LPG Equipment and accessories - Pressure relief valves for LPG pressure vessels

This European Standard specifies the requirements for the design and testing of spring loaded pressure relief valves and thermal expansion valves for use in:
- static LPG pressure vessels,
NOTE   The pressure vessels can be situated above ground, underground or mounded.
- LPG pressure vessels on road tankers, rail tankers, tank-containers or demountable tanks.
This document does not address production testing.
Normative Annex B prescribes testing with conditioning at - 40 °C for valves for use under extreme low temperature conditions.
The requirements for pressure relief valve accessories such as isolating devices, changeover manifolds and vent pipes are specified in EN 14071.
EN 14570 identifies the requirements for the pressure relief valve capacities for static pressure vessels.
EN 12252 identifies the requirements for the pressure relief valve capacities for road tankers.
Valves designed in accordance with this standard are specifically for use in LPG applications. Valves manufactured in accordance with EN ISO 4126 1 may also be used in certain LPG applications.
Terms used with LPG pressure relief valves are described graphically in Annex A.

Flüssiggas-Geräte und Ausrüstungsteile - Druckentlastungsventile für Behälter für Flüssiggas (LPG)

Équipements pour GPL et leurs accessoires - Soupapes de sécurité pour réservoirs de GPL sous pression

Oprema in pribor za utekočinjeni naftni plin (UNP) - Varnostni ventili za tlačne posode za UNP

General Information

Status
Not Published
Current Stage
4020 - Submission to enquiry - Enquiry
Due Date
11-Mar-2021
Completion Date
11-Mar-2021

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SLOVENSKI STANDARD
oSIST prEN 14129:2021
01-marec-2021
Oprema in pribor za utekočinjeni naftni plin (UNP) - Varnostni ventili za tlačne
posode za UNP
LPG Equipment and accessories - Pressure relief valves for LPG pressure vessels

Flüssiggas-Geräte und Ausrüstungsteile - Druckentlastungsventile für Behälter für

Flüssiggas (LPG)

Équipements pour GPL et leurs accessoires - Soupapes de sûreté pour réservoirs de

GPL
Ta slovenski standard je istoveten z: prEN 14129
ICS:
23.020.32 Tlačne posode Pressure vessels
23.060.40 Tlačni regulatorji Pressure regulators
oSIST prEN 14129:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 14129:2021
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oSIST prEN 14129:2021
DRAFT
EUROPEAN STANDARD
prEN 14129
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2021
ICS Will supersede EN 14129:2014
English Version
LPG Equipment and accessories - Pressure relief valves for
LPG pressure vessels

Équipements pour GPL et leurs accessoires - Soupapes Flüssiggas-Geräte und Ausrüstungsteile -

de sûreté pour réservoirs de GPL Druckentlastungsventile für Behälter für Flüssiggas

(LPG)

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 286.

If this draft becomes a European Standard, 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.

This draft European Standard 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-CENELEC

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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14129:2021 E

worldwide for CEN national Members.
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oSIST prEN 14129:2021
prEN 14129:2021 (E)
Contents

European foreword ....................................................................................................................................................... 4

Introduction .................................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 6

3 Terms and definitions ................................................................................................................................... 7

4 Operating conditions .................................................................................................................................. 10

5 Materials .......................................................................................................................................................... 11

5.1 General ............................................................................................................................................................. 11

5.2 Metallic materials ........................................................................................................................................ 11

5.3 Non-metallic materials ............................................................................................................................... 12

5.4 Lubricants, sealants, and adhesives ...................................................................................................... 12

5.5 Certification .................................................................................................................................................... 12

6 Design ............................................................................................................................................................... 13

6.1 General ............................................................................................................................................................. 13

6.2 Design parameters ....................................................................................................................................... 14

6.3 Threads ............................................................................................................................................................ 15

6.4 Springs ............................................................................................................................................................. 15

6.5 Additional requirements ........................................................................................................................... 15

6.6 Pressure relief valve with parallel thread .......................................................................................... 16

6.7 Pressure relief valve for use with a changeover manifold ............................................................ 16

6.8 Pilot operated pressure relief valve ...................................................................................................... 16

7 Testing of the design ................................................................................................................................... 17

