Gas pressure regulators for inlet pressures up to 100 bar

Tolerance of 9 months requested before UAP per CEN/TC 235 C02/2006.

Gas-Druckregelgeräte für Eingangsdrücke bis 100 bar

Appareils de régulation de pression de gaz (régulateurs) pour des pressions amont jusqu'à 100 bar

Regulatorji tlaka plina za vstopne tlake do 100 bar - Dopolnilo A1

General Information

Status
Not Published
Public Enquiry End Date
31-Oct-2008
Technical Committee
Current Stage
98 - Abandoned project (Adopted Project)
Start Date
18-Nov-2011
Due Date
23-Nov-2011
Completion Date
18-Nov-2011

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SLOVENSKI STANDARD
SIST EN 334:2005/kprA1:2008
01-oktober-2008
Regulatorji tlaka plina za vstopne tlake do 100 bar - Dopolnilo A1
Gas pressure regulators for inlet pressures up to 100 bar
Gas-Druckregelgeräte für Eingangsdrücke bis 100 bar
Appareils de régulation de pression de gaz (régulateurs) pour des pressions amont
jusqu'à 100 bar
Ta slovenski standard je istoveten z: EN 334:2005/prA1
ICS:
23.060.40 7ODþQLUHJXODWRUML Pressure regulators
SIST EN 334:2005/kprA1:2008 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 334:2005/kprA1:2008

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SIST EN 334:2005/kprA1:2008
EUROPEAN STANDARD
FINAL DRAFT
EN 334:2005
NORME EUROPÉENNE
EUROPÄISCHE NORM
prA1
August 2008
ICS 23.060.40

English Version
Gas pressure regulators for inlet pressures up to 100 bar
Appareils de régulation de pression de gaz (régulateurs) Gas-Druckregelgeräte für Eingangsdrücke bis 100 bar
pour des pressions amont jusqu'à 100 bar
This draft amendment is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee
CEN/TC 235.
This draft amendment A1, if approved, will modify the European Standard EN 334:2005. If this draft becomes an amendment, CEN
members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this amendment
into the relevant national standard without any alteration.
This draft amendment was established by CEN 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.
: This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
Warning
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 334:2005/prA1:2008: E
worldwide for CEN national Members.

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
Contents Page
Foreword .3
1 Modification to Foreword .4
2 Modification to Clause 1, Scope .4
3 Modification to Clause 2, Normative reference.5
4 Modification to Clause 3, Terms, definition and symbols.7
5 Modification to 4.1, Basic requirements .11
6 Modification to 4.2, Materials .14
7 Modification to 4.3, Strength of housings .16
8 Modification to Clause 5, Functional requirements.19
9 Modification to 7.7, Test and verification methods .19
10 Modification to 8.1.1, Documentation required prior to type test .22
11 Modification to 8.2.2, Documentation provided with the regulator.22
12 Modification to 9.1, General requirements .22
13 Modification to Annex A, Alternative methods for the determination of the accuracy class,
the lock-up pressure class, the maximum accuracy flow rate, the flow coefficients and the
verification of the hysteresis band.22
14 Modification to Annex B, Inspection certificate.23
15 Modification to D.3, Procedure .25
16 Modification to Annex E, Seat leakage .25
17 Modification to G.3, Optional specifications .25
18 Modification of Annex H, Materials .26
19 Addition of Annex I, Glossery.28
20 Modification to Table ZA.1 - Correspondence between this European Standard and
Directive 97/23/EC (PED) .31
21 Modification to Bibliography.31

2

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
Foreword
This document (EN 334:2005/prA1:2008) has been prepared by Technical Committee CEN/TC 235 “Gas
pressure regulators and associated safety devices for use in gas transmission and distribution”, the secretariat
of which is held by UNI.
This document is currently submitted to the Unique Acceptance Procedure.
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.
This document specifies the additions and changes to EN 334:2005 concerning mainly the extension of
harmonized part to differential strength regulators and to various combinations including a pressure regulator
and a safety device and the extension of the non-applicability to the regulators incorporated into pressure-
regulating device use in service lines. Further the Clause 3 dealing with terms, symbols and definitions have
been partially re-organized.
3

