Contents
General provisions Terms
2 Basicrequirements
2
3 4
Seismic checking ...... 5 Horizontal vessel 5.1 General requirements 5.2Earthquake effect and seismic checking 5.3 Seismic measures ........... 6Vertical vesselssupportedbylegs ...... 6.1 General requirements ...... 6.2 Earthquake effect and seismic checking 6.3 Seismicmeasures 7Vertical vessels supported bylugs 7.1 General requirements 7.2 Earthquake effect and seismic checking 7.3Seismic measure 8Vertical vessels supportedby skirts 8. General requirements ......... 8.2 Earthquake effect and seismic checking 8.3Seismic mcasures 9 Sphericaltanks supportedby columns 9.1 General requirements 9.2 Earthquake cffect and seismic checking 9.3Seismic measures 10 Vertical cylindrical storage tanks 10.1 General requirements 10.2 Earthquake effect and seismic checking 10.3Seismicmeasures ............. 11 Heaters
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5） 5） 6） (10) (11) (11) (11) (12) (13) (13) (13) (13) (15) (15) (15) (19) (20 ) (20) (20) (29) (30) (30) (30) (31) (32) (32) (32) (34) (37) (37) (37) (41) (42) (43)
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11.1 General requirements 11.2Earthquake effect and seismic checking 11.3 Seismicmeasures 12Air-cooled heat exchangers.... 12.1 General requirements 12.2 Earthquake effect and seismic checking 12.3Seismic measures Explanation of wording in this standard .... List of quoted standards .....
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. . 1 Generalprovisions
1.0.1This standard is prepared with a view to implement the Law of the People'sRepublic of Chind onProtectingAgainst and Mitigating EarthquakeDisasters and carry out the policy of "prevention first", mitigate earthquake damage, reduce losses, appraise the seismic capability of in-service petrochemical equipment.It is prepared in order to provide a basis for seismic retrofitting or strategy for otherseismicanddisasterreductionalso. 1.0.2This standard is applicable to seismic appraisal of horizontal vessels,vertical vessel supported by legs, vertical vessel supported by lugs, vertical vessel supported by skirt, spherical tank, vertical cylindrical storage tank,heaters,air cooled heat exchangers and other equipment in petrochemical industry which are used in regions where the design basic acceleration of ground motion is not greater than 0.4Og or seismic precautionary intensity is 9 degree orless. 1.0.3 The seismic precautionary objective established in this standard is that in case the in-service petrochemical equipment is subjected to earthquake action corresponding to the seismic precautionary intensity set for the region,it can remain in use without repair and without causing secondary disasters detrimental topersonal andenvironmental safety. 1.0.4The petrochemical equipment which does not experience seismic precaution or which cannot meet the seismic precautionary requirement shall be subjcct to seismic appraisal and provided with necessaryseismicmeasures. 1.0.5The design parameters of ground motion or the seismic precautionary intensity shall be determined in accordancewith the current national standard GB 18306 Seismic Ground Motion Parameters Zonation Map of China.For the regions where the seismic precautionary zoning has been developed or the building sites where the seismic safety evaluation has been completed, the seismic appraisal may be carried out according to the approved design parameters of ground motion or seismic precautionary intensity. 1.0.6In addition to this standard,the seismic appraisal of petrochemical steel vessel shall complywith therelevantcurrentChina'snational standards
. 1 . 2 Terms
2.0.1Seismicprecautionarycriterion A criterion that measures the seismic precautionary requirement,it shall be determined by the design parame ters of ground motion or the seismic precautionary intensity and the importance of the cquipment in service. 2.0.2Designbasic accelerationofgroundmotion A design value of earthquake acceleration with a probability of exceedance being 10% over a 50 year design referenceperiod shall betaken. 2.0.3Seismic appraisal A practice of evaluating the safety of the in-service equipment under the earthquake action according to the specified seismic precautionary requirement by checking thc design, construction quality and service condi- tion of the equipment. 2.0.4Comprehensiveseismic capability The capability of equipment to withstand the earthquake action, which is determined by taking into account the factors of the structure and bearing capabil. 2.0.5 Seismic retrofit Design and construction activities which are carried out to enable the in-service equipment to meet the re quirements of seismic appraisal. 2.0.6 Seismic measures Seismic design contents except for calculation of earthquake action and resistance, which are basic require ments of seismic design and structural measures for seismic.
