1971L0320 — EN — 20.02.1974 — 002.001 — 1
This document is meant purely as a documentation tool and the institutions do not assume any liability for its contents
►B COUNCILDIRECTIVE
of26July1971
ontheapproximationofthelawsoftheMember Statesrelating tothebrakingdevicesofcertain
categories ofmotorvehiclesandoftheirtrailers
(71/320/EEC)
(OJ L 202, 6.9.1971, p. 37)
Amended by:
Official Journal
No page date
►M1Commission Directive 74/132/EEC of 11 February 1974 L 74 7 19.3.1974
Amended by:
►A1Act of Accession of Denmark, Ireland and the United Kingdom of Great
Britain and Northern IrelandL 73 14 27.3.1972
Corrected by:
►C1Consolidated text of corrigenda to instruments published in Special
Editions 1952-72, p. 96 (71/320/EEC)
▼B
COUNCILDIRECTIVE
of26July1971
on the approximationof the lawsofthe Member States relating to
the braking devices of certain categories of motor vehicles and of
theirtrailers
(71/320/EEC)
THE COUNCIL OF THE EUROPEAN COMMUNITIES,
Having regard to the Treaty establishing the European Economic
Community, and in particular Article 100 thereof;
Having regard to the proposal from the Commission;
Having regard to the Opinion of the European Parliament(1);
Having regard to the Opinion of the Economic and Social
Committee(2);
Whereas the technical requirements which motor vehicles must satisfy
pursuant to national laws relate, inter alia , to the braking devices of
certain categories of motor vehicles and of their trailers;
Whereas those requirements differ from one Member State to another;
whereas it is therefore necessary that all Member States adopt the samerequirements either in addition to or instead of their existing rules, inorder, in particular, to allow the EEC type approval procedure whichwas the subject of the Council Directive 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 to be applied in respectof eachtype of veh icle(
3);
Whereas the harmonised requirements must ensure road safety
throughout the whole Community;
HAS ADOPTED THIS DIRECTIVE:
Article 1
1. For the purposes of this Directive, ‘vehicle’ means any motor
vehicle falling within one of the international categories listed belowand intended for use on the road, such vehicle being with or withoutbodywork, having at least four wheels and a maximum design speedexceeding 25 km/h, and its trailers, with the exception of vehicles
which run on rails, agricultural tractors and machinery and public
works vehicles:
(a) Category M: Motor vehicles having at least four wheels or having
three wheels when the maximum weight exceeds 1 metric ton, and
used for the carriage of passengers:
— Category M
1: Vehicles used for the carriage of passengers, and
comprising not more than eight seats in additionto the driver's seat;
— Category M
2: Vehicles used for the carriage of passengers,
comprising more than eight seats in addition to
the driver's seat, and having a maximum weight
not exceeding 5 metric tons;
— Category M3: Vehicles used for the carriage of passengers,
comprising more than eight seats in addition tothe driver's seat, and having a maximum weightexceeding 5 metric tons.1971L0320 — EN — 20.02.1974 — 002.001 — 2
(1) OJ No C 160, 18.12.1969, p. 7.
(2) OJ No C 100, 1.8.1969, p. 13.
(3) OJ No L 42, 23.2.1970, p. 1.
▼B
(b) Category N: Motor vehicles having at least four wheels or having
three wheels when the maximum weight exceeds 1 metric ton, andused for the carriage of goods:
— Category N
1: Vehicles used for the carriage of goods and
having a maximum weight not exceeding 3·5
metric tons;
— Category N2: Vehicles used for the carriage of goods and
having a maximum weight exceeding 3·5 butnot exceeding 12 metric tons;
— Category N
3: Vehicles used for the carriage of goods and
having a maximum weight exceeding 12 metric
tons.
(c) Category O: Trailers (including semi-trailers):
— Category O1: Trailers witha maximum weigh t not exceeding
0·75 metric tons;
— Category O2: Trailers witha maximum weigh t exceeding 0·75
but not exceeding 3·5 metric tons;
— Category O3: Trailers witha maximum weigh t exceeding 3·5
but not exceeding 10 metric tons;
— Category O4: Trailers witha maximum weigh t exceeding 10
metric tons.
2. Articulated category M vehicles made up of two non-separable
but articulated units shall be considered to be single vehicles.
3. In the case of a category M or N drawing vehicle designed to be
coupled to a semi-trailer, the maximum weight to be taken into consid-eration when classifying that vehicle shall be the weight of the drawingvehicle in running order plus the maximum weight transferred to thedrawing vehicle by the semi-trailer and, where appropriate, the
maximum weight of the drawing vehicle's own load.
4. In the case of category N vehicles, the equipment and fittings of
certain special vehicles not intended for the carriage of passengers(such as crane vehicles, workshop vehicles, publicity vehicles) shallbe considered to be goods.
5. The maximum weight to be taken into consideration when classi-
fying a category O semi-trailer shall be the weight transmitted to the
ground by the axle or axles of the semi-trailer when coupled to thedrawing vehicle and laden with a maximum load.
Article 2
No Member State may refuse to grant EEC type approval or national
type approval of a vehicle on grounds relating to its braking devicesif that vehicle is fitted with the devices specified in Annexes I to VIII
and if these devices satisfy the requirements set out therein.
Article 2a
No Member State may refuse or prohibit the sale, registration, entry
into service or use of a vehicle on grounds relating to its brakingdevices if that vehicle is equipped with the braking devices specified
in Annexes I to VIII and if suchbraking devices satisfy th e require-
ments set out therein.
Article 3
The Member State which has granted type approval shall take the
necessary measures to ensure that it is informed of any modification1971L0320 — EN — 20.02.1974 — 002.001 — 3
▼A1
▼B
▼B
to a component or characteristic mentioned in item 1.1 of Annex I. The
competent authorities of that State shall decide whether the modifiedprototype should be submitted to fresh tests and whether a fresh report
should be drawn up thereon. If such tests reveal failure to comply with
the requirements of this Directive, the modification shall not beauthorised.
Article 4
Pending the entry into force of a separate Directive on the definition of
an ‘urban bus’, such vehicles shall continue to be submitted to theType II A test described in Annex II where their maximum weightexceeds 10 metric tons.
Article 5
The amendments necessary for adjusting the requirements of the
Annexes so as to take account of technical progress shall be adopted
in accordance with the procedure laid down in Article 13 of the
Council Directive of 6 February 1970 on the type approval of motorvehicles and their trailers.
Article 6
1. Member States shall put into force the provisions containing the
requirements needed in order to comply with this Directive withineighteen months of its notification and shall forthwith inform theCommission thereof.
2. Witheffect from 1 October 1974, th e provisions of item 2.2.1.4
of Annex I shall also apply to vehicles other than those in category
M
3or category N3.
3. Member States shall ensure that the texts of the main provisions
of national law which they adopt in the field covered by this Directiveare communicated to the Commission.
Article 7
This Directive is addressed to the Member States.1971L0320 — EN — 20.02.1974 — 002.001 — 4
▼B
ANNEX I
DEFINITIONS,REQUIREMENTS,CONSTRUCTIONANDFITTING
1. DEFINITIONS
1.1.‘Typeofvehiclewithrespecttothebrakingdevices’
‘Type of vehicle with respect to the braking devices’ means vehicles
which do not differ in such essential respects as:
1.1.1.In the case of motor vehicles
1.1.1.1. the vehicle category, as defined in Article 1 of this
Directive
1.1.1.2. the maximum weight, as defined in item 1.141.1.1.3. the distribution of weight among the axles
1.1.1.4. the maximum design speed
1.1.1.5. a different type of braking device withparticular refer-
ence to the presence or otherwise of devices for
braking a trailer
1.1.1.6. the number and arrangement of the axles
1.1.1.7. the engine type
1.1.1.8. the number and ratios of gears
1.1.1.9. ratio(s) of rear drive axle(s)
1.1.1.10. the tyre dimensions
1.1.2.In the case of trailers
1.1.2.1. the vehicle category, as defined in Article 1 of this
Directive
1.1.2.2. the maximum weight, as defined in item 1.14
1.1.2.3. the distribution of weight among the axles1.1.2.4. a different type of braking device
1.1.2.5. the number and arrangement of the axles
1.1.2.6. the tyre dimensions
1.2.‘Brakingdevice’
‘Braking device’ means the combination of parts whose function is
progressively to reduce the speed of a moving vehicle or to bring it to
a halt, or to keep it stationary if it is already halted. These functions
are specified in item 2.1.2. The device shall consist of the brake
control, the transmission and the brake proper.
1.3.‘Graduatedbraking’
‘Graduated braking’ means braking during which, within the normal
range of operation of the device, during either the application or the
releasing of the brakes,
— the driver can, at any time, increase or reduce the braking force
through action on the control,
— the braking force acts in the same direction as the action on the
control (monotonic function),
— it is easily possible to make a sufficiently fine adjustment to the
braking force.
1.4.‘Control’
‘Control’ means the part actuated directly by the driver (or, where
appropriate, in the case of a trailer, the driver's mate) to supply to the
transmission the energy required for braking or controlling it. This
energy may be the muscular energy of the driver, or energy from
another source controlled by the driver, or in appropriate cases the
kinetic energy of a trailer, or a combination of these various kinds of
energy.1971L0320 — EN — 20.02.1974 — 002.001 — 5
▼B
1.5.‘Transmission’
‘Transmission’ means the combination of components situated between
the control and the brake and connecting the two operationally. The
transmission may be mechanical, hydraulic, pneumatic, electrical, or
mixed. Where the braking power is derived from or assisted by a
source of energy independent of the driver but controlled by him, the
reserve of energy in the device shall likewise be regarded as part of the
transmission.
1.6.‘Brake’
‘Brake’ means the part in which the forces opposing the movement of
the vehicle develop. It may be a friction brake (when the forces are
generated by the friction between two parts of the vehicle moving rela-
tively to one another); an electrical brake (when the forces are
generated by electromagnetic action between two parts of the vehicle
moving relatively to but not in contact withone anoth er); a fluid brake
(when the forces are generated by the action of a fluid situated between
two parts of the vehicle moving relatively to one another); or an engine
brake (when the forces are derived from a controlled increase in the
braking action of the engine transmitted to the wheels).
1.7.‘Differenttypesofbrakingdevices’
‘Different types of braking devices’ means equipment which differs in
suchessential respects as:
1.7.1. components having different characteristics,1.7.2. a component made of materials having different characteristics
or a component different in shape or size,
1.7.3. a different assembly of the components.
