EN 15611:2008+A1:2010

SLOVENSKI STANDARD
01-maj-2011
Železniške naprave - Zavore - Ventili za kontrolo tlaka
Railway applications - Braking - Relay valves
Bahnanwendungen - Bremse - Relaisventile
Applications ferroviaires - Freinage - Relais pneumatiques
Ta slovenski standard je istoveten z: EN 15611:2008+A1:2010
ICS:
45.040 Materiali in deli za železniško Materials and components
tehniko for railway engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 15611:2008+A1
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2010
ICS 45.060.01 Supersedes EN 15611:2008
English Version
Railway applications - Braking - Relay valves
Applications ferroviaires - Freinage - Relais pneumatiques Bahnanwendungen - Bremse - Relaisventile
This European Standard was approved by CEN on 27 September 2008 and includes Amendment 1 approved by CEN on 30 August 2010.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 15611:2008+A1:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .4
1 Scope .5
2 Normative references .5
3 Terms and definitions, symbols and abbreviations .5
3.1 Terms and definitions .5
3.2 Symbols .9
3.3 Abbreviations . 10
4 Design and manufacture . 10
4.1 General . 10
4.2 Functional requirements . 12
4.2.1 Minimum output pressure . 12
4.2.2 Accuracy of the output pressure and changeover . 13
4.2.3 Load signal characteristics . 13
4.2.4 Enabling of a change of relay valve ratio during brake application of a relay valve of
type B1 . 14
4.2.5 Prevention of a change of relay valve ratio during brake application of a relay valve of
type B2 and a variable load relay valve, types C, C1, D, E . 14
4.2.6 Kinked characteristic of a variable load relay valve (type E) . 14
4.2.7 Interaction of a relay valve and a distributor valve . 15
4.2.8 Hysteresis . 16
4.2.9 Sensitivity . 16
4.2.10 Flow . 16
4.2.11 Leakage . 16
4.2.12 Change of relay valve ratio . 16
4.3 Shock and vibration . 17
4.4 Environment requirements . 17
4.4.1 General . 17
4.4.2 Temperature . 17
4.4.3 Other environmental conditions . 18
4.5 Compressed air quality . 19
4.6 Service life . 20
4.7 Fire behaviour . 20
4.8 External appearance . 20
4.9 Design requirements regarding pressure stress . 20
4.10 Interface . 20
4.10.1 General . 20
4.10.2 Mechanical . 20
4.10.3 Pneumatic . 20
5 Materials . 21
6 Type tests . 21
6.1 General . 21
6.2 Individual relay valve tests . 21
6.2.1 Test bench for individual relay valves . 21
6.2.2 Sampling for type tests . 24
6.2.3 Test temperature and air quality . 24
6.2.4 Procedure for type tests . 24
7 Routine test and inspection . 47
8 Type-validation . 47
9 Documentation . 47
10 Designation . 48
11 Identification and marking . 48
Annex A (informative) In-service trial . 49
A.1 General . 49
A.2 Test set-up and sampling . 49
A.3 Procedure . 49
A.4 Pass/fail criteria . 49
Annex B (informative) Static vehicle and running tests . 50
B.1 General . 50
B.2 Test recommendations . 50
B.2.1 Variable load relay valve . 50
B.2.2 Empty/load relay valve . 51
Annex ZA (informative) !!Relationship between this European Standard and the Essential
!!
Requirements of EU Directive 2008/57/EC of the European Parliament and of the Council
of 17 June 2008 on the interoperability of the rail system within the Community
(Recast)"""" . 52
!!deleted text""
!! ""
Bibliography . 58

Foreword
This document (EN 15611:2008+A1:2010) has been prepared by Technical Committee CEN/TC 256 “Railway
applications”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by April 2011, and conflicting national standards shall be withdrawn at the
latest by April 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document includes Amendment 1, approved by CEN on 2010-08-30.
This document supersedes EN 15611:2008.
The start and finish of text introduced or altered by amendment is indicated in the text by tags ! ".
!This document has been prepared under a mandate given to CEN/CENELEC/ETSI by the European
Commission and the European Free Trade Association, and supports essential requirements of EU Directive
2008/57/EC.
For relationship with EU Directive 2008/57/EC, see informative Annex ZA, which is an integral part of this
document."
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and United Kingdom.
