IS 11852-4: Automotive Vehicles - Brakes and Braking Systems, Part 4: Compressed Air and Air Assisted Brakes - Special Requirements

13 Pages·2001·1.3 MB·English

by  Bureau of Indian Standards

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timely dissemination of this information in an accurate manner to the public.
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“The Right to Information, The Right to Live” “Step Out From the Old to the New”
IS 11852-4 (2001): Automotive Vehicles - Brakes and Braking
Systems, Part 4: Compressed Air and Air Assisted Brakes -
Special Requirements [TED 4: Automotive Braking Systems]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
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“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
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“Knowledge is such a treasure which cannot be stolen”

IS 11852 (Part 4) :2001
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Indian Standard
AUTOMOTIVE VEHICLES — BRAKES AND
BRAKING SYSTEMS
PART 4 COMPRESSED AIR AND AIR ASSISTED BRAKES — SPECIAL REQUIREMENTS
( First Revision)
1(3 43.040.40

0 BIS 2001
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

Murch 2001 Price Group 4
Automotive Braking Systems Sectional Committee, TED 4
FOREWORD
This Indian Standard (Part 4) (First Revision) was adopted by the Bureau of Indian Standards afier the dratl
finalized by the Automotive Braking Systems Sectional Committee had been approved by the Transport
Engineering Division Council.
This standard on brakes and braking systems which was earlier issued in eight parts, has now been revised and
issued in nine parts which are asunde~
Part 1 Terminology;
Part 2 General functions and features;
Part 3 Performance requirements and evaluation;
Part 4 Compressed air and air assisted brakes — Special requirements;
Part 5 Compressed air and air assisted brakes — Pressure test comections;
Part 6 Vacuum braking systems — Special requirements;
Part 7 Inertia dynamometer test method for brake linings;
Part 8 Test procedures; and
Part 9 Requirements for vehicles equipped with anti-lock braking devices.
IS 11852 (Part 7) :1995 Automotive vehicles — Recommendations for brakes and braking systems: Part 7
Model test report has been withdrawn in this revision and has been replaced with a part covering ‘Inertia
dynamometer testmethods for brake linings’. Part 9 covering the requirements for vehicles equipped with anti-
Iock braking devices has been added.
This standard is mainly based on EEC directives 71/320, 74/132, 751524, 79/489, 85/647, 88/194 & 91/422
relating to the braking devices of certain categories of motor vehicles and oftheir trailers. However, apart from
the changes made from EEC directives to suit the Indian conditions, the nomenclature of some of the tests and
categories of vehicle have also been changed asunde~

EEC Directives Indian Standards

Category ‘O’Vehicle Category ‘T’Vehicle
Type ‘O’test Type ‘P’test
Type Itest Type ‘F’test
Type IItest Type ‘H’test
Assistance has also been derived from ECE regulation No. 13(Annex 7— Part A).
The composition of the Committee responsible for formulation of this standard is given in Annex A.
IS 11852 (Part 4): 2001
Indian Standard
AUTOMOTIVE VEHICLES — BRAKES AND
BRAISING SYSTEMS
PART 4 COMPRESSED AIR AND AIR ASSISTED BRAKES — SPECIAL REQUIREMENTS
(First Revision )
1SCOPE systems depends on the use of compressed air shall
be fitted with reservoirs of a capacity meeting the
This standard (Part 4) covers special requirements
requirements of 3.2 and 3.3.
applicable to compressed air and compressed air
assisted braking systems (using compressed air as 3.1.2 However, the energy storage devices shall not
media of energy) for both motor vehicles and trailers. berequired tobeofaprescribed capacity ifthebraking
The requirements covered are: systemissuchthatintheabsence ofanyenergy reserve
it is possible for the system to achieve braking
a) Capacity of reservoirs,
performance at least equal to that prescribed for the
b) Capacity of energy sources,
secondary braking systems.
c) Reaction time and its method of measure-
ments, and 3.1.3 When veri&ing compliance with the require-
d) Spring brakes. ments of 3.2 and 3.3 the brakes shall be adjusted as
closely aspossible.
1.1 This standard is not applicable to the following
types of vehicles: 3.2 Motor Vehicles of Category M and N
a) Agricultural tractors and power tillers; 3.2.1 The air brake reservoirs of motor vehicles shall
b) Earth moving machinery; be so designed that after eight full stroke actuations
c) Construction equipment vehicles; of the service brake control, the pressure remaining
in the air brake reservoir shall be not less than the
d) Vehicles moving on rails;
pressure required to obtain the specified secondary
e) Two wheelers;
braking performance.
o Three wheelers; and
g) Vehicles with maximum designed speed not 3.2.2 During thetest,thefollowing requirements shall
exceeding 25 krnh. be satisfied.