1.8.‘Brakingsystemcomponent’
‘Braking system component’ means one of the individual parts which,
when assembled, constitute the braking device.
1.9.‘Continuousbraking’
‘Continuous braking’ means the braking of combinations of vehicles
through an installation having the following characteristics:
1.9.1. a single control which the driver actuates progressively, by a
single movement, from his driving seat,
1.9.2. the energy used for braking the vehicles constituting the combi-
nation of vehicles is supplied from the same source (which may
be the muscular energy of the driver),
1.9.3. the braking installation ensures simultaneous or suitably phased
braking of each of the constituent vehicles of the combination,
whatever their relative positions.
1.10.‘Semi-continuousbraking’
‘Semi-continuous braking’ means the braking of combinations of vehi-
cles through an installation having the following characteristics:
1.10.1. a single control which the driver can actuate progressively, by
a single movement, from his driving seat,
1.10.2. the energy used for braking the vehicles constituting the
combination of vehicles is supplied from two different sources
(one of which may be the muscular energy of the driver),
1.10.3. the braking installation ensures simultaneous or suitably phased
braking of each of the constituent vehicles of the combination,
whatever their relative positions.
1.11.‘Automaticbraking’
‘Automatic braking’ means braking of the trailer or trailers occurring
automatically in the event of separation of components of the combina-
tion of coupled vehicles, including such separation through coupling
breakage, without the effectiveness of the remainder of the combina-
tion being affected.1971L0320 — EN — 20.02.1974 — 002.001 — 6
▼B
1.12.‘Inertiaor“overrun”braking’
‘Inertia braking’ means braking by utilising the forces generated by the
trailer's moving up on the drawing vehicle.
1.13.‘Ladenvehicle’
‘Laden vehicle’ means, except where otherwise stated, a vehicle laden
to its ‘maximum weight’.
1.14.‘Maximumweight’
‘Maximum weight’ means the maximum weight stated by the vehicle
manufacturer to be technically permissible (this weight may be higher
than the ‘permissible maximum weight’).
2. CONSTRUCTION AND FITTING REQUIREMENTS
2.1.General
2.1.1.Braking device
2.1.1.1. The braking device must be so designed, constructed and
fitted as to enable the vehicle in normal use, despite the
vibration to which it may be subjected, to comply with
the undermentioned requirements.
2.1.1.2. In particular, the braking device must be so designed,
constructed and fitted as to be able to resist the corrosion
and ageing phenomena to which it is exposed.
2.1.2.Functions of the braking device
The braking device defined in item 1.2 must fulfil the following
conditions:
2.1.2.1. Service braking
The service braking must enable the driver to control the
movement of the vehicle and to halt it safely, speedily
and effectively, whatever its speed and load, on any up
or down gradient. It must be possible to graduate this
braking action. The driver must be able to achieve this
braking action from his driving seat without removing
his hands from the steering control.
2.1.2.2. Secondary braking
The secondary braking must make it possible to halt the
vehicle within a reasonable distance in the event of the
failure of the service braking. It must be possible to
graduate this braking action. The driver must be able to
obtain this braking action from his driving seat while
keeping at least one hand on the steering control. For
the purposes of these requirements, it is assumed that
not more than one failure of the service braking can
occur at one time.
2.1.2.3. Parking braking
The parking braking must enable the vehicle to be held
stationary on an up or down gradient even in the absence
of the driver, the working parts being then held in the
locked position by a purely mechanical device. The
driver must be able to achieve this braking action from
his driving seat, subject, in the case of a trailer, to the
requirements of item 2.2.2.10.
2.2.Characteristics ofbrakingdevices
2.2.1.Vehicles of categories M and N
2.2.1.1. The set of braking devices with which a vehicle is
equipped must satisfy the requirements laid down for
the service, secondary and parking brake
2.2.1.2. The devices providing service, secondary and parking
braking may have common components, provided that
they fulfil the following conditions:
2.2.1.2.1. there must be at least two controls, indepen-
dent of eachoth er and readily accessible to1971L0320 — EN — 20.02.1974 — 002.001 — 7
▼B
the driver from the driving seat; this require-
ment must be met even when the driver is
wearing a safety belt;
2.2.1.2.2. the control of the service braking device must
be independent of the control of the parking
braking device;
2.2.1.2.3. where the service and secondary braking
devices have the same control, the effective-
ness of the linkage between that control and
the various components of the transmission
systems must not be liable to diminishafter
a certain period of use;
2.2.1.2.4. where the service and secondary braking
devices have the same control, the parking
braking device must be so designed that it
can be actuated when the vehicle is in
motion;
2.2.1.2.5. in the event of a breakage of any component
other than the brakes (as defined in item 1.6)
or the components specified in item 2.2.1.2.7,
or of any other failure of the service braking
device (malfunction, partial or total exhaus-
tion of an energy reserve), the secondary
braking device or that part of the service
braking device which is not affected by the
failure must be able to bring the vehicle to a
halt in the conditions prescribed for
secondary braking;
2.2.1.2.6. in particular, where the secondary braking
device and the service braking device have a
common control and common transmission;
2.2.1.2.6.1. where the service braking is
actuated by the muscular energy
of the driver assisted by one or
more energy reserves, the
secondary braking must, in the
event of failure of that assistance,
be capable of being ensured by
the muscular energy of the driver
assisted by the energy reserves, if
any, which are unaffected by the
failure, the force applied to the
control not exceeding the
prescribed maxima;
2.2.1.2.6.2. where the force for the service
braking and transmission depend
exclusively on the use of an
energy reserve controlled by the
driver, there must be at least two
completely independent energy
reserves, eachprovided withits
own independent transmission;
each of them may act on the
brakes of only two or more
wheels so selected as to be
capable of ensuring by them-
selves the prescribed degree of
secondary braking without
endangering the stability of the
vehicle during braking; in addi-
tion, eachof th ese energy
reserves must be fitted witha
warning device as defined in
item 2.2.1.13;
2.2.1.2.7. for the purposes of item 2.2.1.2.5, certain
parts, such as the pedal and its bearing, the
master cylinder and its piston or pistons
(hydraulic systems), the control valve (pneu-
matic systems), the linkage between the
pedal and the master cylinder or the control
valve, the brake cylinders and their pistons
(hydraulic and/or pneumatic systems), and1971L0320 — EN — 20.02.1974 — 002.001 — 8
▼B
the lever-and-cam assemblies of brakes, shall
not be regarded as liable to breakage if they
are amply dimensioned, are readily accessible
for maintenance, and exhibit safety features
at least equal to those prescribed for other
essential components (suchas th e steering
linkage) of the vehicle. Where the failure of
any suchpart would make it impossible to
brake the vehicle with a performance at least
equal to that prescribed for the secondary
braking, that part must be made of metal or
of a material withequivalent ch aracteristics
and must not be subject to significant distor-
tion in the normal operation of the braking
devices.
2.2.1.3. Where there are separate controls for the service and
secondary braking devices, simultaneous actuation of
the two controls must not render both the service and
secondary braking devices inoperative, either when
bothbraking devices are in good working order or
when one of them is faulty.
2.2.1.4. In the event of failure in a part of the transmission of
the service brake, the following conditions must be met:
2.2.1.4.1. a sufficient number of wheels must still be
braked by actuation of the service braking
device control, whatever the vehicle load;
2.2.1.4.2. these wheels must be so selected that the
residual performance of the service braking
device is equal to not less than x% of the
performance prescribed for the category to
which the vehicle belongs, the force applied
to the control not exceeding 70 kg:
vehicles at maximum weight (all
categories) x = 30
unladen vehicles: categories M1,
M2,N1,N2x=2 5
categories M3and N3x=3 0
2.2.1.4.3. however, the above requirements shall not
apply to drawing vehicles for semi-trailers
when the transmission of the service braking
device of the semi-trailer is independent of
that of the drawing vehicle.
2.2.1.5. Where use is made of energy other than the muscular
energy of the driver, there need not be more than one
source of such other energy (hydraulic pump, air
compressor, etc.), but the means by which the device
constituting that source is driven must be completely
reliable. In the event of failure in any part of the trans-
mission of a vehicle's braking devices, the supply to the
part not affected by the failure must continue to be
ensured where this is required for the purpose of halting
the vehicle with the degree of effectiveness prescribed
for secondary braking. This condition must be met by
means of devices which can be easily actuated when
the vehicle is stationary, or by automatic means.
2.2.1.6. The requirements of items 2.2.1.2, 2.2.1.4 and 2.2.1.5
must be met without the use of any automatic device
of a kind such that its ineffectiveness might pass unno-
ticed because the parts which are normally in an ‘at
rest’ position are actuated only in the event of failure
of the braking device.
2.2.1.7. The service braking device must act on all the wheels
on the vehicle.
2.2.1.8. The action of the service braking device must be appro-
priately distributed among the axles.
2.2.1.9. The action of the service braking device must be
distributed between the wheels of the same axle
symmetrically in relation to the longitudinal median
plane of the vehicle.1971L0320 — EN — 20.02.1974 — 002.001 — 9
▼B
2.2.1.10. The service braking device and the parking braking
device must act on braking surfaces permanently
connected to the wheels through components of
adequate strength. It must not be possible to disconnect
a braking surface from the wheels; however, in the case
of the servicing device and secondary braking device,
such disconnection of the braking surfaces shall be
permitted provided that it is only momentary, for
instance during a change of gear, and that both the
service braking and the secondary braking continue to
operate withth e prescribed degree of effectiveness. In
addition, any suchdisconnection sh all be permitted in
the case of the parking braking device, provided that it
is controlled exclusively by the driver from his driving
seat by a system which cannot be actuated by a leak(1).
2.2.1.11. Wear on the brakes must be easily compensated by
means of a system of manual or automatic adjustment.
In addition, the control and the components of the
transmission and of the brakes must possess a reserve
of travel such that, when the brakes become heated or
when the brake linings have reached a certain degree
of wear, effective braking is ensured without an
immediate adjustment being necessary.
2.2.1.12. In hydraulic braking devices:
2.2.1.12.1. the filling ports of the fluid reservoirs must
be readily accessible; in addition, the
containers of reserve fluid must be so made
that the level of the reserve fluid can be
easily checked without the containers
having to be opened. Where this last condi-
tion is not fulfilled, a warning light must
indicate to the driver when the reserve fluid
falls to a level liable to cause a failure of
the braking device. The driver must be able
to check easily whether the light is func-
tioning properly;
2.2.1.12.2. the failure of a part of the hydraulic trans-
mission must be indicated to the driver by
a device embodying a red warning signal
which lights up as soon as the control is
actuated. The light must be visible even in
daylight, and the driver must be able to
check easily whether the light is in order.