1 Scope
This European Standard is applicable to relay valves designed to control the brake cylinder pressure of
compressed air brakes fitted to railway vehicles, in association with an air brake distributor valve or other
control device, and in response to a change in vehicle load that is either continuously variable or in two stages
i.e. empty - loaded.
Relay valves operating with other pressures, in particular the brake pipe pressure, are not included.
This European Standard specifies the requirements for the design, manufacture and testing of relay valves.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 14478:2005, Railway applications  Braking  Generic vocabulary
EN 15355, Railway applications  Braking  Distributor valves and distributor-isolating devices
EN 15625, Railway applications  Braking  Automatic variable load sensing devices
EN 50125-1, Railway applications  Environmental conditions for equipment  Part 1: Equipment on board
rolling stock
EN 60721-3-5:1997, Classification of environmental conditions  Part 3: Classification of groups of
environmental parameters and their severities  Section 5: Ground vehicle installations (IEC 60721-3-5:1997)
EN 61373:1999, Railway applications  Rolling stock equipment  Shock and vibration tests
(IEC 61373:1999)
EN ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads  Part 1: Dimensions,
tolerances and designation (ISO 228-1:2000)
ISO 8573-1:2001, Compressed air  Part 1: Contaminants and purity classes
3 Terms and definitions, symbols and abbreviations
For the purposes of this document, the terms and definitions, symbols and abbreviations given in
EN 14478:2005 and the following apply.
3.1 Terms and definitions
3.1.1
relay valve
device, the main function of which is to control a pneumatic output pressure as a function of the variation of
one or more input pressures
NOTE 1 See Figure 1.
Key
1 first input pressure
2 second input pressure
3 control signal - continuous load sensing pressure (Lcp), or control signal - empty/load signal pressure (Lsp), or
mechanical input (lever) or electrical input
4 auxiliary reservoir pressure, supply pressure (AR)
5 output pressure
6 relay valve
Figure 1 — Relay valve, pressures and control signals
NOTE 2 The definition of “relay valve” in EN 14478 is specific to a load dependant relay valve. This EN standard
considers one or more input pressures in accordance with the diagram in Figure 1.
3.1.2
input pressure
control pressure received by the relay valve
NOTE Pressure generally considered as being the output pressure from a distributor or a brake control unit;
sometimes referred to as pilot pressure or dummy brake cylinder pressure.
3.1.3
output pressure
pressure output from the relay valve
NOTE Pressure generally considered as being the brake cylinder pressure when the relay valve is used in a variable
load braking system. This pressure can also be used as the input pressure to another relay valve. The output pressure
can obtain one, two or three fixed levels or it can be changed continuously between a minimum and a maximum or vice
versa.
3.1.4
relay valve ratio
ratio of the output pressure to input pressure
3.1.5
control signal
signal received from the continuous load sensing device (Lcp) or empty - loaded changeover device (Lsp) or a
mechanical input (lever) or an electrical input that varies the relay valve ratio dependant on vehicle load
NOTE This can also be a speed signal or other parameter, dependant on the relay valve application.
3.1.6 Relay valve types
3.1.6.1
single stage relay valve
relay valve type A
relay valve with one fixed relay valve ratio, where the ratio can be less (step-down), equal or greater (step-up)
than 1
3.1.6.2
multi stage relay valve
relay valve type B
relay valve with more than one fixed relay valve ratio, where the ratios can be less (step-down), equal or
greater (step-up) than 1
3.1.6.2.1
relay valve type B1
multi stage relay valve that can change relay valve ratio during a brake application
NOTE Typically used on vehicles normally operated in empty or fully loaded condition.
3.1.6.2.2
relay valve type B2
multi stage relay valve where a change of relay valve ratio cannot take place during a brake application
NOTE Blocking the relay valve ratio during brake application is typically used to avoid frequent changeovers taking
place on vehicles operated near the changeover weight.
3.1.6.2.3
empty/load relay valve
specific type of multi stage relay valve (type B1 or B2) with only two stages, giving an empty (tare) or a loaded
output pressure proportional to input pressure dependant on the load signal input
3.1.6.3
variable load relay valve
relay valve type C
relay valve with a continuously changeable relay valve ratio, where a load signal is used to change the ratio
3.1.6.4
multi stage variable load relay valve
relay valve type C1
relay valve with a continuously changeable relay valve ratio, where a load signal is used to change the ratio
and with a multi stage feature added
NOTE Typically a load signal is used to change the relay valve ratio and a control signal (automatic or manual) is
used to change the stage(s). The typical result is that at the same load and input pressure, in the lower stage (e.g. P-mode,
passenger train) results a lower output pressure and in a higher stage (e.g. R-mode, rapid passenger train) this results in a
higher output pressure.
