SIST EN 14620-1:2007

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 1: General

This European Standard is a specification for vertical, cylindrical tanks, built on site, above ground and of which the primary liquid container is made of steel. The secondary container, if applicable, may be of steel or of concrete or a combination of both. An inner tank made only of pre-stressed concrete is excluded from the scope of this European Standard.
This European Standard specifies principles and application rules for the structural design of the “containment” during construction, testing, commissioning, operation (accidental included), and decommissioning. It does not address the requirements for ancillary equipment such as pumps, pumpwells, valves, piping, instrumentation, staircases etc. unless they can affect the structural design of the tank.
This European Standard applies to storage tanks designed to store products, having an atmospheric boiling point below ambient temperature, in a dual phase, i.e. liquid and vapour. The equilibrium between liquid and vapour phases being maintained by cooling down the product to a temperature equal to, or just below, its atmospheric boiling point in combination with a slight overpressure in the storage tank.
The maximum design pressure of the tanks covered by this European Standard is limited to 500 mbar. For higher pressures, reference can be made to EN 13445, Parts 1 to 5.
The operating range of the gasses to be stored is between 0 °C and –165 °C. The tanks for the storage of liquefied oxygen, nitrogen and argon are excluded.
The tanks are used to store large volumes of hydrocarbon products and ammonia with low temperature boiling points, generally called “Refrigerated Liquefied Gases” (RLG’s). Typical products stored in the tanks are: methane, ethane, propane, butane, ethylene, propylene, butadiene (this range includes the LNG’s and LPG’s).
NOTE   Properties of the gases are given in Annex A.
The requirements of this European Standard cannot cover all details of design and construction because of the variet

Auslegung und Herstellung standortgefertigter, stehender, zylindrischer Flachboden-Stahltanks für die Lagerung von tiefkalt verflüssigten Gasen bei Betriebstemperaturen zwischen 0 C und -165 C - Teil 1: Allgemeines

Diese Europäische Norm enthält Festlegungen für stehende, zylindrische, standortgefertigte, oberirdische Tanks, deren zur Aufnahme der Flüssigkeit vorgesehener Primärbehälter aus Stahl besteht. Der Sekundär-behälter, falls vorhanden, darf aus Stahl oder Beton, oder aus einer Kombination von beiden bestehen. Innentanks, die nur aus Spannbeton hergestellt werden, fallen nicht in den Anwendungsbereich dieser Norm.
Diese Europäische Norm legt Grundsätze und Anwendungsregeln für die Bemessung der ?Sicherheitshülle" während bei Bau, Prüfung, Inbetriebnahme, Betrieb (unbeabsichtigter Betrieb eingeschlossen) und Außer-betriebsetzung fest. Anforderungen an Zusatzausrüstungen wie Pumpen, Pumpsonden, Armaturen, Rohrleitungen, Messgeräte, Treppen usw. werden nicht festgelegt.
Diese Europäische Norm gilt für Lagertanks, die für die Lagerung von Produkten vorgesehen sind, die in der dualen Phase, d. h. in der Flüssigkeits- und Dampfphase, bei atmosphärischem Druck einen Siedepunkt unterhalb der Umgebungstemperatur haben. Das Gleichgewicht zwischen Flüssigkeits- und Dampfphase wird aufrechterhalten durch Abkühlung des Produkts auf eine Temperatur, die dem Siedepunkt bei atmo-sphärischem Druck oder einer etwas niedrigeren Temperatur entspricht, verbunden mit einem leichten Überdruck im Lagertank.
Der maximale Auslegungsüberdruck für die in dieser Europäischen Norm behandelten Tanks ist auf 500 mbar begrenzt. Für höhere Drücke kann auf EN 13445 Bezug genommen werden.
Die Tanks werden zur Lagerung großer Volumina von Kohlenwasserstoffprodukten und Ammoniak mit niedrigen Siedepunkten verwendet, die allgemein als ?Tiefkalt verflüssigte Gase" (RLG) bezeichnet werden. In den Tanks werden üblicherweise Methan, Ethan, Propan, Butan, Ethylen, Propylen, Butadien gelagert (Flüssigerdgas (LNG) und Flüssiggas (LPG) sind eingeschlossen).