Any failure of a component of the device
must not cause total loss of effectiveness of
the braking device.
2.2.1.13. Every vehicle fitted with a brake actuated from an
energy reservoir must, ►C1where braking with the
performance prescribed for secondary braking is
impossible ◄without the use of stored energy, be
fitted witha warning device, in addition to a pressure
gauge where fitted, giving an optical or acoustical
signal when the energy, in any part of the installation
preceding the control valve, falls to 65% or less of its
normal value. This device must be directly and perma-
nently connected to the circuit.
2.2.1.14. Without prejudice to the requirements of item 2.1.2.3,
where the use of an auxiliary energy source is essential
for the operation of a braking device, the energy reserve
must be such as to ensure that, should the engine stop,
the braking performance remains sufficient to bring the
vehicle to a halt in the prescribed conditions. In addi-
tion, if the muscular energy applied by the driver to
the parking braking device is reinforced by some aid,
the actuation of the parking braking must be ensured
in the event of failure of that aid, if necessary by using
a reserve of energy independent of that normally
supplying such aid. This reserve of energy may be that1971L0320 — EN — 20.02.1974 — 002.001 — 10
(1) This item must be interpreted in the following way: The performance of the service and
secondary braking devices must remain within the limits prescribed in the Directive,
even during momentary disconnection.
▼B
intended for the service braking. The expression ‘actua-
tion’ also covers the action of releasing.
2.2.1.15. In the case of a motor vehicle to which the coupling of
a trailer equipped witha brake controlled by th e driver
of the drawing vehicle is authorised, the service braking
device of the drawing vehicle must be fitted with a
device so designed that if the trailer braking device
should fail, or the air supply pipe (or such other type
of connection as may be adopted) between the drawing
vehicle and trailer should break, it will still be possible
to brake the drawing vehicle with the effectiveness
prescribed for the secondary braking; it is accordingly
prescribed, in particular, that this device be fitted to
the drawing vehicle(1).
2.2.1.16. The auxiliary equipment must draw its energy only in
such a way that its operation, even in the event of
damage to the energy source, cannot cause the reserves
of energy feeding the braking devices to fall below the
level indicated in item 2.2.1.13.
2.2.1.17. In the case of a braking device operated by compressed
air, the pneumatic link with the trailer must be of the
type withtwo or more pipes.
2.2.1.18. Where the trailer belongs to category O3or O4,t he
service braking device must be of a continuous orsemi-continuous type.
2.2.1.19. In the case of a vehicle authorised to draw a category
O
3or O4trailer, the braking devices must satisfy the
following conditions:
2.2.1.19.1. when the secondary braking device of the
drawing vehicle is actuated, there must also
be a graduated braking action on the trailer;
2.2.1.19.2. should the main braking device of the
drawing vehicle fail, and if this device is
made up of at least two independent
sections, the section or sections not affected
by this failure must be able partially or fully
to actuate the trailer brakes. It must be
possible to graduate this braking action;
2.2.1.19.3. in the case of a break or leak in one of the
air supply pipes (or in suchoth er type of
connection as may be adopted), it must
nevertheless be possible for the driver to
fully or partially actuate the trailer brakes,
by means either of the service braking
control or of the secondary braking control
or of a separate control, unless the break or
leak automatically causes the trailer to be
braked.
2.2.1.20. Except in the case of ‘urban buses’, vehicles used for
the carriage of passengers comprising more than eight
seats in addition to the driver's seat, and having a
maximum weight exceeding 10 metric tons, must
satisfy the Type II A test described in item 1.5 of
Annex II and not the Type II test described in item 1.4
of that Annex.
2.2.2.Vehicles of category O
2.2.2.1. Trailers of category O1need not be fitted witha service
braking device; however, if trailers of this category are
equipped witha service braking device th is must
comply with the same requirements as those of category
O2.
2.2.2.2. Every trailer of category O2must be fitted witha
service braking device either of the continuous or1971L0320 — EN — 20.02.1974 — 002.001 — 11
(1) This point is to be interpreted in the following way: It is essential, in all cases, that the
service braking device should be fitted with a device (for instance a limiting valve)ensuring that the vehicle can still be braked by the service brake, but with a perfor-
mance equal to that of the secondary brake.
▼B
semi-continuous type or of the inertia (overrun) type.
The latter type shall be authorised only for trailers other
than semi-trailers.
2.2.2.3. Every trailer of category O3or O4must be fitted witha
service braking device of the continuous or semi-contin-
uous type.
2.2.2.4. The service braking device must act on all the wheels
of the trailer.
2.2.2.5. The action of the service braking device must be
suitably distributed among the axles.
2.2.2.6. The action of every braking device must be distributed
between the wheels of each axle symmetrically in rela-
tion to the longitudinal median plane of the vehicle.
2.2.2.7. The braking surfaces required to attain the prescribed
degree of effectiveness must be in constant contact
with the wheels, either rigidly or through components
not liable to failure.
2.2.2.8. Wear on the brakes must be easily compensated by a
system of manual or automatic adjustment. In addition,
the control and the components of the transmission and
of the brakes must possess a reserve of travel such that,
when the brakes become heated or when the brake
linings have reached a certain degree of wear, braking
is ensured without immediate adjustment being neces-
sary.
2.2.2.9. The braking devices must be such that the trailer is
stopped automatically if the coupling breaks while the
trailer is in motion. However, this requirement shall
not apply to single-axled trailers witha maximum
weight not exceeding 1·5 metric tons provided that the
trailers are fitted, in addition to the main coupling, with
a secondary coupling (chain, cable, etc.) which, in the
event of breakage of the main coupling, can stop the
drawbar from touching the ground and provide some
residual steering action on the trailer.
2.2.2.10. On every trailer which is required to be fitted with a
service braking device, parking braking must be
ensured even when the trailer is separated from the
drawing vehicle. It must be possible for a person
standing on the ground to actuate the parking braking
device; however, in the case of a trailer used for the
carriage of passengers, it must be possible to actuate
this brake from inside the trailer. The expression
‘actuate’ also covers the action of releasing.
2.2.2.11. Where a trailer is fitted with a device enabling
compressed-air actuation of the braking device to be
cut out, the first-mentioned device must be so designed
and constructed that it is positively restored to the ‘at
rest’ position not later than on the resumption of the
supply of compressed air to the trailer.1971L0320 — EN — 20.02.1974 — 002.001 — 12
▼B
ANNEX II
BRAKINGTESTSANDPERFORMANCEOFBRAKINGDEVICES
1. BRAKING TESTS
1.1.General
1.1.1. The performance prescribed for braking devices shall be based on
the stopping distance. The performance of a braking device shall
be determined either by measuring the stopping distance in rela-
tion to the initial speed or by measuring the reaction time of the
device and the mean deceleration in normal operation as
prescribed in Annex III.
1.1.2. The stopping distance shall be the distance covered by the vehicle
from the moment when the driver begins to actuate the control of
the device until the moment when the vehicle stops; the initial
speed shall be the speed at the moment when the driver begins
to actuate the control of the device. In the formulae given below,
for the measurement of braking performance,
v = initial speed in km/h
s = stopping distance in metres.
1.1.3. For the type approval of any vehicle, the braking performance
shall be measured during road tests conducted in the following
conditions:
1.1.3.1. the vehicle's condition as regards weight must be as
prescribed for eachtype of test and be specified in th e
test report;
1.1.3.2. the test must be carried out at the speeds prescribed for
each type of test. Where a vehicle is so constructed that
its maximum speed is lower than that prescribed for a
test, the test must be performed at the maximum speed
of the vehicle;
1.1.3.3. during the tests the force applied to the brake control in
order to obtain the prescribed performance must not
exceed the maximum laid down for the test vehicle's
category;
1.1.3.4. ►M1without prejudice to the requirements contained in
item 1.1.4.2 below, the road shall possess a surface
having good adhesion ◄;
1.1.3.5. the tests must be performed when there is no wind liable
to affect the results;
1.1.3.6. at the start of the tests the tyres must be cold and at the
pressure prescribed for the load actually borne by the
wheels when the vehicle is stationary;
1.1.3.7. the prescribed performance must be obtained without
locking of the wheels, without deviation of the vehiclefrom its course, and without abnormal vibration.
1.1.4.Behaviour of the vehicle during braking
1.1.4.1. In braking tests, and in particular in those at high speed,
the general behaviour of the vehicle during braking must
be checked.
1.1.4.2. The behaviour of vehicles in categories M
1,M2,M3,N1,
N2,N3,O3and O4on a road surface having reduced adhe-
sion shall fulfil the conditions laid down in the
Appendix.
1.2.TypeOtest
(ordinary performance test withbrakes cold)1971L0320 — EN — 20.02.1974 — 002.001 — 13
▼M1
▼B
▼B
1.2.1.General
1.2.1.1. The brakes must be cold. A brake is deemed to be cold
when the temperature measured on the disc or on the
outside of the drum is below 100ºC.
1.2.1.2. The test must be conducted in the following conditions:
1.2.1.2.1. the vehicle must be laden, the distribution of
its weight among the axles being that stated
by the maker. Where provision is made for
several arrangements of the load on the axles
the distribution of the maximum weight among
the axles must be such that the load on each
axle is proportional to the maximum permis-
sible load for eachaxle;
1.2.1.2.2. in the case of a motor vehicle, every test must
be repeated on the unladen vehicle carrying
only the driver and possibly one person—pre-
ferably sitting on the front seat—responsible
for noting the results of the test;
1.2.1.2.3. the limits prescribed for minimum perfor-
mance, both for tests with the vehicle unladen
and for tests with the vehicle laden, shall be
those laid down hereunder for each category
of vehicle;
1.2.1.2.4. the road must be level.
1.2.2.Type O test with engine disconnected
1.2.2.1. The test must be carried out at the speed prescribed for
the category to which the vehicle belongs, the figures
prescribed in this connection being subject to a certain
margin of tolerance. The minimum performance
prescribed for eachcategory must be attained.