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· 2 3Basicrequirements
3.0.1The seismic appraisal shall involve the following activities and requirements :
1Collect the original data such as the survey report, design documents, and as-built acceptance report of the construction site where the equipment is located. Where the data are incomplete, supplementary survey shall be carried out according to the needs for seismic appraisal;
2Check the conformity of status of the equipment with the original data; 3Use the appropriate appraisal method to analyze the seismic capability of the equipment
comprehensively according to structural characteristics,layout and surrounding environment,etc;
4For the equipment which cannot meet the seismic precautionary requirements through seismic appraisal,final solution shall be proposed according to the application requirement. 3.0.2If required,seismic measures shall be comprehensively determined according to the characteristics of the equipment,the surrounding environment and other factors,and the measures shall be convenient implement so as to reduce the impact to production process. 3.0.3The building(structure)and foundation where the equipment is mounted,and other facilities that may cause damage to the equipment shall meet the relevant seismic precautionary requirement. 3.0.4When basic seismic acceleration is 0.05g or seismic precautionary intensity is 6 degree,it is not necessary to perform scismic checking. However,the requirements for seismic measures shall be met. 3.0.5 The on-site appearance inspection of the equipment shall include following items:
1 Theequipment isunfixedornot; 2 The anchor bolts of the equipment are fastened with double nuts or with anti-loosening devices
ornot;
3 Themain equipment is attached with accessory equipment or not; 4The framework that supports the equipment is provided with bracings or not; 5 The equipment isplaced on framework or not;
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Flexible connection is used between equipment and large-size pipeline or not.
3.0.6 Except for air-cooled heat exchangers,the earthquake action on equipment in the area where it is mounted shall be determined according to the requirements of the current national standard GB/T50761 StandardforSeismicDesignofPetrochemical SteelEquipments. 3.0.7 The equipment that requires seismic appraisal shall be classified in terms of importance according to its application and degree of hazard after earthquake.The importance degree of equipment shall be classified according to the requirements of the current national standard GB/T 50761 Standard forSeismicDesignofPetrochemicalSteelEquipments. 3.0.8The importance degree of framework of heater and air cooler shall be classified according to the requirementsofthecurrentnational standardGB50453Standard forClassification ofSeismicProtection of Buildingsand Special Structures inPetrochemical Engineering.
.3. Seismicchecking
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4.0.1 The earthquake action on the equipment that require seismic checking may be calculated according to the requirements of the current national standard GB/T50761 Standard for Seismic Design of Petrochemical Steel Equipments orGB 5001lCode forSeismicDesignof Buildings.For horizontal vessels and vertical vessels supported by legs installed on framework,the amplification of earthquake action contributed by the framework shall be taken into account. 4.0.2Except for air-cooled heat exchangers,the allowable stress used for seismic appraisal of vessel materials shall be taken as 120% of the allowable stress for seismic design as specified in GB/T 50761 StandardforSeismicDesignofPetrochemical SteelEquipments. 4.0.3The effective thickness of cross-section of vessel subjected to seismic checking shall be determinedasfollows:
1The effective thicknessmay betaken asthenominal thickness shown on the assemblydrawing minus the additional thickness(i.e.,corrosion allowance plus negative deviation of steel plate).
2The effective thickness may be taken as the in-service examination data minus the corrosion allowance overthe expected lifetime.
3The effective thickness may be taken as the measured wall thickness minus the corrosion allowance over the expected life time.The quantity of test points shall be greater than 1o.The wall thickness shall be calculated according to thefollowing formulas:
t, =X-6
(4.0.3-1) (4.0.3-2)
X-↓2t 1(X-t)
：
(4.0.3-3)
Where:
t,measuredwallthickness(mm); Xaverageofthemeasuredwallthickness(mm); mean squared errorofthemeasured wall thickness(mm); nquantity of points measured wall thickness; tmeasuredwall thickness at theitpoint(mm)
: 4·