Conception et fabrication de réservoirs en acier a fond plat, verticaux, cylindriques, construits sur site, destinés au stockage de gaz réfrigérés, liquéfiés, dont les températures de service sont comprises entre 0° C et –165° C - Partie 1: Généralités

La présente Norme européenne spécifie les exigences relatives aux réservoirs verticaux, cylindriques, construits sur site, situés au dessus du sol et dont la cuve primaire est en acier. La cuve secondaire, le cas échéant, peut etre en acier ou en béton ou mixte. La présente norme ne s'applique pas aux réservoirs dans lesquels la cuve interne est en béton précontraint.
La présente Norme européenne présente des principes et des regles d'application pour la conception de la structure du « confinement » lors de la construction, des essais, de la mise en service, du fonctionnement (y compris en cas d'accident) et de la mise hors service. Elle n'aborde pas les exigences relatives aux équipements auxiliaires, tels que les pompes, les puits de pompe, les vannes, les tuyauteries, l'instrumentation, les cages d'escalier, etc.
La présente Norme européenne s'applique aux réservoirs de stockage de produits dont le point d'ébullition atmosphérique est inférieur a la température ambiante en phase double, c'est-a-dire, liquide et gazeuse, l'équilibre entre les phases liquide et vapeur étant maintenu par mise en froid du produit a une température égale ou légerement inférieure a son point d'ébullition atmosphérique, associée a une légere surpression dans le réservoir de stockage.
La pression maximale de calcul des réservoirs couverts par la présente Norme européenne est limitée a 500 mbarg. Pour des pressions supérieures, il est possible de consulter l'EN 13445.
La plage de fonctionnement, correspondant au gaz devant etre stocké, est entre 0 °C et -165 °C.  Les réservoirs de stockage pour l'oxygene, l'azote et l'argon liquéfiés sont exclus.
Les réservoirs sont utilisés pour le stockage de grands volumes de produits hydrocarbonés et d'ammoniac se vaporisant a basse température, généralement appelés « Gaz liquéfiés réfrigérés » (GLR). Les produits types stockés dans les réservoirs sont : le méthane, l'éthane, le propane, le butane, l'éthylene, le propylene, le butadiene

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 –165 °C - 1. del: Splošno

General Information

• Status: Published
• Publication Date: 31-Dec-2006
• ICS: 23.020.10 - Stationary containers and tanks
• Technical Committee: TLP - Pressure vessels
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jan-2007
• Due Date: 01-Jan-2007
• Completion Date: 01-Jan-2007
• Ref Project: EN 14620-1:2006 - 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 1: General

Relations

• Revises: oSIST prEN 14620-1:2022 - 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
• Effective Date: 18-Jan-2023
• Revises: oSIST prEN 14620-1:2022 - 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
• Effective Date: 19-Jan-2023
• Revised: oSIST prEN 14620-1:2022 - 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
• Effective Date: 01-Mar-2022

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.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 1: GeneralConception et fabrication de réservoirs en acier a fond plat, verticaux, cylindriques, construits sur site, destinés au stockage de gaz réfrigérés, liquéfiés, dont les températures de service sont comprises entre 0° C et –165° C - Partie 1: GénéralitésAuslegung und Herstellung standortgefertigter, stehender, zylindrischer Flachboden-Stahltanks für die Lagerung von tiefkalt verflüssigten Gasen bei Betriebstemperaturen zwischen 0
C und -165
C - Teil 1: AllgemeinesTa slovenski standard je istoveten z:EN 14620-1:2006SIST EN 14620-1:2007en23.020.10UH]HUYRDUMLStationary containers and tanksICS:SLOVENSKI
STANDARDSIST EN 14620-1:200701-januar-2007







EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14620-1
September 2006 ICS 23.020.10 English Version
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 1: General
Conception et fabrication de réservoirs en acier à fond plat, verticaux, cylindriques, construits sur site, destinés au stockage de gaz réfrigérés, liquéfiés, dont les températuresde service sont comprises entre 0 °C et -165 °C - Partie 1: Généralités
Auslegung und Herstellung standortgefertigter, stehender, zylindrischer Flachboden-Stahltanks für die Lagerung von tiefkalt verflüssigten Gasen bei Betriebstemperaturen zwischen 0 °C und -165 °C - Teil 1: Allgemeines This European Standard was approved by CEN on 20 February 2006.
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. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists 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 Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36
B-1050 Brussels © 2006 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14620-1:2006: E



EN 14620-1:2006 (E) 2 Contents Page Foreword.3 1 Scope.4 2 Normative references.4 3 Terms and definitions.5 4 Concept selection.9 4.1 Types of tank.9 Figure 1 — Examples of single containment tanks.11 Figure 2 — Examples of double containment tanks.12 Figure 3 — Examples of full containment tanks.13 Figure 4 — Example of membrane tank.14 4.2 Risk assessment.14 5 Quality assurance and quality control.17 6 Health, safety and environment plan.17 7 General design considerations.17 7.1 General.17 7.2 Protection systems.21 7.3 Actions (loadings).23 8 Inspection and maintenance.27 Annex A (informative)
Physical properties of gases.28 Table A.1 — Physical properties of pure gases.28 Annex B (normative)
Design information.29 Annex C (normative)
Seismic analysis.31 Annex D (informative)
Tank heating system.34 Bibliography.36



EN 14620-1:2006 (E) 3 Foreword This European Standard (EN 14620-1:2006) 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 European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 2007, and conflicting national standards shall be withdrawn at the latest by March 2007. EN 14620 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 consists of the following parts:  Part 1: General;  Part 2: Metallic components;  Part 3: Concrete components;  Part 4: Insulation components;  Part 5: Testing, drying, purging and cool-down. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, 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.



EN 14620-1:2006 (E) 4 1 Scope This European Standard is a specification for vertical, cylindrical tanks, built on site, above ground and of which the primary liquid container is made of steel. The secondary container, if applicable, may be of steel or of concrete or a combination of both. An inner tank made only of pre-stressed concrete is excluded from the scope of this European Standard. This European Standard specifies principles and application rules for the structural design of the “containment” during construction, testing, commissioning, operation (accidental included), and decommissioning. It does not address the requirements for ancillary equipment such as pumps, pumpwells, valves, piping, instrumentation, staircases etc. unless they can affect the structural design of the tank. This European Standard applies to storage tanks designed to store products, having an atmospheric boiling point below ambient temperature, in a dual phase, i.e. liquid and vapour. The equilibrium between liquid and vapour phases being maintained by cooling down the product to a temperature equal to, or just below, its atmospheric boiling point in combination with a slight overpressure in the storage tank. The maximum design pressure of the tanks covered by this European Standard is limited to 500 mbar. For higher pressures, reference can be made to EN 13445, Parts 1 to 5. The operating range of the gasses to be stored is between 0 °C and –165 °C. The tanks for the storage of liquefied oxygen, nitrogen and argon are excluded. The tanks are used to store large volumes of hydrocarbon products and ammonia with low temperature boiling points, generally called “Refrigerated Liquefied Gases” (RLG’s). Typical products stored in the tanks are: methane, ethane, propane, butane, ethylene, propylene, butadiene (this range includes the LNG’s and LPG’s). NOTE Properties of the gases are given in Annex A. The requirements of this European Standard cannot cover all details of design and construction because of the variety of sizes and configurations that may be employed. Where complete requirements for a specific design are not provided, the intention is for the designer, subject to approval of the purchaser's authorized representative, to provide design and details that are as safe as those laid out in this European Standard. This European Standard specifies general requirements for the tank concept, selection and general design considerations. 2 Normative references The following referenced documents are indispensable for the application of this European Standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1991-1-4, Eurocode 1: Actions on structures — Part 1-4: Wind actions EN 1991-1-6, Eurocode 1: Actions on structures — Part 1-6: General actions — Actions during execution EN 1992-1-1:2004, Eurocode 2: Design of concrete structures — Part 1-1: General rules and rules for buildings EN 1997-1:2004, Eurocode 7: Geotechnical design — Part 1: General rules