3.1.6.5
two (multi) input relay valve
relay valve type D
relay valve (type A, B or C) with two (or more) input pressures, controlling a single output pressure
3.1.6.6
variable load relay valve with kinked characteristic
relay valve type E
variable load relay valve (Type C) with a special, non-linear characteristic, which automatically comes into
operation when the vehicle has more than a certain load
NOTE This function reduces (in comparison with a linear characteristic) the output pressure for low input pressures to
a certain level to limit the heat impact to the wheels during continuous braking.
3.1.7
sensitivity
change of input pressure causing a variation of output pressure, when the change of input pressure is in the
same direction, with no overshoot or reversal
3.1.8
initial sensitivity
change of input pressure, starting at 0 bar which causes the output pressure to start increasing
NOTE See Figure 2.
3.1.9
sensitivity at reversal
change of input pressure causing a variation of output pressure, when the change of input pressure is
changing its direction from increasing to decreasing
NOTE See Figure 2.
3.1.10
hysteresis
difference in output pressure with the same input pressure, where the input pressure is first rising to a value
and then, having been taken past that value, subsequently falls to the same value
NOTE See Figure 2.
Key
1 initial sensitivity
2 hysteresis
3 sensitivity at reversal
NOTE The figure is simplified for illustrative purposes, e.g. the real pressure development is not shown.
Figure 2 — Hysteresis and sensitivity
3.1.11
initial braking position
first braking step corresponding to a reduction of the brake pipe pressure of 0,4 bar to 0,5 bar, which results in
an input pressure to the relay valve of (0,7 ± 0,1) bar
3.1.12
normal litre
Nl
unit of mass for gases equal to the mass of 1 l at a pressure of 1,013 2 bar (1 atmosphere) and at a standard
temperature, often 0 °C or 20 °C
NOTE Airflow is often stated in normal litres per minute (Nl/min).
3.2 Symbols
p pressure
p input pressure
i
p output pressure
o
t time
3.3 Abbreviations
BCP brake cylinder pressure
Lcp Control signal - continuous load sensing pressure
Lsp Control signal - empty/load signal pressure
AR Auxiliary reservoir pressure, supply pressure
4 Design and manufacture
4.1 General
4.1.1 A relay valve shall enable a distributor valve to be used without any vehicle specific modification to the
distributor, related to the brake cylinder volume. This includes the independence of the brake application and
release times, the inshot feature and the output pressure development for any output (brake cylinder and
piping) volume.
4.1.2 The use of a relay valve shall not alter any of the characteristics of the distributor and/or a brake
control unit that are not specified in this standard.
4.1.3 The use of a relay valve shall enable the vehicle to maintain a nominally constant brake application or
release time.
4.1.4 The use of a relay valve shall enable the brake cylinder pressure to be maintained between
prescribed limits (e.g. interoperable or national). These limits may be defined by different brake modes or
speed-dependent requirements or where there is a requirement to maintain a nominal constant brake mass
percentage irrespective of load.
4.1.5 Table 1 below provides a description of relay valve types described in this standard with the relevant
clause references.
