标准编号:	GB/T 26978-2021
中文名称:	现场组装立式圆筒平底钢质低温液化气储罐的设计与建造
英文名称:	Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of cryogenic liquefied gas
中标分类:	E24    天然气
行业分类:	GB    国家标准
ICS分类:	75.060 75.060    天然气 75.060
发布机构:	国家市场监督管理总局 国家标准化管理委员会
发布日期:	2021-12-31
实施日期:	2022-7-1
标准状态:	现行
替代旧标准:	GB/T 26978.1-2011 现场组装立式圆筒平底钢质液化天然气储罐的设计与建造 第1部分：总则 GB/T 26978.2-2011 现场组装立式圆筒平底钢质液化天然气储罐的设计与建造 第2部分：金属构件 GB/T 26978.3-2011 现场组装立式圆筒平底钢质液化天然气储罐的设计与建造 第3部分：混凝土构件 GB/T 26978.4-2011 现场组装立式圆筒平底钢质液化天然气储罐的设计与建造 第4部分：绝热构件 GB/T 26978.5-2011 现场组装立式圆筒平底钢质液化天然气储罐的设计与建造 第5部分：试验、干燥、置换及冷却
翻译语言:	英文
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Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.



This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization—Part 1: Rules for the structure and drafting of standardizing documents.



This document replaces GB/T 26978.1-2011 Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of liquefied natural gases—Part 1: General, GB/T 26978.2-2011 Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of liquefied natural gases—Part 2: Metallic components, GB/T 26978.3-2011 Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of liquefied natural gases—Part 3: Concrete components, GB/T 26978.4-2011 Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of liquefied natural gases—Part 4: Insulation components and GB/T 26978.5-2011 Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of liquefied natural gases—Part 5: Testing, drying, purging and cool-down. This document consolidates GB/T 26978-2011 (all parts) into one document. The following main technical changes have been made in addition to structural adjustment and editorial changes:



a) The tank type is redefined (see 4.1 hereof; Clause 4 of Part 1 of Edition 2011);



b) The clause “tank risk assessment” is deleted (see Clause 4 of Part 1 of Edition 2011);



c) The responsibility requirements for the development organization or the buyer are deleted (see Clause 7 of Part 1 of Edition 2011);



d) The provisions of limit state and permissible stress theory are modified, and the definition description of two states in limit state theory is modified (see 4.2.3 hereof; Clause 7 of Part 1 of Edition 2011);



e) The requirement that “seismic safety assessment report, site ground motion parameters and characteristic parameters of seismic influence coefficient shall be provided for seismic design” is added, and the requirement that “the coordinate value of vertical component response spectrum shall not be less than 65% of the coordinate value of corresponding horizontal component response spectrum” is modified (see 4.2.4 hereof; Clause 7 of Part 1 of Edition 2011);



f) The requirement for tightness is modified (see 4.2.5 hereof; Clause 7 of Part 1 of Edition 2011);



g) Regulations and technical requirements for foundation and isolation system are added (see 4.2.9 hereof);



h) Height requirements for thermal protection system of concrete tank are modified (see 4.2.11 hereof; Clause 7 of Part 1 of Edition 2011);



i) Other requirements for membrane tank are added (see 4.2.13 hereof);



j) Reference specifications and requirements for permanent action and variable action are modified (see 4.4.2 and 4.4.3 hereof; Clause 7 of Part 1 of Edition 2011);



k) The requirement for accidental action is modified (see 4.4.4 hereof; Clause 7 of Part 1 of Edition 2011);



l) The requirement that "according to ENV 1998-4: 1998, the inelastic characteristic coefficient q shall not be greater than 1, unless it is reasonable to adjust according to EN 1998-1: 2004 and DD ENV 1998-4: 1998.” is deleted (see Clause 7 of Part 1 of Edition 2011);



m) The clause “quality assurance and quality control” is deleted (see Clause 5 of Part 1 of Edition 2011);



n) The subclause “health, safety and environmental plan” is modified (see 4.6 hereof; Clause 6 of Part 1 of Edition 2011);



o) The requirements for Charpy V-notch impact and maximum permissible design stress of steel classification and new steel classification are modified (see 5.2 hereof; Clause 4 of Part 2 of Edition 2011);



p) The requirements for material selection of bolts and pipe components are modified, and some China standards are cited. (see 5.2 hereof; Clause 4 of Part 2 of Edition 2011);



q) The minimum width requirement of the bottom edge plate is modified; the minimum straight edge length requirement of the bottom center plate is modified; the requirements for design load of suspended deck is added; allowable pressure difference on both sides of suspended deck is added; the design requirements of nozzle are modified; the surface corrosion allowance requirements of tank anchor system are modified; and the assembly deviation and prefabrication requirements of bent roof, suspended deck, liner, thermal angle protection, inner tank bottom plate, inner tank shell plate and accessories are added (see 5.3 hereof; Clauses 5 and 6 of Part 2 of Edition 2011):



r) The reference standards for qualification certification, welding procedure qualification and nondestructive testing of welders, welding operators and flaw inspectors are modified, and the RT testing ratio of girth welded joints of tank shell plate is modified (see 5.5 hereof; Clause 7 of Part 2 of Edition 2011);



s) The requirements for pneumatic jacking are added (see 5.8 hereof);



t) The curve used to determine the load and fatigue on the membrane in Annex B is deleted (see Annex B of Part 2 of Edition 2011);



u) The design, construction and acceptance standards of concrete materials are modified (see 6.1.1 hereof; 6.2 of Part 3 of Edition 2011);



v) The reference specifications for prestressing system and low temperature reinforcement are modified (see 6.1.2 hereof; 6.3 of Part 3 of Edition 2011);



w) The reference specifications for load design value, load effect and geometric parameters are modified (see 6.2 hereof; 7.2 of Part 3 of Edition 2011);



x) The “liquid tightness” section is deleted (see 7.3 of Part 3 of Edition 2011);



y) Annex A “Materials” and Annex B “Prestressed concrete tank” are deleted (see Annexes A and B of Part 3 of Edition 2011);



z) The design requirements for prestressed system are added (see 6.3.1 hereof);



aa) The seismic fortification classification of prestressed concrete outer tank, the design requirements of shells and the minimum requirements for the height of the minimum compression area of shell are added (see 6.3.2 hereof);



bb) The requirements that “crack width of pile and pile cap shall be checked under the serviceability limit state, and the crack width shall be controlled” are added (see 6.3.3 hereof);



cc) The reference specifications of concrete cover thickness are modified (see 6.3.6 hereof; 8.7 of Part 3 of Edition 2011);



dd) The minimum reinforcement area requirements are modified (see 6.3.7 hereof; 8.8 of Part 3 of Edition 2011);



ee) The structural strength design requirements of the tank shell are added (see 6.5.2 hereof);



ff) The “construction joints” section is deleted (see 8.5 of Part 3 of Edition 2011);



gg) The “reinforced concrete cofferdam” section is deleted (see 8.9 of Part 3 of Edition 2011);



hh) The “formwork and tie rods” section is deleted (see 9.3 of Part 3 of Edition 2011);