EN 14620-1:2006 (E) 5 EN 1998-1:2004, Eurocode 8: Design of structures for earthquake resistance — Part 1: General rules, seismic actions and rules for buildings ENV 1998-4:1998, Eurocode 8: Design provisions for earthquake resistance of structures — Part 4: Silos, tanks and pipelines EN 14620-2:, 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 EN 14620-3:2006, 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 3: Concrete components EN 14620-4, 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 4: Insulation components EN 14620-5, 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 5: Testing, drying, purging and cool-down 3 Terms and definitions For the purposes of this European Standard, the following terms and definitions apply. 3.1 action a) set of forces (loads) applied to the structure (direct action) b) set of imposed deformation or accelerations caused for example, by temperature changes, moisture variation, uneven settlement or earthquakes (indirect action) 3.2 annular space space between the inner shell and outer shell or wall of self-supporting tanks 3.3 base slab continuous concrete base supporting the tank (either on the ground or elevated) 3.4 boil-off process of vaporization of refrigerated liquid by heat conducted through the insulation surrounding the storage tank 3.5 bund wall low construction of earth or concrete surrounding the storage tank at a considerable distance to contain spilled liquid 3.6 polymeric vapour barrier reinforced or un-reinforced polymeric layer applied to the concrete to function as a product vapour, water vapour and in some cases as liquid barrier



EN 14620-1:2006 (E) 6 3.7 contractor company with which the purchaser agrees a proposal for the design, construction, testing and commissioning of a tank 3.8 design pressure maximum permissible pressure
3.9 design negative pressure maximum permissible negative pressure (vacuum) 3.10 design metal temperature minimum temperature for which the metal component is designed NOTE It may be the minimum design temperature (in the case of the primary container) or a higher calculated temperature. 3.11 double containment tank see 4.1.2 3.12 foundations elements of the construction that comprise the base slab, ring-wall or pile system required to support the tank and contents 3.13 full containment tank see 4.1.3. NOTE The secondary container contains the vapour in normal operation and ensures controlled venting in the case of a primary container leakage. 3.14 hazard event having the potential to cause harm, including ill health and injury, damage to property, products or the environment, production losses or increased liabilities 3.15 inner tank metallic self-supporting cylindrical primary container 3.16 insulation space volume containing insulation material in the tank annular space, and between the tank bottoms or roofs 3.17 liner metallic plate installed against the inside of the concrete outer tank, impervious to product vapour and water vapour 3.18 load bearing insulation thermal insulation with special properties capable of transferring loads to the appropriate load bearing structures



EN 14620-1:2006 (E) 7 3.19 lodmat lowest one-day average ambient temperature.
Note The average temperature is half the sum of the maximum and minimum temperature 3.20 maximum design liquid level maximum liquid level that will be maintained during operation of the tank used for the static shell thickness determination 3.21 maximum normal operating level Maximum liquid level that will be maintained during normal operation of the tank. Normally the level at which the first high level alarm is set 3.22 membrane thin metallic primary container of a membrane tank 3.23 membrane tank containment whereby a membrane (primary container) together with load bearing thermal insulation and a concrete tank are forming jointly an integrated, composite tank structure 3.24 minimum design temperature assumed temperature of the product, specified by the purchaser, for which the tank is designed NOTE This temperature may be lower than the actual product temperature. 3.25 Operating Basis Earthquake (OBE) maximum earthquake event for which no damage is sustained and restart and safe operation can continue NOTE This event would result in no loss to the operational integrity and public safety is assured. 3.26 outer tank self-supporting cylindrical secondary container made of steel or concrete 3.27 purchaser company who gives an order to the contractor for the design, construction and testing of a tank 3.28 primary liquid container part of a single, double, full containment or membrane tank that contains the liquid during normal operation 3.29 product vapour barrier polymeric vapour barrier or a liner to prevent escape of product vapours from the tank 3.30 ringbeam circular support under the shell of the tank