Table 1 — Relay valve types and corresponding clauses
Type Description Comment Definitions Functional Testing
Symbol Clause Requirement
Clauses
Reference Clauses
A One fixed relay  3.1.6.1 4.2.1 4.2.2.1 6.2.4.2 6.2.4.3
valve ratio Single stage 4.2.3 4.2.7 6.2.4.11 6.2.4.12
relay valve 4.2.8 4.2.9 6.2.4.14 6.2.4.15
4.2.10 4.2.11 6.2.4.16 6.2.4.17
4.3 4.4
4.5 4.6
4.7 4.8
4.9 4.10
B – Basis Two or more Empty/loaded or 3.1.6.2 4.2.1 4.2.2.1 6.2.4.2 6.2.4.3
of either fixed relay valve
low/high Multi stage relay 4.2.2.2 4.2.3 6.2.4.4 6.2.4.11
B1 or B2 ratios valve
4.2.7 4.2.8 6.2.4.12 6.2.4.14
Types
4.2.9 4.2.10 6.2.4.15 6.2.4.16
below
6.2.4.17
4.2.11
4.3 4.4
4.5 4.6
4.7 4.8
4.9 4.10
B1  Change of relay valve 3.1.6.2.1 As for Type B plus As for type B plus 6.2.4.5
ratios required/allowed 4.2.4
during brake
application
B2  Change of relay valve 3.1.6.2.2 As for Type B plus As for Type B plus 6.2.4.6
ratio not allowed 4.2.5
during brake
application
C Continuously 3.1.6.3 4.2.1 4.2.2.1 6.2.4.2 6.2.4.3
changing relay Variable load 4.2.3 4.2.5 6.2.4.6 6.2.4.7
valve ratio
relay valve 4.2.7 4.2.8 6.2.4.8
4.2.9 4.2.10 6.2.4.12 6.2.4.14
4.2.11 6.2.4.15 6.2.4.16
4.3 4.4 6.2.4.17
4.5 4.6
4.7 4.8
4.9 4.10
C1 Continuously changing 3.1.6.4 As for Type C plus As for Type C plus
relay valve ratio, with a 4.2.2.3 6.2.4.10
Multi stage
multi stage feature variable load
added relay valve
D Two or more overlay function to 3.1.6.5 As for Type A, B or As for Type A, B or C plus
input pressures type A – C C plus 4.2.2.4 6.2.4.13
Two (multi)
with „select input relay valve
high“ feature
E Kinked additional overlay 3.1.6.6 As for Type C plus As for Type C plus 6.2.4.9
characteristic function to type C Variable load 4.2.6
relay valve with
kinked
characteristic
4.2 Functional requirements
4.2.1 Minimum output pressure
The minimum output pressure of the relay valve (brake cylinder pressure) shall be such that a minimum brake
force of 10 % of the maximum brake force in all conditions of vehicle load, is achieved in response to a
nominal input pressure of 0,7 bar (Initial braking position). Figure 3 gives an example of the output pressure of
a relay valve for different conditions of vehicle load.
NOTE The relay valve design may provide means to make the minimum output pressure changeable according to
the requirements of different applications.

Key
1 empty condition
2 loaded condition
3 initial input pressure (0,7 ± 0,1) bar
4 initial output pressure loaded
5 initial output pressure unloaded
Figure 3 — Example of the output pressure p of a relay valve (brake cylinder pressure) in relation to
o
the input pressure p for different conditions of vehicle load
i
4.2.2 Accuracy of the output pressure and changeover
4.2.2.1 General (type A, B1, B2, C, C1, E)
The output pressure of the relay valve shall be within the following tolerances, related to the minimum
(empty)/maximum (loaded) figures, given by the type plate and the installation drawing of the relay valve:
 ± 0,1 bar for nominal output pressures ≤ 3,8 bar at an input pressure of (3,8 ± 0,02) bar;
 ± 0,15 bar for nominal output pressures > 3,8 bar at an input pressure of (3,8 ± 0,02) bar.
This requirement shall be tested in accordance with 6.2.4.4 (type B1 and B2), 6.2.4.7 (type C and C1), 6.2.4.9
(type E) and 6.2.4.11 (type A, B1 and B2).
4.2.2.2 Accuracy of the changeover of a two, or more, stage relay valve (type B, B1 and B2)
The relay valve shall be designed to changeover from the empty (low), to intermediate (if applicable), and to
the loaded (high) condition and reverse, as defined in 4.2.3, at nominal values of the load signal pressures
(Lsp).
The accuracy of the changeover shall be tested in accordance with 6.2.4.4.
4.2.2.3 Accuracy of the change of a variable load relay valve with a two stage function overlaid to
the variable load brake function (type C1)
It shall be possible at any input pressure and any load control pressure (Lcp) to change from a lower to a
higher level of the output pressure or vice versa.
The ratio of the gradient of the output to the input pressures between the higher value of the output pressure
to the lower value shall be constant between initial and full service and within a tolerance of ± 10 % for any
load condition; this condition is related to a nominal input pressure of 3,8 bar and shall be initiated by a
pneumatic or electric control signal.
This requirement shall be tested in accordance with 6.2.4.10.
