EN 88-2:2007

SLOVENSKI STANDARD
01-januar-2008
7ODþQLUHJXODWRUMLLQSULSDGDMRþHYDUQRVWQHQDSUDYH]DSOLQVNHDSDUDWHGHO
7ODþQLUHJXODWRUML]DYVWRSQHWODNHQDGEDUGRYNOMXþQREDU
Pressure regulators and associated safety devices for gas appliances - Part 2: Pressure
regulators for inlet pressures above 500 mbar up to and including 5 bar
Druckregler und zugehörige Sicherheitseinrichtungen für Gasgeräte - Teil 2: Druckregler
für Eingangsdrücke über 500 mbar bis einschließlich 5 bar
Régulateurs de pression et dispositifs de sécurité associés pour appareils a gaz - Partie
2: Régulateurs de pression pour pression amont supérieure a 500 mbar et inférieure ou
égale a 5 bar
Ta slovenski standard je istoveten z: EN 88-2:2007
ICS:
23.060.40 7ODþQLUHJXODWRUML Pressure regulators
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 88-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2007
ICS 23.060.40
English Version
Pressure regulators and associated safety devices for gas
appliances - Part 2: Pressure regulators for inlet pressures
above 500 mbar up to and including 5 bar
Régulateurs de pression et dispositifs de sécurité associés Druckregler und zugehörige Sicherheitseinrichtungen für
pour appareils à gaz - Partie 2: Régulateurs de pression Gasgeräte - Teil 2: Druckregler für Eingangsdrücke über
pour pression amont supérieure à 500 mbar et inférieure ou 500 mbar bis einschließlich 5 bar
égale à 5 bar
This European Standard was approved by CEN on 8 May 2007.
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, 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: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 88-2:2007: E
worldwide for CEN national Members.

Contents Page
Foreword. 4
Introduction . 5
1 Scope. 6
2 Normative references . 6
3 Terms and definitions. 7
3.1 Pressure regulator . 7
3.2 Components . 7
3.3 Safety shut-off devices. 9
3.4 Control variables. 10
3.4.1 Reference values. 10
3.4.2 Variables in the controlling process. 11
3.4.3 Possible values of all variables . 11
3.4.4 Terms pertinent to the controlled variable. 12
3.5 Operating features in stable conditions . 12
3.6 Features pertinent to accuracy. 14
3.7 Features pertinent to lock-up behaviour . 15
3.8 Further functional terminology. 16
3.8.1 Pressures pertinent to design of gas pressure regulator. 16
3.8.2 nominal pressure . 17
3.8.3 operating temperature range temperature range at which the pressure regulator
components and fixtures are capable of operating continuously. 17
4 Classification. 17
5 Units of measurement and test conditions . 17
5.1 Units of measurement . 17
5.2 Test conditions. 17
6 Construction requirements. 18
6.1 General. 18
6.2 Construction. 18
6.2.1 General. 18
6.2.2 Breather holes . 18
6.2.3 External visual Indication of the position of the closure member. 18
6.2.4 Parts transmitting actuating forces . 19
6.2.5 Pressure adjustment. 19
6.3 Materials. 19
6.3.1 General. 19
6.3.2 Springs. 19
6.3.3 Requirements for elastomers (including vulcanized rubbers). 19
6.4 Gas connections . 19
6.4.1 General. 19
6.4.2 Connection sizes. 19
6.4.3 Threads . 20
6.4.4 Pressure test nipples (applicable only for outlet connections operating at ≤
500 mbar) . 20
7 Performance requirements . 20
7.1 General. 20
7.2 Strength of housings. 20
7.2.1 Requirement . 20
7.2.2 Performance test. 21
7.3 External and internal leak tightness . 21
7.4 Torsion and bending. 21
7.5 Control classification. 21
7.5.1 General. 21
7.5.2 Control classifications for pressure regulators. 21
7.5.3 Safety shut-off device accuracy group for over-pressure. 22
7.6 Safety devices . 22
7.6.1 Over-pressure safety shut-off device . 22
7.6.2 Under-pressure safety shut-off devices . 23
7.6.3 Bypass. 23
7.6.4 Response time. 23
7.7 Durability of performance . 23
7.7.1 Pressure regulator . 23
7.7.2 Safety slam-shut device . 23
8 Marking, installation and operating instructions. 24
8.1 Marking . 24
8.2 Installation, operating and servicing instructions. 24
8.3 Warning notice . 25