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
1 Modification to Foreword
th
Replace the text after the last comma of the 7 paragraph with the following:
"except the external corrosion resistance in case of environmental conditions where corrosion is likely to
occur" to read:
"For standard gas pressure regulators used in pressure regulating stations complying with EN 12186 or
EN 12279, Table ZA.1 given in Annex ZA includes all applicable Essential Requirements given in Annex I of
PED, except the external corrosion resistance in case of environmental conditions where corrosion is likely to
occur.".
Delete the third-last paragraph.
Replace "The continuing" in the second-last paragraph with "Continued" to read:
"Continued integrity of gas pressure regulators is assured by periodic functional checks. For periodic functional
checks it is common to refer to national regulations/standards where existing or users/manufacturers
practices.".
2 Modification to Clause 1, Scope
st st
Replace the 1 sentence of the 1 paragraph with the following:
"This document specifies constructional, functional, testing and marking requirements, sizing and
documentation of gas pressure regulators used in the pressure regulating stations in accordance with
EN 12186 or EN 12279:".
rd
Replace the 3 paragraph with the following:
"For standard regulators when used in pressure regulating stations complying with EN 12186 or EN 12279,
Annex ZA lists all applicable Essential Requirements except the external corrosion resistance in case of
environmental conditions where corrosion is likely to occur.".
st th
Replace the 1 line of the 4 paragraph with the following:
"This document considers the following classes/types of regulators:".
nd
and add after its 2 indent the following two new indents: "
 type IS: (integral strength type);
 type DS: (differential strength type).".
nd
Replace the 2 indent of the last paragraph with the following new indent including its footnote to text: "
1
 regulators incorporated into pressure-regulating devices used in service lines with volumetric flow rate
3
≤ 200 m /h at normal conditions and inlet pressure ≤ 5 bar;".

1
The services lines are those defined in EN 12279.
4

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
3 Modification to Clause 2, Normative reference
Delete the following standards:
"EN 287 (all parts). QuEN 288 (all parts), Specification and approval of welding procedures for metallic
materials.",
"EN 571-1, Non destructive testing – Penetrant testing – Part 1: General principles.",
"EN 1289, Non-destructive examination of welds – Penetrant testing of welds – Acceptance levels.
EN 1290, Non-destructive examination of welds – Magnetic particle examination of welds.
EN 1291, Non-destructive examination of welds – Magnetic particle testing of welds – Acceptance levels.",
"EN 1435, Non-destructive examination of welds – Radiographic examination of welded joints.
EN 1712, Non-destructive examination of welds – Ultrasonic examination of welded joints – Acceptance levels.
EN 1713, Non-destructive examination of welds – Ultrasonic examination – Characterization of indications in
welds.
EN 1714, Non- destructive examination of welds – Ultrasonic examination of welded joints.",
"EN 12517, Non-destructive examination of welds – Radiographic examination of welded joints – Acceptance
levels."
"ISO 7-1, Pipe threads where pressure tight joints are made on threads – Part 1: Dimensions, tolerances and
designation" and
"ANSI/ASME B1.20.1:1983, Pipe threads, general purpose (inch)
ASME B16.34:1996, Valves – Flanged, threaded and welding end.".
Add the following standards:
"EN 287-1, Qu
"EN 1092-1:2007, Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories, PN
designated – Part 1: Steel flanges
EN 1092-2:1999, Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories, PN
designated – Part 2: Cast iron flanges
EN 1092-3:2005, Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories, PN
designated – Part 3: Copper alloy flanges
EN 1092-4:2004, Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories, PN
designated – Part 4: Aluminium alloy flanges",
"EN 1759-1, Flanges and their joint – Circular flanges for pipes, valves, fittings and accessories, Class
designated – Part 1: Steel flanges, NPS ½ to 24
EN 1759-3, Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories, Class
designated – Part 3: Copper alloy flanges
EN 1759-4, Flanges and their joint – Circular flanges for pipes, valves, fittings and accessories, class
designated – Part 4: Aluminium alloy flanges",
5