4.2.2.4 Accuracy of the output pressure of a relay valve designed for two or more input pressures
(type D)
The output pressure of the relay valve shall correspond to the highest of the input pressures. The tolerance of
the maximum output pressure nominal values shall be ± 0,1 bar, if the nominal value is ≤ 3,8 bar and
± 0,15 bar, if the nominal value is > 3,8 bar. In the case where two or more input pressures are acting
simultaneously, the output pressure tolerance shall be a maximum of ± 0,20 bar, if the nominal value is
≤ 3,8 bar and ± 0,30 bar, if the nominal value is > 3,8 bar.
This requirement shall be tested in accordance with 6.2.4.13.
4.2.3 Load signal characteristics
The design of the relay valve shall allow interaction with at least one of the following load signal types:
a) manual empty-loaded signal, where this signal is provided by a lever, either mounted directly on the relay
valve, or remotely operated on the vehicle to manually change from the low to the high output pressure,
or vice versa;
b) pneumatic empty/load signal, where the relay valve shall be designed to operate on receipt of the
relevant signal pressure dependant on the brake system design, as follows:
1) Where the changeover device is supplied from the AR, and Lsp/Lcp pressure is ≤ 0,5 bar this
indicates a load that is less than the switching point and shall cause the relay valve to output its lower
ratio. If Lsp/Lcp pressure is ≥ 3,0 bar this indicates a load greater than the switching point and shall
cause the relay valve to output its higher ratio.
2) Where the changeover device is supplied from the BCP, the Lsp/Lcp indicating the loaded condition
can either be 0 bar or equivalent to the brake cylinder pressure and shall cause relay valve to output
its higher ratio.
NOTE The signal pressure is typically supplied as a load control signal pressure (Lsp) from a manually
operated pneumatic device e.g. a changeover cock, or an automatic empty-loaded changeover device. Alternatively it
is supplied as a continuous load sensing pressure (Lcp).
c) variable load signal, i.e. where the load sensing pressure (Lcp) comes from an automatic continuously
variable load sensing device (weighing valve) giving continuous load information. See EN 15625.
4.2.4 Enabling of a change of relay valve ratio during brake application of a relay valve of type B1
Whilst the brakes are applied with a brake cylinder pressure > 1 bar, changes of the load sensing pressure
(Lcp or Lsp) outside the limits of ≤ 0,5 bar and ≥ 3 bar shall initiate the change of the relay valve ratio.
For relay valves designated for a changeover during brake application (for speed dependent braking) the relay
valve shall not prevent the changeover. See 4.2.5.
This requirement shall be tested in accordance with 6.2.4.5.
Higher values of the load sensing pressure may be required to achieve a change of relay valve ratio for other
than freight applications e.g. for locomotives or multiple units. In this case the values of the load sensing
pressure will be higher than the values contained in this requirement and the test in 6.2.4.5 shall be amended
to meet the requirements of the specific relay valve application.
4.2.5 Prevention of a change of relay valve ratio during brake application of a relay valve of type B2
and a variable load relay valve, types C, C1, D, E
Whilst the brakes are applied with an output pressure ≥ 1 bar, changes of the load sensing pressure (Lcp or
Lsp) of ± 0,5 bar shall not initiate a change of the relay valve ratio.
NOTE For specific applications, where the load is either fully loaded or tare, this requirement need not apply (for
example tank wagons).
This requirement shall be tested in accordance with 6.2.4.6.
4.2.6 Kinked characteristic of a variable load relay valve (type E)
A variable load relay valve with kinked characteristic may be specified for use on SS-Wagons with tread
brakes.
A relay valve with a kinked characteristic shall be designed to operate in association with distributor valves
compliant with EN 15355, for use on tread braked wagons of greater than 14,5 t axle loads. The required
characteristic shall reduce the output pressure (BCP) at lower brake demands whilst raising the output
pressure (BCP), at moderate to high brake demands, to the equivalent value required to achieve the
maximum braking rate at full load.
The relay valve characteristic shall be designed such that a change of characteristic is achieved at input
pressures A and B, see Figure 11, established for equivalent brake pipe reductions of 0,8 bar and 1,2 bar
respectively as sensed by the distributor. The values of input pressures A and B shall be in the range of
1,8 bar to 2,0 bar and 2,9 bar to 3,15 bar respectively. The increase in output pressure (BCP) achieved
between the input pressure values A and B shall increase in relation to the increase in input pressure.
The output pressure achieved for input pressure values below input pressure A shall be lower than the
equivalent straight line characteristic for the maximum axle load. The output pressure achieved for input
pressure values above input pressure B shall return to the equivalent straight line characteristic for the
maximum axle load.