ii) The requirements for concrete positioning cushions are deleted (see 9.4 of Part 3 of Edition 2011);



jj) The requirements for concrete curing are deleted (see 9.5 of Part 3 of Edition 2011);



kk) The “error” section is deleted (see 9.6 of Part 3 of Edition 2011);



ll) The coating related contents are deleted (see Clause 10 of Part 3 of Edition 2011);



mm) The acceptance requirements for main insulation materials are added (see 7.2.5 and Annex E hereof);



nn) The reference to Clause 9 of GB/T 26978.3-2011 on the protective structure formed by the outer tank of the vapour barrier is deleted (see Clause 5 of Part 4 of Edition 2011);



oo) The essentials for the design of each component of the full containment tank insulation system are added (see 7.4 hereof);



pp) The general requirements for insulation system installation, tank bottom insulation installation requirements, annulus space insulation installation requirements, suspended deck insulation installation requirements and tank roof space cryogenic pipeline insulation installation requirements are added (see 7.5 and Annex G hereof);



qq) The testing method of insulation materials is modified and China standards are adopted (see Annex D hereof; Annex B of Part 4 of Edition 2011);



rr) The hydrostatic test requirements for cryogenic liquid hydrocarbon tanks such as butane, ethylene and ethane are added (see 8.1.1.2 hereof; 4.1.2 of Part 5 of Edition 2011);



ss) The requirements of water quality for tank test are modified (see 8.1.1.4 hereof; 4.1.4 of Part 5 of Edition 2011);



tt) The inspection of piping and inner tank support prior to hydrostatic test is added (see 8.1.1.5 hereof);



uu) The requirements for settlement observation points in circumferential inspection are modified, and the settlement observation at 1/4 test liquid level height is supplemented (see 8.1.1.6.1 hereof; 4.1.6.1 of Part 5 of Edition 2011);



vv) The requirements for water filling time are modified (see 8.1.1.7 hereof; 4.1.7 of Part 5 of Edition 2011);



ww) The requirements of opening the intake valve after passing the negative pressure test are added (see 8.1.1.2 hereof);



xx) The requirement that “the drying scheme shall meet the requirements of SY/T 4114” is added (see 8.2.2 hereof);



yy) The requirements for oxygen concentration during purging are modified (see 8.2.3 hereof; 5.3 of Part 5 of Edition 2011);



zz) The requirements for cool-down are modified (see 8.2.4 hereof; 5.4 of Part 5 of Edition 2011);



Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.



This standard was proposed by and is under the jurisdiction of National Technical Committee on Petroleum and Natural Gas of Standardization Administration of China (SAT/TC 355).



This document was firstly issued in 2011 as GB/T 26978.1-2011, GB/T 26978.2-2011, GB/T 26978.3-2011, GB/T 26978.4-2011 and GB/T 26978.5-2011. This is the first revision.

 

Introduction



The preparation of a basic national standard is necessarily required in order to standardize the design and manufacture of cryogenic liquefied gas storage tanks and promote the development and standardization of cryogenic liquefied gas storage tank industry in China.



Cryogenic liquefaction tanks are used to store products with standard boiling points below ambient temperature in two-phase state (i.e. liquid and boil-off gas). Balance between the liquid and gas phases is maintained by cooling the product to a temperature equal to or slightly below the standard boiling point and by placing the tank at a slightly positive pressure.



The manufacture process of cryogenic liquefied gas storage tank includes design, construction, test, trial operation, operation (including failure) and cessation of use. Based on the above conditions, this document specifies the design and manufacture principles of cryogenic liquefied gas storage tanks.



The cryogenic liquefied gas storage tank comprises a main structure and auxiliary facilities. Auxiliary facilities will not affect the overall structural design of the storage tank, therefore this document only specifies the design of the main structure of the storage tank.



At present, the materials used in cryogenic liquefied gas storage tanks have been basically localized, therefore the materials involved in this document are all GB and ISO designations. If other foreign standards are referred to in the design of storage tank materials, the designations quoted in relevant standards may be used to replace the GB designations.







Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of cryogenic liquefied gas



1 Scope



This document specifies the general requirements for the design, manufacture and installation of site built, vertical, cylindrical, flat-bottomed steel main container storage tanks (including metallic components, concrete components, insulation components, etc.), and describes the procedures and methods for testing, drying, purging and cool-down of storage tanks.



This document is applicable to cryogenic liquefied gases with storage temperature ranging from -165°C to 0°C, including cryogenic frozen hydrocarbons such as liquefied natural gas (LNG) and cryogenic liquefied petroleum gas (LPG), and its components are mainly methane, ethane, propane, butane, ethylene, propylene, etc.



This document is applicable to tanks with maximum design pressure not greater than 50kPa.



This document is not applicable to tanks whose main container is made of concrete.



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 150.2-2011 Pressure vessels—Part 2: Materials

GB/T 150.3 Pressure vessels—Part 3: Design

GB/T 193 General purpose metric screw threads—General plan

GB/T 229 Metallic materials—Charpy pendulum impact test method

GB/T 709-2019 Dimension, shape, weight and tolerances for hot-rolled steel strip, plate and sheet

GB/T 985.1 Recommended joint preparation for gas welding, manual metal arc welding, gas-shield arc welding and beam welding

GB/T 1220 Stainless steel bars

GB/T 2518 Continuously hot-dip zinc and zinc alloy coated steel sheet and strip

GB 3097 Marine water quality standard

GB/T 3531 Steel plates for low temperature pressure vessels

GB/T 5224 Steel strand for prestressed concrete

GB/T 6478 Steels for cold heading and cold extruding

GB/T 9145-2003 General purpose metric screw threads—Limits of sizes for the screw threads of medium quality and preferable plan

GB/T 12459 Steel buttwelding pipe fittings—Types and parameter

GB/T 13401 Steel buttwelding pipe fittings—Technical specification

GB/T 13480 Thermal insulating products for building applications—Determination of compression behaviour

GB/T 14370 Anchorage, grip and coupler for prestressing tendons

GB/T 19001 Quality Management Systems—Requirements

GB/T 23248 Code for design of seawater treatment for recirculating cooling seawater system

GB/T 24001 Environmental management systems—Requirements with guidance for use

GB/T 24510 Nickel alloy steel plates for low temperature pressure vessels

GB/T 24511 Stainless steel and heat resisting steel plates, sheets and strips for pressure equipment

GB/T 32983 Thermal insulating products for building applications—Determination of compressive creep

GB/T 45001 Occupational health and safety management systems—Requirements with guidance for use

GB 50009 Load code for the design of building structures

GB 50010 Code for design of concrete structures

GB 50011 Code for seismic design of buildings

GB 50017 Standard for design of steel structures

GB 50021 Code for investigation of geotechnical engineering

GB/T 50046 Standard for anticorrosion design of industrial constructions

GB 50057 Code for design protection of structures against lightning

GB 50204 Code for acceptance of constructional quality of concrete structures

GB/T 50448 Code for application technique of cementitious grout

GB 51006 Load code for design of buildings and special structures in petrochemical industry