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
"EN 10226-1, Pipe threads where pressure tight joints are made on the threads – Part 1: Taper external
threads and parallel internal threads – Dimensions, tolerances and designation
EN 10226-2, Pipe threads where pressure tight joints are made on the threads – Part 2: Taper external
threads and taper internal threads – Dimensions, tolerances and designation",
"EN 12516-1:2005, Industrial valves – Shell design strength – Part 1: Tabulation method for steel valves shells
EN 12516-2:2004, Industrial valves – Shell design strength – Part 2: Calculation method for steel valve shells
EN 12516-4:2008, Industrial valves – Shell design strength – Part 4: Calculation method for valve shells in
metallic materials other than steel",
"EN 60534-8-3, Industrial-process control valves – Part 8-3: Noise considerations – Control valve aerodynamic
noise prediction method (IEC 60534-8-3:2000)" and
"EN ISO 9606-2, Qualification test of welders – Fusion welding – Part 2: Aluminium and aluminium alloys
(ISO 9606-2:2004)
EN ISO 9606-3, Qualification test of welders – Fusion welding – Part 3: Copper and copper alloys
(ISO 9606-3:1999)
EN ISO 9606-4, Qualification test of welders – Fusion welding – Part 4: Nickel and nickel alloys
(ISO 9606-4:1999)
EN ISO 15607:2003, Specification and qualification of welding procedures for metallic materials – General
rules (ISO 15607:2003)
EN ISO 15609-1:2005, Specification and qualification of welding procedures for metallic materials – Welding
procedure specification – Part 1: Arc welding (ISO 15609-1:2004)
EN ISO 15610:2003, Specification and qualification of welding procedures for metallic materials – Qualification
based on tested welding consumables (ISO 15610:2003)
EN ISO 15611:2003, Specification and qualification of welding procedures for metallic materials – Qualification
based on previous welding experience (ISO 15611:2003)
EN ISO 15612:2004, Specification and qualification of welding procedures for metallic materials – Qualification
by adoption of a standard welding procedure (ISO 15612:2004)
EN ISO 15613:2004, Specification and qualification of welding procedures for metallic materials – Qualification
based on pre-production welding test (ISO 15613:2004)
EN ISO 15614-1:2004, Specification and qualification of welding procedures for metallic materials – Welding
procedure test – Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
(ISO 15614-1:2004)
EN ISO 15614-2:2005, Specification and qualification of welding procedures for metallic materials – Welding
procedure test – Part 2: Arc welding of aluminium and its alloys (ISO 15614-2:2005)".
Replace "EN 473" with "EN 473:2000", "EN 970" with "EN 970:1997", "EN 1418" with "EN 1418:1997",
"EN 10204" with "EN 10204:2004" and "EN 14382:2005" with "EN 14382:2005".
Delete all full stops.
6

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
4 Modification to Clause 3, Terms, definition and symbols
Delete following actual terms or sub-clause titles:
3.1.1.7, 3.1.1.8, 3.1.1.10, 3.1.3, 3.2.1, 3.2.1.2, 3.2.4.4 and 3.4.1.
Add the following standard paragraph and NOTE after the title of Clause 3:
"For the purposes of this document, the following terms, definitions and symbols apply.
NOTE Annex I list all terms in alphabetic order for English language, the relevant translation in French and German
language and the relevant sub-clause of this clause.".
Replace the title of actual sub-clause 3.1 with the following:
"General terms and definitions of types of gas pressure regulators"
and delete the standard paragraph.
Replace the reference within bracket in actual term 3.1.1 with the following:
"(see 3.3.4.1)".
st
Replace the 1 line of the actual term 3.1.1.3 with the following (this term will be re-numbered as 3.1.4):
"second regulator installed in series with an active regulator, normally upstream, which has the task of
maintaining the" to read: "second regulator installed in series with an active regulator, normally upstream,
which has the task of maintaining the controlled variable within allowable limits in the event of its value
exceeds a pre-established value (e.g. in the event of opening of the active regulator due to a failure, etc.)".
Replace the definition of the actual term 3.1.1.9 with the following (this term will be re-numbered as 3.1.7):
"nominal size DN of the inlet connection in accordance with EN ISO 6708" (deletion of "nominal inlet
diameter").
nd
Replace the text of 2 indent of the definition of the actual terms 3.1.2.7 and 3.1.2.8 with the following (these
terms will be re-numbered as 3.2.1.7 and 3.2.1.8 respectively): "
 a pressure detector element, normally a diaphragm, for the controlled variable".
Replace the text of the definition of the actual term 3.1.2.10 with the following (this term will be re-numbered
as 3.2.2):
"parts whose failure to function would result in a release of the retained fuel gas to the atmosphere
NOTE These include bodies, control member, bonnets, the casing of the actuator, blind flanges and pipes for process
and sensing lines but exclude compression fittings, diaphragms, bolts and other fasteners.".
Replace the text of the definition and of the NOTE of the actual term 3.1.3.2 with the following (this term will be
re-numbered as 3.2.5):
"line connecting the atmosphere side of the pressure detector element to atmosphere
NOTE In the event of a fault in the pressure detector element this line may become an exhaust line.".
7

