure 4 
Microphone positions for measurement of compressed air noise 
Microphone 6 » Microphone 
The measurement is performed at the stationary vehicle according to Figure 4, using two microphone 
positions at a distance of 7 m from the contour of the vehicles, and at 1,2 m above the ground 
^B^I C^^c^lJourn^lo^th^Furoo^nC^ornrnun^n^ ^o^I^B^t 
EECTYPEAPPROVALOEEXHAUSTSYSTEMS AS SEPARATETECHNICALUNITS (REPLACEMENT EXHAUST 
SYSTEMS^ 
0 SCCOPE 
This Annex applies to the type-approvals as separate technical units within the meaning of Article ^a of directive 
^OBt^DBEEC^ of exhaust systems or components thereof to he fitted to one or more given types of motor vehicle 
incategonesM^andN^ as replacement parts 
t OEEINITICNS 
tt Replacement exhaust system or component thereof means any part of the exhaust system defined in item t^tof 
Annex ^ intended to replace on a vehicle apartof the typegranted EEC type-approval^vith the vehicle in 
accordance ^ithAnnexl 
^ APPLICATIC^N^CoREECTYPE-APPRCVAL 
^^ Application for ECC type-approval in respect ofareplacement exhaust system or component thereof asaseparate 
technical unit must he suhmittedhy the vehicle manufacturer of the separate technical unit in question or hy their 
authorised representatives 
^^ Application forEEC type-approval in respect of each type of replacement exhaust system or component thereof 
must he accompamedhythe undermentioned document in triplicate and the following information 
^t a description of the type(s^ of vehicle to ^hich the system or components thereof are to he fitted ^vith reference to 
thecharactensticsmentionedinitem tt of Annexl ThenumhersandBorsymholsdesignanngtheengineand 
vehicle type must he indicated^ 
^^^ a description of the replacement exhaust system indicating the relative position of each system components 
together ^vith mounting instructions^ 
^^^ detailed dra^vingsof eachcomponent^ so thattheycanheeasily locatedand identified^ andreference to the 
materials used 
These drawings must indicate the place provided for the compulsory affixing of the EEC type-approval 
^^ At the request of the technical service concernedm^^pphcant must suhmit 
^^t t^o examples of the system in respect of ^hich application for EEC type-approval has heenmade^ 
^^^ an exhaust system of the type originally fitted to the vehicle ^hen EEC type-approval ^vas granted^ 
^^^ a vehicle representative of the type to ^hich the system is to he fitted 
— ^hich^ as far as its noise level ^hen moving is concerned^ must he in suchacondition that it respects the limits 
initem^^^^ of Annexland does not exceed hy more than^d^^the values ohtained during the type-
approvals 
— ^vhich, as far as its noise level ^vhen stationary isconcerne^ respects thevalueohtained curing the type-
apprDval^ 
^^^t a separate engine corresponding to the type of vehicle descnhedahove 
^^t The competent authority shall verify the existence of satisfactory arrangements for ensuring effective controlof 
the conformity of production hefore type approval is granted 
^ MAR^INC5 
^t The replacement exhaust system or its components^ excluding fixing hardware and pipes must hear 
^t t the trade marker trade name of the manufacturer of the replacement system and its components^ 
^t^ the manufacturer^scommercial descriptions 
No C 193/22 Official Journal of the European Communities 24. 7. 91 
3.1.3. the EEC type-approval number preceded by the distinctive letter(s) of the country granting EEC type-approval ('). 
3.2 These marks must be clearly legible and indelible. 
4. EEC TYPE-APPROVAL 
4.1. If an application within the meaning of item 2.1 is approved, the competent authority will draw up a certificate 
corresponding to the model shown in Annex IV. The type-approval number must be preceded by the distinctive 
letter(s) of the country granting EEC type-approval. 
5. SPECIFICATIONS 
5.1. General specifications 
5.1.1. The replacement exhaust systems or component thereof must be designed, constructed and capable of being 
mounted so as to ensure that the vehicle complies with the provisions of this Directive under normal conditions of 
use, notwithstanding any vibrations to which it may be subject. 