GB 51081 Technical code for application of concrete under cryogenic circumstance

GB 51156-2015 Code for design of liquefied natural gas receiving terminal

GB/T 51408 Standard for seismic isolation design of building

HG/T 20592 Steel pipe flanges (PN designated)

HG/T 20606 Non-metallic flat gaskets for use with steel pipe flanges (PN designated)

HG/T 20607 PTFE envelope gaskets for use with steel pipe flanges (PN designated)

HG/T 20609 Metal jacketed gaskets for use with steel pipe flanges (PN designated)

HG/T 20610 Spiral wound gaskets for use with steel pipe flanges (PN designated)

HG/T 20611 Covered serrated metal gaskets for use with steel pipe flanges (PN designated)

HG/T 20612 Metallic ring joint gaskets for use with steel pipe flanges (PN designated)

HG/T 20613 Bolting for use with steel pipe flanges (PN designated)

HG/T 20614 Specification for selection of steel pipe flanges, gaskets and bolting (PN designated)

HG/T 20615 Steel pipe flanges (Class designated)

HG/T 20623 Large diameter steel pipe flanges (Class designated)

HG/T 20627 Non-metallic flat gaskets for use with steel pipe flanges (Class designated)

HG/T 20628 PTFE envelope gaskets for use with steel pipe flanges (Class designated)

HG/T 20630 Metal jacketed gaskets for use with steel pipe flanges (Class designated)

HG/T 20631 Spiral wound gaskets for use with steel pipe flanges (Class designated)

HG/T 20632 Covered serrated metal gaskets for use with steel pipe flanges (Class designated)

HG/T 20633 Metallic ring joint gaskets for use with steel pipe flanges (Class designated)

HG/T 20634 Bolting for use with steel pipe flanges (Class designated)

HG/T 20635 Specification for selection of steel pipe flanges, gaskets and bolting (Class designated)

JGJ/T 225 Technical specification for large-diameter belled cast-in-place pile foundation

JGJ 369 Code for design of prestressed concrete structures

NB/T 47013.2 Nondestructive testing of pressure equipments—Part 2: Radiographic testing

NB/T 47013.3 Nondestructive testing of pressure equipments—Part 3: Ultrasonic testing

NB/T 47013.4 Nondestructive testing of pressure equipment—Part 4: Magnetic particle testing

NB/T 47013.5 Nondestructive testing of pressure equipment—Part 5: Penetrant testing

NB/T 47013.7 Nondestructive testing of pressure equipments—Part 7: Visual examination

NB/T 47013.8 Nondestructive testing of pressure equipments—Part 8: Leakage testing

NB/T 47014 Welding procedure qualification for pressure equipment

NB/T 47015 Welding specification for pressure vessels

SY/T 4114 Technical code for drying construction of gas pipeline, liquefied gas station (plant)

YB/T 4641 Cryogenic ribbed bars for the reinforced concrete tanks of LNG

CECS 226 Technical specification for welding of stud

TSG Z6002 Examination rules for welding operators of special equipment

TSG Z8001 Examination rules for non-destructive testing inspectors of special equipment



3 Terms, definitions, symbols and abbreviations



3.1 Terms and definitions



For the purposes of this document, the following terms and definitions apply.



3.1.1

boil-off gas; BOG

gas produced by the gasification of cryogenic liquefied gas due to the introduction of external heat and the flashing when the pressure changes during the feeding and discharging of the container



[Source: GB/T 8423.3-2018, 5.2.4, modified]



3.1.2

daily boil-off rate

percentage of daily boil-off of a tank due to heat leakage to the tank gross capacity



[Source: GB 51156-2015, 2.0.11, modified]



3.1.3

tank gross capacity

maximum permissible storage capacity of the tank under normal operating conditions



Note: The capacity is calculated according to the design liquid level of the inner tank.



3.1.4

tank net capacity

effective working capacity



capacity between the maximum operating level and the minimum operating level allowed under normal operating conditions of the tank



3.1.5

impounding area

area delineated on site with protective embankment or using topographic conditions to prevent accidental overflow of cryogenic liquefied gas or flammable refrigerant



[Source: GB/T 8423.3-2018, 5.2.22, modified]



3.1.6

foundations

structural units used to support the tank and its internal storage



Note: It consists of base slab, ring wall or pile.



3.1.7

base slab

continuous concrete base for supporting tanks



Note: It includes ground type or overhead type.



3.1.8

primary container

container used for holding cryogenic liquids and in direct contact with cryogenic liquids



[Source: GB/T 8423.3-2018, 5.2.24]



3.1.9

secondary container

container that is generally located outside the primary container, contains cryogenic liquid when leaking, and does not contact with cryogenic liquid under normal operating conditions



[Source: GB/T 8423.3-2018, 5.2.25]



3.1.10

inner tank

metallic self supporting cylindrical primary container



3.1.11

outer tank

self supporting cylindrical secondary container made of steel or concrete



3.1.12

annular space

space between the inner shell and outer shell or wall of self supporting tanks



3.1.13

insulation space

space containing insulation material in the tank annular space, and between the tank bottoms or roofs



 

3.1.14

vapour barrier

barrier to prevent entry of water vapour and other atmospheric gases into the insulation or into the outer tank



[Source: GB/T 8423.3-2018, 5.2.33]



3.1.15

liner

metallic plate installed against the inside of the concrete outer tank, impervious to product vapour and water vapour



3.1.16

ring beam

annular support placed under the inner tank shell plate when the tank is in a low temperature environment during operation



3.1.17

roof

structure on top of a shell or wall containing the vapour pressure and sealing off the contents from the atmosphere



3.1.18

shell

metallic vertical cylinder



3.1.19

wall

concrete vertical cylinder



3.1.20

suspended deck

structure used to bear the insulation layer on the roof of tank, prevent perlite from falling into the inner tank, and connect with the steel dome through a suspender



3.1.21

thermal corner protection; TCP

structure composed of secondary base, shell and thermal insulation materials arranged between the inner and outer tanks in order to protect the tank bottom and the outer wall of the concrete bottom layer in case of a small amount of leakage of the inner tank and to prevent the tank from failure



 

3.1.22

self supporting

container designed to carry the hydrostatic forces of the stored liquid and the vapour pressure loads, if applicable



3.1.23

vapour container

part of a single, double, full containment or membrane tank that contains the boil-off gas during normal operation



3.1.24

design pressure

maximum permissible pressure



[Source: GB/T 150.1-2011, 3.1.3, modified]



3.1.25

operating pressure

maximum possible pressure of the container under normal working condition



3.1.26

test pressure

pressure of the container during pressure test or leakage test



[Source: GB/T 150.1-2011, 3.1.5, modified]



3.1.27

maximum design liquid level

maximum liquid level that will be maintained during operation of the tank used for the static shell thickness determination



3.1.28

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



3.1.29

design temperature

set temperature of element, i.e. the average temperature along the element cross section, under normal operating conditions of tank



[Source: GB/T 150.1-2011, 3.1.7, modified]



 

3.1.30

operating base 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.



3.1.31

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.



3.1.32

roll-over

refrigerated liquefied gas at different depths in a container (generally a storage tank) generates heat and mass transfer due to the difference in temperature and / or density, resulting in the rapid mixing of layered liquids and the rapid release of a large amount of evaporated gas from the refrigerated liquefied gas container.