3.2.2.1 The initial pressure in the reservoirs shall be
2 REFERENCES
that indicated by the manufacturer. This pressure, P2
The following Indian Standards contain provisions
shall be such asto enable the prescribed performance
which through reference in this text, constitute
for the service braking to be achieved (see 4.2.2).
provisions ofthis standard. Atthetime ofpublication,
the editions indicated were valid. All standards are 3.2.2.2 The reservoir or reservoirs shall not be
subject to revision, and parties to agreements based replenished. In addition, the reservoir orreservoirs of
on this standard are encouraged to investigate the auxiliary equipment shall be isolated.
possibility of applying the most recent editions ofthe
3.2.2.3 In the case of motor vehicles to which the
standards indicated below:
coupling of a-trailer or semi-trailer is authorised, the
IS No. Title feed line (emergency line) shall be blocked off and a
11852 Automotive vehicles — Brakes and reservoir of 0.5 litre capacity shall be ccmnected to
braking systems: the control line “(service line). The pressure in this
(Part 2) :2001 General functions and features (@t reservoir shall be exhausted before each actuation of
revision) the brakes. After the test referred to in 3.2.1, the
(Part 5) :2001 Cornpressed air and air assisted -pressure in the control line shall not be less than one
brakes — Pressure test connections half of the pressure obtained at the first brake
(fh-strevision) application.
3 CAPACITY OF RESERVOIRS
3.3 Trailers(Including Semi-Trailers)-ofCategory T
3.1 General Requirements
3.3.1 Reservoirs fitted tothetrailers shallbesuchthat,
3.1.1 Vehicles in which the operation of the braking aftereightfullstroke actuations ofthetowingyehicle’s

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IS 11852 (Part 4) :2001
service braking device, the pressure supplied to the 4.4 Interpretation of Results
operating parts using it does not fall below a level
4.4.1Thetimet,fortheleastfavorable reservoir shall
equal toonehalf ofthevalueobtained atthefirstbrake
not exceed:
application and without actuating either theautomatic
or the parking brake of the trailer. a) three minutes inthecaseofvehicles towhich
the coupling of atrailer or semi-trailer isnot
3.3.2 During thetest,thefollowing requirements shall
authorized, and
be satisfied.
b) six minutes in the case of vehicles to which
3.3.2.1 Themaximum pressure (P~J inthereservoirs the coupling of a trailer or semi-trailer is
at the beginning of the test shall be equal to the authorised.
maximum specified by the manufacturer.
4.4.2Thetimet2fortheleastfavorable reservoir shall
3.3.2.2 The supply line shall be blocked-off. In not exceed:
addition, the auxiliary equipment reservoirs shall be
a) six minutes in the case of vehicles to which
isolated.
the coupling of atrailer orsemi-trailer isnot
3.3.2.3 The reservoir shall not be replenished during authorised, and
the test. b) nine minutes inthecaseofvehicles towhich
the coupling of a trailer or semi-trailer is
3.3.2.4 Foreach application ofthebrakes, thepressure
authorised.
in the control line shall correspond to the maximum
specified by the manufacturer (P~,X). 4.5 Additional Test
4 CAPACITY OF ENERGY SOURCES 4.5.1 When”the vehicle is equipped with an auxiliary
equipment reservoir or reservoir with atotal capacity
4.1 General Provisions
exceeding 20percent ofthetotal capacity ofthebrake
Compressors shall satisfy therequirements laiddown reservoirs, amadditional testshallbeearned outduring
in 4.2 to 4.5. thecourse ofwhich there shallbenointerference with
thefunctioning ofthe valves controlling the tilling of
4.2 Definitions the auxiliary equipment reservoirs(s). Acheck shall
bemade during the course of this test that the period
4.2.1 P, is the pressure corresponding to 65 percent
t3required to bring about arise inthe pressure inthe
of the pressure Pz specified by the manufacturer.
brake reservoirs from zero to P2is lessthan:
4.2.2 t, isthe time required for the reservoir pressure
a) eight minutes inthecaseofvehicles towhich
to rise from zero to PI and tzis th e time required for
thecoupling of atrailer or semi-trailer isnot
the reservoir pressure to rise from ze r o to Pz.
authorised, and
4.3 Conditions of Measurement b) eleven minutes in the case of vehicles to
which thecoupling ofatrailer orsemi-trailer
4.3.1 In all-cases the speed of the compressor (in rev/
authorised.
rein) shallbethat obtained when theengine isrunning
atthe speed corresponding tothe maximum power or 4.6Towing Vehicles
atthe speed allowed by the governor.
4.6.1 Vehicle to which the coupling of acategmy T
4.3.2 The auxiliary equipment reservoirs shall be vehicle isauthorised shall alsocomply withtheabove
isolated during the tests for determining the periods requirements. For vehicles not soauthorised, thetests
t,and tz. in 4.4.1, 4.4.2 and 4.5.1 shall be conducted without
the reservoir mentioned in 4.3.4.
4.3.3 Where spring brakes are used, they are to be in
brake released condition. 5METHOD OF MEASURING THE REACTION
TIME
4.3.4 On motor vehicles constructed to tow trailers,
the trailer shall be represented by a reservoir whose 5.1 General Requirements
maximum pressure, P (expressed inbars) isthatwhich
5.1.1“Thereaction time for the braking device shall
canbe supplied through the feed circuit ofthetowing
bedetermined withthevehicle stationary, thepressure
vehicle and whose volume, V(expressed in litres), is
being measured atthe opening ofthe leastfavorable
given by the formula P x V= 20R (R being the
brake cylinder. In the case of vehicles fitted with
permissible maximum loadexpressed intonnes onthe
combined compressed ain’hydraulic braking systems,