The relay valve shall also be designed for defined output pressures which correspond to 33 %, 67 %, 80 %
and 100 % of the equivalent fully loaded condition signal (see Figure 11).
These requirements shall be tested in accordance with 6.2.4.9.
4.2.7 Interaction of a relay valve and a distributor valve
Any combination of a distributor and a relay valve (either integral or separate) shall be approved according to
this standard and the relevant distributor valve standard.
The following accuracy shall be achieved when the pair is fitted to a vehicle if necessary by adjustment of the
relay valve output. The design of the relay valve shall allow for this adjustment to be made. In combination
with a distributor valve of a defined type the relay valve shall ensure the following characteristics.
a) For brake application:
1) For all distributor valve/relay valve combinations, except matched pairs of interoperable distributor
valves and relay valves:
i) For a test conducted using an actual distributor in combination with a relay valve for an input
pressure to the distributor of 0 bar (emergency brake application) and with the distributor output
pressure of (3,8 ± 0,1) bar, which forms the input to the relay valve, the accuracy of the relay
valve output pressure shall be ± 0,2 bar. This applies to the empty and loaded conditions.
ii) The output pressure rise time (brake application time measured using an emergency brake
application from the start of the rise of the output pressure to 95 % of its maximum value) of the
relay valve shall be 3 s to 6 s with an input pressure rise time to the relay valve of 3 s to 5 s.
2) For matched pairs of interoperable distributor valves and relay valves, if specifically required by the
customer:
i) For a test conducted using an actual distributor in combination with a relay valve for an input
pressure to the distributor of 0 bar (emergency brake application) and with the distributor output
pressure of (3,8 ± 0,1) bar, which forms the input to the relay valve, the accuracy of the relay
valve output pressure shall be ± 0,1 bar, when achieved by adjustment of the matched pair. This
applies to the empty and loaded conditions.
ii) The output pressure rise time (brake application time measured using an emergency brake
application from the start of the rise of the output pressure to 95 % of its maximum value) of the
relay valve shall be 3 s to 6 s with an input pressure rise time to the relay valve of 3 s to 5 s.
iii) For relay valves of type C, C1, D and E when used in a matched pair, this combination shall
have a performance at intermediate load conditions Lcp3 and Lcp5 (see Table 6), providing an
output pressure accuracy of ± 0,15 bar. At load condition Lcp4 the output pressure accuracy
shall be ± 0,1 bar. This shall be tested with the load sensing pressure increasing from Lcp3.
b) For brake release, all distributor valve/relay valve combinations:
1) The output pressure shall continuously follow the drop of the input pressure from its maximum to
0,1 bar. The time delay for the start of the drop of the output pressure shall be ≤ 10 % of the total
allowed release time for the distributor valve;
2) When the input pressure has fallen to 0,05 bar, the output pressure shall fall to ≤ 0,05 bar not more
than 15 s later.
These requirements shall be tested in accordance with 6.2.4.14 and 6.2.4.17.
4.2.8 Hysteresis
The maximum hysteresis of any relay valve shall be ≤ 0,15 bar, at a relay valve ratio of 1.
For single stage relay valves (type A) the maximum hysteresis shall be ≤ 0,10 bar.
This requirement shall be tested in accordance with 6.2.4.8 to 6.2.4.11.
4.2.9 Sensitivity
The sensitivity of a relay valve with a relay valve ratio of 1 or greater at 20 °C shall be ≤ 0,1 bar.
The sensitivity of a relay valve with a relay valve ratio less than 1 shall be such that a minimum of 5 steps of
output pressure can be achieved between the initial input pressure and maximum input pressure.
The initial sensitivity of any relay valve at 20 °C shall be ≤ 0,3 bar. An input pressure of 0,3 bar shall cause an
output pressure of ≥ 0,1 bar in any load situation.
The sensitivity at reversal of a relay valve with a relay valve ratio of 1 or greater, shall be ≤ 0,2 bar.
The sensitivity at reversal of a relay valve with a relay valve ratio greater than 0,5 and less than 1 shall be
≤ 0,4 bar.
There is no requirement for the sensitivity at reversal of a relay valve with a relay valve ratio less than 0,5.
These requirements shall be tested in accordance with 6.2.4.12.
4.2.10 Flow
The relay valve shall be capable of operating within the requirements of this standard with the possibility of a
wide variation in the volume attached to the output. Any volume limitations of a specific relay valve shall be
identified by the manufacturer in the relevant technical documents and the operating capability confirmed as
part of the vehicle test.