[Source: GB/T 8423.3-2018, 5.2.7, modified]



3.1.33

action

concentrated or distributed forces exerted on a structure and the causes of external or constrained deformation of the structure. The former is direct action, also known as load; the latter is indirect



[Source: GB 50068-2018, 2.1.36]



3.1.34

progressive deformation

phenomenon in which the deformations in each part of the membrane increase progressively under the cyclic loads



3.2 Symbols



For the purposes of this document, the following symbols apply.



A: compression area required, mm2;



a: welding shrinkage of each longitudinal welded joint, mm;



C: equivalent radiation variation coefficient;



c: corrosion allowance, mm;



Di: diameter of inner tank, m;



Do: diameter of outer tank, m;



Dp: design point;



E: modulus of elasticity;



e: plate thickness, mm;



ea: thickness of the annular plate, mm;



ea, min: minimum thickness of annular plates (excluding corrosion allowance), mm;



ear: thickness of top corner ring, mm;



eb: thickness of center plate, mm;



ec: calculated plate thickness, mm;



eg: thickness of the horizontal girder, mm;



eo: shell thickness (excluding corrosion allowance), mm;



eos: calculated thickness of shell plate under internal pressure condition, mm;



ep: thickness of roof plate at compression ring (excluding corrosion allowance), mm;



er: roof plate thickness (excluding corrosion allowance), mm;



es: thickness of inner tank shell plate, mm;



es, c: calculated thickness of shell plate under operating condition, mm;



esi: as ordered thickness of each course in turn, mm;



est: as ordered thickness of the top course, mm;



es, t: calculated thickness of shell plate under hydrostatic test condition, mm;



es, l: thickness of the bottom shell course, mm;



F: force, N;



fPLDF: permissible load coefficient of thermal insulation creep-prone materials;



H: maximum design liquid height, m.



He: equivalent stable height of each course at est, m;



Hh: calculated height between the bottom of the shell plate and the maximum design liquid level, m;



Hp: maximum allowable spacing of reinforced support on the shell with minimum thickness, m;



Ht: calculated height between the bottom of the shell plate and the test liquid level, m;



hs: height of each course in turn, m;



K: calculated stiffening ring coefficient;



k: S-N curve coefficient;



L: single allowable minimum value of compressive strength;



Lr: effective roof length, mm;



Ls: effective shell length, mm;



la: minimum width between the edge of the irregular plate of the outer ring of the tank bottom and the inner side of the shell plate, mm;



m: mean of all test data from fatigue test;



nj: number of longitudinal welded joints of the first course;



ns: sample quantity of sampling batch;



P: design pressure (for open top inner tank, design pressure is 0), kPa;



Pe: external loading, kPa;



Pi: internal pressure, as a combination of internal gas pressure and insulation pressure, kPa;



PLD: permissible load of thermal insulation creep-prone materials, MPa;



Pr: internal pressure minus roof plate weight, kPa;



Pt: hydrostatic test pressure (for open top inner tank, design pressure is 0), kPa;



Q: quality statistics of acceptance sampling inspection;



Qe: quality statistics of compressive strength of sampling batches;



Qt: quality statistics of conductivity factor of sampling batches;



R: characteristic strength value of insulation material, MPa;



Rb: radius of assembly circle in the first course, mm;



Rel: yield strength of the steel or weld material, whichever is the lesser, MPa;



Rf: final radius of 9% nickel steel plate, mm;



Ri: radius of inner tank, mm;



Rl: radius of outer tank, m;



Rm: lower limit of standard tensile strength of steel or weld metal, MPa;



Rr: radius of curvature of roof (Rr=R/sinθ for conical roof), m;



Ro: initial radius of 9% nickel steel plate (infinity for plate), mm;



S: standard deviation;



SF: safety factor;



s: standard deviation of sampling batch;



U: maximum single allowable conductivity factor;



Va: design internal negative pressure, kPa;



Vw: design wind speed, m/s;



: average;



: average compressive strength of sampling batch;



: average conductivity factor of sampling batch;



α: tensile to yield strength ratio Rm/Rel;



αn: horizontal seismic influence coefficient of component n before isolation, which is calculated by the mode decomposition response spectrum method according to the seismic influence coefficient curve of the site;



αn1: horizontal seismic influence coefficient of component n after isolation;



βn: horizontal damping coefficient of the component n, which is the ratio of the maximum acceleration of the component n after isolation to the maximum acceleration of the component n before isolation. The acceleration of the component before and after isolation shall be calculated by using the time-history analysis method according to the OBE seismic acceleration input. The parameters of the isolation support shall be based on the hysteresis curve obtained from the test;



γc: safety factor of cylinder effect;



γF: material partial coefficient;



γi: safety factor of installation;



γL: safety factor applied to load;



γM: factor for material strength;



γm: safety factor of insulation materials;



γt: coefficients of possible differences between the reference method for testing insulating products and their installation methods;



ε: strain;



εef: extreme fiber strain, %;



ε1: first principal strain;



ε2: second principal strain;



ε3: third principal strain;



η: welded joint efficiency factor;



θ: slope of the roof meridian at roof-shell connection, °;



ρ——maximum density of storage medium under operating conditions, kg/m3;



ρt: maximum density of test medium under hydrostatic test condition, kg/m3;



σ: permissible stress, MPa;



σ1: first principal stress, MPa;



σ2: second principal stress, MPa;



σ3: third principal stress, MPa;



σc: permissible compressive stress, MPa;



σi: compressive stress applied in the test of load-bearing insulation creep-prone materials, MPa;



σm: maximum compressive strength of load-bearing insulation material when yield or failure occurs when deformation is less than 10%, MPa;



σn: nominal compressive strength of load-bearing insulation material, MPa;



σs: permissible tensile stress, MPa;



σst: design permissible tensile stress under hydrostatic test condition, MPa;



σ10: compressive stress of load-bearing insulation creep-prone material without yielding or failure at 10% deformation, MPa;



φ: foundation slope angle, °;



ψ: adjustment coefficient of isolation bearing, which is taken as 0.80 for general rubber bearing; and 0.85 in case of Category S-A bearing shear performance deviation;



Δε: equivalent strain radiation;



∑x: sum of compressive strength or conductivity factor of all samples in the sampling batch;



∑x2: sum of squares of compressive strength or conductivity factor of all samples in the sampling batch.



3.3 Abbreviations



For the purposes of this document, the following abbreviations apply.



ALE——Aftershock Level Earthquake



AQL——Acceptance Quality Limit



BL——Block Type



BOG——Boil-off Gas



FIP——Foamed in Place



GR——Glass Fibre Reinforced



HAZ——Heat Affected Zone



HD——High Density



LNG——Liquefied Natural Gas



LPG——Liquefied Petroleum Gas



LQ——Limiting Quality



MD——Medium Density



ND——Normal Density



NDE——Non-destructive Examination



OBE——Operating Base Earthquake



PIR——Poly Isocyanurate Foam



PQR——Procedure Qualification Records



PUF——Polyurethane Foam



PVC——Polyvinyl Chloride Foam



RLG——Refrigerated Liquefied Gas



SLS——Serviceability Limit States



SPR——Spray Type



SSE——Safe Shutdown Earthquake



TCP——Thermal Corner Protection



ULS——Ultimate Limit States



WPS——Welding Procedure Specification



4 Basic requirements and general provisions



4.1 Tank type



4.1.1 Single containment tank



It is a tank that has only one self supporting steel storage tank for cryogenic liquids, which can be composed of single-wall or double-wall structures with insulation, and has liquid tightness and air tightness.