EN 14620-1:2006 (E) 8 3.31 roll-over uncontrolled mass movement of stored liquid, correcting an unstable state of stratified liquids of different densities and resulting in a significant evolution of product vapour 3.32 roof structure on top of a shell or wall containing the vapour pressure and sealing off the contents from the atmosphere 3.33 Safe Shutdown Earthquake (SSE) maximum earthquake event for which the essential fail-safe functions and mechanisms are designed to be preserved NOTE Permanent damage can be accepted, but without the loss of overall integrity and containment. The tank would not remain in operation without a detailed examination and structural assessment. 3.34 secondary liquid container part of the outer container of a double, full containment or membrane tank that contains the liquid 3.35 self supporting tank container designed to carry the hydrostatic forces of the stored liquid and the vapour pressure loads, if applicable 3.36 set pressure pressure at which the pressure relief device first opens 3.37 shell metallic vertical cylinder 3.38 single containment tank see 4.1.1 NOTE The product vapour is contained by the primary container or by means of a metallic outer tank. 3.39 suspended roof structure for supporting the internal insulation of the roof 3.40 test pressure air pressure in the tank during testing 3.41 Thermal Protection System (TPS) thermally insulating and liquid tight structure in order to protect the outer tank against low temperatures NOTE Examples include bottom and bottom corner (see also 7.1.11). 3.42 vapour container part of a single, double, full containment or membrane tank that contains the vapour during normal operation



EN 14620-1:2006 (E) 9 3.43 wall concrete vertical cylinder 3.44 vapour barrier barrier to prevent entry of water vapour and other atmospheric gases into the insulation or into the outer tank 4 Concept selection 4.1 Types of tank 4.1.1 Single containment A single containment tank shall consist of only one container to store the liquid product (primary liquid container). This primary liquid container shall be a self-supporting, steel, cylindrical tank. The product vapours shall be contained by:  either the steel dome roof of the container;  or, when the primary liquid container is an open top cup, by a gas-tight metallic outer tank encompassing the primary liquid container, but being only designed to contain the product vapours and to hold and protect the thermal insulation. NOTE 1 Depending on the options taken for vapour containment and thermal insulation; several types of single containment tanks exist. A single containment tank shall be surrounded by a bund wall to contain possible product leakage. NOTE 2 For examples of single containment tanks, see Figure 1. 4.1.2 Double containment A double containment tank shall consist of a liquid and vapour tight primary container, which itself is a single containment tank, built inside a liquid-tight secondary container. The secondary container shall be designed to hold all the liquid contents of the primary container in case it leaks. The annular space, between the primary and secondary containers, shall not be more than 6,0 m. NOTE 1 The secondary container is open at the top and therefore cannot prevent the escape of product vapours. The space between primary and secondary container can be covered by a “rain shield” to prevent the entry of rain, snow, dirt etc. NOTE 2 For examples of double containment tanks, see Figure 2. 4.1.3 Full containment A full containment tank shall consist of a primary container and a secondary container, which together form an integrated storage tank. The primary container shall be a self-standing steel, single shell tank, holding the liquid product. The primary container shall:  either be open at the top, in which case it does not contain the product vapours