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
Replace the text of the definition of the actual term 3.1.3.3 with the following (this term will be re-numbered as
3.2.6):
"line connecting the regulator or its fixtures to atmosphere for the safe exhausting of gas in the event of failure
of any part".
Replace the reference within bracket in the actual term 3.1.3.4 with the following (this term will be re-
numbered as 3.2.7):
"(see 3.2.1)".
Replace the actual title of sub-clause 3.2 with the following (this sub-clause header will be re-numbered as
3.3):
"Terms, symbols and definitions of components of functional performance".
Replace the text of the definition of the actual term 3.2.1.2.3 with the following (this term will be re-numbered
as 3.3.2.1.2):
"volume of gas which flows through the regulator per unit of time, at normal conditions".
Replace the text of the definition of the actual term 3.2.2.2 with the following (this term will be re-numbered as
3.3.4.2):
"variables acting from outside on the controlling process.
In the case of regulators with the outlet pressure as the controlled variable, the disturbance variables are
essentially:
changes in the inlet pressure
 ;
changes in the volumetric flow rate".

Replace the title of actual sub-clause 3.2.3 with the following (this sub-clause will be re-numbered as 3.3.5):
"Terms and definitions related to possible values of all variables".
Replace the title of actual sub-clause 3.2.4 with the following (this sub-clause will be re-numbered as 3.3.6):
"Terms, symbols and definitions related to the controlled process".
Replace the text of the definition of the actual term 3.2.4.1 with the following (this term will be re-numbered as
3.3.6.1):
"nominal value of the controlled variable under specified conditions"
Replace the text of the definition of the actual term 3.2.4.5 with the following (this term will be re-numbered as
3.3.6.4):
"difference between the actual value of the controlled variable and the set point expressed as a percentage of
the set point".
Replace the title of actual sub-clause 3.3 with the following (this sub-clause title will be re-numbered as 3.3.7):
"Terms, symbols and definitions of functional performance".
8

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
Replace the actual title of sub-clause 3.3.5 with the following (this sub-clause title will be re-numbered as
3.3.8):
"Feature related to accuracy".
Replace the text of the definition of the actual term 3.3.5.1 with the following (this term will be re-numbered as
3.3.8.1):
"maximum absolute value of regulation change under specified operating range".
Replace the text of the definition of the actual term 3.3.5.2 with the following (this term will be re-numbered as
3.3.8.2):
"maximum permissible value of the accuracy under specified operating range".
Replace the title of actual sub-clause 3.3.6 with the following (this sub-clause title will be re-numbered as
3.3.9):
"Terms, symbols and definitions related to lock-up behaviour".
Replace the title of actual sub-clause 3.4 with the following:
"Terms, symbols and definitions related to design and tests".
Replace the text of the definition of the actual term 3.4.1.3 with the following (this term will be re-numbered as
3.4.3):
"maximum pressure for which the body, its inner metallic partition walls and some other pressure containing
parts are designed in accordance with the strength requirements in this document".
Replace the text of the definition of the actual term 3.4.1.6 with the following (this term will be re-numbered as
3.4.7):
"ratio of the limit pressure p to the maximum allowable pressure PS or to the specific maximum allowable
l
pressure PSD applied to:
 the regulator body: S (only PS);
b
 the other pressure containing parts of the regulator: S (PS or PSD)".
Replace in the text of NOTE 2 of actual term 3.4.2 the reference with (this term will be re-numbered as 3.4.11):
"3.4.3".
9