5.1.2. The exhaust system or components thereof must be designed, constructed and capable of being mounted so that 
reasonable resistance to the corrosion phenomena to which it/they is/are exposed is obtained having regard to the 
conditions of use of the vehicle. 
5.2. Specifications relating to sound levels 
5.2.1. The acoustic efficiency of the replacement exhaust system or component thereof must be checked using the 
methods described in items 5.2.2.4 and 5.2.3.4 of Annex I. 
When the replacement exhaust system or component thereof is mounted on the vehicle referred to in item 2.3.3 of 
this Annex, the sound levels obtained using the two methods (stationary and moving vehicle) must satisfy one of 
the following conditions: 
5.2.1.1. they must not exceed the values obtained when this type of vehicle was granted EEC type-approval; 
5.2.1.2. they must not exceed the sound level values measured on the vehicle, referred to in item 2.3.3, when this is fitted 
with an exhaust system of the same type as that fitted to the vehicle when EEC type-approval was granted. 
5.3. Measurement of vehicle performance 
5.3.1. The replacement exhaust system or components thereof must be such as to ensure that vehicle performance is 
comparable with that achieved with the original equipment exhaust system or component thereof. 
5.3.2. The replacement exhaust system or, depending on the manufacturer's choice, the components of this system must 
be compared with the original equipment exhaust system or components thereof, which are also in new condition, 
fitted in turn to the vehicle referred to in item 2.3.3. 
5.3.3. The check must take the form of a measurement of pressure loss under the conditions specified in item 5.3.4.1 or 
5.3.4.2. The value measured with the replacement exhaust system must not exceed the value measured with the 
original equipment system by more than 25 % under the conditions mentioned below. 
5.3.4. Test method 
5.3.4.1. Engine test method 
The measurement must be conducted on the engine referred to in item 2.3.4 coupled to a dynamometer. 
With the throttle completely open, the bench shall be so adjusted as to obtain the engine speed (S) corresponding 
to the rated maximum power of the engine. 
For the measurement of back pressure, the pressure tap must be placed at the distance from the exhaust manifold 
specified in Figures 1, 2 and 3. 
(') B = Belgium, D = Federal Republic of Germany, DK = Denmark, E = Spain, F = France, GR = Greece, I = Italy, IRL = Ireland, 
L = Luxembourg, NL = Netherlands, P = Portugal, UK = United Kingdom. 
24. 7. 91 Official Journal of the European Communities No C 193/23 
5.3.4.2. Vehicle test method 
The measurements must be carried out on the vehicle referred to in item 2.3.3. 
The test must be conducted: 
— either on road, or 
— on a roller dynamometer. 
With the throttle completely open, the engine must be loaded so as to obtain the engine speed (S) corresponding 
to the rated maximum power. 
For the measurement of back pressure, the pressure tap must be placed at the distance from the exhaust manifold 
specified in Figures 1, 2 and 3. 
5.4. Additional provisions in respect of exhaust systems or components thereof filled with fibrous materials 
Fibrous materials must not be used in the manufacture of replacement exhaust systems or components thereof 
unless appropriate measures are taken during the design and production stages to ensure that a level of efficiency 
is attained corresponding to the limits set out in item 5.2.2.1 of Annex I. 
Such a silencing system is deemed to be effective in traffic if the exhaust gases are not in contact with the fibrous 
materials or if, after the removal of the fibrous materials, the sound levels comply with the requirements set out in 
item 5.2.1, when the exhaust system is tested on a vehicle in accordance with the methods described in items 5.2.2 
and 5.2.3 of Annex I. 
If this condition is not observed, the entire exhaust system must be subjected to conditioning. This must be done 
using one of the three methods described in items 5.3.1.1, 5.3.1.2 and 5.3.1.3 of Annex I. 
After conditioning, the sound level must be checked as specified in item 5.2.1. 
When the procedure described in item 5.2.1.2 is employed, the applicant for EEC type-approval may ask for the 
conditioning of the original equipment exhaust system or submit one which has been emptied. 
6. CONFORMITY OF PRODUCTION 
6.1. Any replacement exhaust system or component thereof bearing an EEC type-approval number pursuant to this 
Directive must conform to the approved type of exhaust system and comply with the requirements of item 5. 