Annex A (informative) Main components for direct acting and pilot controlled pressure
regulators. 26
A.1 Main components of a pressure regulator . 26
A.2 Main components of a gas safety shut-off device. 27
Annex B (informative) Use of ISO 7-1 and EN ISO 228-1 threads for gas connections (see
6.4.3) . 29
Annex C (normative) Performance test methods . 30
C.1 General. 30
C.2 Apparatus and test rig. 30
C.3 Performance tests under stable conditions. 32
C.3.1 General. 32
C.3.2 Determination of a performance curve. 34
C.3.3 Determination of the lock-up pressure. 35
C.3.4 Regulator accuracy class. 36
C.4 Safety shut-off device accuracy group. 37
C.4.1 General conditions and apparatus. 37
C.4.2 Test at ambient temperature. 39
C.4.3 Test at the limit temperatures between 0 ºC and 60 ºC. 39
C.4.4 Verification of the upper limit of the highest set range . 40
C.4.5 Response time. 40
C.5 Durability of performance . 41
C.5.1 General. 41
C.5.2 Pressure regulator . 41
C.5.3 Safety shut-off devices. 42
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 90/396/EEC. 43
Bibliography . 45

Foreword
This document (EN 88-2:2007) has been prepared by Technical Committee CEN/TC 58 “Safety and
control devices for gas-burners and gas-burning appliances”, the secretariat of which is held by BSI.
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 May 2008, and conflicting national standards shall be
withdrawn at the latest by May 2008.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this
document.
EN 88 consists of the following parts under the general title “Pressure regulators and associated
safety devices for gas appliances”:
Part 1: Pressure regulators for inlet pressures up to and including 500 mbar;
Part 2: Pressure regulators for inlet pressures above 500 mbar up to and including 5 bar.
This European Standard should be used in conjunction with EN 13611 ‘’Safety and control devices for
gas burners and gas burning appliances — General requirements.’’
SIL classification according to EN 61508 cannot automatically be claimed based upon compliance
with this standard. Pressure regulators with SIL classification do not meet automatically the
requirements of this standard.
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,
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.
Introduction
This standard is a particular standard for Pressure Regulators for gas-burners and gas-burning
appliances which cites EN 13611 ‘’Safety and control devices for gas burners and gas-burning
appliances - General requirements’’ wherever possible. This standard supplements or modifies the
corresponding clauses of EN 13611. The construction and performance requirements are as far as
applicable in total conformity with EN 13611.
1 Scope
This European Standard specifies the safety, construction and performance requirements for pressure
regulators (hereafter referred to as regulators) intended for use with gas burners and gas-burning
st nd rd
appliances using fuel gases of the 1 , 2 and 3 families. This European Standard covers type
testing only. It also provides additional information for the purchaser and user.
This European Standard is applicable to regulators that may be tested independently of gas burners
and gas-burning appliances, which have a declared working pressure from above 500 mbar up to and
including 5 bar.
This European Standard is also applicable to regulators incorporating safety devices.
NOTE 1 For safety accessories and pressure accessories, the requirements of EN 13611:2007, Annex F also
apply.
NOTE 2 Regulators conforming to EN 88-2 fulfil also the requirements of EN 88-1.
Regulators intended to be used on pipe work installations for third family gases are also covered by
EN 13785 and EN 13786.
This European Standard is not applicable to:
a) pressure regulators that are connected directly to mains pipe-work or to a container that
maintains a standard distribution pressure;
b) pressure regulators which use electrical auxiliary energy.