4.2.11 Leakage
The sealing arrangement within the relay valve shall prevent any unacceptable loss of air.
At an environmental temperature of (20 ± 5) °C, the relay valve shall not have a leakage rate of greater than
0,005 Nl/min for the AR, 0,001 Nl/min for the input pressure and 0,003 Nl/min for the output pressure and
Lcp/Lsp, at normal working pressures. This requirement shall be tested in accordance with 6.2.4.3.
At an environmental temperature of – 25 °C, also at + 70 °C the relay valve shall not have a leakage rate of
greater than 0,01 Nl/min at the normal working pressures. This shall be tested in accordance with 6.2.4.16.
At – 40 °C ≤ environmental temperature < – 25 °C the relay valve shall not have a leakage rate of greater than
0,1 Nl/min at normal working pressures. This shall be tested in accordance with 6.2.4.16.
4.2.12 Change of relay valve ratio
The design shall enable the relay valve ratio to be controlled by one or more of the following means:
a) a mechanical means e.g. a screw for adjusting the relay valve ratio (fixed setting, unchangeable during
operation);
b) mechanical means e.g. a lever or electrical means e.g. a magnet valve to switch the relay valve ratio
during operation;
c) signal pressure(s) to switch the relay valve ratio from a first to a second (third) level of output pressure or
to change the relay valve ratio continuously.
4.3 Shock and vibration
The relay valve shall be able to operate without restriction under shock and vibration conditions as specified
by EN 61373:1999, Category 1, Class A or B.
The relay valve shall fulfil the specified requirements during a random vibration test in accordance with
EN 61373:1999, Clause 8.
The relay valve shall withstand a simulated long life test at increased random vibration levels in accordance
with EN 61373:1999, Clause 9 without any loss of performance.
The relay valve shall withstand shock testing in accordance with EN 61373:1999, Clause 10 without any loss
of performance.
These requirements shall be tested in accordance with 6.2.4.15.
4.4 Environment requirements
4.4.1 General
The design shall take into account that the relay valve shall be able to be put into service and operate
normally in the conditions and climatic zones for which it is designed and in which it is likely to run, as
specified in this standard.
NOTE 1 The environmental conditions are expressed in classes for temperature, humidity, etc., thereby giving the
vehicle designer the choice of a relay valve suitable for operation on a vehicle all over Europe, or have a restricted use.
NOTE 2 The environment range limits specified are those that have a low probability of being exceeded. All specified
values are maximum or limit values. These values may be reached, but do not occur permanently. Depending on the
situation there may be different frequencies of occurrence related to a certain period of time.
NOTE 3 The environment requirements of this document cover the environment requirements of the HS RST TSI
which only refers to EN 50125-1.
The relay valve shall be tested in accordance with requirements given in Clause 6 of this standard including
where required environmental/climatic testing.
4.4.2 Temperature
The relay valves covered by this standard shall be able to operate:
 at – 25 °C ≤ environmental temperature ≤ 70 °C without any deviation from the technical requirements
specified in Clause 4 in this standard;
 at – 40 °C ≤ environmental temperature < – 25 °C with allowed deviation from the technical requirements
specified in this standard but without affecting the function of the relay valve.
In the range from – 40 °C ≤ environmental temperature < – 25 °C the values of sensitivity and hysteresis shall
be not more than two times higher than at normal temperatures. The tolerances of the pressures shall be not
more than four times higher than at normal temperatures.
The leakage rate from – 40 °C ≤ environmental temperature < – 25 °C and at + 70 °C is defined in 4.2.11.
These requirements shall be tested in accordance with 6.2.4.16.
The purchaser can specify higher or lower extreme temperature limit values if operational constraints demand
it. In this case the temperature limit values used in the extreme temperature tests 6.2.4.16 shall be changed
accordingly.
4.4.3 Other environmental conditions
4.4.3.1 General
The following environmental conditions shall be considered in the design of the relay valve.
It shall be demonstrated that these environmental conditions have been taken into account in the design of the
relay valve. It is sufficient for the supplier to make a declaration of conformity stating how the environmental
conditions in the following clauses have been taken into account.
If not specifically required to be tested as part of the type testing requirements in Clause 6 of this standard,
suitable tests and/or design assessments considering the effect of the following environmental
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