axles of the trailer or semi-trailer).
the pressure may be measured at the opening of the
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IS 11852 (Part 4) :2001
least favorable pneumatic unit. the pressure measured at the coupling head of the
control pipe reaches the specified value percentage at
5.1.2 During the test, the stroke ofthebrake cylinders
itsasymptotic value shall not exceed the values listed
of the individual axles shall be that corresponding to
below:
the most closely adjusted brakes.
Pressure Time
5.1.3 The times determined in implementing the
(aspercent) (seconds)
provisions of this standard shall berounded off tothe
10 0.2
nearest tenth of a second. If the figure representing
75 0.4
the 1/1OOthisfive or more, the reaction time shall be
rounded up to the next higher tenth. 5.2.7 Inthe case ofmotor vehicles authorized todraw
trailers of category T3 or T4 fitted with compressed
5.2 Motor Vehicles
airbraking systems, inaddition totheabovementioned
requirements, the requirements of 4.2.1.19(a) of
5.2.1 At the start of each test, the pressure in the
IS 11852 (Part 2) shall be verified by conducting the
reservoir shall be equal to the minimum pressure at
which the governor starts feeding the installation following tests
again. For installations not fitted with agovernor, (for
a) by measuring the pressure at the extremity
example, pressure limited compressor), the pressure ofapipe 2.5mlongwith aninternal diameter
inthe reservoir at the start of each test shall be equal of 13 mm which shall be joined to the
to 90 percent of the pressure stated by the
coupling head of the supply line.
manufacturer, as defined in 3.2.2.1. Air supply shall
b) by simulating a failure of the control line at
be cut off during each test.
the coupling head.
5.2.2 The reaction time is determined as the time c) by actuating the service braking control
elapsing between the beginning of the actuation of device in 0.2 second asdescribed in 5.2.3.
the control pedal and the moment the pressure in the
braking cylinder reaches 75percent of its asymptotic 5.3 Trailers (Including Semi-Trailers)
value.
5.3.1 The reaction times for trailers shallbemeasured
5.2.3 Reaction times, interms ofactuation times, shall without a towing vehicle. To simulate the towing
beobtained byaseriesofactuationstothefbllestextent vehicle, itisnecessary toprovides simulator towhich
starting from the shortest possible time to about 0.45 the coupling heads of the control line and of the feed
second. The values so measured shall be given on a line of the trailer are to be connected.
graph from which the reaction time corresponding to
5.3.2 The pressure in the feed line shall be 6.5 bars.
an actuation time of 0.2 second shall be determined
by interpolation. 5.3.3 The simulator shall have the following features;
5.2.4Thereaction timemeasured f r omtheabovegraph 5.3.3.1 It shall have areservoir with acapacity of 30
for an actuation time of 0.2 second shall not exceed Iitreswhich shall be charged to apressure of 6.5 bars
0.6 second. before each test and which shall not be re-charged
during each test. At the outlet of the braking control
5.2.5 In the case of motor vehicles having a brake
device the simulator shall incorporate an orifice with
coupling for trailers, in addition to the requirements
adiameter of4.0 and 4.3 mm. The volume ofthepipe
of 5.1, the reaction time shall be measured at the measured from the orifice up to and including the
extremity of a pipe 2.5 m long with an internal coupling head shall be 385 + 5 cm (to represent
diameter of 13 mm which shall be joined to the the extra volume of .2.5 m long pipe). The control
coupling head of the control line ofthe service brake. line pressure referred to in 4.3 shall be measured
During this test, avolume of 385* 5cm3torepresent immediately downstream of the orifice.
theextra volume of2.5mlongpipe shallbeconnected
5.3.3.2The-braking control deviceshallbesodesigned
to the coupling head of the supply line.
thatitsperformance inuseisnot affected bythetester.
5.2.5.1 Tractive units for semi-trailers shall be
5.3.3.3 The simulator shall be set, for example,
equipped withflexible linesformaking theconnection
through the choice of orifice in accordance with
to semi-trailers. The coupling heads shall, therefore,
5.3.3.1, in such a way that, if a reservoir of 385 +
be at the extremity of these flexible lines. The length
5cm3isattached to it, the time taken for thepressure
and internal diameter of the lines shall be entered in
to increase from 0.65 to 4.9 bars (10 percent and 75
report for type approval.
percent respectike$ of the nominal pressure of 6.5
5.2.6 The time which elapses between the start of the bars) shall be 0.2 * 0.01 second. If a reservoir of
activation of the control pedal and the moment when 1155+”15cm3is substituted fortheabovementioned
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IS 11852 (Part 4) :2001
reservoir, the time taken for the pressure to increase coupling head without using flexible pipes. The
from 0.65 to4.9 bars without further adjustment shall connections shall have aninternal diameter ofnot less
be 0.38 &0.02 second. Between these two pressure than 10mm.
values, thepressure shallincrease inanapproximately
5.3.3.4 Figures 1and 2 give examples of the correct
linear way. These reservoirs shall beconnected tothe
configuration and use of the simulator.
R2/R3
TO THE ELECTRIC CHRONOMETER
FIG. 1SETTINGOFTHESIMULATOR
L- TRAILER UNDER TEST I
I ‘1 I
VRU