EN 14620-1:2006 (E) 10  or equipped with a dome roof so that the product vapours are contained. The secondary container shall be a self-supporting steel or concrete tank equipped with a dome roof and designed to combine the following functions:  in normal tank service: to provide the primary vapour containment of the tank (this in case of open top primary container) and to hold the thermal insulation of the primary container;  in case of leakage of the primary container: to contain all liquid product and to remain structurally vapour tight. Venting release is acceptable but shall be controlled (pressure relief system). The annular space between the primary and secondary containers shall not be more than 2,0 m. NOTE 1 Full containment tanks with thermal insulation placed external to the secondary container are also covered by these requirements. NOTE 2 For examples of full containment tanks, see Figure 3. 4.1.4 Membrane containment A membrane tank shall consist of a thin steel primary container (membrane) together with thermal insulation and a concrete tank jointly forming an integrated, composite structure. This composite structure shall provide the liquid containment. All hydrostatic loads and other loadings on the membrane shall be transferred via the load-bearing insulation onto the concrete tank. The vapours shall be contained by the tank roof, which can be either a similar composite structure or with a gas-tight dome roof and insulation on a suspended roof. NOTE For an example of a membrane tank, see Figure 4. In case of leakage of the membrane, the concrete tank, in combination with the insulation system, shall be designed such that it can contain the liquid.



EN 14620-1:2006 (E) 11 101397618453 a) 1213711451683 b) Key 1 primary container (steel) 8 roof (steel) 3 bottom insulation 9 external shell insulation 4 foundation 10 external water vapour barrier 5 foundation heating system 11 loose fill insulation 6 flexible insulating seal 12 outer steel shell (not capable of containing liquid) 7 suspended roof (insulated) 13 bund wall Figure 1 — Examples of single containment tanks



EN 14620-1:2006 (E) 12 1097618134532 a) 12711452161383 b) Key 1 primary container (steel) 8 roof (steel) 2 secondary container (steel or concrete) 9 external insulation 3 bottom insulation 10 external water vapour barrier 4 foundation 11 loose fill insulation 5 foundation heating system 12 outer shell (not capable of containing liquid) 6 flexible insulating seal 13 cover (rain shield) 7 suspended roof (insulated)
Figure 2 — Examples of double containment tanks



EN 14620-1:2006 (E) 13 794521683 a) 121176110453 b) Key 1 primary container (steel) 7 suspended roof (insulated) 2 secondary container (steel) 8 roof (steel) 3 bottom insulation 9 loose fill insulation 4 foundation 10 concrete roof 5 foundation heating system 11 pre-stressed concrete outer tank (secondary container) 6 flexible insulating seal 12 insulation on inside of pre-stressed concrete outer tank Figure 3 — Examples of full containment tanks



EN 14620-1:2006 (E) 14 976184523 Key 1 Primary container (membrane) 6 Flexible insulating seal 2 Secondary container (concrete) 7 Suspended roof (insulated) 3 Bottom insulation 8 Concrete roof 4 Foundation 9 Insulation on inside of pre-stressed 5 Foundation heating system
concrete outer tank
Figure 4 — Example of membrane tank 4.2 Risk assessment 4.2.1 General The type of tank shall be selected based on a risk assessment. The purchaser shall be responsible for the risk assessment (specifying/justifying the risk criteria). NOTE A consultant may carry out the assessment. Assistance may be needed from the contractor. 4.2.2 Site selection Before identification of hazards can be carried out, the site shall be selected. In general, the storage tank shall be placed such that the pipe connections to the receiving and supply sources are as short as possible. However, other requirements e.g. local regulations and safety distances (adjacent installations and plant boundaries) site and soil conditions, possible earthquake loading and pipe routings shall be considered. 4.2.3 Pre-selection of storage type A pre-selection of the storage type shall be carried out. This shall mainly be based on the environment of the tank. NOTE In “remote” located areas, where limited population or facilities are present, a single containment tank may be appropriate. For other areas, the double or full containment tank or a membrane tank may be required.