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
nd
Re-number the actual sub-clause titles and terms as hereafter showed in the 2 column:
Actual numbering New numbering  Actual numbering New numbering
3.1.1.1 3.1.2 3.2.3 3.3.5
3.1.1.2 3.1.3 3.2.3.1 3.3.5.1
3.1.1.3 3.1.4 3.2.3.2 3.3.5.2
3.1.1.4 3.1.8 3.2.3.3 3.3.5.3
3.1.1.5 3.1.5 3.2.4 3.3.6
3.1.1.6 3.1.6 3.2.4.1 3.3.6.1
3.1.1.9 3.1.7 3.2.4.2 3.3.6.2
3.1.2 3.2.1 3.2.4.3 3.3.6.3
3.1.2.1 3.2.1.1 3.2.4.5 3.3.6.4
3.1.2.2 3.2.1.2 3.3 3.3.7
3.1.2.3 3.2.1.3 3.3.1 3.3.7.1
3.1.2.4 3.2.1.4 3.3.2 3.3.7.2
3.1.2.5 3.2.1.5 3.3.3 3.3.7.3
3.1.2.6 3.2.1.6 3.3.4 3.3.7.4
3.1.2.7 3.2.1.7 3.3.5 3.3.8
3.1.2.8 3.2.1.8 3.3.5.1 3.3.8.1
3.1.2.9 3.2.1.9 3.3.5.2 3.3.8.2
3.1.2.10 3.2.2 3.3.5.3 3.3.8.3
3.1.2.11 3.2.3 3.3.5.4 3.3.8.4
3.1.3.1 3.2.4 3.3.6 3.3.9
3.1.3.2 3.2.5 3.3.6.1 3.3.9.1
3.1.3.3 3.2.6 3.3.6.2 3.3.9.2
3.1.3.4 3.2.7 3.3.6.3 3.3.9.3
3.2 3.3 3.3.6.4 3.3.9.4
3.2.1.1 3.3.1 3.3.6.5 3.3.9.5
3.2.1.1.1 3.3.1.1 3.3.6.6 3.3.9.6
3.2.1.1.2 3.3.1.2 3.4.1.1 3.4.1
3.2.1.1.3 3.3.1.3 3.4.1.2 3.4.2
3.2.1.1.4 3.3.1.4 3.4.1.3 3.4.3
3.2.1.1.5 3.3.1.5 3.4.1.4 3.4.5
3.2.1.2.1 3.3.2.1 3.4.1.5 3.4.6
3.2.1.2.2 3.3.2.1.1 3.4.1.6 3.4.7
3.2.1.2.3 3.3.2.1.2 3.4.1.7 3.4.8
3.2.1.3 3.3.3 3.4.1.8 3.4.9
3.2.2 3.3.4 3.4.1.9 3.4.10
3.2.2.1 3.3.4.1 3.4.2 3.4.11
3.2.2.2 3.3.4.2 3.4.3 3.4.12
and sort the terms and definitions where necessary.
Add following new sub-clause titles:
“3.2 Terms and definitions of components of gas pressure regulators” and
"3.3.2 Terms, symbols and definitions related to flow".
10

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
Add following new term and definition:
"3.4.4
specific maximum allowable pressure
PSD
pressure for which some pressure containing parts of differential strength regulators are designed where
PSD < PS".
Add to Figure 1 "Example of a direct acting regulator" the following detail:

and replace the key 2 with the following:
"2 pressure detector element"

and add key 11 as follows:

"11 scheme 1a".
5 Modification to 4.1, Basic requirements
In 4.1.1, General:
rd
Replace the 3 paragraph with the following text and corresponding footnote to text:
"Regulators shall be so designed that the external tightness and internal sealing meet the requirements of 5.2.
If in the event of failure of the regulator (e.g. failure of a diaphragm) leakage to atmosphere is possible, the
breather shall be provided with a threaded connection of at least DN 10 to enable an exhaust line to be
2
connected . This connection may be used for a specific device (e.g. a dumping device).".
Delete the third last paragraph.
Add the following new paragraph at the end:
"A regulator used as stand-by monitor should be fitted with an external visual device, which indicates whether
the control member is in the closed or in fully open position.".

