prEN 14129

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

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

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

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

de sûreté pour réservoirs de GPL Druckentlastungsventile für Behälter für Flüssiggas

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

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

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

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

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

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

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

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

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

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

For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this

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 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

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:

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

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

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].

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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,

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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,

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

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

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

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.

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.

5.3.1 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

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

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