Design and manufacture of site built, vertical, cylindrical,flat-bottomed steel tanks for the storage of liquefied natural gases - Part 4: Insulation components
Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of liquefied natural gases—Part 4: Insulation components
1 Scope
This part specifies the insulation materials, insulation design and installation requirements of liquefied natural gas (LNG) storage tanks.
LNG storage tanks store liquefied natural gas with a low boiling point, i.e., below normal ambient temperature.
The storage of such liquid products in atmospheric storage tanks depends on the combination of latent heat of vaporization and thermal insulation.
Consequently, thermal insulation system of LNG storage tank 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. And the storage tank cannot operate without a properly designed, installed and maintained insulation system.
The main functions of the insulation in LNG storage tanks are:
——to maintain the boil-off below the specific limits;
——to protect the non-low temperature parts/materials of the tank (mainly the outer tank) by maintaining these parts at their required ambient temperature;
——to limit the cool-down of the foundations/soil underneath the tank to prevent damage by frost heave;
——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 part, only general guidance on selection of materials is given.
Note: See Annex A for general guidance on material selection.
This Part is applicable to 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.
2 Normative references
The following referenced documents are indispensable for the application 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.
GB/T 10294 Thermal insulation—Determination of steady-state thermal resistance and related properties - Guarded hot plate apparatus
GB/T 10295 Thermal insulation—Determination of steady-state thermal resistance and related properties—Heat flow meter apparatus
GB/T 26978.1 Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of liquefied natural gases consists of the following five parts:
ISO 844 Rigid cellular plastics—Determination of compression properties
ISO 4897 Cellular plastics—Determination of the coefficient of linear thermal expansion of rigid materials at sub-ambient temperatures
EN ISO 62:1999 Plastics—Determination of water absorption
EN ISO 3582:2000 Flexible cellular polymeric materials—Laboratory assessment of horizontal burning characteristics of small specimens subjected to a small flame
EN ISO 4590:2002 Rigid cellular plastics—Determination of the volume percentage of open cells and closed cells
EN ISO 4624:2002 Paints and varnishes—Pull-off test for adhesion
EN 826:1996 Thermal insulating products for building applications—Determination of compression behavior
EN 1604 Thermal insulating products for building applications—Determination of dimensional stability under specified temperature and humidity conditions
EN 1606 Thermal insulating products for building applications—Determination of compressive creep
EN 1607 Thermal insulating products for building applications—Determination of tensile strength perpendicular to faces
EN 1608 Thermal insulating products for building applications—Determination of tensile strength parallel to faces
EN 1609 Thermal insulating products for building applications — Determination of short term water absorption by partial immersion
EN 12066 Installations and equipment for liquefied natural gas—Testing of insulating linings for liquefied natural gas impounding areas
EN 12086 Thermal insulating products for building applications— Determination of water vapor transmission properties
EN 12087 Thermal insulating products for building applications — Determination of long term water absorption by immersion
EN 12088 Thermal insulating products for building applications — Determination of long term water absorption by diffusion
EN 12090:1997 Thermal insulating products for building applications—Determination of shear behaviors
EN 12091 Thermal insulating products for building applications — Determination of freeze-thaw resistance
EN 12667 Thermal performance of building materials and products — Determination of thermal resistance by means of guarded hot plate and heat flow meter methods - Products of high and medium thermal resistance
EN 12939 Thermal performance of building materials and products — Determination of thermal resistance by means of guarded hot plate and heat flow meter methods —Thick products of high and medium thermal resistance
EN 13468 Thermal insulating products for building equipment and industrial installations — Determination of trace quantities of water-soluble chloride, fluoride, silicate, sodium ions and pH
EN 13471 Thermal insulating products for building equipment and industrial installations — Determination of the coefficient of thermal expansion
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 26978.1-2011 apply.
4 Design requirements, performance characteristics, testing and selection of insulation materials
4.1 General
The selection of the appropriate insulation system and materials shall be based on the following:
——analysis of design requirements (see 4.2);
——assessment of the performance characteristics of the materials (see 4.3)
For the insulation materials used, see Annex A.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Design requirements, performance characteristics, testing and selection of insulation materials
4.1 General
4.2 Analysis of design requirements
4.2.1 General
4.2.2 Thermal resistance performance
4.2.3 Structure requirements
4.2.4 Specific design requirements
4.3 Assessment of the material performance characteristics
4.3.1 General
4.3.2 Thermal resistance performance
4.3.3 Mechanical properties
4.3.4 Temperature resistance
4.3.5 Resistance to water and water vapor
4.3.6 Influences of stored product
4.3.7 Chemical properties
4.3.8 Reaction to fire
4.4 Testing of materials and systems
4.4.1 General
4.4.2 Test methods
5 Protection of insulation—water vapor barrier
5.1 General
5.2 Protective structure formed by the outer tank
5.3 Protective cover for external insulation
6 Design of insulation system
6.1 General
6.2 Thermal design
6.3 Structural design
6.3.1 General
6.3.2 Load bearing insulation/compressive action
6.3.3 Load bearing insulation/other actions
6.4 Insulation for each tank component
6.4.1 General
6.4.2 Supporting ring beam
6.4.3 Bottom insulation
6.4.4 Shell insulation (external)
6.4.5 Shell/wall insulation (internal)
6.4.6 Roof insulation (external)
6.4.7 Roof insulation on suspended roof
6.5 Design for different types of containment
7 Installation
7.1 Introduction
7.2 General requirements
7.2.1 Materials
7.2.2 Conditions of work on site
7.2.3 Anti-corrosive protection
7.2.4 Construction tolerances
7.2.5 Prevention of damage
7.3 Inspection and test
Annex A (Informative) Thermal insulation material
Annex B (Normative) Test methods
Annex C (Normative) Tank bottom insulation—Limit state theory
Annex NA (Informative) Technical differences and reasons between this part and EN 14620-4:2006
Bibliography