Product boil-off gas shall be stored:



a) in the steel dome of the container;



b) in an airtight metal outer tank surrounding the main container when the primary container is shaped in an open cup, which is only designed to store product boil-off gas and support and protect the thermal insulation.



Cofferdams shall be built around each single containment tank to accommodate products that may leak.

Foreword i
Introduction vi
1 Scope
2 Normative references
3 Terms, definitions, symbols and abbreviations
3.1 Terms and definitions
3.2 Symbols
3.3 Abbreviations
4 Basic requirements and general provisions
4.1 Tank type
4.2 Overall design basis
4.3 Protection system
4.4 Action
4.5 Inspection and maintenance
4.6 Quality management, environmental management, and occupational health and safety management
5 Metal components
5.1 General requirements
5.2 Material
5.3 Design
5.4 Manufacture
5.5 Welding procedures
5.6 Welding
5.7 Inspection
5.8 Pneumatic jacking
6 Concrete component
6.1 Material
6.2 Combination of loads
6.3 Design requirements
6.4 Construction requirements
6.5 Liner
7 Insulation components
7.1 General
7.2 Design, property, testing and selection of insulation materials
7.3 Insulation protection—vapour barrier
7.4 Design of insulation system
7.5 Installation of insulation system
8 Testing, drying, purging and cool-down
8.1 Hydrostatic test and pneumatic test
8.2 Drying, purging and cool-down
8.3 Shutdown
Annex A (Informative) Design example of intermediate ring stiffener
Annex B (Informative) Loads on membrane
Annex C (Informative) Insulation material
Annex D (Informative) Testing method for insulation materials
Annex E (Informative) Acceptance of main insulation materials
E.1 Pressure-bearing foam glass brick at tank bottom
E.2 Expanded perlite
E.3 Glass wool
E.4 Elastic felt
E.5 Asphalt felt
Annex F (Informative) Thermal insulation at the bottom of main tank — limit state theory
Annex G (Informative) Construction and installation of tank insulation system
G.1 Tank bottom insulation installation
G.2 Annular space insulation installation
G.3 Installation of suspended deck insulation
G.4 Insulation installation of cryogenic pipeline in roof space
Bibliography
Figure 1 Single containment tank
Figure 2 Double containment tank
Figure 3 Full containment tank
Figure 4 Membrane tank
Figure 5 Typical bottom layout
Figure 6 Design flowchart for membranes
Figure 7 Typical shell-roof compression areas
Figure 8 Typical roof nozzle with insulation component
Figure 9 Measuring parts of geometric dimension of dome sheet
Figure 10 Measuring parts of geometric dimension of bottom edge plate
Figure 11 Measuring parts of geometric dimension of shell
Figure 12 Outward and inward peaking
Figure 13 Gauge for measuring peaking
Figure 14 Schematic diagram of suspended deck
Figure 15 Schematic diagram of three layer plate lapping
Table 1 Steel types of tank at product storage temperature
Table 2 Steel grades and lower limit of storage temperature
Table 3 Minimum Charpy V-notch impact test energy
Table 4 Steel used for boil-off gas container
Table 5 Design permissible tensile stress
Table 6 Partial load and material coefficient of low alloy steel plate for low temperature service, low nickel steel and 9% nickel steel
Table 7 Minimum shell thickness
Table 8 Coefficient k of S-N curve (assumed under normal distribution)
Table 9 Minimum dimension of top corner ring
Table 10 Mechanical properties of welding stud
Table 11 Allowable deviation of geometric dimension of dome sheet
Table 12 Allowable deviation of geometric dimension of bottom edge plate
Table 13 Allowable deviation of geometric dimension of shell plate
Table 14 Radius tolerances
Table 15 Maximum deviation between the design and the as built profile
Table 16 Tolerance limits on local deformation at welded joints
Table 17 Maximum misalignment at vertical joint
Table 18 Misalignment of shell plate assembly
Table 19 Allowable deviation of radius of any point on the inner surface of bottom ring shell plate
Table 20 Angular deformation of welded joint of shell plate
Table 21 Concave-convex deformation of shell plate
Table 22 Holding time at lower temperatures
Table 23 Inspection of welded joints of primary and secondary containers
Table 24 Radiographic/ultrasonic testing for shell welded joints
Table 25 Inspection of boil-off gas barrier/liner
Table 26 Extent of radiographic/ultrasonic testing of shell plate welded joint of vapour containers
Table 27 Partial load factor under accidental action
Table 28 Requirements for cracks
Table 29 Hydraulic test requirement
Table A.1 Shell plate dimensions
Table B.1 Static load
Table B.2 Cyclic load
Table B.3 Accidental load
Table C.1 Single and double containment tank
Table C.2 Full containment tank
Table C.3 Membrane tank
Table D.1 Thermal resistance property testing
Table D.2 Mechanical property testing
Table D.3 Temperature resistance testing
Table D.4 Permeability testing and influence testing of water and water vapour
Table D.5 Testing of material properties immersed in refrigerated liquefied gas environment
Table D.6 Chemical characteristic testing
Table D.7 Flame retardance/reaction to fire testing
Table E.1 Main property requirements of foam glass brick
Table E.2 Property requirements of conductivity factor of foam glass brick with temperature change
Table E.3 Foam glass brick size, appearance inspection sample size and qualification judgment
Table E.4 Sample size and qualification judgment requirements for compressive strength and conductivity factor of foam glass brick in end-of-manufacturing inspection
Table E.5 Property inspection of perlite ore
Table E.6 Grain size sieving of perlite ore
Table E.7 Property inspection of expanded perlite powder
Table E.8 Grain size sieving of expanded perlite powder