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 88-1:2007, Pressure regulators and associated safety devices for gas appliances — Part 1:
Pressure regulators for inlet pressures up to and including 500 mbar
EN 549, Rubber materials for seals and diaphragms for gas appliances and gas equipment
EN 682, Elastomeric seals — Materials requirements for seals used in pipes and fittings carrying gas
and hydrocarbon fluids
EN 13611:2007, Safety and control devices for gas burners and gas burning appliances — General
requirements
EN 13787, Elastomers for gas pressure regulators and associated safety devices for inlet pressures
up to 100 bar
EN 60534-1:2005, Industrial-process control valves — Part 1: Control valve terminology and general
considerations (IEC 60534-1:2005)
EN 60534-2-3, Industrial-process control valves — Part 2-3: Flow capacity — Test procedures (IEC
60534-2-3:1997)
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)
EN ISO 6708, Pipework components — Definition and selection of DN (nominal size) (ISO
6708:1995)
ISO 7-1, Pipe threads where pressure tight joints are made on the threads —
Part 1: Designation, dimensions and tolerances
ISO 3419, Non-alloy and alloy steel butt-welding fittings
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 13611:2007, EN 60534-
1:2005 and the following apply.
3.1 Pressure regulator
3.1.1
pressure regulator
device that maintains the outlet pressure constant independent of the variations in inlet pressure
and/or flow rate within defined limits
3.1.2
nominal inlet diameter
nominal size DN of the inlet connection in accordance with EN ISO 6708
3.1.3
nominal outlet diameter
nominal size DN of the outlet connection in accordance with EN ISO 6708
3.2 Components
NOTE The main components of a pressure regulator and a safety shut-off device are shown in Annex A.
3.2.1
control member
movable part of the pressure regulator that is positioned in the flow path to restrict the flow through
the pressure regulator
NOTE A control member may be a plug, ball, disk, vane, gate, diaphragm, etc.
3.2.2
body
part of the pressure regulator that is the main pressure containing envelope
3.2.3
valve seat
corresponding sealing surfaces within a pressure regulator, or SSD that make full contact only when
the pressure regulator or SSD is in the closed position
3.2.4
seat ring
replaceable component of a regulator valve seat assembly
3.2.5
actuator
device or mechanism which changes the signal from the controller into a corresponding movement
controlling the position of the control member
3.2.6
casing of actuator
housing of the actuator
NOTE There may be two chambers under pressure within it. When the pressure in each chamber is
different from atmospheric pressure, the chamber at the higher pressure is termed the "motorization chamber"
3.2.7
controller
device that controls the regulator
NOTE It includes:
 setting element, normally a spring, to obtain the set value of the controlled variable;
 detector element, normally a diaphragm, for the controlled variable.
3.2.8
pilot controller
device that controls the regulator
NOTE It includes:
 setting element to obtain the set value of the controlled variable;
 detector element for the controlled variable;
 unit which compares the set value of the controlled variable with its feedback value;
 system which provides the motorization energy for the actuator.
3.2.9
main diaphragm
device that detects the controlled variable feedback pressure and provides the force to position the
valve
3.2.10
pressure containing parts
parts where failure would result in release of gas to the atmosphere
NOTE Such parts comprise bodies, control member, bonnets, the casing of the actuator, blind flanges and
pipes for process and sensing lines.
3.2.11
inner metallic partition wall
metallic wall that divides internal chambers which have differing operating pressures
3.2.12
process and sensing line
line that connects impulse points to the pressure regulator
NOTE Sensing and process lines may be integrated into the pressure regulator or external to the pressure
regulator. Those lines with no internal flow are termed "sensing lines"; those with internal flow are termed
"process lines".
3.2.13
breather line
line between the controller and/or pilot regulator and atmosphere which equalizes the pressure on a
detector element when it changes its position
3.2.14
exhaust line
line to atmosphere between the regulator or fixtures for the safe venting of gas in the event of a
component failure
3.2.15
fixtures
functional devices connected to the main components of the pressure regulator or SSD
3.3 Safety shut-off devices
3.3.1
safety shut-off device
SSD
device whose function is to stay in the open position under normal operating conditions and to shut off
the gas flow automatically and completely when the monitored pressure deviates above or below the
pre-set value
3.3.2
closure member
movable part of the safety shut off device that shuts off the gas flow
3.3.3
trip mechanism
mechanism that releases the closure member when activated by the controller
3.3.4
actuator
device that is activated by the trip mechanism which shuts the closure member
3.3.5
relatching device
device that enables the complete opening of an SSD
3.3.6
safety shut-off device controller
safety device for the regulator
NOTE It may include:
 setting element to adjust the set value of the trip pressure;
 sensing element for the control of the monitored pressure (e.g. a diaphragm);
 unit which compares the set value of the trip pressure with the monitored pressure;
 system which gives the energy to operate the trip mechanism.