1.2.3.Type O test with engine connected
1.2.3.1. Apart from the tests prescribed in item 1.2.2, additional
tests shall be carried out at various speeds with the
engine connected, the lowest being equal to 30% of the
maximum speed of the vehicle and the highest being
equal to 80% of that speed. The performance figures
measured and the behaviour of the vehicle shall be
recorded in the test report.
1.3.TypeItest
(fade test)1.3.1.With repeated braking
1.3.1.1. The service brakes of vehicles in categories M
1,M2,M3,
N1,N2and N3shall be tested by successively applying
and releasing the brakes a number of times, the vehicle
being laden, in accordance with the conditions shown in
the following table:
Conditions
Category
of vehiclev1
km/hv2
km/h∆t
secsn
M180% vmax-≤120½v145 15
M280% vmax-≤100½v155 15
M380% vmax-≤60½v160 20
N180% vmax-≤120½v155 15
N280% vmax-≤60½v160 201971L0320 — EN — 20.02.1974 — 002.001 — 14
▼B
Conditions
Category
of vehiclev1
km/hv2
km/h∆t
secsn
N380% vmax-≤60½v160 20
where:
v1= initial speed, when braking starts,
v2= speed at end of braking,
vmax= maximum speed of the vehicle,
n = number of times brakes applied,∆t = duration of a braking cycle (time elapsing
between the initiation of one brake application
and the initiation of the next).
1.3.1.2. If the characteristics of the vehicle do not allow for the
period of time prescribed for ∆t, the duration may be
increased; in any event, in addition to the time necessary
for braking and accelerating the vehicle, a period of 10
seconds must be allowed in eachcycle for stabilising
the speed v
1.
1.3.1.3. In these tests, the force applied to the control must be so
adjusted as to attain a mean deceleration of 3 m/sec2at
the first application of the brakes. This force must
remain constant throughout the succeeding brake applica-
tions.
1.3.1.4. During brake applications the highest gear ratio
(excluding overdrive, etc.) must be continuously
engaged.
1.3.1.5. For regaining speed after braking, the gearbox must be
used in sucha way as to attain th e speed v1in the
shortest possible time (maximum acceleration allowed
by the engine and gearbox).
1.3.2.With continuous braking
1.3.2.1. The service brakes of trailers of categories O3and O4shall be tested in such a manner that, the vehicle being
laden, the energy input to the brakes is equivalent to
that recorded in the same period of time with a laden
vehicle driven at a steady speed of 40 km/h on a 7%
down gradient for a distance of 1·7 km.
1.3.2.2. The test may be carried out on a level road, the trailer
being drawn by a motor vehicle; during the test, the
force applied to the control must be adjusted so as to
keep the resistance of the trailer constant (7% of the
weight of the trailer). If the power available for hauling
is insufficient, the test can be conducted at a lower speed
but over a greater distance, as shown in the following
table:
Speed
(km/h)Distance
(metres)
40 1 700
30 1 950
20 2 500
15 3 100
1.3.3.Residual performance
1.3.3.1. At the end of the Type I test (test described in item
1.3.1. or test described in item 1.3.2 of this Annex) the
residual performance of the service braking device shall
be measured under the same conditions as for the Type
O test with the engine disconnected (the temperature
conditions may be different); this residual performance
must not be less than 80% of that prescribed for the cate-1971L0320 — EN — 20.02.1974 — 002.001 — 15
▼B
gory in question nor less than 60% of the figure recorded
in the Type O test with the engine disconnected.
1.4.TypeIItest
(downhill behaviour test)1.4.1. Laden vehicles shall be tested in such a manner that the energy
input is equivalent to that recorded in the same period of time
witha laden veh icle driven at an average speed of 30 km/hon a
6% down gradient for a distance of 6 km, withth e appropriate
gear engaged (if the vehicle is a motor vehicle) and the retarder,
if the vehicle is fitted with one, being used. The gear engaged
must be such that the rpm of the engine does not exceed the
maximum value prescribed by the manufacturer.
1.4.2. For vehicles in which the energy is absorbed by the braking
action of the engine alone, a tolerance of ± 5 km/h on the average
speed shall be permitted, and the gear enabling the speed to be
stabilised at the value closest to 30 km/h on the 6% down
gradient shall be engaged. If the performance of the braking
action of the engine alone is determined by a measurement of
deceleration, it shall be sufficient if the mean deceleration
measured is at least 0·5 m/sec
2.
1.4.3. At the end of the test, the residual performance of the service
braking device shall be measured in the same conditions as for
the Type O test with the engine disconnected (the temperature
conditions, of course, are different); this residual performance
must not be less than 75% of that prescribed for the Type O test
withth e engine disconnected.
1.5.TypeIIAtest
(test for vehicles, other than ‘urban buses’, used for the carriage of
passengers comprising more than eight seats in addition to the driver'sseat and having a maximum weight exceeding 10 metric tons)
1.5.1. Laden vehicles shall be tested in such a manner that the energy
input is equivalent to that recorded in the same period of time
witha laden veh icle driven at an average speed of 30 km/hon a
7% down gradient for a distance of 6 km. During the test, the
service, secondary and parking braking devices must not be
engaged. The gear engaged must be such that the rpm of the
engine does not exceed the maximum value prescribed by the
manufacturer.
1.5.2. For vehicles in which the energy is absorbed by the braking
action of the engine alone, a tolerance of ± 5 km/h on the average
speed shall be permitted and the gear enabling the speed to be
stabilised at the value closest to 30 km/h on a 7% down gradient
shall be engaged. If the performance of the braking action of the
engine alone is determined by a measurement of deceleration, it
shall be sufficient if the mean deceleration measured is at least
0·6 m/sec
2.
2. PERFORMANCE OF BRAKING DEVICES
2.1.Vehiclesofcategories MandN
2.1.1.Service braking devices
2.1.1.1. Provisions relating to tests
2.1.1.1.1. The service brakes of vehicles of categories
M1,M2,M3,N1,N2and N3shall be tested
under the conditions shown in the following
table:
M1M2M3N1N2N3
Type of
test 0—I 0—I 0—I—II 0—I 0—I 0—I—II
v 80 km/h 60 km/h60 km/h70 km/h50 km/h40 km/h
s≤0/C11vþv2
1500/C115 v þv2
1300/C115 v þv2
115
dm≥ 5·8 m/s25 m/s24·4 m/s21971L0320 — EN — 20.02.1974 — 002.001 — 16
▼B
M1M2M3N1N2N3
f≤ 50 kgf 70 kgf 70 kgf 70 kgf 70 kgf 70 kgf
where:
v = test speed
s = stopping distancedm = mean braking deceleration at normal
engine speed
f = force applied to foot control
2.1.2.Secondary braking devices
2.1.2.1. The secondary braking, even if the device which actuates
it is also used for other braking functions, must give a
stopping distance not exceeding the first term plus twice
the second term of the binomial expression giving the
service-braking stopping distance for the category in
question.
2.1.2.2. If the secondary braking control is a manual control, the
prescribed performance must be obtained by applying to
the control a force not exceeding 40 kgf in the case of
category M
1vehicles and 60 kgf in the case of other
vehicles, and the control must be so placed that it can
be easily and quickly grasped by the driver.
2.1.2.3. If the secondary braking control is a foot control, the
prescribed performance must be obtained by applying to
the control a force not exceeding 50 kgf in the case of
category M1vehicles and 70 kgf in the case of other
vehicles, and the control must be so placed that it can
be easily and quickly actuated by the driver.
2.1.2.4. The performance of the secondary braking device shall
be checked by the Type O test.
2.1.3.Parking braking devices
2.1.3.1. The parking braking device must, even if it is combined
with one of the other braking devices, be capable of
holding a laden vehicle stationary on an 18% up or
down gradient.
2.1.3.2. On vehicles to which the coupling of a trailer is
authorised, the parking braking device of the drawing
vehicle must be capable of holding the combination of
vehicles stationary on a 12% gradient.
2.1.3.3. If the control is a manual control, the force applied to it
must not exceed 40 kgf in the case of category M1vehi-
cles and 60 kgf in the case of all other vehicles.
2.1.3.4. If it is a foot control, the force exerted on the control
must not exceed 50 kgf in the case of category M1vehi-
cles and 70 kgf in the case of all other vehicles.
2.1.3.5. A parking braking device which has to be actuated
several times before attaining the prescribed performance
is admissible.
2.2.Vehiclesofcategory O
2.2.1.Service braking devices
2.2.1.1. Requirement relating to tests of category O1vehicles.
2.2.1.1.1. Where the provision of a service braking
device is mandatory, the performance of the
device must meet the requirements laid down
for category O2.
2.2.1.2. Requirements relating to tests of category O2vehicles.
2.2.1.2.1. Where the service braking device of the trailer
is of the continuous or semi-continuous type,
the sum of the forces exerted at the periphery
of the braked wheels must be equal to not less1971L0320 — EN — 20.02.1974 — 002.001 — 17
▼B
than 45% of the maximum weight borne by
the wheels when the vehicle is stationary.
Where the trailer is fitted with a compressed
air brake, the check must be made with a pres-
sure not exceeding 6·5 bars in the brake
cylinders(1).
2.2.1.2.2. Where the braking device is of the inertia
type, it must comply withth e conditions laid
down in Annex VIII.
2.2.1.2.3. In addition, these vehicles must be subjected
to the Type I test.
2.2.1.2.4. In the Type I test of a semi-trailer, the weight
braked by its axles must be that corresponding
to the load on the axle or axles of the semi-
trailer when the latter is carrying its maximum
load.
2.2.1.3. Requirements relating to tests of category O3vehicles.
The same requirements apply as apply to category O2;i n
addition, these vehicles must undergo the Type I test.
2.2.1.4. Requirements relating to tests of category O4vehicles.
2.2.1.4.1. The same requirements apply as apply to cate-
gory O2; in addition, these vehicles must be
subjected to the Type I and Type II tests.
2.2.1.4.2. In the Type I and Type II tests of a semi-
trailer, the weight braked by its axles must be
that corresponding to the load on the axle or
axles of the semi-trailer when the latter is
carrying its maximum load.
2.2.2.Parking braking devices
2.2.2.1. The parking brake with which the trailer or semi-trailer
is fitted must be capable of holding the laden trailer or
semi-trailer stationary, when separated from the drawing
vehicle, on an 18% up or down gradient. The force
applied to the control must not exceed 60 kgf.