现场组装立式圆筒平底钢质低温
液化气储罐的设计与建造
1 范围
本文件规定了现场组装的地上立式圆筒平底钢质主容器储罐(含金属构件、混凝土构件、绝热构件等)设计、建造和安装的一般要求，描述了储罐的试验、干燥、置换和冷却的程序和方法。
本文件适用于存储温度范围介于－165℃～0℃的低温液化气体，包括液化天然气(LNG)和低温液化石油气(LPG)等低温冷冻烃，其组分主要为甲烷、乙烷、丙烷、丁烷、乙烯、丙烯等。
本文件适用于最大设计压力不大于50kPa的储罐。
本文件不适用于主容器为混凝土的储罐。
2 规范性引用文件
下列文件中的内容通过文中的规范性引用而构成本文件必不可少的条款。其中，注日期的引用文件，仅该日期对应的版本适用于本文件；不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。
GB／T 150.2—2011 压力容器 第2部分：材料
GB／T 150.3 压力容器 第3部分：设计
GB／T 193 普通螺纹 直径与螺距系列
GB／T 229 金属材料 夏比摆锤冲击试验方法
GB／T 709—2019 热轧钢板和钢带的尺寸、外形、重量及允许偏差
GB／T 985.1 气焊、焊条电弧焊、气体保护焊和高能束焊的推荐坡口
GB／T 1220 不锈钢棒
GB／T 2518 连续热镀锌和锌合金镀层钢板及钢带
GB 3097 海水水质标准
GB／T 3531 低温压力容器用钢板
GB／T 5224 预应力混凝土用钢绞线
GB／T 6478 冷镦和冷挤压用钢
GB／T 9145—2003 普通螺纹 中等精度、优选系列的极限尺寸
GB／T 12459 钢制对焊管件 类型与参数
GB／T 13401 钢制对焊管件 技术规范
GB／T 13480 建筑用绝热制品 压缩性能的测定
GB／T 14370 预应力筋用锚具、夹具和连接器
GB／T 19001 质量管理体系 要求
GB／T 23248 海水循环冷却水处理设计规范
GB／T 24001 环境管理体系 要求及使用指南
GB／T 24510 低温压力容器用镍合金钢板
GB／T 24511 承压设备用不锈钢和耐热钢钢板和钢带
GB／T 32983 建筑用绝热制品 压缩蠕变性能的测定
GB／T 45001 职业健康安全管理体系 要求及使用指南
GB 50009 建筑结构荷载规范
GB 50010 混凝土结构设计规范
GB 50011 建筑抗震设计规范
GB 50017 钢结构设计标准
GB 50021 岩土工程勘察规范
GB／T 50046 工业建筑防腐蚀设计标准
GB 50057 建筑物防雷设计规范
GB 50204 混凝土结构工程施工质量验收规范
GB／T 50448 水泥基灌浆材料应用技术规范
GB 51006 石油化工建(构)筑物结构荷载规范
GB 51081 低温环境混凝土应用技术规范
GB 51156—2015 液化天然气接收站工程设计规范
GB／T 51408 建筑隔震设计标准
HG／T 20592 钢制管法兰(PN系列)
HG／T 20606 钢制管法兰用非金属平垫片(PN系列)
HG／T 20607 钢制管法兰用聚四氟乙烯包覆垫片(PN系列)
HG／T 20609 钢制管法兰用金属包覆垫片(PN系列)
HG／T 20610 钢制管法兰用缠绕式垫片(PN系列)
HG／T 20611 钢制管法兰用具有覆盖层的齿形组合垫(PN系列)
HG／T 20612 钢制管法兰用金属环形垫(PN系列)
HG／T 20613 钢制管法兰用紧固件(PN系列)
HG／T 20614 钢制管法兰、垫片、紧固件选配规定(PN系列)
HG／T 20615 钢制管法兰(Class系列)
HG／T 20623 大直径钢制管法兰(Class系列)
HG／T 20627 钢制管法兰用非金属平垫片(Class系列)
HG／T 20628 钢制管法兰用聚四氟乙烯包覆垫片(Class系列)
HG／T 20630 钢制管法兰用金属包覆垫片(Class系列)
HG／T 20631 钢制管法兰用缠绕式垫片(Class系列)
HG／T 20632 钢制管法兰用具有覆盖层的齿形组合垫(Class系列)
HG／T 20633 钢制管法兰用金属环形垫(Class系列)
HG／T 20634 钢制管法兰用紧固件(Class系列)
HG／T 20635 钢制管法兰、垫片、紧固件选配规定(Class系列)
JGJ／T 225 大直径扩底灌注桩技术规程
JGJ 369 预应力混凝土结构设计规范
NB／T 47013.2 承压设备无损检测 第2部分：射线检测
NB／T 47013.3 承压设备无损检测 第3部分：超声检测
NB／T 47013.4 承压设备无损检测 第4部分：磁粉检测
NB／T 47013.5 承压设备无损检测 第5部分：渗透检测
NB／T 47013.7 承压设备无损检测 第7部分：目视检测
NB／T 47013.8 承压设备无损检测 第8部分：泄漏检测
NB／T 47014 承压设备焊接工艺评定
NB／T 47015 压力容器焊接规程
SY／T 4114 天然气管道、液化天然气站(厂)干燥施工技术规范
YB／T 4641 液化天然气储罐用低温钢筋
CECS 226 栓钉焊接技术规程(附条文说明)
TSG Z6002 特种设备焊接操作人员考核细则
TSG Z8001 特种设备无损检测人员考核规则
3 术语、定义、符号和缩略语
3.1 术语和定义
下列术语和定义适用于本文件。
3.1.1
蒸发气 boil-off gas；BOG
由于外界的热量引入以及在容器进出料过程中压力变化时的闪蒸等原因，引起低温液化气气化产生的气体。
[来源：GB／T 8423.3—2018，5.2.4，有修改]
3.1.2
日蒸发率 daily boil-off rate
储罐因漏热产生的日蒸发量与储罐总容积的百分比。
[来源：GB 51156—2015，2.0.11，有修改]
3.1.3
储罐总容积 tank gross capacity
储罐正常操作条件下允许储存的最大容积。
注：按照内罐的设计液位计算出来的容积。
3.1.4
储罐净容积 tank net capacity
有效工作容积
储罐正常操作条件下允许的最高操作液位和最低操作液位之间容积。
3.1.5
拦蓄区 impounding basin
现场用防护堤或利用地形条件圈定的用于防止低温液化气或易燃制冷剂事故溢出的区域。
[来源：GB／T 8423.3—2018，5.2.22，有修改]
3.1.6
基础 foundations
所有用于支撑储罐及其内部储存物的结构单元。
注：由底板、环墙或桩组成。
3.1.7
基础底板 base slab
支撑储罐的连续式混凝土基座。
注：包括地面式或架空式。
3.1.8
主容器 primary container
用来盛装低温液体，并直接与低温液体接触的容器。
[来源：GB／T 8423.3—2018，5.2.24]
3.1.9
次容器 secondary container
一般位于主容器之外，泄漏时盛装低温液体，正常运行工况下不与低温液体接触的容器。
[来源：GB／T 8423.3—2018，5.2.25]
3.1.10
内罐 inner tank
金属自支撑式圆筒形主容器。
3.1.11
外罐 outer tank
由钢材或混凝土构成的自支撑式圆筒形次容器。
3.1.12
环形空间 annular space
自支撑式储罐的内壁与外壁或外墙之间的空间。
3.1.13
绝热空间 insulation space
储罐环形空间以及储罐底部和顶部容纳绝热材料的空间。
3.1.14
隔气层 vapour barrier
防止罐外气体进入绝热材料或罐内的隔离层。
[来源：GB／T 8423.3—2018，5.2.33]
3.1.15
衬里 liner
为了阻止产品蒸发气和水蒸气渗透，紧贴在混凝土外罐内侧安装的金属板。
3.1.16
环梁 ring beam
储罐运行状态下处于低温环境，置于内罐壁板下面的环形支承。
3.1.17
罐顶 roof
用于抑制蒸发气压力，使罐内物质不与大气接触的罐壁或墙体顶部结构。
3.1.18
罐壁 shell
金属立式圆筒。
3.1.19
墙体 wall
混凝土立式圆筒
3.1.20
吊顶 suspended deck
用于承载储罐顶部绝热层，避免珍珠岩掉入内罐，与钢穹顶通过吊杆连接的结构。
3.1.21
热角保护 thermal corner protection；TCP
在内罐少量泄漏的情况下，为了保护罐底和混凝土底层的外壁，且罐体不失效，在内外罐之间设置的由二次底、壁以及保温材料组成的结构。
3.1.22
自支撑式 self supporting
在适用的情况下，容器形式可承载所储存液体的静态压力和蒸发气压力荷载。
3.1.23
蒸发气容器 vapour container
在正常操作条件下单容罐、双容罐、全容罐或薄膜罐储存蒸发气的部分。
3.1.24
设计压力 design pressure
为储罐设定的储罐容器的最高压力。
[来源：GB／T 150.1—2011，3.1.3，有修改]
3.1.25
操作压力 operating pressure
在正常工作情况下，容器可能达到的最大压力。
3.1.26
试验压力 test pressure
进行耐压试验或泄漏试验时，容器的压力。
[来源：GB／T 150.1—2011，3.1.5，有修改]
3.1.27
最高设计液位 maximum design liquid level
确定静态下罐壁厚度的参数之一，为储罐运行期间的最高液位。
3.1.28
最高正常操作液位 maximum normal operating level
第一个高液位报警的设定值，为储罐正常运行期间的最高液位。
3.1.29
设计温度 design temperature