6.2. In order to verify that the requirements of item 6.1 are met, suitable controls of the production shall be carried 
out. 
6.3. The holder of the approval shall in particular: 
6.3.1. ensure existence of procedures for the effective control of the quality of products; 
6.3.2. have access to the control equipment necessary for checking the conformity of each approved type; 
6.3.3. ensure that data of test results are recorded and that annexed documents shall remain available for a period to be 
determined in accordance with the administrative service; 
6.3.4. analyse the results of each type of test, in order to verify and ensure the stability of the product characteristics 
making allowance for variation of an industrial production; 
6.3.5. ensure that for each type of product at least the tests prescribed in Annex V, point II, are carried out; 
6.3.6. ensure that sampling or test pieces giving evidence of non-conformity with the type of test considered shall give 
rise to another sampling and another test. All the necessary steps shall be taken to re-establish the conformity of 
the corresponding production. 
6.4. The competent authority which has granted type-approval may at any time verify the conformity control method 
applicable to each production unit. 
6.4.1. In every inspection the test books and production survey records shall be presented to the visiting inspector. 
No C 193/24 Official Journal of the European Communities 24. 7. 91 
6.4.2. The inspector may take samples at random which will be tested in the manufacturer's laboratory. The minimum 
number of samples may de determined according to the results of the manufacturer's own verification. 
6.4.3. When the quality level appears unsatisfactory or when it seems necessary to verify the validity of the tests carried 
out in application of item 6.4.2 above the inspector shall select samples to be sent to the technical service which 
has conducted the type approval tests. 
6.4.4. The competent authority may carry out any test prescribed in this Annex. 
6.4.5. The normal frequency of inspections by the competent authority shall be one every two years. If unsatisfactory 
results are recorded during one of these visits, the competent authority shall ensure that all necessary steps are 
taken to re-establish the conformity of production as rapidly as possible. 
24. 7. 91 Official Journal of the European Communities No C 193/25 
Back pressure — measuring points 
Figure 1 
Single 
pipe 
min. 150 mm 
Figure 2 V) 
min. 150 mm 
min. 150 mm 
Two measuring points joined to give one reading 
(') If this is not possible, use Figure 3. 
No C 193/26 Official Journal of the European Communities 24. 7. 91 
ANNEX III 
MODEL 
Maximum size: A4 (210 x 297 mm) 
(Name of administration) 
ANNEX TO THE EEC VEHICLE TYPE-APPROVAL CERTIFICATE RELATING TO SOUND 
LEVEL 
(Articles 4 (2) and 10 of Council Directive 70/156/EEC of 6 February 1970 on the approximation of the laws 
of the Member States relating to the type-approval of motor vehicles and their trailers) 
In the light of the amendments made pursuant to Directive 81/334/EEC 
EEC type-approval No: 
1. Trademark or trade name of vehicle: 
2. Vehicle type: 
2.1. If necessary, list of vehicles covered by item 5.2.2.4.3.3.1.2 of Annex I: 
3. Manufacturer's name and address: 
4. If applicable, name and address of the manufacturer's authorized representative: 
5. Engine: 
5.1. Manufacturer: 
5.2. Type: 
5.3. Model: 
5.4. Rated maximum power ('): kW at rev/min. 
6. Transmission: non-automatic gearbox/automatic gearbox (2). 
6.1. Number of gears: 
7. Equipment: 
7.1. Exhaust silencer: 
7.1.1. Manufacturer or authorized representative (if any): 
O Established in accordance with Directive 80/1269/EEC (OJ No L 375, 31. 12. 1980, p. 46). 
(2) Delete where inapplicable. 