2
For proper operation of the regulator any exhaust line should be designed in such a way to prevent the ingress of foreign
materials.
11

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
In 4.1.2, Gas pressure regulators with integrated safety devices, replace the whole sub-clause with the
following new sub-clauses 4.1.2, 4.1.2.1, 4.1.2.2 and 4.1.2.3:
"4.1.2 Gas pressure regulators with associated safety devices
4.1.2.1 Gas pressure regulators with integrated safety devices
3
Additional integrated (same body) safety devices i.e. gas safety shut-off devices (SSD) and/or a monitor shall
be functionally independent from the regulator.
This requirement is met if:
a) the function of the regulator is not affected in the event of the failure and/or loss of functionality of one or
more of the following safety shut-off device / monitor components:
 closure / control member;
 seat ring;
 actuator;
 casing of actuator;
 controller;
 pilot (in case of pilot-controlled monitor type);
 sensing and process lines;
and if:
b) the function of the safety shut-off device / monitor is not affected in the event of the failure and/or loss
of functionality of one or more of the following regulator components:
 control member;
 seat ring;
 actuator;
 casing of actuator;
 controller;
 pilot (in case of pilot-controlled regulator type);
 sensing and process lines.
When the regulator incorporates more than one safety devices (e.g. a monitor and a SSD or two SSDs), the
functional independence shall be met by each device from the other ones in similar way as detailed above.
Further, when the integrated safety device utilizes pipeline gas as a source of energy for its operation, this
shall be taken upstream of the regulator.

3
For this subject see EN 14382.
12

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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
When the integrated safety device is a slam shut device or a cut-off device or a monitor, the motorization
energy for the regulator, when it is a pilot-controlled type, shall be provided by the gas downstream of the
safety device.
4.1.2.2 Gas pressure regulators with in-line monitor
The system includes a regulator with the function of active regulator and a second (in series) regulator with the
function of monitor. The monitor shall be installed directly upstream of the active regulator and both equipment
shall control the pressure at the same location.
The associated in-line monitor shall be functionally independent from the active regulator.
This requirement is met if:
a) the function of the regulator is not affected in the event of the failure and/or loss of functionality of one or
more of the following monitor components:
 pilot (in case of pilot-controlled monitor type);
 sensing and process lines;
and if:
b) the function of the monitor is not affected in the event of the failure and/or loss of functionality of one or
more of the following regulator components:
 pilot (in case of pilot-controlled regulator type);
 sensing and process lines.
The motorization energy for active regulator in case of pilot-controlled type shall be taken downstream of the
monitor.
For in-line monitor stand-by type (in full open position in normal operating conditions), it is necessary to adopt
appropriate design measures to avoid sticking actions that may occur between movable and fixed parts.
4.1.2.3 Gas pressure regulator with in-line safety shut off device
The system includes a regulator with the function of active regulator and an in-line SSD (in series).
The SSD shall be installed directly upstream of active regulator and both devices shall control the pressure at
the same location.
The associated in-line SSD shall be functionally independent from the active regulator.
The requirement is met if:
a) the function of active regulator is not affected in the event of the failure and/or loss of functionality of one
or more of the following SSD components:
 controller;
 sensing and process lines;
and if:
b) the function of SSD is not affected in the event of the failure and/or loss of functionality of one or more of
the following active regulator components:
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SIST EN 334:2005/kprA1:2008
EN 334:2005/prA1:2008
 pilot (in case of pilot-controlled regulator type);
 sensing and process lines.
The motorization energy for active regulator, in case of pilot-controlled type, shall be taken downstream of the
SSD.".
rd
In 4.1.3, End connections, replace the 3 indent with the following: "
 threaded connections in accordance with EN 10226-1 or EN 10226-2 for:
 DN ≤ 50;
 DN ≤ 80 and PS ≤ 16 bar;
...

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