n S-I--W--T, ~

RI
G “ 7+%4=-I =%+ ‘p c’
I “, ~c2
,
TO THE ELECTRIC CHRONOMETER
FIG. 2TESTINGTHETRAILERBRAKESYSTEMVIATHESIMULATOR
Supply connection with shut-off valve pp . pressure test connection
Pressure switch insimulator, set at0.65 bar and at4.9 bar RI = 30Iitres airreservoir with drain valve
Pressure switch tobeconnected tobrake actuator oftrailer R2 = Calibrating reservoir including its coupling head TCtobe
tooperate at75percent ofasymptotic pressure inthebrake 385 * 5cm3
actuator CF R3 = Calibrating reservoir including itscoupling headcontrol line,
Brake actuator TCto be 1155* 15cm3
Line from orifice Qup toand including its coupling head R4= Shut-off valve
TChaving aninner volume of385*5 cm3under apressure TA = Coupling head, supply line
of6.5 bars
TC = Coupling head, control line
Pressure gauge v. Braking control device
Orifice with adiameter ofnotless than 4mm and notmore VRu=
Emergency relay valve
than 4.3 mm

4
IS 11852 (Part 4): 2001
5.3.4 Thetime elapsing between themoment whenthe uncoupling. These conditions shall be satisfied when
pressure produced in the control line by the simulator thebrakesareadjustedascloselyaspossible.Inaddition,
reaches 0.65 bar andthemoment when thepressure in it shall be possible to apply and release the parking
the brake actuator ofthe trailers reaches 75percent of brakeasspecifiedin4.2.2.10 ofIS 11852(Part2),when
itsasymptotic value shall not exceed 0.4 second. the trailer iscoupled tothe towing vehicle.
6 PRESSURE TEST CONNECTIONS 7.1.5 In case of motor vehicles, the pressure in the
spring compression chamber beyond whichthesprings
6.1 Pressure test connections shall beprovided on all
begin to actuate the brakes, the latter being adjusted
vehicles offered for type approval.
as closely as possible, shall not be greater than 80
6.2 Apressure test connection shallbe fitted close to percent of the minimum level ofthe normal available
the least favorably placed reservoir within the pressure (F?2).
meaning of 4.4.
7.1.5.1 In case of trailers, this pressure level is the
6.3Oneach independent circuit ofthebraking system pressure which isobtained after four stroke actuations
apressure test connection-shall be fitted asclosely as of the service brake control. The initial pressure is
possible to the brake cyl;nder which is the least fixed at 6.5 bars.
favorably placed asfarasreaction timeisconcerned.
7.1.6 When the pressure inthe line feeding energy to
6.4 The pressure test comections shall comply with the spring compression chamber excluding lines of
IS 11852 (Part 5). anauxiliary releasedeviceusingafluidunderpressure,
falls to the level at which the brake parts begin to
7 SPRING BRAKES move, anopticaloraudible warning deviceasspecified
in 4.2.1.13 of IS 11852 (Part 2) shall be actuated.
7.1 General Requirements
This provision does not apply to trailers.
7.L1 Spring brake shallnotbeusedasaservicebrake.
7.1.7 On motor vehicles fitted with spring brakes and