7.1 General ............................................................................................................................................................. 17

7.2 Test requirements ....................................................................................................................................... 19

7.3 Dimensional checks ..................................................................................................................................... 20

7.4 Hydraulic proof test .................................................................................................................................... 20

7.5 Overtorquing test ......................................................................................................................................... 20

7.6 Start to discharge pressure test .............................................................................................................. 21

7.7 Discharge capacity test .............................................................................................................................. 21

7.8 Leak tightness tests ..................................................................................................................................... 21

7.9 Ageing test ...................................................................................................................................................... 22

7.10 Endurance test .............................................................................................................................................. 22

7.11 Stress cracking test ...................................................................................................................................... 22

7.11.1 General ............................................................................................................................................................. 22

7.11.2 Mercurous nitrate immersion test ......................................................................................................... 22

7.11.3 Moist ammonia air stress cracking test ............................................................................................... 22

7.12 Vacuum test .................................................................................................................................................... 23

7.13 Visual inspection .......................................................................................................................................... 23

7.14 Test records ................................................................................................................................................... 23

8 Marking ............................................................................................................................................................ 23

8.1 Pressure relief valves ................................................................................................................................. 23

8.2 Thermal expansion valves ........................................................................................................................ 24

8.3 Pilot operated pressure relief valve ...................................................................................................... 24

9 Operating instructions ............................................................................................................................... 25

10 Packaging ........................................................................................................................................................ 25

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prEN 14129:2021 (E)

Annex A (informative) Terms used with LPG pressure relief valves ...................................................... 26

Annex B (normative) Special low temperature requirements for valves ............................................. 27

Annex C (normative) Ageing test .......................................................................................................................... 28

C.1 General ............................................................................................................................................................. 28

C.2 Ultraviolet light ............................................................................................................................................. 28

C.3 Rain .................................................................................................................................................................... 28

Annex ZA (informative) Relationship between this European Standard and the Essential

Requirements of EU Directive 2014/68/EU aimed to be covered .............................................. 31

Bibliography ................................................................................................................................................................. 33

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oSIST prEN 14129:2021
prEN 14129:2021 (E)
European foreword

This document (prEN 14129:2021) has been prepared by Technical Committee CEN/TC 286 “LPG

equipmwnt and accessories”, the secretariat of which is held by NSAI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 14129:2014.

This document has been prepared under a standardization request 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 has been submitted for reference in
— the RID [8] and/or
— the technical annexes of the ADR [9].

NOTE These regulations take precedence over any clause of this standard. It is emphasized that RID/ADR are

being revised regularly at intervals of two years which may lead to temporary non-compliances with the clauses of

this standard.
The main changes with respect to the previous edition include:
— Addition of normative references;
— Revision of 5.1, 5.2, 5.3, 6.4, 7.1, 7.11.3; and
— Revision of Annex ZA.
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oSIST prEN 14129:2021
prEN 14129:2021 (E)
Introduction

This document calls for the use of substances and procedures that may be injurious to health and/or the

environment if adequate precautions are not taken. It refers only to technical suitability: it does not

absolve the user from their legal obligations at any stage.

Protection of the environment is a key political issue in Europe and elsewhere. For CEN/TC 286 this is

covered in CEN/TS 16765 [1] and this Technical Specification should be read in conjunction with this

document. The Technical Specification provides guidance on the environmental aspects to be considered

regarding equipment and accessories produced for the LPG industry and the following is addressed:

a) design;
b) manufacture;
c) packaging;
d) use and operation; and
e) disposal.

Provisions have to be restricted to a general guidance. Limit values are specified in national laws.

It is recommended that manufacturers develop an environmental management policy. For guidance see

the EN ISO 14000 series [7], [8] and [9].

It has been assumed in the drafting of this document that the execution of its provisions is entrusted to

appropriately qualified and experienced people.
All pressures are gauge pressures unless otherwise stated.

Valves designed in accordance with this standard are specifically for use in LPG applications. Valves

manufactured in accordance EN ISO 4126-1 [4] may also be used in certain LPG applications.

