prEN 14071

SLOVENSKI STANDARD
oSIST prEN 14071:2021
01-marec-2021
Oprema in pribor za utekočinjeni naftni plin (UNP) - Varnostni ventili za tlačne
posode za UNP - Pomožna oprema

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

Flüssiggas-Geräte und Ausrüstungsteile - Druckentlastungsventile für Druckbehälter für

Équipements pour GPL et leurs accessoires - Soupapes de sécurité des 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 sécurité des réservoirs de gaz de pétrole liquéfié Druckentlastungsventile für Druckbehälter für

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 14071:2021 E

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

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

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

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

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

4 Operating conditions ..................................................................................................................................... 9

5 Materials ............................................................................................................................................................. 9

5.1 General ................................................................................................................................................................ 9

5.2 Metallic materials ........................................................................................................................................... 9

5.3 Non-metallic components ......................................................................................................................... 10

5.4 Lubricants, sealants, and adhesives ...................................................................................................... 10

5.5 Inspection Documents ................................................................................................................................ 10

6 Design ............................................................................................................................................................... 11

6.1 Introduction ................................................................................................................................................... 11

6.2 Pressure relief valve isolating devices ................................................................................................. 11

6.2.1 General ............................................................................................................................................................. 11

6.2.2 Actuation ......................................................................................................................................................... 11

6.2.3 Indication of closure ................................................................................................................................... 11

6.2.4 Guiding arrangements ................................................................................................................................ 12

6.2.5 Isolating mechanism security .................................................................................................................. 12

6.2.6 Interchangeability ....................................................................................................................................... 12

6.3 PRV manifold ................................................................................................................................................. 12

6.3.1 General ............................................................................................................................................................. 12

6.3.2 Indication of port closure .......................................................................................................................... 15

6.3.3 Port closure .................................................................................................................................................... 15

6.4 Vent pipe ......................................................................................................................................................... 15

6.4.1 Design ............................................................................................................................................................... 15

6.4.2 Materials .......................................................................................................................................................... 15

6.4.3 Effect from external conditions............................................................................................................... 15

6.5 Connections .................................................................................................................................................... 15

6.6 Threads ............................................................................................................................................................ 15

6.7 Minimum requirements for springs ...................................................................................................... 16

7 Testing of the design ................................................................................................................................... 16

7.1 General ............................................................................................................................................................. 16

7.2 Test requirements ....................................................................................................................................... 16

7.3 Hydraulic proof test .................................................................................................................................... 17

7.4 Relief valve isolator test ............................................................................................................................ 17

7.5 Testing of audible signal of isolating devices and residual flow of isolating devices

and PRV manifolds ....................................................................................................................................... 17

7.6 Resistance of the isolating mechanism ................................................................................................ 17

7.7 Over-torque deformation test ................................................................................................................. 17

7.8 Operation test ................................................................................................................................................ 18

7.8.1 General ............................................................................................................................................................. 18

7.8.2 System test ...................................................................................................................................................... 18

7.9 Stress cracking test ...................................................................................................................................... 18

7.9.1 General ............................................................................................................................................................. 18

7.9.2 Mercury(I)nitrate immersion test .......................................................................................................... 18

7.9.3 Moist ammonia air stress cracking test ................................................................................................ 18

8 Production testing of isolating devices and PRV manifolds .......................................................... 18

9 Marking and labelling ................................................................................................................................. 19

9.1 PRV isolating device .................................................................................................................................... 19

9.2 Pressure relief valve PRV manifolds...................................................................................................... 19

10 User instructions........................................................................................................................................... 19

10.1 PRV isolating devices .................................................................................................................................. 19

10.2 PRV manifolds ................................................................................................................................................ 20

Annex A (normative) Dimensions of master test pieces for PRV and isolating devices ................... 21

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

covered ............................................................................................................................................................. 23

Bibliography ................................................................................................................................................................. 24

This document (prEN 14071:2021) 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

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

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

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

in CEN/TS 16765 [4] LPG equipment and accessories - Environmental considerations for CEN/TC 286

standards, 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:

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

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 [5].

This document specifies the design, testing and inspection requirements for pressure relief valve

isolating devices, valve manifolds, vent pipes and system assemblies which are, where necessary, used

with pressure relief valves for use in static pressure vessels for Liquefied Petroleum Gas (LPG) service.