2.3.Reactiontime
Where a vehicle is fitted with a service braking device which is totally
or partially dependent on a source of energy other than the muscular
effort of the driver, the following requirements must be satisfied:
2.3.1. in an emergency manoeuvre, the time clapsing between the
moment when the control begins to be actuated and the moment
when the braking force on the least favourably placed axle
reaches the level corresponding to the prescribed performance
must not exceed 0·6 seconds;
2.3.2. the requirements of Annex III shall apply to compressed air
devices withdouble pipes.1971L0320 — EN — 20.02.1974 — 002.001 — 18
(1) The pressures specified here and in the following Annexes are relative pressures
measured in bars.
▼M1
Appendix (See 1.1.4.2)
DISTRIBUTIONOFBRAKINGEFFORTAMONGVEHICLEAXLES
1. GENERAL REQUIREMENTS
Vehicles of categories M1,M2,M3,N1,N2,N3,O3and O4which are not fitted
with a wheel anti-locking device shall fulfil the conditions of the present
Appendix.
2. NOTATION
i = axle index (i = 1, front axle; i = 2, rear axle).
Pi= normal reaction of road surface on axle i under static conditions.
Ni= normal reaction of road surface on axle i under braking.
Ti= force exerted by the brakes on axle i.
fi=Ti/Niadhesion used by axle i.
J = deceleration of vehicle.
g = acceleration of gravity = 10 m/s2.
z = braking ratio of vehicle = J/g(1)
P = weight of vehicle.h = height of centre of gravity.E = wheelbase.k = theoretical coefficient of adhesion between tyre and road.
Adhesion curves used by the vehicle means curves showing the adhesion
used by the front axle and the rear axle plotted against the vehicle braking
ratio on the specified load conditions.
3. REQUIREMENTS FOR MOTOR VEHICLES
3.1.Twoaxlevehicles
3.1.1.(
2) Under all load conditions of the vehicle the adhesion curve for the
front wheels shall be above that for the rear wheels:
— for all braking ratios of between 0·15 and 0·8 in the case of
vehicles of category M1;
— for braking ratios of between 0·15 and 0·30 in the case of vehi-
cles of other categories, with the exeption of urban buses.
In addition, for k values of between 0·2 and 0·8,
3.1.2. The above conditions shall be fulfilled automatically.
3.1.3. The pressure at the coupling head of a motor vehicle authorized to
draw a trailer fitted with air brakes shall not be affected by the
operation of the pressure-regulating devices on the axles of the
drawing vehicle.
3.1.4. In order to verify the requirement of item 3.1.1., the manufacturer
shall provide the adhesion utilization curves for the front and rear
axles calculated by the formulas:1971L0320 — EN — 20.02.1974 — 002.001 — 19
(1) For semi-trailers z is the braking force divided by the static weight on the trailer
axle(s).
(2) The requirement for Item 3.1.1 shall not be interpreted as requiring a level of efficiency
higher than that laid down in Annex II.
▼M1
f1¼T1
N1¼T1
P1þzh
EPf2¼T2
N2¼T2
P2/C0zh
EP
3.1.4.1. Vehicles other than tractive units for semi-trailers.
The graphs shall be plotted for both the following load conditions:
— unladen, in running order withth e driver on board,
— laden. Where provision is made for several possibilities of load
distribution, the one whereby the front axle is the most heavily
laden shall be the one to be taken into consideration.
The values specified by the manufacturer shall be taken for h.
3.1.4.2. Tractive units for semi-trailers.
3.1.4.2.1. Solotractive units. The graphs shall be plotted for an unladen
vehicle in running order with the driver on board and h shall be
taken as the value specified by the manufacturer.
3.1.4.2.2. Laden tractive units. The dynamic load of the semi-trailer on the
tractive unit shall be represented by a static weight Psapplied to
the coupling kingpin, equal to:
Ps¼Pso1þ0/C145 z ðÞ
where Psorepresents the difference between the maximum laden
weight of the tractive unit and its unladen weight.
For h the following value shall be takenhoPoþhsPs
P
where
—hois the value specified in item 3.1.4.2.1,
—hsis the height of the plane of the coupling on which the semi-
trailer rests.
—Pois the unladen weight of the solotractive unit,
—P=Po+Ps.
3.2.Vehicleswithmorethantwoaxles
The requirements of Item 3.1. shall apply to vehicles with more
than two axles. These requirements shall be considered to be met,
if, in the case of braking ratios between 0·15 — 0·30, the adhesion
used by the front axle is greater than that used by at least one of
the rear axles.
4. REQUIREMENTS FOR SEMI-TRAILERS
4.1. The following requirements shall only apply to semi-trailers fitted with
compressed air brakes.
4.2. The braking systems fitted to these semi-trailers shall be such that the
curve representing the braking ratio of the semi-trailer's axles plotted
against the service line pressure measured at the coupling head within
the hatched area of the attached diagram.
4.3. This requirement shall be met for all permissible load conditions of the
semi-trailer axles.
5. REQUIREMENTS FOR TRAILERS
5.1. The following requirements shall only apply to trailers fitted with air
brakes. They shall not apply to single-axle trailers nor to twin-axle trai-
lers where the axle spread is less than 2 metres.
5.2. The requirements set out in item 3.1 shall apply to twin-axle trailers not
excluded by the requirements contained in 5.1.
5.3. Trailers with more than two axles shall be subject to the requirements
contained in item 3.2.1971L0320 — EN — 20.02.1974 — 002.001 — 20
▼M1
6. CONDITIONS TO BE FULFILLED IN THE CASE OF FAILURE OF THE
BRAKING DISTRIBUTION SYSTEM
When the requirements of this Appendix are met by means of a special
device (e.g., controlled mechanically by the suspension of the vehicle), it
shall be possible in the case of failure of this device or its control unit to
stop the vehicle under the conditions prescribed for emergency braking.
7. MARKINGS
7.1. Vehicles, other than those of category M1, which meet the requirements
of this Appendix by means of a device mechanically controlled by the
suspension of the vehicle, shall be marked to show the useful travel of
the device between the positions corresponding to vehicle unladen and
laden states respectively.
7.2. When the requirements of this Appendix are met by means of a device
actuated by compressed air, the vehicle shall be marked to show the
pressure values at the outlet side of the device during full braking of
the vehicle under both unladen and laden conditions.
7.3. The markings referred to under items 7.1 and 7.2 above shall be affixed
in a visible position in indelible form.
8. VEHICLE INSPECTION
During the EEC type-approval testing of a vehicle the technical inspection
authority shall verify conformity with the requirements contained in the
present Appendix and carry out any further tests considered necessary to
this end. The report on the additional tests shall be appended to the EEC
type-approval certificate.1971L0320 — EN — 20.02.1974 — 002.001 — 21
▼M1
Diagram(Seeitem4.2oftheAppendix)
1971L0320 — EN — 20.02.1974 — 002.001 — 22
▼B
ANNEX III
METHODOF MEASURING THE REACTION TIME FOR VEHICLES
FITTEDWITH COMPRESSEDAIR BRAKING D EVICES WITH
DOUBLEPIPES
1. GENERAL REQUIREMENTS
1.1. The reaction time for the braking device shall be determined with the
vehicle stationary, the pressure being measured at the opening of the
least efficient brake cylinder.
1.2. During the tests, the stroke of the brake cylinders of the individual axles
must be that corresponding to the most closely adjusted brakes.
1.3. The following tests shall apply to standard road trains for which the
maximum pressure in the feed pipe varies between 6·5 and 8·0 bars
and the maximum pressure in the control pipe is between 6·0 and
7·5 bars.
1.4. Pressures differing from those specified in item 1·3 may be used for
components designed for other pressure maxima levels at the coupling
heads. In such cases, this must be noted in the test report; a plate indi-
cating clearly the operating pressure maxima and minima must be fixed
to the vehicle.
2. MOTOR VEHICLES
2.1. At the start of each test, the pressure in the reservoirs must be equal to
the minimum pressure at which the governor starts feeding the installa-
tion again. In installations not fitted witha governor (e.g. pressure
limited compressor) the pressure in the reservoir at the start of each
test must be equal to 90% of the pressure stated by the manufacturer,
as defined in item 1.2.2.1 of Annex IV, to be used for tests prescribed
in this Annex.
2.2. Reaction times in terms of actuation time (tf) shall be obtained by a
series of actuations to the fullest extent, starting from the shortest
possible up to a time of about 0·4 seconds. The values measured must
be given on a diagram.
2.3. Reaction times corresponding to an actuation time of 0·2 seconds shall
be determinant for the test. This reaction time can be obtained from the
diagram by interpolation.
2.4. In the case of the actuation time of 0·2 seconds, the time elapsing
between the beginning of actuation of the control pedal and the moment
when the pressure in the brake cylinder reaches 75% of its asymptotic
value must not exceed 0·6 seconds.
The value thus noted may be rounded to the nearest tenth of a second.
2.5. In the case of motor vehicles having a brake coupling for trailers, it is
advisable, as an exception to the requirements of item 1.1, not tomeasure the reaction time at the braking cylinder, but at the extremity
of a pipe witha lengthof about 2·5 metres and an internal diameter of
13 mm which shall be joined to the brake coupling (coupling head) of
the motor vehicle.
2.6. The time which elapses between the start of the activation of the control
pedal and the moment when the pressure measured at the coupling head
of the control pipe reaches x% of its asymptotic value must not exceed
the values listed in the table below:
x (%) t (seconds)
10 0·2
75 0·4
3. TRAILERS (including semi-trailers)
3.1. The reaction times for trailers shall be measured without a drawing
vehicle. To simulate the drawing vehicle it is necessary to provide a
simulator to which the coupling heads of the control pipe and of the
feed pipe of the trailer are to be connected.1971L0320 — EN — 20.02.1974 — 002.001 — 23
▼B
3.2. The pressure in the feed pipe must be 6·5 bars. The pressure in the
reservoir or reservoirs of the trailer must be that corresponding to a
pressure of 6·5 bars in the feed pipe.
3.3. The simulator must have the following features:
3.3.1. it must have a thirty litre reservoir filled to a pressure of 6·5 bars;3.3.2. it must be adjusted in sucha way th at if a tube witha lengthof
2·5 metres and an internal diameter of 13 mm is joined to it, the
time taken for the pressure to increase from 10% to 75%, i.e.
from 0·65 bars to 4·9 bars, would be 0·2 seconds. Between these
two values, the pressure must increase in an approximately linear
way. The sketch in the Appendix to this Annex gives an example
of the correct use of the simulator.