7.1.2 A small variation in any of the pressure limits authorised to draw trailers with continuous or semi-
which may occur in the spring compression chamber continuous brakes, automatic application ofthespring
feed circuit shall not cause a significant variation in brakes shall cause the trailer brakes to be applied.
the braking force.
7.2 Release System
7.1:3 The feed circuit to the spring compression
chamber shall either include an own energy reserve 7.2.1 A spring braking system shall be so designed
or shall be fed from at least two independent energy that, in the event of a failure in that system, it shall
reserves. Thetrailer supply linemaybebranched from make it possible to release the brake. This may be
achieved by the use of an auxiliary release device
this supply line under the condition that a pressure
(pneumatic, mechanical, etc). Auxiliary release
drop inthetrailer supply lineshallnotbeabletoapply

the spring brake actuators. Aux iliary equipment may devices using an energy reserve for releasing, shall

draw their energy from an energy reserve which is
onlydrawitsenergy fromthe supplylineforthespring
independent from the energy reserve normally used
brake actuators under the condition that itsoperation,
for the spring braking system.
evenintheeventofdamagetotheenergysourcecannot
causetheenergy reserve forthespring brake actuators The pneumatic or hydraulic fluid ir.such anauxiliary
to fall below a level from which one release of the release device may act on the same piston surface in
spring brake actuators ispossible. In any case, during the spring compression chamber, which is used for
re-charging ofthebraking system from zeropressure,
thenormal spring braking system, under thecondition
the spring brakes shall not release until the pressure
that tie auxiliary release device uses a separate line.
inthe service braking system issufficient to ensure at The junction of this line with the normal line
least the prescribed secondary braking performance
connecting the control device with the spring brake
of the laden vehicle, using the service brake control.
actuators, shall be each spring brake actuator
This requirement does not apply to trailers.
immediately before theport tothespring compression
7.1.4Inmotor vehicle, the systemshallbesodesigned chamber, ifnot integrated inthe body of the actuator.
that it is possible to apply and release the brakes at This junction shall include a device which prevents
leastthree times withthe initial pressure inthe system aninfluence ofonelineontheother. Therequirements
being sameasthat referred to in3.2.2.1. Inthecaseof of4.2.1.6 ofIS 11852(Part 2)alsoapplytothisdevice.
trailers, itshallbepossibletoreleasethebrakes atleast
7.2.2 Iftheoperation oftheauxiliarydevicereferredto
three times after the trailer has been uncoupled, the
in7.2.1requirestheuse ofatoolor spanner,thetoolor
pressure @ the supply line being 6.5 bars before
spannershallbe available inthetoolkitofthevehicle.

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