This document addresses both prototype testing and production testing of isolating devices and PRV

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 gases

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

2) As impacted by EN 13445-2:2014/A1:2016, EN 13445-2:2014/A2:2018 and EN 13445-2:2014/A3:2018.

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

EN 14129:2014, LPG Equipment and accessories - Pressure relief valves for LPG pressure vessels

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

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

pressure relief valve(s) for use on the pressure vessel complete with isolating device or PRV manifold,

device fitted between the storage tank and the external pressure relief valve, which permits the

replacement of the pressure relief valve without de-pressuring the pressure vessel

ratio of the actual measured flow capacity divided by the calculated theoretical capacity for the same fluid

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

capacity at the flow rating pressure of a pressure relief valve expressed in cubic metres per minute of free

open-ended pipe, fitted with a protection cap and attached to the pressure relief valve outlet, to direct

limited flow of LPG intended to equalise pressures so that a replacement PRV can be properly fitted to an

isolating device; indicate the effectiveness of the internal shut off in an isolating device before the PRV is

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

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

numerical designation of the size of a component, which is a convenient round number, approximately

4.2 For some parts of Europe and certain applications, temperatures lower than – 20 °C can be

NOTE 1 In service, temperatures below this can be encountered during short periods, for example, during

NOTE 2 Vacuum conditions on the isolating device or PRV manifold, 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.

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

5.1.2 Material for components shall be selected for adequate strength in service. The material shall

resist atmospheric corrosion, brass dezincification, stress corrosion, impact and material failure. Where

stress corrosion could be present in a material, stress relieving heat treatment shall be carried out where

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

NOTE Alternative materials to those listed in 5.2 are not precluded, providing they comply with a standard or

specification that ensures control of chemical and physical properties, and quality appropriate to the end use.

5.2.1 Equipment 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,

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

than 7 % nickel. Springs shall be manufactured from stainless steel wire and shall contain not less than

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

Leaded brass shall be CW614N or CW617N in accordance with EN 12420:2014, EN 12164:2016 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, also known as folds, or

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

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

5.2.6 Components manufactured from hot stamped brass or contents gauge bodies made of drawn

brass or machined from brass rod shall be capable of withstanding, without cracking, the stress-cracking

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

All non-metallic materials in contact with LPG shall not distort, harden or adhere to the body or seat face

All rubber materials shall also comply with the requirements of EN 549:2019. The ozone test in

EN 549:2019 shall only be carried out where gaskets/seals are exposed to the atmosphere.

NOTE For guidance on the choice of non-metallic materials, see EN ISO 11114-2 [8].

Where used on threads and seals; lubricants, sealants, and adhesives shall be compatible with LPG and

The main metallic pressure-bearing parts shall be provided with material manufacturers’ certificates

Springs and other metallic parts shall have certificates conforming to EN 10204:2004 certificate type 2.2.

Non-metallic parts shall be provided with certificates confirming their conformance with the

6.1.1 This section identifies essential requirements for the design of ancillary equipment.

6.1.2 The design shall allow the equipment to operate with the flow characteristics as identified in 7.8.

6.1.3 Equipment components shall be designed with adequate strength and clearances to ensure

— minimizing the environmental impact of in-service maintenance and end of life disposal; and

Pressure relief valves intended for use with these isolating devices shall be in accordance with

If interchangeability of pressure relief valves of diverse manufacturers is required, the requirements of

Isolating devices shall only be actuated by the fitting or removal of the pressure relief valve. The isolating

Isolating devices shall have positive means to determine that closure has occurred when the PRV has

— the use of two tell-tale holes in the pressure relief valve. When one complete hole is visible above the

bonded seal, the isolating device shall close within one further revolution. (The valve should be

closed within five revolutions when removing a fully engaged relief valve from an isolating device).

When the isolating device is closed there shall be three full revolutions remaining before

disengagement. The use of visible marking (e.g. machined groove) may be used on a thermal

expansion valve which shall be visible when three full turns of engagement remain;

— a noticeable audible change in the release of gas which shall have taken place when removing the

pressure relief valve indicating closure of the isolating device while a minimum of three threads

When the isolating device is closed the residual flow shall not exceed 600 l/h at 1 bar differential and

The residual flow through a port of a PRV manifold, with a PRV removed, shall not exceed 2,5 l/h at 1 bar