3.4. The time elapsing between the moment when the pressure produced in
the control pipe by the simulator reached 10% of the asymptotic pres-
sure and the moment when the pressure in the brake cylinder of the
trailer reaches 75% of its asymptotic value must not exceed 0·4 seconds.1971L0320 — EN — 20.02.1974 — 002.001 — 24
▼B
APPENDIX
Simulator(see3.3.2)
1971L0320 — EN — 20.02.1974 — 002.001 — 25
▼B
ANNEX IV
ENERGY RESERVOIRS ANDSOURCES OF ENERGY FOR
COMPRESSEDAIRBRAKES
1. CAPACITY OF RESERVOIRS
1.1.General requirements
1.1.1. Vehicles on which the operation of the braking devices depends
on the use of compressed air must be fitted with reservoirs of a
capacity meeting the requirements of items 1.2 and 1.3 below.
1.1.2. Nevertheless, the capacity of reservoirs shall not be laid down
where the braking system is such that in the absence of any
energy reserve it is possible to achieve a braking performance at
least equal to that prescribed for the secondary braking.
1.1.3. When verifying compliance with the requirements of items 1.2
and 1.3 the brakes must be adjusted as closely as possible.
1.2.Motorvehicles
1.2.1. The reservoirs of brakes of motor vehicles must be such that after
eight full-stroke actuations of the service braking control it is still
possible to achieve the performance prescribed for secondary
braking.
1.2.2. During the test, the following requirements are to be satisfied:
1.2.2.1. The initial pressure in the reservoirs must be that indi-
cated by the manufacturer. This pressure must be such
as to enable the prescribed performance for the service
braking to be achieved;
1.2.2.2. The reservoir or reservoirs must not be replenished; in
addition, the reservoir or reservoirs of auxiliary equip-
ment must be isolated;
1.2.2.3. In the case of motor vehicles to which the coupling of a
trailer or semi-trailer is authorised, the feed line must be
blocked off and a reservoir of 0·5 litre capacity must be
connected to the control line. The pressure in this reser-
voir must be exhausted before each actuation of the
brakes. After the test referred to in item 1.2.1 the pres-
sure in the control line must not be less than one half of
the pressure obtained at the first brake application.
1.3.Trailers (includingsemi-trailers)
1.3.1. Reservoirs fitted to trailers must be such that after eight full-
stroke actuations of the drawing vehicle's service braking device,
the pressure supplied to the operating parts using it is not less
than one half of the pressure obtained at the first brake applica-
tion.
1.3.2. During the test, the following requirements are to be satisfied:
1.3.2.1. The pressure in the reservoirs at the beginning of the test
must be equal to the maximum specified by the manufac-
turers;
1.3.2.2. The feed line must be blocked off; in addition, the
auxiliary equipment reservoirs must be isolated;
1.3.2.3. There must be no significant replenishment of the reser-
voir during the test;
1.3.2.4. For each application of the brakes, the pressure in the
control pipe must correspond to the maximum specified
by the manufacturer.
2. CAPACITY OF ENERGY SOURCES
2.1.General provisions
Compressors must satisfy the requirements laid down in the following
items:1971L0320 — EN — 20.02.1974 — 002.001 — 26
▼B
2.2.Definitions
2.2.1. p1is the pressure corresponding to 65% of the pressure p2defined
in item 2.2.2
2.2.2. p2is the value specified by the manufacturer and referred to in
item 1.2.2.1
2.2.3. T1is the time required for the relative pressure to rise from O to
p1;T2is the time required for the relative pressure to rise from O
to p2.
2.3.Conditionsofmeasurement
2.3.1. In all cases the rpm speed of the compressor shall be that
obtained when the engine is running at the speed corresponding
to its maximum power or at the speed allowed by the control
valve.
2.3.2. The auxiliary equipment reservoirs shall be isolated during the
tests for determining the periods T1and T2.
2.3.3. On motor vehicles constructed to draw trailers, the trailer shall be
represented by a reservoir whose maximum relative pressure p
(expressed in bars) is that which can be supplied through the
feed circuit of the drawing vehicle and whose volume V
(expressed in litres) is given by the formula p · V = 20 R (R
being the permissible maximum load, expressed in metric tons,
on the axles of the trailer or semi-trailer).
2.4.Interpretationofresults
2.4.1. The time T1for the least efficient reservoir must not exceed:
— three minutes in the case of vehicles to which the coupling of
a trailer or semi-trailer is not authorised;
— six minutes in the case of vehicles to which the coupling of a
trailer or semi-trailer is authorised.
2.4.2. The time T2for the least efficient reservoir must not exceed:
— six minutes in the case of vehicles to which the coupling of a
trailer or semi-trailer is not authorised;
— nine minutes in the case of vehicles to which the coupling of
a trailer or semi-trailer is authorised.
2.5.Additionaltest
2.5.1. When the vehicle is equipped with an auxiliary equipment reser-
voir or reservoirs witha total capacity exceeding 20% of th e total
capacity of the brake reservoirs, an additional test must be carried
out during the course of which there must be no interference with
the functioning of the valves controlling the filling of the
auxiliary equipment reservoir(s). A check must be made during
the course of this test that the period T3required to bring about
a rise in the pressure in the brake reservoirs from O to p2is less
than:
— eight minutes in the case of vehicles to which the coupling of
a trailer or semi-trailer is not authorised;
— eleven minutes in the case of vehicles to which the coupling
of a trailer or semi-trailer is authorised.1971L0320 — EN — 20.02.1974 — 002.001 — 27
▼B
ANNEX V
SPRINGBRAKES
1. DEFINITION
‘Spring brakes’ are braking devices for which the energy required for braking
is supplied by one or more springs acting as an energy accumulator.
2. GENERAL REQUIREMENTS
2.1. A spring brake shall not be used as a service brake.
2.2. A small variation in any of the pressure limits which may occur in the
brake compression chamber feed circuit must not cause a significant
variation in the braking force.
2.3. The feed circuit to the spring compression chamber must include an
energy reserve which does not supply any other device or equipment.
This provision shall not apply if the springs can be maintained in the
compressed state by using two or more independent systems.
2.4. The device must be so designed that it is possible to apply and release
the brakes at least three times starting with an initial pressure in the
spring compression chamber equal to the maximum design pressure.
This requirement must be met when the brakes are adjusted as closely
as possible.
2.5. The pressure in the compression chamber beyond which the springs
begin to actuate the brakes, the latter being adjusted as closely as
possible, must not be greater than 80% of the minimum level (pm) of
the normal available pressure.
2.6. When the pressure in the compression chamber falls to the level at
which the brake parts begin to move, an optical or audible warning
device must be actuated. Provided this requirement is met, the warning
device may be that specified in item 2.2.1.13 of Annex I.
2.7. On motor vehicles fitted with spring brakes and authorised to draw trai-
lers withcontinuous or semi-continuous brakes, automatic application of
the spring brakes must cause the trailer brakes to be applied.
3. RELEASE SYSTEM
3.1. Spring brakes must be so designed that, in the event of failure, it is
possible to release them without using their normal control. This may
be achieved by the use of an auxiliary device (pneumatic, mechanical,
etc.).
3.2. If the operation of the auxiliary device referred to in item 3.1 requires
the use of a tool or spanner, the tool or spanner must be kept on the
vehicle.1971L0320 — EN — 20.02.1974 — 002.001 — 28
▼B
ANNEX VI
PARKING BRAKING BY MECHANICAL LOCKING OF THE BRAKE
CYLINDERS
(lockactuators)
1. DEFINITION
‘Mechanical locking of the brake cylinders’ means a device for ensuring
parking braking by mechanical wedging of the brake piston rod.
Mechanical locking occurs when the locking chamber is emptied of
compressed air; the mechanical locking device shall be designed in such a
way that it can be released when the locking chamber is again subjected to
pressure.
2. SPECIAL PROVISIONS
2.1. When the pressure in the locking chamber approaches the level corre-
sponding to mechanical locking, an optical or audible warning system
must be actuated.
2.2. In the case of brake actuators fitted with a mechanical locking device,
the brake actuator must be capable of being actuated by either of two
energy reserves.
2.3. The locked brake cylinder may only be released if it is certain that the
brake can be operated again after suchrelease.
2.4. In the event of a failure of the source of energy supplying the locking
chamber, an auxiliary unlocking device (mechanical or pneumatic, for
instance) using, for example, the air in one of the tyres of the vehicle,
must be provided.1971L0320 — EN — 20.02.1974 — 002.001 — 29
▼B
ANNEX VII
CASESINWHICHTYPEIAND/ORII(ORIIA)TESTSDONOTHAVE
TO BE CARRIEDOUT ON A VEHICLE SUBMITTEDFOR TYPE
APPROVAL
1. Type I and/or II (or II A) tests do not have to be carried out on a vehicle
submitted for type approval in the following three cases:
1.1. where the vehicle in question is a motor vehicle, a trailer or a semi-
trailer which, in respect of tyres, braking energy absorbed by each axle
and method of fitting of tyres and brakes, is identical, as far as braking
is concerned, to a motor vehicle, a trailer, or a semi-trailer which:
1.1.1. has passed a Type I and/or II (or II A) test;1.1.2. has been type approved, with regard to braking energy absorbed,
for axle weights greater than or equal to those of the vehicle
submitted for type approval.
1.2. where the vehicle in question is a motor vehicle, a trailer or a semi-
trailer of which the axle or axles, in respect of tyres, braking energy
absorbed by eachaxle and meth od of fitting of tyres and brakes, is or
are identical, as far as braking is concerned, to an axle or axles which
has or have individually passed a Type I and/or II test for axle weights
greater than or equal to those of the vehicle submitted for type approval,
provided that the braking energy absorbed by each axle does not exceed
the energy absorbed by that axle during the reference test or tests carried
out separately on that axle.
1.3. where the vehicle submitted for type approval is fitted with a retarder,
other than an engine brake, identical to a retarder which has already
been tested under the following conditions:
1.3.1. in a test carried out on a gradient of at least 6% (Type II test) or
of at least 7% (Type II A test), this retarder has, on its own, stabi-
lised the speed of a vehicle with a maximum weight at the time
of testing at least equal to the maximum weight of the vehicle
submitted for type approval;
1.3.2. in the above test, a check must be made as to whether the speed
of rotation of the revolving parts of the retarder is such that,
when the vehicle submitted for type approval is travelling at a
speed of 30 km/h, the retarding torque is at least equal to the
retarding torque in the test mentioned in item 1.3.1.