储罐在正常工作情况下，设定元件的温度(沿元件截面的温度平均值)。
[来源：GB／T 150.1—2011，3.1.7，有修改]
3.1.30
操作基准地震 operating base earthquake；OBE
不会造成系统损坏、不影响系统重新启动并继续安全运行的最大地震。
注：该级别的地震作用不会损害储罐系统运行的完整性，能够保证公共安全。
3.1.31
安全停运地震 safe shutdown earthquake；SSE
不会造成系统基本功能失效和破坏的最大地震。
注：该级别的地震作用可能会造成装置和储罐的局部永久性损坏，但不会破坏系统的完整性。
3.1.32
翻滚 roll-over
容器(通常为储罐)中不同深度的低温液化气因温度和(或)密度的差异而产生传热、传质，致使分层的液体发生快速的混合并伴随大量的蒸发气从低温液化气容器中急剧释放的现象。
[来源：GB／T 8423.3—2018，5.2.7，有修改]
3.1.33
作用 action
施加在结构上的集中力或分布力和引起结构外加变形或约束变形的原因。前者为直接作用，也称为荷载；后者为间接作用。
[来源：GB 50068—2018，2.1.36]
3.1.34
递进变形 progressive deformation
在循环荷载作用下，薄膜的每部分的变形逐渐增加的现象。
3.2 符号
下列符号适用于本文件。
A：所需要的受压面积，单位为平方毫米(mm2)；
a：每条纵向焊接接头焊接收缩量，单位为毫米(mm)；
C：等效应变辐系数；
c：腐蚀裕量，单位为毫米(mm)；
Di：储罐内罐直径，单位为米(m)；
Do：储罐外罐内径，单位为米(m)；
Dp：设计点；
E：弹性模量，单位为兆帕(MPa)；
e：板材厚度，单位为毫米(mm)；
ea：环形板厚度，单位为毫米(mm)；
ea，min：环形板的最小厚度(不包括腐蚀裕量)，单位为毫米( mm)；
ear：顶端角环的厚度，单位为毫米(mm)；
eb：中幅板厚度，单位为毫米(mm)；
ec：板材计算厚度，单位为毫米(mm)；
eg：水平桁钢的厚度，单位为毫米(mm)；
eo：罐壁厚度(不考虑腐蚀裕量)，单位为毫米(mm)；
eos：内压工况下的壁板计算厚度，单位为毫米(mm)；
ep：在抗压环处顶板的厚度(不考虑腐蚀裕量)，单位为毫米(mm)；
er：顶板厚度(不包含腐蚀裕量)，单位为毫米(mm)；
es：内罐壁板厚度，单位为毫米(mm)；
es，c：操作工况下壁板计算厚度，单位为毫米(mm)；
esi：依次排定的每圈壁板的厚度，单位为毫米(mm)；
est：排在最上一圈壁板的厚度，单位为毫米(mm)；
es，t：水压试验工况下的壁板计算厚度，单位为毫米(mm)；
es，l：底圈罐壁板厚度，单位为毫米(mm)；
F：作用力，单位为牛(N)；
fPLDF：承载绝热易蠕变材料许用荷载系数；
H：最高设计液位，单位为米(m)；
He：每圈壁板的厚度为est时的等效稳定高度，单位为米(m)；
Hh：计算的壁板底部与最大设计液位之间的高度，单位为米(m)；
Hp：加强支撑在最小厚度罐壁上的最大允许间距，单位为米(m)；
Ht：计算的壁板底部与试验液位之间的高度，单位为米(m)；
hs：每圈壁板的高度，单位为米(m)；
K：计算加强圈系数；
k：S-N曲线系数；
L：抗压强度单次允许最小值；
Lr：有效顶长度，单位为毫米(mm)；
Ls：有效罐壁长度，单位为毫米(mm)；
la：罐底外圈不规则板的边缘与壁板内侧之间的最小宽度，单位为毫米(mm)；
m：疲劳试验全体试验数据的平均值；
nj：首圈壁板纵向焊接接头数；
ns：抽检批次样本数量；
P：设计压力(顶部开口内罐，设计压力取值为0)，单位为千帕(kPa)；
Pe：外部荷载，单位为千帕(kPa)；
Pi：内部压力，内部气压和绝热系统压力之和，单位为千帕(kPa)；
PLD：承载绝热易蠕变材料许用荷载，单位为兆帕(MPa)；
Pr：内部压力减去顶板重量，单位为千帕(kPa)；
Pt：水压试验压力(顶部开口内罐，设计压力取值为0)，单位为千帕(kPa)；
Q：验收抽样检验的质量统计量；
Qe：抽检批次的抗压强度质量统计量；
Qt：抽检批次的导热系数质量统计量；
R：绝热材料的特征强度值，单位为兆帕(MPa)；
Rb：首圈壁板内组装圆半径，单位为毫米(mm)；
Rel：钢材或焊缝金属的屈服强度，取二者之间的较小者，单位为兆帕(MPa)；
Rf：9％镍钢板最终半径，单位为毫米(mm)；
Ri：储罐内罐半径，单位为毫米(mm)；
Rl：外罐半径，单位为米(m)；
Rm：钢材或焊缝金属标准抗拉强度的下限值，单位为兆帕(MPa)；
Rr：罐顶的曲率半径(锥形顶Rr＝R／sinθ)，单位为米(m)；
Ro：9％镍钢板初始半径(平板为无限大)，单位为毫米(mm)；
S：标准偏差；
SF：安全系数；
s：抽检批次的标准差；
U：导热系数单次允许最大值；
Va：设计内部负压，单位为千帕(kPa)；
Vw：设计风速，单位为米每秒(m／s)；
：平均值；
：抽检批次的抗压强度平均值；
：抽检批次的导热系数平均值；
α：拉伸强度与屈服强度之比Rm／Rel；
αn：隔震前构件n的水平地震影响系数，根据场地的地震影响系数曲线，采用振型分解反应谱法计算；
αn1：隔震后构件n的水平地震影响系数；
βn：构件n水平方向减震系数，为隔震后构件n最大加速度与隔震前构件n最大加速度比值，隔震前后构件的加速度应该采用时程分析法按照OBE地震加速度输入进行计算，隔震支座参数应该以试验所得滞回曲线作为依据；
γc：圆筒效应的安全系数；
γF：材料分项系数；
γi：安装的安全系数；
γL：应用于荷载的安全系数；
γM：材料强度系数；
γm：绝热材料的安全系数；
γt：测试绝热产品的参考方法与其安装方法之间可能存在差异的系数；
ε：应变；
εef：极端纤维应变，％；
ε1：第一主应变；
ε2：第二主应变；
ε3：第三主应变；
η：焊缝的焊接接头系数；
θ：顶-壁相连接位置上，子午线上顶的坡度角，单位为度(°)；
ρ：操作工况下储存介质的最大密度，单位为千克每立方米(kg／m3)；
ρt：水压试验工况下试验介质的最大密度，单位为千克每立方米(kg／m3)；
σ：许用应力，单位为兆帕(MPa)；
σ1：第一主应力，单位为兆帕(MPa)；
σ2：第二主应力，单位为兆帕(MPa)；
σ3：第三主应力，单位为兆帕(MPa)；
σc：许用压应力，单位为兆帕(MPa)；.
σi：承载绝热易蠕变材料试验施加的压应力，单位为兆帕(MPa)；
σm：承载绝热材料在小于10％变形出现屈服或破坏时的最大抗压强度，单位为兆帕(MPa)；
σn：承载绝热材料公称抗压强度，单位为兆帕(MPa)；
σs：许用拉应力，单位为兆帕(MPa)；
σst：水压试验工况下的设计许用拉应力，单位为兆帕(MPa)；
σ10：承载绝热易蠕变材料在10％变形未出现屈服或破坏时的压应力，单位为兆帕(MPa)；
φ：基础坡度角，单位为度(°)；
ψ：隔震支座调整系数，一般橡胶支座，取0.80；支座剪切性能偏差为S-A类，取0.85；
Δε：等效应变辐；
∑x：抽检批次所有样本抗压强度或导热系数的平方总和；
∑x2：抽检批次所有样本抗压强度或导热系数的总和。
3.3 缩略语
下列缩略语适用于本文件。
ALE——安全停运地震余震(Aftershock Level Earthquake)
AQL——接收质量限(Acceptance Quality Limit)
BL——块状(Block Type)
BOG——蒸发气( Boil-off Gas)
FIP——现场发泡(Foamed in Place)
GR——增强玻璃纤维(Glass Fibre Reinforced)
HAZ——热影响区(Heat Affected Zone)
HD——高密度(High Density)
LNG——液化天然气(Liquefied Natural Gas)
LPG——液化石油气(Liquefied Petroleum Gas)
LQ——极限质量(Limiting Quality)
MD——中密度(Medium Density)
ND——常规密度(Normal Density)
NDE——无损检测(Non- destructive Examination)
OBE——操作基准地震(Operating Base Earthquake)
PIR——聚异氰脲酸酯泡沫(Poly Isocyanurate Foam)
PQR——焊接工艺评定报告(Procedure Qualification Records)
PUF——聚氨酯泡沫(Polyurethane Foam)
PVC——聚氯乙烯泡沫(Polyvinyl Chloride Foam)
RLG——低温液化气(Refrigerated Liquefied Gas)
SLS——正常使用极限状态(serviceability limit states)
SPR——喷射类型(Spray Type)
SSE——安全停运地震(Safe Shutdown Earthquake)
TCP——热角保护(Thermal Corner Protection)
ULS——承载能力极限状态(Ultimate Limit States)
WPS——焊接工艺规程(Welding Procedure Specification)
4 基本规定与总则
4.1 储罐类型
4.1.1 单容罐
只有一个储存低温液体的自支撑式钢质储罐，该储罐可由带绝热层的单壁或双壁结构组成，具有液密性和气密性。
产品蒸发气应储存在：
a) 容器的钢质拱顶内；
b) 当主容器是一个敞开的杯状体时，储存在包围主容器的气密金属外罐内，金属外罐仅设计用于储存产品蒸发气及支撑和保护绝热层。
每个单容罐的周围应筑有围堰，以容纳可能泄漏的产品。
根据蒸发气储存和绝热的方式不同，有多种形式的单容罐。单容罐示例见图1。