3.4 Control variables
3.4.1 Reference values
3.4.1.1 Pressure
NOTE All pressures specified in this European Standard are static gauge pressures. They are measured in
1)
bar .
3.4.1.1.1
inlet pressure
p
e
gas pressure at the inlet of the pressure regulator
3.4.1.1.2
outlet pressure
p
a
gas pressure at the outlet of the pressure regulator
3.4.1.1.3
differential pressure
∆p
difference between values of pressure measured at two different points
3.4.1.1.4
motorization pressure,
p
m
gas pressure in the motorization chamber
3.4.1.1.5
motorization chamber
chamber at the higher pressure of two chambers under pressure within the casing of actuator
3.4.1.1.6
pilot feeding pressure
p
ep
gas pressure at the inlet of the pilot
3.4.1.2 Flow conditions
3.4.1.2.1
normal conditions
absolute pressure p of 1 013,25 mbar and temperature T of 0 °C (273,15 K)
n n
NOTE For calculation purposes a value of 273 K is used in this European Standard.
3.4.1.2.2
gas volume
volume of gas at normal conditions
NOTE It is expressed in m .
3.4.1.2.3
volumetric flow rate
Q
volume of gas which flows through the pressure regulator in unit time

5 2 5 -1
1) 1 bar = 1000 mbar = 10 N/m = 10 Pa = 10 MPa.
NOTE It is expressed in m /h at normal conditions.
3.4.2 Variables in the controlling process
3.4.2.1
controlled variable
X
variable which is monitored by the controlling process
NOTE 1 This controlled variable in pressure regulators may be:
inlet pressure, p
e
 ;
outlet pressure, p
a
 ;
 differential pressure, ∆p.
NOTE 2 In this European Standard, only the outlet pressure "p " is considered as the controlled variable.
a
3.4.2.2
disturbance variable
Z
variables acting from outside on the controlling process
NOTE In the case of pressure regulators with the outlet pressure as the controlled variable, the disturbance
variables are essentially:
fluctuations in the inlet pressure, p
e
 ;
 changes in the volumetric flow rate, Q.
3.4.2.3
monitored pressure
pressure monitored and safeguarded by the SSD
3.4.2.4
trip pressure
pressure value at which the closing member starts to move
3.4.2.5
upper trip pressure
p
o
upper limit of the monitored pressure (over-pressure)
3.4.2.6
lower trip pressure
p
u
lower limit of the monitored pressure (under pressure)
3.4.3 Possible values of all variables
3.4.3.1
actual value
instantaneous value of any variable at any instant
NOTE It is specified by the subscript "i" added to the symbol of the variable
3.4.3.2
maximum value
highest value to which any variable can be adjusted, limited or reached during a series of
measurements or during a certain time period
NOTE It is specified by the subscript "max" added to the symbol of the variable.
3.4.3.3
minimum value
lowest value to which any variable can be adjusted, limited or reached during a series of
measurements or during a certain time period
NOTE It is specified by the subscript "min" added to the symbol of the variable.
3.4.4 Terms pertinent to the controlled variable
3.4.4.1
set point
p
as
nominal value of the controlled variable
NOTE The set point is not directly measurable but determined as shown in Figure 1.
3.4.4.2
set point range
W
h
whole range of set points, which can be obtained from a pressure regulator by adjustment and/or the
replacement of some components
NOTE Components might be replacement of the valve seat or adjustment element e.g. spring.
3.4.4.3
specific set point range
W
a
whole range of set points which can be obtained in a pressure regulator by adjustment and with no
replacement of its components
3.4.4.4
control deviation
X
w
difference between the actual value of the controlled variable and the set point
3.4.4.5
regulation change
control deviation, X expressed as a percentage of the set point
w
3.5 Operating features in stable conditions
3.5.1
stable conditions
conditions when the controlled variable settles to a stable value after a disturbance has occurred
3.5.2
performance curve
graphic representation of the controlled variable as a function of the volumetric flow rate
NOTE This curve is determined by increasing and then decreasing the volumetric flow rate with constant
inlet pressure and set point (see Figure 1).