2. The term ‘identical’ as used in items 1.1, 1.2 and 1.3 means identical as
regards the geometrical and mechanical characteristics of the vehicle parts
mentioned in those items, and also as regards the characteristics of the mate-
rials from which these parts are made.
3. When advantage is taken of the above provisions, the type approval commu-
nication in respect of braking (Annex IX) must contain the following
particulars:
3.1. where item 1.1 is applicable, the type of the approval number of the
vehicle on which the Type I and/or II (or II A) test serving as a refer-
ence test has been carried out (item 14.7.1 of Annex IX);
3.2. where item 1.2 is applicable, the table in item 14.7.2 of the model item
of the communication in Annex IV must be completed;
3.3. where item 1.3 is applicable, the table in item 14.7.3 of the model of the
communication in Annex IX must be completed.
4. When a person applying for type approval in a Member State refers to a type
approval granted in another Member State, that person must produce the
documents relating to suchapproval.1971L0320 — EN — 20.02.1974 — 002.001 — 30
▼B
ANNEX VIII
CONDITIONSGOVERNINGTHETESTINGOFVEHICLESEQUIPPED
WITHINERTIA(OVERRUN)BRAKES
1. GENERAL PROVISIONS
1.1. The inertia (overrun) braking device of a trailer comprises the control
device, the transmission and the brakes proper, hereinafter called
‘brakes’.
1.2. The control device is the combination of components comprising the
coupling head.
1.3. The transmission is the combination of components comprised between
the coupling head and the first part of the brake.
1.4. The ‘brake’ is the part in which the forces opposing the movement of
the vehicle develop. The first part of the brake is either the lever
actuating the brake cam or similar parts (mechanical-transmission
inertia brake) or the brake cylinder (hydraulic-transmission inertia
brake).
1.5. Braking devices in which accumulated energy (for instance, electric,
pneumatic or hydraulic) is transmitted to the trailer by the drawing
vehicle and is only controlled by the force at the coupling shall not
be deemed to be inertia braking devices within the meaning of this
Directive.
1.6. Two axles with a wheelbase of less than one metre (tandem axle) shall,
for the purposes of this Annex, also be deemed to be one axle.
1.7.Tests
1.7.1. Determination of the main characteristics of the brake.
1.7.2. Determination of the main characteristics of the control device
and testing as to whether that device conforms with the provi-
sions of this Directive.
1.7.3. Testing on the vehicle
— the compatibility of the control device and the brake
— the transmission.
2. SYMBOLS AND DEFINITIONS
2.1.Unitsused
2.1.1. Weights and forces: kg2.1.2. Torques and moments: m · kg
2.1.3. Areas: cm
2
2.1.4. Pressures: kg/cm2
2.1.5. Lengths: units specified in each case.
2.2.Symbolsvalidforalltypesofbrakes (see diagram in Appendix 1, p.
771)
2.2.1. GA: ‘total weight’ of the trailer declared to be technically
permissible by the manufacturer;
2.2.2. G ′A: ‘total weight’ of the trailer which, according to the
manufacturer's declaration, can be braked by the
control device;
2.2.3. GB: ‘total weight’ of the trailer which can be braked by the
joint operation of all the trailer brakes
GB¼n/C1GBo
2.2.4. GBo: Fraction of the permissible ‘total weight’ which,
according to the manufacturer's declaration, can be
braked by one brake;
2.2.5. B*: braking force required;2.2.6. B: required braking force taking account of rolling resis-
tance;1971L0320 — EN — 20.02.1974 — 002.001 — 31
▼B
2.2.7. D*: permitted thrust on coupling;
2.2.8. D: load on the coupling;
2.2.9. P ′: control device output force;
2.2.10. K: supplementary force of control device by convention;
this is defined as the force D corresponding to the
point of intersection of the x axes of the extrapolated
curve expressing P ′in terms of D, measured withth e
control system in the mid-travel position (see graph in
Appendix 1, p. 772);
2.2.11. KA: threshold force of control device—this is the
maximum force on the coupling head which can be
applied for a short period of time without producing
any output force on the control device. By convention,
KAis defined as the force measured when force begins
to be exerted on the coupling head at a speed of from
10 to 15 mm/s, the control device transmission being
uncoupled;
2.2.12. D1: this is the maximum force applied to the coupling
head when it is forced rearward at a speed of s mm/
s ± 10%, the transmission being uncoupled;
2.2.13. D2: this is the maximum force applied to the coupling
head when this is pulled forward at a speed of s mm/
s ± 10% from its rearmost position, the transmission
being uncoupled;
2.2.14. ηHo: efficiency of the inertia control device;
2.2.15. ηH1: efficiency of the transmission system;
2.2.16. ηH: total efficiency of the control device and of the trans-
mission
ηH¼ηHo/C1ηH1;
2.2.17. s: travel of control (expressed in millimetres);2.2.18. s ′: effective travel of control (expressed in millimetres)
fixed in accordance withth e requirements of item
9.4.1;
2.2.19. s ′: safe travel of the master cylinder actuator, measured in
millimetres at the coupling head;
2.2.20. s
o: loss of travel, that is to say the travel, measured in
millimetres, of the coupling head when it is actuated
in sucha way as to travel from a point 300 mm above
the horizontal plane to a point 300 mm below, the
transmission remaining stationary;
2.2.21. 2sB: brake-shoe lift measured on the diameter parallel to
the operating mechanism and without the brakes being
adjusted during the test (expressed in millimetres);
2.2.22. 2sB*: minimum brake-shoe lift (expressed in millimetres)
2sB/C3¼2/C14þ4
1000/C12r;
2r being the diameter of the brake drum expressed in
millimetres (see diagram in Appendix 1, p. 773);
2.2.23. M: braking moment;
2.2.24. R: radius of pneumatic tyres (in metres) measured under
load from wheel centre to ground level on the vehicle
being tested (rounded to the nearest centimetre);
2.2.24. n: number of brakes;
2.3.Symbols for mechanical transmission brakes (see diagram in
Appendix 1, p. 774)
2.3.1. iHo: reduction ratio between travel of the coupling head
and travel of the lever at the output side of the control
device;
2.3.2. iH1: reduction ratio between travel of the lever at the
output side of the control device and travel of the
brake lever (gearing down of transmission);1971L0320 — EN — 20.02.1974 — 002.001 — 32
▼B
2.3.3. iH: reduction ratio between travel of the coupling head
and travel of the brake lever
iH¼iHo/C1iH1;
2.3.4. ig: reduction ratio between travel of the brake lever and
the brake-shoe centre lift (see diagram in Appendix 1,
page 773);
2.3.5. P: force applied to the brake control lever;2.3.6. P
o: brake retraction force; that is, in the graph M = f (P),
the value of the force P at the point of intersection of
the extrapolation of this function with the abscissa (see
graphin Appendix 1, p. 775);
2.3.7. ρ:characteristic of the brake defined by: M ¼ρP/C0Po ðÞ
2.4.Symbols for hydraulic-transmission brakes (see diagram in
Appendix 1, p. 776).
2.4.1. ih: reduction ratio between travel of the coupling head
and travel of the piston in master cylinder;
2.4.2. ig′: reduction ratio between travel of the actuation point of
the cylinders and the brake-shoe centre lift;
2.4.3. FRZ: surface area of piston in brake cylinder;
2.4.4. FHZ: surface area of piston in master cylinder;
2.4.5. p: hydraulic pressure in brake cylinder;
2.4.6. po: retraction pressure in brake cylinder; that is, in the
graph M = f(p), the value of the pressure p at the point
of intersection of the extension of this function with
the abscissa (see graph in Appendix 1, p. 775).
2.4.7. ρ′: characteristic of the brake defined by:
M¼ρ0p/C0po ðÞ :
3. GENERAL REQUIREMENTS
3.1. The transmission of braking power from the coupling head to the trai-
ler's brakes must be effected either by a rod linkage or by means of
one or more fluids. However, a sheathed cable (Bowden cable) may
be used to provide part of the transmission. This part must be as short
as possible.
3.2. All pins at joints must be adequately protected. In addition, these joints
must be either self-lubricating or easily accessible for lubrication.
3.3. Inertia braking devices withh ydraulic transmission must be arranged in
such a way that, even when the coupling head is forced rearward to its
fullest extent, it is possible to avoid damage created by excessive
forces in the transmission and the braking device. Any device which
is used to enable this to be done (stress reducer) may only reduce the
braking force to the extent that the prescribed braking force can still be
achieved.
3.3.1. Item 3.3 shall apply mutatis mutandis if the inertia braking
device withmech anical transmission is fitted witha stress
reducer.
3.3.2. Inertia braking devices with mechanical transmission without a
stress reducer must be arranged in such a way that, in the case
where the coupling head travels to its fullest extent, no part of
the transmission becomes jammed, or suffers any permanent
distortion, or fails. This must be checked by uncoupling the first
element of the transmission from the brake control levers.
4. REQUIREMENTS FOR CONTROL DEVICES
4.1. The sliding members of the control device must be long enough to
enable the brake to be fully applied, even when the trailer is coupled.
4.2. The sliding members must be protected by a bellows or some equiva-
lent device. They must either be lubricated or be constructed of self-
lubricating materials. The surfaces in frictional contact must be made
of a material such that there is neither electrochemical torque nor any
mechanical incompatibility liable to cause the sliding members to
seize.1971L0320 — EN — 20.02.1974 — 002.001 — 33
▼B
4.3. The stress reducer equipment mentioned in item 3·3 must only
commence to function when the pressure on the coupling reaches
0·12 G′Ain the case of single-axle trailers and 0·08 G ′Ain the case of
multi-axle trailers. They must prevent the braking force on the wheels
from exceeding that corresponding to a pressure on the coupling of
0·18 GBin the case of single-axle trailers and of more than 0·12 GBin
the case of multi-axle trailers.
4.4. The threshold force of the control equipment (KA) must be not less
than 0·02 G ′Aand not more than 0·04 G ′A.
4.5. The maximum depression force of D1may not exceed 0·09 G ′Ain the
case of single-axle trailers and 0·06 G ′Ain the case of multi-axle trai-
lers.
4.6. The maximum towing force D2must be between 0·1 G ′Aand 0·5 G ′A.
5. TESTS AND MEASUREMENTS TO BE CARRIED OUT ON THE
CONTROL SYSTEM
5.1. Compliance withth e requirements of items 3 and 4 above must be
verified on the control device submitted to the technical service
conducting the tests.