NOTE This document requires measurement of material properties, dimensions and pressures. All such

measurements are subject to a degree of uncertainty due to tolerances in measuring equipment, etc. It may be

beneficial to refer to the leaflet “measurement uncertainty leaflet” SP INFO 2000 27 [12].

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oSIST prEN 14129:2021
prEN 14129:2021 (E)
1 Scope

This document specifies the requirements for the design and testing of spring loaded pressure relief

valves and thermal expansion valves for use in:
— static LPG pressure vessels,
NOTE The pressure vessels can be situated above ground, underground or mounded.

— LPG pressure vessels on road tankers, rail tankers, tank-containers or demountable tanks.

This document does not address production testing.

Normative Annex B prescribes testing with conditioning at - 40 °C for valves for use under extreme low

temperature conditions.

The requirements for pressure relief valve accessories such as isolating devices, changeover manifolds

and vent pipes are specified in EN 14071:2015+A1:2019.

EN 14570 [2] identifies the requirements for the pressure relief valve capacities for static pressure

vessels.

EN 12252 [3] identifies the requirements for the pressure relief valve capacities for road tankers.

Valves designed in accordance with this document are specifically for use in LPG applications. Valves

manufactured in accordance with EN ISO 4126-1 [4] may also be used in certain LPG applications.

Terms used with LPG pressure relief valves are described graphically in Annex A.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 549:2019, Rubber materials for seals and diaphragms for gas appliances and gas equipment

EN 751-1:1996, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases

and hot water - Part 1: Anaerobic jointing compounds

EN 751-2:1996, Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family gases

and hot water - Part 2: Non-hardening jointing compounds

EN 751-3:1996 , Sealing materials for metallic threaded joints in contact with 1st, 2nd and 3rd family

gases and hot water - Part 3: Unsintered PTFE tapes

EN 837-1:1996 , Pressure gauges - Part 1: Bourdon tube pressure gauges - Dimensions, metrology,

requirements and testing

EN 1092-1:2018, Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, PN

designated - Part 1: Steel flanges
Document impacted by AC:1997.
Document impacted by AC:1998.
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oSIST prEN 14129:2021
prEN 14129:2021 (E)
EN 1563:2018, Founding - Spheroidal graphite cast irons
EN 10204:2004, Metallic products - Types of inspection documents
EN 12164:2016, Copper and copper alloys - Rod for free machining purposes
EN 12165:2016, Copper and copper alloys - Wrought and unwrought forging stock
EN 12420:2014, Copper and copper alloys - Forgings

EN 12516-1:2014+A1:2018, Industrial valves - Shell design strength - Part 1: Tabulation method for steel

valve shells

EN 12516-4:2014+A1:2018, Industrial valves - Shell design strength - Part 4: Calculation method for valve

shells manufactured in metallic materials other than steel
EN 13445-2:2014/A3:2018, Unfired pressure vessels - Part 2: Materials

EN 13906-1:2013, Cylindrical helical springs made from round wire and bar - Calculation and design - Part

1 : Compression springs

EN 14071:2015+A1:2019, LPG equipment and accessories - Pressure relief valves for LPG pressure vessels -

Ancillary equipment

EN ISO 11114-1:2020, Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part

1: Metallic materials (ISO 11114-1:2020)

EN ISO 11114-2:2013, Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part

2: Non-metallic materials (ISO 11114-2:2013)

ISO 7-1:1994 , Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions,

tolerances and designation
ISO 6957:1988, Copper alloys — Ammonia test for stress corrosion resistance
ANSI/ASME B1.20.1–1983, Pipe Threads, General Purpose (Inch)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
Document impacted by Cor 1:2007.
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oSIST prEN 14129:2021
prEN 14129:2021 (E)
3.1
liquefied petroleum gas
LPG

low pressure liquefied gas composed of one or more light hydrocarbons which are assigned to UN 1011,

UN 1075, UN 1965, UN 1969 or UN 1978 only and which consists mainly of propane, propene, butane,

butane isomers, butene with traces of other hydrocarbon gases
3.2
pressure vessel

assembly of the pressure-retaining envelope (including the openings and their closures) and non-

pressure-retaining parts attached directly to it
3.3
pressure relief valve

self-closing valve which automatically, without the assistance of any energy other than that of the vapour

concerned, discharges vapour at a predetermined pressure, and operates with a pop action