EN 14620-1:2006 (E) 15 The materials of the main components, steel or concrete, and design details, e.g. the inlet/outlet, elevated or grade level foundation and protection systems, shall be selected so that sufficient information is available for the risk assessment. The risk assessment shall demonstrate that the risks to property and life are acceptable, both inside and outside the plant boundary. The risk assessment process shall start with the hazard identification study. 4.2.4 Hazard identification A hazard identification study shall not only be carried out for the normal operation of the tank, but also for all other phases in the design life of the tank (design, construction, cool down, commissioning, decommissioning and even possible abandonment). As a minimum, the following shall be considered: 1) external threats to tank integrity:  natural/environmental (snow, earthquake, high wind, lightning, flood, high temperature);  infrastructure (aircraft crash, impacts from adjacent facilities including fire, explosion, transport);  site lay-out (fire and explosion in plant, relief valve fire, construction, traffic etc.);  operational philosophy/practice and plant upsets; 2) internal threats to tank integrity:  mechanical failure e.g. thermal shock, corrosion, frost heave of foundation, leakage of flanges;  equipment failure (relief valves, liquid level gauging etc.);  operational and maintenance errors (overfilling, rollover, dropped pump, overpressure etc.). 3) consequences of failure of tank integrity:  effects on people off-site (leakage of toxic vapour/liquid, fires and explosions);  effects on people on-site (leakage of toxic vapour/liquid, fires and explosions);  environmental damage (leakage vapour/liquid and fires);  effects on adjacent plant (plant damage);  effects on other parts of the facility (knock-on effect, production loss). 4.2.5 Methodology 4.2.5.1 General The methodology of the risk assessment shall be either probabilistic or deterministic. 4.2.5.2 Probabilistic The probabilistic approach shall consist of:  listing of potential hazards of external and internal origin;



EN 14620-1:2006 (E) 16  collecting failure rate data;  determination of the frequency of these hazards;  determination of the effects on event consequences and probabilities of available mitigation measures;  examination of the potential knock-on effects;  determination of the consequences of each hazard;  determination of risk by multiplying frequency and consequence and summing over all scenarios;  comparison of risk levels with predetermined target values. 4.2.5.3 Deterministic The deterministic approach consists of:  listing of hazards;  establishment of credible scenarios;  determination of the consequences;  justification of the necessary safety improvement measures to limit the risks. 4.2.6 Changes 4.2.6.1 Potential changes Attention shall be paid to possible changes of the hazard situation during the lifetime of the tank/plant to avoid lack of safety in the future. NOTE Other facilities can be built near the tank or outside the plant boundaries. Otherwise, in the case of a major change, the risk and damage potential may have to be assessed again and improvements may be required. 4.2.6.2 Changes based on findings The outcome of the risk assessment shall be evaluated carefully. If changes have to be carried out then the risk assessment shall be repeated. 4.2.7 Determination of actions The risk assessment shall identify critical factors that shall be taken into account in the design of the tank. The accidental actions (spillages, fires, explosions etc.) shall be identified. 4.2.8 Risk profiles When required by local authorities, risk profiles shall be calculated by determining the consequences from a number of scenarios. By adapting certain criteria for death from toxic substances, radiation from fires and explosion over pressure, effect distances shall be determined. Based on incident frequencies and effects from meteorological conditions (wind direction, stability etc.) the contribution from each scenario to a point at a distance from the activity shall be calculated. By putting a grid over the area surrounding the activity and summing the contribution from all scenarios for each grid point a three dimensional (x, y, risk) picture shall emerge.



EN 14620-1:2006 (E) 17 NOTE Usually this picture is then reduced to 2D by connecting points of equal risk (e.g. 10-5, 10-6 and 10-7 fatalities per year) creating the risk profiles. Legalized risk criteria exist for a number of countries or can be developed in consultation with authorities. 5 Quality assurance and quality control A quality management system for the design, procurement of materials, construction and testing of the tank shall be incorporated. NOTE The guidance given in EN ISO 9001 is highly recommended. 6 Health, safety and environment plan The contractor shall prepare a Health, Safety and Environment (HSE) plan for the design, construction and commissioning of the tank which shall conform to the overall objectives set out by the purchaser. The plan shall include the
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