24. 7. 91 Official Journal of the European Communities No C 193/27 
7.1.2. Model: 
7.1.3. Type: in accordance with drawing No: 
7.2. Intake silencer: 
7.2.1. Manufacturer or authorized representative (if any): 
7.2.2. Model: 
7.2.3. Type: in accordance with drawing No: 
7.3. Tyre size: 
8. Measurements: 
8.1. Sound level of moving vehicle: 
Measurement results 
First measurement 
Second measurement 
Third measurement 
Fourth measurement Left-hand side 
dB (A) (') Right-hand side 
dB (A) (') Position of gear lever 
Test result: dB (A)/E (2) 
8.2. Sound level of stationary vehicle: 
First measurement 
Second measurement 
Third measurement dB (A) Engine speed 
Test result: dB (A)/E (2) 
(') The measurement values are given with the 1 dB (A) deduction in accordance with provisions of item 5.2.2.5.1 of 
Annex 1. 
(') 'E' indicates that the measurements in question were conducted in accordance with Directive 81/334/EEC. 
No C 193/28 Official Journal of the European Communities 24. 7. 91 
8.3. Sound level of compressed air noise 
Measurement results 
First measurement 
Second measurement 
Third measurement 
Fourth measurement Left-hand side dB (A) Right-hand side dB (A) 
Test result: dB (A) 
8.4. Ambient conditions 
8.4.1. Test site (surface characteristics): 
8.4.2. Temperatures (in °C): 
8.4.2.1. Temperature of ambient air: 
8.4.2.2. Temperature of test track surface: 
8.4.3. Atmospheric pressure (kPa): 
8.4.4. Humidity (%): 
8.4.5. Wind speed (km/h): 
8.4.6. Wind direction: 
8.4.7. Background noise (dB (A)): 
9. Vehicle submitted for type-approval on: 
10. Technical service responsible for type-approval tests: 
11. Date of test report issued by that service: 
12. Nummer of test report issued by that service: 
13. Type-approval in respect of sound levels is hereby granted/refused (') (*) 
(*) Decision reached in accordance with Directive 81/334/EEC (OJ No L 131, 18. 5. 1981). 
(J) Delete where inapplicable. 
24. 7. 91 Official Journal of the European Communities No C 193/29 
14. Place: 
15. Date: 
16. Signature: 
17. The following documents bearing the abovementioned type-approval number are attached to 
this Annex (to be completed if necessary): 
18. Remarks: 
No C 193/30 Official Journal of the European Communities 24 
ANNEX IV 
MODEL 
Maximum size: A4 (210 x 297 mm) 
(Name of administration) 
EEC TYPE-APPROVAL CERTIFICATE IN RESPECT OF A SEPARATE TECHNICAL UNIT 
(Article 9a of Council Directive 70/156/EEC of 6 February 1970 on the approximation of the laws of the 
Member States relating to the type-approval of motor vehicles and their trailers) 
Separate technical unit: replacement exhaust system 
EEC type-approval number of the separate technical unit ('): 
1. Trademark or trade name: 
2. Type: 
3. Manufacturer's name and address: 
4. If applicable, name and address of the manufacturer's authorized representative: 
5. Composition of the separate technical unit: 
6. Trademark or trade name of the type(s) of motor vehicle to which the silencer is to be fitted (J): 
7. Type(s) of vehicle, ranging from serial No: 
to serial No: 
8. Engine 
8.1. Type (positive ignition, diesel): 
8.2. Cycles: two-stroke, four-stroke: 
8.3. Total cylinder capacity: 
8.4. Rated maximum engine power (J): kW at rev/min. 
9. Number of gear ratios: 
10. Gear ratios employed: 
11. Drive-axle (ratio(s)): 
(') Preceded by the distinctive lettcr(s) of the country granting type-approval: B = Belgium, D = Federal Republic of 
Germany, DK — Denmark, E — Spain, F — France, GR =» Greece, I = Italy, IRL = Ireland, L = Luxembourg, 
NL = Netherlands, P = Portugal, UK — United Kingdom. 
(2) If several types are indicated, items 7 to 14 inclusive must be completed in respect of each type. 
(3) Established in accordance with Directive 80/1269/EEC (OJ No L 375, 31. 12. 1980, p. 46). 
24. 7. 91 Official Journal of the European Communities No C 193/31 
12.1. Sound-level values: 
— moving vehicle: dB (A), speed stabilized before acceleration at km/h, 
— stationary vehicle: dB (A), at rev/min. 