3.4
thermal expansion valve

self-closing valve which automatically, without the assistance of any energy other than that of the fluid

concerned, discharges fluid at a predetermined pressure
3.5
spring loaded pressure relief valve

valve in which the loading due to the vapour pressure underneath the sealing element is opposed only by

the force of a spring
3.6
external pressure relief valve

pressure relief valve which when fitted to the LPG pressure vessel has the spring external to the pressure

envelope
Note 1 to entry: See Figure 1.
3.7
pilot operated pressure relief valve

external pressure relief valve where the pressure setting is separate from the discharge function

Note 1 to entry: See Figure 2.
3.8
internal pressure relief valve

pressure relief valve which when fitted to the LPG pressure vessel has the spring internal to the pressure

envelope
3.9
semi-Internal pressure relief valve

pressure relief valve which when fitted has the spring inside the pressure envelope and which has some

of the working parts and the wrenching section outside the pressure envelope
Note 1 to entry: See Figure 3.
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oSIST prEN 14129:2021
prEN 14129:2021 (E)
3.10
fully internal pressure relief valve

pressure relief valve which, when fitted, has the spring, all working parts and the wrenching section

inside the pressure envelope
Note 1 to entry: See Figure 4.
3.11
nominal set pressure

predetermined pressure of the pressure relief valve at which the valve is set to start to discharge

Note 1 to entry: RID [8] and ADR [9] require a capability of automatic opening under a pressure between 0,9

times and 1,0 times the test pressure of the pressure vessel to which they are fitted.

3.12
start to discharge pressure

inlet pressure at which a steady stream of bubbles appear at the outlet of a pressure relief valve through

a water seal of not more than 50 mm water column, or other equivalent method
3.13
overpressure

pressure increase between the nominal set pressure and the flow rating pressure, usually expressed as a

percentage of nominal set pressure
3.14
reseal pressure

inlet pressure at which leakage ceases through a water seal of not more than 50 mm water column on the

outlet of the valve, after the valve has been subjected to a pressure equal to or above the start to discharge

pressure but below the “pop” pressure
3.15
reseat pressure

inlet pressure at which the sealing element effects a seal with the valve seat after the valve has been

subjected to pop action
3.16
flow rating pressure
inlet pressure at which the discharge capacity is measured
3.17
maximum allowable pressure

maximum pressure for which the valve is designed, as specified by the manufacturer

3.18
pop action

rapid opening of the valve sealing element to achieve full lift, resulting from an increase of inlet pressure

creating a sudden increase in force and compression of the spring
3.19
pop pressure
pressure at which pop action occurs
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oSIST prEN 14129:2021
prEN 14129:2021 (E)
3.20
blowdown

difference between start to discharge and reseat pressures, usually expressed as a percentage of the

nominal set pressure
3.21
discharge capacity

capacity at the flow rating pressure of a pressure relief valve expressed in m /min of free air at STP

3.22
nominal discharge capacity

minimum discharge capacity at the flow rating pressure expressed in m3/min of free air at STP rounded

down to one decimal place
3.23
sealing element

non-metallic resilient component which effects a seal by contact with the pressure relief valve seat

3.24
valve seat

normally raised area of the pressure relief valve body on to which the sealing element effects the seal

3.25
pressure relief valve isolating device

device fitted between the storage pressure vessel and an external pressure relief valve (including pilot

operated), which permits replacement of the pressure relief valve without depressurising the pressure

vessel
3.26
changeover manifold

device fitted to a storage vessel permitting two or more pressure relief valves to be fitted, only one of

which can be isolated at a time, which permits replacement of the isolated pressure relief valve without

depressurising the vessel
3.27
leak tightness

resistance to leakage to atmosphere across the valve seat or any other pressure containing component

when the valve is closed
3.28
Standard Temperature and Pressure
STP
15,6 °C (288,7 K), 1,013 bar absolute (0,1013 MPa absolute)
4 Operating conditions

4.1 The pressure relief valve shall be suitable for a minimum operating temperature of - 20 °C, the

temperature to which the valve is expected to be exposed during normal use. Temperatures below this

may be encountered during short periods, for example, during discharge.

