prEN 14620-5

SLOVENSKI STANDARD
01-september-2023
Načrtovanje in proizvodnja na mestu postavitve grajenih navpičnih, valjastih
jeklenih posod z ravnim dnom za shranjevanje hlajenih utekočinjenih plinov z
delovnimi temperaturami med 0 °C in –196 °C - 5. del: Preskušanje, sušenje,
čiščenje in ohlajanje
Design and manufacture of site built, vertical, cylindrical, flat-bottomed tank systems for
the storage of refrigerated, liquefied gases with operating temperatures between 0 °C
and -196 °C - Part 5: Testing, drying, purging and cool-down
Auslegung und Herstellung standortgefertigter, stehender, zylindrischer Flachboden-
Stahltanks für die Lagerung von tiefkalt verflüssigten Gasen bei Betriebstemperaturen
zwischen 0 °C und -165 °C - Teil 5: Prüfen, Trocknen, Inertisieren und Kaltfahren
Conception et fabrication de réservoirs à fond plat, verticaux, cylindriques, construits sur
site, destinés au stockage des gaz réfrigérés, liquéfiés, dont les températures de service
sont comprises entre 0 °C et -196 °C - Partie 5 : Essais, séchage, inertage et mise en
froid
Ta slovenski standard je istoveten z: prEN 14620-5
ICS:
23.020.10 Nepremične posode in Stationary containers and
rezervoarji tanks
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2023
ICS 23.020.10 Will supersede EN 14620-5:2006
English Version
Design and manufacture of site built, vertical, cylindrical,
flat-bottomed tank systems for the storage of refrigerated,
liquefied gases with operating temperatures between 0 °C
and -196 °C - Part 5: Testing, drying, purging and cool-
down
Conception et fabrication de réservoirs à fond plat, Auslegung und Herstellung standortgefertigter,
verticaux, cylindriques, construits sur site, destinés au stehender, zylindrischer Flachboden-Stahltanks für die
stockage des gaz réfrigérés, liquéfiés, dont les Lagerung von tiefkalt verflüssigten Gasen bei
températures de service sont comprises entre 0 °C et - Betriebstemperaturen zwischen 0 °C und -165 °C - Teil
196 °C - Partie 5 : Essais, séchage, inertage et mise en 5: Prüfen, Trocknen, Inertisieren und Kaltfahren
froid
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 265.
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, Türkiye 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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14620-5:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Hydrostatic and pneumatic testing . 4
5 Commissioning . 13
6 Decommissioning . 15
Annex A (informative) Cool-down of the primary liquid container/membrane . 16
Annex B (informative) Global test for membrane tanks . 17
Bibliography . 21
European foreword
This document (prEN 14620-5:2023) has been prepared by Technical Committee CEN/TC 265 “Site built
metallic tanks for the storage of liquids”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 14620-5:2006.
EN 14620-5:2006:
— Table 1 ‘Hydrostatic test requirements’ updated and adjusted to relate to product temperature;
— permitted use of small temporary safety opening in primary steel liquid container after hydrostatic
test added;
— requirements for inspection of concrete surfaces during pressure test added;
— negative pressure test details clarified;
— negative pressure test requirements for double wall double roof tanks clarified;
— purging of bottom insulation space clarified;
— decommissioning guidance improved.
— new informative annex for global test for membrane tanks added.
A list of all parts in the EN 14620 series can be found on the CEN website.
1 Scope
This document specifies the requirements for testing, drying, purging, cool-down and decommissioning
of refrigerated liquefied gas storage tanks.
This document deals with the design and manufacture of site built, vertical, cylindrical, flat-bottomed
tank systems for the storage of refrigerated, liquefied gases with operating temperatures between 0 °C
and –196°C.
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 14620-1:—, Design and manufacture of site built, vertical, cylindrical, flat-bottomed tank systems for
the storage of refrigerated, liquefied gases with operating temperatures between 0°C and –196 °C — Part
1: General
EN 14620-2:2006, Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for
the storage of refrigerated, liquefied gases with operating temperatures between 0 °C and -165 °C - Part 2:
Metallic components
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 14620-1:— apply.
4 Hydrostatic and pneumatic testing
4.1 Hydrostatic test
4.1.1 General
A hydrostatic test shall be carried out. The hydrostatic test shall demonstrate that:
— the tank system is designed and constructed to contain the product;
— the foundation is able to support the tank contents.
NOTE A hydrostatic test also aids the relief of residual stresses for steel tanks.
4.1.2 Test requirements for each type of tank
For the various tank types, the hydrostatic test shall be carried out in accordance with Table 1.
A specification shall be prepared with all the actions to be taken. The test results shall be documented.
NOTE See Annex C.
Under preparation. Current stage: prEN 14620-1:2023.