3.5.3
hysteresis band
difference between the two values of outlet pressure for a given volumetric flow rate
NOTE See Figure 1.
p
a
p
Q
Key
1 Max hysteresis band
2 Hysteresis band
Start setting
Measured values
Figure 1 — Performance curve (p constant, p constant)
as e
3.5.4
family of performance curves
set of the performance curves for each value of inlet pressure determined for a given set point
NOTE See Figure 2.
p
a
p p p
emin e emax
Q
Figure 2 — Family of performance curves (p constant)
as
3.6 Features pertinent to accuracy
3.6.1
accuracy
average, expressed as a percentage of the set point, of the absolute maximum values of the positive
and negative control deviation within the operating range
3.6.2
accuracy class
AC
maximum permissible value of the accuracy
NOTE In German AC was designated RG.
3.6.3
inlet pressure range
b
pe
range of the inlet pressure for which the pressure regulator ensures a given accuracy class.
NOTE The inlet pressure range is characterized by its limit values p and p .
emax emin
3.6.4
maximum accuracy flow rate
lowest value of the maximum volumetric flow rate
NOTE 1 Below this flow rate, and for a given set point within the ambient temperature range specified, a given
accuracy class is ensured at:
 the lowest inlet pressure: Q
max,pemin
 the highest inlet pressure: Q
max,pemax
 an intermediate inlet pressure between p and p : Q
emax emin max,pe.
NOTE 2 See Figure 3.
p
a
p ( 1+ SG/100)
as
p ( 1+ AC/100)
as
p
as
p ( 1- AC/100)
as
p p p
emin e emax
Q Q Q
min,pemax max,pe
Q Q Q
min,pe max,pemin max,pemax
Q
min,pemin
Key
= Q with the control member at the limit imposed by the mechanical stop
max
Figure 3 — Family of performance curves indicating maximum accuracy flow rates and
minimum flow rates (p constant, stable conditions)
as
3.7 Features pertinent to lock-up behaviour
3.7.1
lock-up time
t
f
time taken for the control member to move from an open position to the closed position
3.7.2
lock-up pressure
p
f
outlet pressure at which a pressure regulator closes when the outlet of the pressure regulator is
sealed
NOTE The increase in outlet pressure is expressed either in mbar or as a percentage.
3.7.3
lock-up pressure class
SG
maximum permissible positive difference between the actual lock-up pressure and the set point
expressed as a percentage of the set point
NOTE The lock-pressure pressure class, SG, is given by the following equation:
p − p
f as
SG= ×100
p
as
where:
p = lock-up pressure
f
p = set point
as
3.7.4
minimum flow rate
largest value of the minimum volumetric flow rate
NOTE 1 Above this flow rate, and for a given set point within the ambient temperature range specified, stable
conditions are obtained:
 at the lowest inlet pressure: Q
min,pemin
 at the highest inlet pressure: Q
min,pemax
 at an intermediate inlet pressure between p and p : Q .
emax emin min,pe
NOTE 2 See Figure 3.
3.8 Further functional terminology
3.8.1 Pressures pertinent to design of gas pressure regulator
3.8.1.1
component operating pressure
p
gas pressure occurring in any part of a pressure regulator during operation
3.8.1.2
maximum component operating pressure
p
max
highest operating pressure at which any component of a pressure regulator will continuously operate
within specified conditions
3.8.1.3
maximum allowable pressure
PS
maximum pressure for which the equipment is designed, as specified by the manufacturer
NOTE In accordance with the strength requirements of this European Standard.