4.2 In some parts of Europe, and for certain applications, lower minimum operating temperatures are

encountered. When equipment is designed for a temperature lower than −20 °C, the pressure relief valve

shall meet the requirements of Annex B.
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oSIST prEN 14129:2021
prEN 14129:2021 (E)

4.3 The pressure relief valve shall be suitable for the maximum operating temperature of 65 °C.

4.4 The pressure relief valve shall be suitable for the minimum pressure a valve or fitting is normally

exposed to, which is 1 bar absolute. Vacuum conditions on the valve, arising from butane at low

temperature or evacuation of the pressure vessel can expose the valve or fitting to a vacuum of 50 mbar

absolute.

4.5 Pressure relief valves manufactured in accordance with this European Standard are expected to

have a useful safe service life expectancy of a minimum of 15 years from the date of

manufacture/reconditioning, under normal operating conditions. This requirement does not apply to the

protective cap or plug.
5 Materials
5.1 General

5.1.1 The manufacturer shall endeavour to acquire materials and components from suppliers who have

a declared environmental policy; see EN ISO 14021 [5], EN ISO 14024 [6] and EN ISO 14025 [7].

5.1.2 All materials in contact with LPG shall be physically and chemically compatible with LPG under

all normal operating conditions for which the valve is intended to be used and shall meet the

requirements in accordance with EN ISO 11114-1: and EN ISO 11114-2.

5.1.3 Material for components shall be selected for adequate strength in service. Consideration should

be given to all modes of failure including atmospheric corrosion, brass dezincification, stress corrosion,

impact or material failure. If stress corrosion could be present in a material, stress relieving heat

treatment shall be carried out as necessary.

5.1.4 The components exposed to atmosphere shall be manufactured from corrosion resistant

materials or suitably protected against corrosion.
5.2 Metallic materials

5.2.1 Valves shall be made from steel, stainless steel, copper alloys or other suitable materials.

5.2.2 Shell materials shall be selected in accordance with EN 12516-1:2014+A1:2018,

EN 12516-4:2014+A1:2018 or EN 13445-2:2014/A3:2018.

5.2.3 Components made from stainless steel shall contain not less than 16 % chromium, and not less

than 6 % nickel.

5.2.4 Springs shall be manufactured from stainless steel wire and shall contain not less than 16 %

chromium and not less than 6 % nickel.

5.2.5 When carbon steel is used for a spring for an external relief valve, due to material strength

requirements, it shall be adequately protected against corrosion.

5.2.6 Hot stamped brass shall be non-porous and suitable for machining or other processes. Leaded

brass shall be CW614N, in accordance with EN 12164:2016 or CW617N in accordance with

EN 12420:2014 or EN 12165:2016. Sand-cast brass shall not be used. Cold drawn brass rods shall only

be used for machining after adequate testing for internal cracking, porosity or other inclusions and shall

be heat treated if required. Components produced from stamping brass shall not exhibit cold shuts or

surface defects. Components manufactured from hot stamped brass or made of drawn brass or machined

from brass rod shall be capable of withstanding, without cracking, the stress-cracking test.

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oSIST prEN 14129:2021
prEN 14129:2021 (E)

5.2.7 Spheroidal graphite cast iron shall comply with EN 1563:2018, with an elongation at fracture of

more than 18 %. Other ductile irons or cast irons shall not be used. Castings shall be free from inclusions

and surface defects, which could adversely affect the strength, leak tightness or performance of the valve.

5.2.8 For guidance on the choice of metallic materials, see EN ISO 11114-1:2020.
5.3 Non-metallic materials

5.3.1 Non-metallic materials in contact with LPG shall be compatible with LPG and shall not fail during

the valve service life. They shall not distort, harden, swell or adhere to the body or seat face to such an

extent as to impair the function of the valve.

5.3.2 For guidance on the selection of non-metallic materials, see EN ISO 11114-2:2013

5.3.3 Non-metallic materials which are exposed to UV shall be UV resistant as confirmed by the

material manufacturer.

5.3.4 Rubber materials in contact with LPG, for temperatures of –20 °C (−40 °C for low temperature

applications) to + 65 °C, shall meet the req
...

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