5.2. The following shall be measured in respect of all types of brakes:
5.2.1. the travel s and the available travel s ′;
5.2.2. the supplementary force K;5.2.3. the threshold force K
A;
5.2.4. the damping force D1;
5.2.5. the towing force D2.
5.3. In the case of mechanical-transmission inertia brakes, the following
shall be determined:
5.3.1. the reduction ratio iHo, measured at the mid-travel portion of the
control;
5.3.2. the force P ′at the output side of the control device as a function
of the thrust D on the drawbar.
The supplementary force K and the efficiency are derived from
the representative curve obtained from these measurements.
ηHo¼1
iHo/C1P0
D/C0K
(see graphin Appendix 1, p. 772)
5.4. In the case of hydraulic-transmission inertia brakes, the following shall
be determined:
5.4.1. the reduction ratio ihmeasured at the mid-travel position of the
control;
5.4.2. the pressure p at the output side of the master cylinder as a
function of the thrust D on the drawbar and of the surface area
FHZin the master cylinder piston, as specified by the manufac-
turer. The supplementary force K and the efficiency are derived
from the representative curve obtained from these measurements
ηHo¼1
ih/C1p/C1FHZ
D/C0K
(see graphin Appendix 1, page 772);
5.4.3. the safe travel of the master cylinder actuator s ″mentioned in
item 2.2.19.
5.5. In the case of inertia brakes fitted with the devices mentioned in item
3.3 (stress reducers), it is necessary to check whether the limits
mentioned in item 4.3 are observed.
5.6. In the case of inertia brakes on multi-axle trailers, the loss of travel somentioned in item 9.4.1 shall be measured.
6. REQUIREMENTS FOR BRAKES
6.1. The manufacturer must make available to the technical service respon-
sible for the tests, in addition to the brakes to be tested, drawings of
the brakes showing the type, dimensions and material of the main1971L0320 — EN — 20.02.1974 — 002.001 — 34
▼B
parts, and the make and type of the linings. These drawings must indi-
cate the surface area FRZof the brake cylinders in the case of hydraulic
brakes. The manufacturer must also indicate the maximum braking
torque Mmaxwhich is allowed, as well as the weight GBomentioned in
item 2.2.4.
6.2. The braking torque Mmaxindicated by the manufacturer must be at least
twice the force P or at least twice the pressure p required to give a
braking force of 0·45 GBo.
6.3. The devices mentioned in item 3.3 must only commence to function
when the force P or the pressure p has reached the value corresponding
to a braking force of 0.6 GBo. They must prevent twice the force P or
twice the pressure p mentioned in item 6.2 being exceeded.
7. TESTS AND MEASUREMENTS TO BE CARRIED OUT ON THE
BRAKES
7.1. The brakes and items of equipment made available to the technical
service responsible for the tests must be tested to check whether they
conform to the requirements of item 6.
7.2. The following shall be determined:
7.2.1. the minimum shoe centre lift 2sB*;
7.2.2. the shoe centre lift 2sB(which must be greater than 2sB*);
7.2.3. the braking moment M as a function of the force P applied to
the control lever in the case of devices with mechanical trans-
mission, and of the pressure p in the brake cylinder in the case
of devices withh ydraulic transmission.
The speed at which the braking surfaces rotate must correspond
to an initial vehicle speed of 50 km/h. The following shall be
deducted from the curve obtained from these measurements:
7.2.3.1. the retraction force P and the characteristic ρin the
case of mechanically actuated brakes (see graph in
Appendix 1, p. 775).
7.2.3.2. the retraction pressure poand the characteristic ρin the
case of hydraulically actuated brakes (see graph in
Appendix 1, p. 775).
8. TEST REPORTS
Where applications are made for type approval of trailers fitted with inertia
brakes, suchapplications are to be accompanied by th e test reports relating
to the control system and the brakes, as well as the test report on the
compatibility between the inertia control device, the transmission and the
brakes on the trailer; these reports are to include at least the particulars
shown in Appendices 2, 3 and 4 to this Annex.
9. COMPATIBILITY OF THE CONTROL DEVICE AND THE INERTIA
BRAKES OF A VEHICLE
9.1. A check must be made on the vehicle, taking into account the charac-
teristics of the control device (Appendix 2) and of the brakes
(Appendix 3) as well as the trailer characteristics mentioned in item 4
of Appendix 4, as to whether the inertia braking device of the trailer
complies withth e requirements laid down.
9.2.General testsforalltypesofbrakes
9.2.1. Those parts of the transmission which have not been tested at
the same time as the brake control device or the brakes must
be tested on the vehicle. The results of the test must be entered
in Appendix 4 (for example iH1andηH1).
9.2.2.Weight
9.2.2.1. The total weight of the trailer GAmust not exceed the
total weight G ′Afor which the control device is
authorised.
9.2.2.2. The total weight of the trailer GAmust not exceed the
total weight GBwhich can be braked by the joint opera-
tion of all the trailer brakes.1971L0320 — EN — 20.02.1974 — 002.001 — 35
▼B
9.2.3.Forces
9.2.3.1. The threshold force KAmust not be less than 0·02 GAnor greater than 0·04 GA.
9.2.3.2. The maximum damping force D1must not exceed
0·09 GAin the case of single-axle trailers, nor 0·06 GAin the case of multi-axle trailers.
9.2.3.3. The maximum pulling force D2must be between 0·1 GAand 0·5 GA.
9.2.4.Device mentioned in item 3·3 (stress reducer)
9.2.4.1. A check must be made as to whether the control device
or the brakes are fitted with such a device.
9.2.4.2. Where this device forms part of the control device, the
minimum value of GBfixed in item 4·3 for the control
device must not be less than the total permissible
weight GBfor the brakes used on the trailer which is
being tested.
9.3.Testofbrakingefficiency
9.3.1. The sum of the braking forces exerted on the circumference of
the trailer wheels must be at least B* = 0·45 GA, including a
rolling resistance of 0·01 GA. This represents a braking force of
0·44 GA. In this case, the maximum permitted thrust on the
coupling shall be:
D* = 0·06 GAin the case of multi-axle trailers,
D* = 0·09 GAin the case of single-axle trailers.
In order to check whether these conditions are observed, the
following inequalities must be applied:
9.3.1.1. In the case of inertia brakes with mechanical transmis-
sion:
B/C1R
ρþnPo/C20/C211
D/C3/C0K ðÞ /C1 ηΗ/C20iH
9.3.1.2. In the case of inertia brakes with hydraulic transmis-
sion:
B/C1R
n/C1ρ0þpo/C20/C211
D/C3/C0K ðÞ /C1 ηΗ/C20ih
FHZ
9.4.Controltraveltest
9.4.1. In the case of control devices for multi-axle trailers of which the
brake rod system is dependent upon the position of the towing
vehicle, the travel of the control s must be greater than the avail-
able travel of the control s ′; the difference in length must be at
least equivalent to the loss of travel so. The travel somust not
exceed 40 mm.
9.4.2. The available travel of the control s ′shall be determined in the
following way:
9.4.2.1. if the brake rod system is affected by the relative posi-
tion of the towing device, then:
s0¼s/C0so;
9.4.2.2. if there is no loss of travel, then:
s0¼s;
9.4.2.3. in the case of hydraulic braking systems:
s0¼s/C0s00:
9.4.3. The following inequalities shall be applied in order to check
whether the travel of the control is adequate:
9.4.3.1. in the case of inertia brakes with mechanical transmis-
sion:
iH/C20s0
sB/C3/C1ig
9.4.3.2. in the case of inertia brakes with hydraulic transmis-
sion:1971L0320 — EN — 20.02.1974 — 002.001 — 36
▼Bih
FHZ/C20s0
2sB/C3/C1nFRZ/C1i0
g
9.5.Additionaltests
9.5.1. In the case of inertia brakes with mechanical transmission, a
check shall be made as to whether the rod system by which the
forces are transmitted from the control device is correctly fitted.
9.5.2. In the case of inertia brakes with hydraulic transmission, a check
shall be made as to whether the travel of the master cylinder
actuator reaches a minimum level of s/ih.
A lower level will not be permitted.
9.5.3. A road test must be carried out to determine the general reaction
of the vehicle to braking.
10. GENERAL COMMENTS
The above provisions apply to the latest models of inertia brakes with
mechanical or hydraulic transmission; in the case of these models, in parti-
cular, all the wheels of the trailer are fitted with the same type of brake and
the same type of tyre.
When testing special models, the above requirements are to be adapted.1971L0320 — EN — 20.02.1974 — 002.001 — 37
▼B
Appendix 1
See 2.2
See 2.2.10 and 5.3.2 (devices with mechanical transmission)
1971L0320 — EN — 20.02.1974 — 002.001 — 38
▼B
See 2.2.10 and 5.4.2 (devices with hydraulic transmission)
1971L0320 — EN — 20.02.1974 — 002.001 — 39
▼B
See 2.2.22 and 2.3.4
Teststobecarried outonthebrakes1971L0320 — EN — 20.02.1974 — 002.001 — 40
▼B
Brakeswithmechanicaltransmission
See 2.3
1971L0320 — EN — 20.02.1974 — 002.001 — 41
▼B
See 2.3.6 and 7.2.3.1 (mechanical brake)
See 2.4.6 and 7.2.3.2 (hydraulic brake)
1971L0320 — EN — 20.02.1974 — 002.001 — 42
▼B
Brakeswithhydraulictransmission
See 2.4
1971L0320 — EN — 20.02.1974 — 002.001 — 43
▼B
Appendix 2
Testreportoninertiabrakecontroldevice
1971L0320 — EN — 20.02.1974 — 002.001 — 44
▼B
Appendix 3
Braketestreport
1971L0320 — EN — 20.02.1974 — 002.001 — 45
▼B
Appendix 4
Testreportonthecompatibilityoftheinertiacontroldevice,thetransmissionandthebrakeson
thetrailer
1971L0320 — EN — 20.02.1974 — 002.001 — 46
▼B
1971L0320 — EN — 20.02.1974 — 002.001 — 47
▼B
ANNEX IX
1971L0320 — EN — 20.02.1974 — 002.001 — 48
▼B
1971L0320 — EN — 20.02.1974 — 002.001 — 49
▼B
►(1)M11971L0320 — EN — 20.02.1974 — 002.001 — 50