12.2. Ambient conditions 
12.2.1. Test site (surface characteristics): 
12.2.2. Temperatures (°C) 
12.2.2.1. Temperature of ambient air: 
12.2.2.2. Temperature of test track surface: 
12.2.3. Atmospheric pressure (kPa): 
12.2.4. Humidity (%): 
12.2.5. Wind speed (km/h): 
12.2.6. Wind direction: 
12.2.7. Background noise (dB(A)): 
13. Variation in back pressure: 
14. Any restrictions in respect of use and mounting requirements: 
15. Date on which the model was submitted for the issue of an EEC type-approval certificate in 
respect of a separate technical unit: 
16. Technical service: 
17. Date of the test report issued by that technical service: 
18. Number of test report issued by that technical service: 
19. EEC type-approval of the separate technical unit is hereby granted/refused ('): 
20. Place: 
21. Date: 
(') Delete where inapplicable. 
No C 193/32 Official Journal of the European Communities 24. 7. 91 
22. Signature: 
23. The following documents bearing the abovementioned type-approval number of the separate 
technical unit in question are attached to this Annex (to be completed if necessary): 
24. Remarks: 
24. 7. 91 Official Journal of the European Communities No C 193/33 
ANNEX V 
CHECKS ON CONFORMITY OF PRODUCTION 
I. VEHICLES 
1. General 
These requirements are consistant with test to be held to check conformity of production, according 
to items 7.3.5 and 7.4.3 of Annex I. 
2. Testing procedures 
The methods of testing, measuring instruments and interpretation of results shall be those described in 
Annex I. The vehicle(s) under test shall be subjected to the test for measurement of noise of vehicle in 
motion as described in item 5.2.2.4 of Annex I. 
3. Sampling 
One vehicle has to be chosen. If after the test of item 4.1 the vehicle is not considered to conform to 
the requirements of this Directive two more vehicles have to be tested. 
4. Evaluation of the results 
4.1. If the sound level of the vehicle tested pursuant to items 1 and 2 does not exceed by more than 1 dB 
(A) the limit values prescribed in item 5.2.2.1 of Annex I, the vehicle type shall be considered to 
conform to the requirements of this Directive. 
4.2. If the vehicle tested according to item 4.1 does not satisfy the requirements laid down in that item, 
two more vehicles of the same type have to be tested pursuant to items 1 and 2. 
4.3. If the sound level of the second and/or third vehicle of item 4.2 exceeds by more than 1 dB (A) the 
limit values prescribed in item 5.2.2.1 of Annex I, the vehicle type shall be considered not to conform 
to the requirements of this Directive and the manufacturer shall take the necessary measures to 
re-establish the conformity. 
II. REPLACEMENT EXHAUST SYSTEMS 
1. General 
These requirements are consistant with test to be held to check conformity of production, according 
to items 6.3.5 and 6.4.3 of Annex II. 
2. Testing procedures 
The methods of testing, measuring instruments and interpretation of results shall be those described in 
Annex II. The exhaust system or component under test shall be subjected to the test as described in 
Annex II, item 5. 
3. Sampling 
An exhaust system or component has to be chosen. If after the test of item 4.1 the sample is not 
considered to conform to the requirements of this Directive two more samples have to be tested. 
4. Evaluation of the results 
4.1. If the sound levels of the exhaust system or component, tested pursuant to items 1 and 2, measured in 
accordance with item 5.2 of Annex II do not exceed by more than 1 dB (A) the level measured during 
the EEC type-approval tests of this type of exhaust system or component, the exhaust system or 
component type shall be considered to conform to the requirements of this Directive. 
4.2. If the exhaust system or component tested according to item 4.1 does not satisfy the requirements laid 
down in that item, two more exhaust systems or components of the same type have to be tested 
pursuant to items 1 and 2 above. 
4.3. If the sound level of the second and/or third sample of item 4.2 exceeds by more than 1 dB (A) the 
level measured during the EEC type-approval tests of this type of exhaust system or component, the 
exhaust system or component type shall be considered not to conform to the requirements of this 
Directive and the manufacturer shall take the nesessary measures to re-establish the conformity.