a) 单容罐典型结构形式一

b) 单容罐典型结构形式二
标引序号说明：
1——主容器(钢质)；
2——底部绝热层；
3——基础；
4——基础加热系统；
5——柔性绝热密封；
6——吊顶(绝热)；
7——顶(钢质)；
8——罐壁外部绝热层；
9——外部水汽隔层；
10——松散充填的绝热层；
11——外钢壳(不能装存液体)；
12——围堰。
图1 单容罐图
4.1.2 双容罐
具有液密性的次容器和建立在次容器之中的单容罐共同组成的储罐，次容器与主容器水平距离不大于6m且顶部向大气开口。
次容器顶部为敞开式，无法防止产品蒸发气的逸出。主容器与次容器之间的环形空间可用一个“防雨罩”遮盖，以防止雨水、雪、尘土等进入。双容罐示例见图2。

a) 双容罐典型结构形式一

b) 双容罐典型结构形式二
标引序号说明：
1——主容器(钢质)；
2——次容器(钢质或混凝土)；
3——底部绝热层；
4——基础；
5——基础加热系统；
6——柔性绝热密封；
7——吊顶(绝热)；
8——顶(钢质)；
9——外部绝热层；
10——外部水汽隔层；
11——松散充填绝热层；
12——外壳(不能装存液体)；
13——防雨罩。
图2 双容罐图
4.1.3 全容罐
具有液密性、气密性的次容器和建立在次容器之中的主容器共同组成的储罐，次容器为独立的自支撑带拱顶的闭式结构。
主容器应为以下两种形式之一：
——在顶部开口，不储存产品蒸发气；
——配备拱顶，可储存产品蒸发气。
次容器应是一个具有拱顶的自支撑式钢质或混凝土储罐，其设计应同时满足以下要求：
——在储罐正常操作条件下：作为储罐的主要蒸发气容器(此情况适用于顶部开口的主容器)，并支撑主容器的绝热层；
——在主容器泄漏的情况下：装存全部的液体产品，并保持结构上的气密性。可以进行排气，但应通过卸压系统对其进行控制。
主容器和次容器之间的环形空间径向宽度不应大于2.0m。
在次容器外部设置有绝热层的全容罐也应符合上述要求。全容罐示例见图3。