CEN/TC 265/WG 10 - Revision of EN 14620

This document is a specification for vertical, cylindrical tank systems, built on site, above ground and of which either the primary liquid container or the liquid tight barrier is made of steel. The secondary liquid container, if applicable, can be of steel or of concrete or a combination of both. A primary liquid container made of pre-stressed concrete is excluded from the scope of this document.
This document provides general requirements and specifies principles and application rules for the structural design of the tank system during construction, testing, commissioning, operation (accidental included), and decommissioning. This document applies to all tank system components attached to and located within the liquid, vapour, purge gas, membrane or membrane tank outer containers of the tank system. It does not address the requirements for ancillary equipment such as pumps, pumpwells, valves, instrumentation, external staircases and walkways, roof mounted platforms, external pipe supports, etc. The requirements for those components are covered by the relevant European Standards, structurally designed in accordance with Eurocodes where appropriate, and meeting applicable safety regulations.
This document also does not address tank system operating procedures unless specified for determination of the relevant resistance and protection criteria for the tank systems. It specifies minimum performance requirements for the tank system, tank system foundation and protection systems. From a process piping standpoint, the scope of this document is limited to the following boundaries:
a)   the face of the first flange outside of the tank in bolted flanged connection;
b)   the first threaded joint outside of the tank in threaded connection;
c)   the first circumferential pipe welded joint outside of the tank in welding-end pipe connection, which does not have a flange.
This document is applicable to storage tank systems 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 system.
The maximum design pressure of the tank systems covered by this document is limited to 500 mbar. For higher pressures, reference can be made to EN 13445, Parts 1 to 5.
The operating range of the gases to be stored is between 0 °C and −196°C.
The tank systems covered by this document are used to store large volumes of hydrocarbon products, ammonia and other non-hydrocarbon gases with low temperature boiling points, generally called “Refrigerated Liquefied Gases” (RLGs). Typical products stored in the tank systems are: methane, ethane, propane, butane, ethylene, propylene, butadiene (this range includes the Liquefied Natural Gas (LNG’s) and Liquefied Petroleum Gas (LPG’s)), ammonia, nitrogen, oxygen and argon.
NOTE 1   Properties of the gases are given in Annex A.
The requirements of this document 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 and of the regulatory body, to provide design and details that are as safe as those laid out in this document.
EN 14620 consists of multiple parts.  This document specifies general requirements for the tank system concept, selection and general design considerations.
In case of a conflict between general requirements of this document and the requirements in other parts of EN 14620 related to a specific liquefied gas, the product-specific requirements set forth in the other parts prevail.

This European Standard specifies the requirements for testing, drying, purging and cool-down of the refrigerated liquefied gas storage tanks.
This European Standards deals with the 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.

This European Standard specifies general requirements for materials, design and construction of the concrete components of the refrigerated liquefied gas storage tanks.
This European Standard deals with the 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.

This European Standard specifies general requirements for the materials, design, construction and installation of the metallic components of refrigerated liquefied gas storage tanks.
This European Standard deals with the 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.

This European Standard specifies the requirements for materials, design and installation of the insulation of refrigerated liquefied gas (RLG) storage tanks.
RLG storage tanks store liquefied gas with a low boiling point, i.e. below normal ambient temperature.
The concept of storing such products in liquid form and in non-pressurized tanks therefore depends on the combination of latent heat of vaporization and thermal insulation.
Consequently thermal insulation for RLG storage tanks is not an ancillary part of the containment system (as for most ambient atmospheric hydrocarbon tanks) but it is an essential component and the storage tank cannot operate without a properly designed, installed and maintained insulation system.
The main functions of the insulation in RLG storage tanks are:
¾   to maintain the boil off below the specific limits;
¾   to protect the non low temperature parts/materials of the tank (mainly the outer tank) by maintaining these parts at their required ambient temperature;
¾   to limit the cool-down of the foundations/soil underneath the tank to prevent damage by frost heave;
¾   to prevent/minimize condensation and icing on the outer surfaces of the tank.
A wide range of insulation materials is available. However the material properties differ greatly amongst the various generically different materials and also within the same generic group of materials.
Therefore within the scope of this European Standard, only general guidance on selection of materials is given.
NOTE   For general guidance on selection of materials see Annex A.
This European Standard deals with the 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.

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.

This document specifies the requirements for materials, design and installation of the insulation of refrigerated liquefied gas (RLG) storage tank systems.
RLG storage tank systems store liquefied gas with a low boiling point, i.e. below normal ambient temperature.
The concept of storing such products in liquid form and in non-pressurized tanks therefore depends on the combination of latent heat of vaporization and thermal insulation.
Consequently, thermal insulation for RLG storage tank systems is not an ancillary part of the containment system (as for most ambient atmospheric hydrocarbon tanks) but it is an essential component and the storage tank system cannot operate without a properly designed, installed and maintained insulation system.
The main functions of the insulation in RLG storage tank systems are:
-   to maintain the boil off due to heat in-leak at or below the specified limits;
-   to limit the thermal loading of the outer tank components, so to prevent both their sudden damage and premature ageing (e.g. due to external condensation and ice formation);
-   to prevent damage by frost heave of the foundation/soil beneath the tank base slab (in combination with the slab heating system for tanks resting at grade);
-   to minimize condensation and icing on the outer surfaces of the tank.
A wide range of insulation materials is available. However, the material properties differ greatly amongst the various generically different materials and also within the same generic group of materials.
Therefore, within the scope of this document, only general guidance on selection of materials is given.
NOTE   For general guidance on selection of materials, see Annex A.
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.
refrigerated, liquefied gases with operating temperatures between 0 °C and −196 °C.

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