Table 1 — Hydrostatic test requirements
Contents Single Double Full Membrane tank
containment containment containment
Tank system Primary liquid Primary liquid Primary liquid Membrane barrier
design container - steel container - steel container – steel
temperature
FH FH FH No test
≥ −50 °C
(see NOTE 2)
Secondary liquid Secondary liquid Outer container -
container - steel container - steel steel
FH (see NOTE 3) FH (see NOTE 3) FH
Secondary liquid Secondary liquid Outer container -
container - pre- container – pre- pre-stressed
stressed concrete stressed concrete concrete
No test No test PH (see NOTE 2)
Tank system Primary liquid Primary liquid Primary liquid Membrane barrier
design container - steel container - steel container - steel
temperature
PH PH PH No test
< −50 °C
(see NOTE 2)
Secondary liquid Secondary liquid Outer container -
container - steel container - steel steel
PH (see NOTE 3) PH (see NOTE 3) PH
Secondary liquid Secondary liquid Outer container –
container – pre- container – pre- pre-stressed
stressed concrete stressed concrete concrete
No test No test PH (see NOTE 2)
NOTE 1 FH means Full height hydrostatic test, PH means Partial height hydrostatic test.
NOTE 2 In the case of a membrane tank, there is no requirement for the membrane barrier to be
hydrostatically tested. Refer to cl 4.3 for hydrotesting of membrane tank outer container
NOTE 3 The requirement to conduct a full or partial height hydrotest of steel secondary liquid container
can be waived by written agreement by the purchaser.
4.1.3 Additional requirements
The following additional requirements shall apply:
— Leak testing shall be completed by means of the welding examination and inspection requirements
described in EN 14620-2:2006.
— For a full height hydrostatic test, the primary liquid container shall be filled to the maximum design
liquid level. The same quantity of water shall be used when testing the outer tank;
— For a partial height hydrostatic test of the primary liquid container, the test pressure applied by
hydrotest water to the tank bottom shall be equal to 1,25 times the pressure applied to the tank
bottom by the product at the height of the maximum design liquid level. The same quantity of water
contained shall be used when testing the secondary liquid container.
— When secondary liquid containers are hydrostatically tested, a suitable water barrier shall be
provided to prevent test water ingress in to the bottom insulation.
— Care shall be taken during filling of the annular space that water levels are controlled and regulated
to prevent differential levels between the inner tank and annular spaces.
— The hydrostatic test shall not be carried out until all welded accessories to the shell and the bottom
of the tank are in place. Welding shall not generally be allowed after completion of the hydrostatic
test. The exception is when approved by the Purchaser, to assist quick emergency evacuation of
construction personnel for tank systems without wall penetrations. A single circular temporary
opening, not smaller than 600mm and not larger than 1000mm in diameter, may be allowed in the
tank after hydrotest. The opening shall be permanently closed by the welding of a closure plate after
personnel access into the hydrotested container is no longer necessary.
— The circular opening shall be positioned so that it does not cross any shell seams. It should also be at
least the greater of 300mm or 10 times the shell thickness from any other weld in the shell. This
includes shell to bottom weld, shell seams or welds to attachments.
— The butt weld around the perimeter of the closure plate shall be examined over the entirety of its
length. Examination shall comprise liquid penetrant method and radiographic method. The liquid
penetrant inspection is needed on the root pass, on the back gouged surface and on the inside and
outside surfaces of the finished weld. The whole weld shall also be vacuum box leak tested. The
welding and testing procedures shall be in accordance with EN 14620-2:2006.
— For tanks which are to be insulated with expanded perlite, the hydrostatic test shall be carried out
before installation of the expanded perlite and resilient layer (if applicable).
— Test level of a membrane tank shall be based on the partial hydrostatic test requirement indicated
above.
— The water shall be of a quality such that no damage to the steel/concrete can occur.
NOTE See Annex C.
4.1.4 Quality of the water
The suitability of the water for hydrostatic testing shall be demonstrated. Special attention shall be paid
to possible corrosion.
The following types of corrosion shall be considered:
— general corrosion;
— galvanic corrosion; and
— localized corrosion (pitting, under deposit corrosion, bacterial corrosion).
NOTE 1 galvanic corrosion (fresh and seawater) is an electrochemical form of corrosion. It can occur when a
metal or alloy is electrically connected to another metal or alloy with a different electrochemical potential and the
metals (alloys) are exposed to a common electrolyte and electrical path. Welding of metals can lead to dissimilar
metal compositions between the weld, Heat Affected Zone (HAZ) and the plate material. The most anodic material
area will corrode because of the galvanic effect with the cathodic material areas.
NOTE 2 Localized corrosion can occur under the following circumstances in the presence of deposits and or
solids:
a)  presence of sulphate reducing bacteria;
b)  locat
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