3.8.1.4
test pressure
pressure applied to a section of the pressure regulator for a limited period of time in order to prove
certain characteristics
3.8.1.5
limit pressure
p
l
pressure at which yielding becomes apparent in any component of the pressure regulator or its
fixtures
3.8.1.6
safety factor
S , S
b
ratio of the value of the limit pressure p to the value of the maximum allowable pressure PS
l
NOTE This term applies to two separate discrete regions of the pressure regulator:
 applied to the pressure regulator body: S ;
b
 applied to the other pressure containing parts of the pressure regulator: S
3.8.1.7
permissible inlet pressure
p
emax
highest inlet pressure at which the pressure regulator can continuously operate within specified
conditions
3.8.1.8
permissible outlet pressure
p
amax
highest outlet pressure at which the pressure regulator can continuously operate within specified
conditions
3.8.1.9
minimum operating differential pressure
∆p
min
minimum operating differential pressure between the inlet and outlet pressures below which the
pressure regulator will no longer function correctly within specified conditions
3.8.2
nominal pressure
PN
numerical designation that applies to flanges relating to pressure
3.8.3
operating temperature range
temperature range at which the pressure regulator components and fixtures are capable of operating
continuously
4 Classification
Pressure regulators shall be classified as group 2 in accordance with EN 13611:2007, 4.2.

NOTE Group 1 controls are excluded from this European Standard.
5 Units of measurement and test conditions
5.1 Units of measurement
Units of measurement shall be as given in EN 13611:2007, 5.1, 5.2 and 5.3.
5.2 Test conditions
Test conditions shall be in accordance with EN 13611:2007, 5.4.
6 Construction requirements
6.1 General
General construction requirements shall be in accordance with EN 13611:2007, 6.1 with the following
additional requirements.
External and internal leak tightness shall meet the requirements of 7.3. If in the event of a failure (e.g.
of a diaphragm) leakage is possible, a tapping connection of at least DN 10 for an exhaust line shall
be provided.
If a safety shut-off device for over-pressure is provided, it shall be functionally independent from the
pressure regulator.
Further, when the integral shut-off safety device utilizes pipeline gas as a source of energy for its
operation this shall be taken from upstream of the pressure regulator.
When the integral shut-off safety device is a slam-shut device or a cut-off device or a monitor, the
motorization energy for a pilot controlled regulator shall be provided by the gas pressure downstream
from the safety device.
NOTE A safety relief or under pressure device may be incorporated in the control member of a pressure
regulator.
6.2 Construction
6.2.1 General
With the exception of breather holes (6.2.2), construction shall be in accordance with EN 13611:2007,
6.2, with the additional requirements given in 6.2.3, 6.2.4 and 6.2.5 of this European Standard.
6.2.2 Breather holes
6.2.2.1 Breather holes without a connection for a vent pipe
Breather holes without a connection for a vent pipe shall conform to EN 13611:2007, 6.2.3.
6.2.2.2 Breather holes with a connection for a vent pipe
If the vented capacity is greater than 70 dm /h of air, a connection for a vent pipe shall be provided.
Any breather/exhaust line or device fitted shall be designed to prevent the ingress of foreign materials
which could damage internal parts.
If a leakage rate limiter is used, it shall be able to withstand three times the maximum inlet pressure. If
a safety diaphragm is used as a leakage rate limiter, it shall not take the place of the working
diaphragm in case of a fault.
Breather holes shall be protected against blockage or shall be located so that they do not easily
become blocked. They shall be so arranged that the diaphragm cannot be damaged by a sharp
device inserted through the breather hole.
6.2.3 External visual Indication of the position of the closure member
A SSD may be fitted with an external visual device to indicate the closure member position. Where an
external visual device is fitted, it shall clearly indicate whether it is in the open or closed position.
6.2.4 Parts transmitting actuating forces
Parts transmitting actuating forces shall be metallic and designed with a safety factor of ≥ 3 against
permanent deformation.
6.2.5 Pressure adjustment
The outlet pressure adjustment shall be readily accessible to authorised persons, but there shall be
provision for sealing after adjustment. Means shall be provided to discourage interference by
unauthorized persons.
6.3 Materials
6.3.1 General
Materials shall conform to EN 13611:2007, 6.3.1, 6.3.3, 6.3.4, 6.3.6, 6.3.7 and 6.3.8, with the
additional requirements given in 6.3.2 and 6.3.3 of this European Standard.
6.3.2 Springs
6.3.2.1 General
Springs shall conform to EN 13611:2007, 6.3.5, with the additional requirements given in 6.3.2.2 of
this European Standard.
6.3.2.2 Stresses and buckling
Springs shall not be overstressed under any operating conditions and there shall be sufficient free
movement to allow satisfactory operation.
Springs shall be designed such that buckling does not occur, in accordance with EN 13906, parts 1 to
3.
6.3.3 Requirements for elastomers (including vulcanized rubbers)
Elastomers shall conform to EN 682 or EN 13787 or EN 549.
6.4 Gas connections
6.4.1 General
Gas connections shall conform to EN 13611:2007, 6.4.1, 6.4.4, 6.4.5, 6.4.6 and 6.4.8, with the
modifications and additional requirements given in 6.4.2, 6.4.3 and 6.4.4 of this European Standard.
6.4.2 Connection sizes
Equivalent connection sizes are given in Table 1.
Table 1 — Connection Sizes
Designation of thread Nominal size of Outside diameter of
Nominal size flanges tubes for compression
DN inches fittings
DN (mm)
6 1/8 6 2 ≤ 5
8 1/4 8 6 ≤ 8
10 3/8 10 10 ≤ 12
15 1/2 15 14 ≤ 16
20 3/4 20 18 ≤ 22
25 1 25 25 ≤ 28
32 1 1/4 32 30 ≤ 32
40 1 1/2 40 35 ≤ 40
50 2 50 42 ≤ 50
65 2 1/2 65
80 3 80
100 - 100
125 - 125
150 - 150
200 - 200
250 - 250
6.4.3 Threads
When the inlet or outlet thread of a pressure regulator is a pipe thread, it shall be in accordance with
either ISO 7-1 or EN ISO 228-1, and shall be chosen from the series given in Table 1.
NOTE Additional information concerning the use of these threads is given in Annex B.
6.4.4 Pressure test nipples (applicable only for outlet connections operating at ≤ 500 mbar)
Pressure test nipples, where fitted, shall have an external diameter of (9 ± 0,5) mm and a useful
length of at least 10 mm for connection to tubing. The equivalent diameter of the bore shall not
exceed 1 mm.
NOTE For special test nipples with screwed connections and internal valves there are no pressure
limitations.
7 Performance requirements
7.1 General
Pressure regulators and safety shut-off devices shall conform to EN 13611:2007, 7.1.

7.2 Strength of housings
7.2.1 Requirement
The safety factor, f shall be equal to 4 for the test pressure where f is the multiplication factor for the
maximum inlet pressure.
When tested in accordance with 7.2.2 followed by 7.3, the external leakage shall not be higher than
the values in Table 2 of EN 13611:2007.

7.2.2 Performance test
A pressure of f times the maximum inlet pressure is applied to the control at maximum ambient
temperature for a minimum of 5 min. Then the control is cooled to (20 ± 5) °C.

7.3 External and internal leak tightness
When tested in accordance with EN 13611:2007, 7.3 with the following additions, the pressure
containing parts and all connecting joints shall conform to EN 13611:2007, 7.2.
The internal leakage test of the assembled SSD and its fixtures shall be carried out at ambient
temperature with two different test pressures, 0,1 bar and 1,1 PS, upstream of the closure member
and at atmospheric pressure downstream of the closure member.
SSDs shall be tested with the pressure regulator in the open position.
7.4 Torsion and bending
When tested in accordance with EN 13611:2007, 7.5, the torsion and bending moment shall conform
to EN 13611:2007, 7.4.
7.5 Control classification
7.5.1 General
If more than one function exists (e.g. pressure regulator and integral safety shut-off device) then the
performance of each function shall be considered separately.
7.5.2 Control classifications for pressure regulators
7.5.2.1 Regulator accuracy
When tested in accordance with C.3.4, pressure regulators shall conform to accuracy requirements
relevant to the declared accuracy class(es) chosen from Table 2 within the declared class.
Table 2 — Accuracy classes
Accuracy class Permissible positive and negative regulation change
a
AC 5 ± 5 %
AC 10 ± 10 %
AC 20 ± 20 %
a
Not lower than ± 1 mbar.
NOTE The same type of pressure regulator may have different accuracy classes depending on the set
range W and/or the inlet pres
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