JB/T 4731-2005ContentsForeword (2)1. Scope (3)2. Normative references (3)3. Terms and definitions (3)4. General rules (4)5. Material (12)6. Structure (13)7. Strength calculation (14)8. Manufacturing, inspection and acceptance (46)Appendix A (Informative Exhibit) Calibration and Calculation of Strength and Stability of Horizontal Vessels under Additional Load (49)Interpretations to JB/T 4731-200 (62)JB/T 4731-2005ForewordThis standard is stipulated based on Chapter 8: “Horizontal Vessels”of GB 150-1989---Steel Pressure Vessels through incorporation and revision of some contents in design calculation and supplement of requirements for manufacturing, inspection and acceptance of horizontal vessels. Such contents as horizontal vessels of normal pressure, manufacturing conditions as well as calculation of load as incurred by centralized mass and strength verification are supplemented simultaneously with the stipulation of this standard.This standard is compiled in reference to PD 5500-2003 Pressure Vessels of Indirect Fired Process and JIS B 8278-1993 Saddle supported horizontal pressure vessels based on practice in design, manufacturing and inspection of horizontal vessels in China in recent years.Appendix A to this standard belongs to normative exhibit.This standard will substitute JB/T 4731-2000 from the date of implementation. JB/T 4731-2000 has not been published due to references. The standard as substantially substituted is Chapter 8 of GB 150-1989---Steel Pressure Vessels.This standard is proposed by China Standardization Committee on Boilers and Pressure Vessels (SAC/TC 262)This standard is under the jurisdiction of China Standardization Committee on Boilers and Pressure Vessels (SAC/TC 262).This standard is drafted by Hualu Engineering & Technology Co., LtdMajor drafters of this standard: Pei Deyu, Liu Shaojuan and Wang XinjingPersonnel participating in compilation of this standard:Economics & Development Research Institute, SINOPEC: Shou Binan, Gu Zhenming, Li Jianguo, Wang Weiguo and Chen Chaohui.Hualu Engineering & Technology Co., Ltd: Li Zhaoliu Yang YongchengSinopec Engineering Incorporation: Li Shiyu and Yu CunyiNational Technology Center of Process Equipment: Huang Zhenglin and Qin ShujingLanzhou Petroleum Machinery Research Institute: Song BingtangSteel Horizontal Vessels1. ScopeThis standard specifies requirements for design, manufacturing, inspection and acceptance of steel horizontal vessels (hereinafter referred to as horizontal vessels).This standard is applicable to horizontal vessels with design pressure no more than 35MPa as supported by two symmetrical saddle supports under the uniformly distributed load.This standard is not applicable to the following horizontal vessels:a)Vessels subjecting to fired process and nuclear radiation;b)Horizontal vessels frequently transported;c)Vessels requiring fatigue analysis;d)Vessels with sleeves2. Normative referencesThe following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to applicanes based on this standard encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. GB 150: Steel Pressure VesselsGB/T 700-1988: Carbon Structural SteelsGB/T 1804-2000: General Tolerances---Tolerances for Linear Dimensions without Individual Tolerance IndicationsGB/T 1591-1994: Low-alloy High-Strength Structural SteelsGB 50017-2003: Code for Design of Steel StructuresJB/T4712: Saddle SupportsJB 4733-1996: Explosive Stainless Clad Steel Plate for Pressure VesselsJB/T 4735-1997: Steel welded atmospheric pressure vesselsTechnologic Supervision Regulations On Safety Of Pressure Vessels (issued by formal State Administration of Quality and Technological Supervision in 1999)3. Terms and DefinitionsThe following terms and definitions are applicable to this standard.3.1 PressurePressure indicates gage pressure, if not specified.3.2 Working pressureWorking pressure is defined as the maximum pressure that may occur at the top of the vessel under normal operating conditions.3.3 Design pressureDesign pressure is defined as the maximum set pressure at the top of the vessel and shall be applied as the conditions of design load with the coincident design temperature. The design pressure shall be not less than the working pressure.3.4 Calculating pressureCalculating pressure is defined as the pressure used to determine the thickness of the vessel parts with the coincident design temperature.3.5 Test pressureTest pressure is defined as the pressure on the top of the vessel during pressure test for horizontal vessel.3.6 Design temperatureDesign temperature is defined as the set metal temperature of element under normal operating conditions of the vessel (the mean metal temperature through the cross section of the element). The design temperature shall be applied as the conditions of design load with the coincident design pressure.3.7 Test temperatureTest temperature is defined as the metal temperature of the shell during test.3.8 Thickness3.9 Calculated thicknessCalculated thickness refers to the thickness as obtained by using formula in GB 150 or JB/T 4735 and this standard. If necessary, thickness as required by other load shall be incorporated.3.10 Design thicknessDesign thickness refers to the sum of calculated thickness and corrosion allowance.3.11 Nominal thicknessNominal thickness is defined as the sum of the design thickness and the minus deviation of steel material thickness, then rounded off to the nearest greater thickness specified.3.12 Effective thicknessEffective thickness is defined as the nominal thickness minus the sum of the corrosion allowance and the minus deviation of steel material thickness.4. General rules4.1 The design, fabrication, testing and inspection, and acceptance of horizontal vessels must fully comply with all the applicable requirements of this standard, and be necessary to meet the requirements of appropriate laws, decrees and regulations issued by the Government.4.2 Scope of vessels4.2.1 Horizontal vessels connected with external pipelinesa) The first ring as connected through welding should be oriented towards the bevel end;b) The first threaded joint should be oriented towards the joint end;c) The first flanged sealing face;d) The first sealing face as connected with special connectors or pipe fittings.4.2.2 Bearing end seal and flat cap on connecting tube of horizontal vessel and fasteners.4.2.3 Welded joint between non-load bearing element and horizontal vessel.Elements other than joints, such as saddle support and saddle stiffener should also in compliance with provisions as stipulated in this standard or relevant standards.4.2.4 Overpressure discharging devices as directly connected with horizontal vessel should be in compliance with relevant provisions as stipulated in GB 150. Accessories, such as instruments connected to the horizontal vessel, should be selected as per relevant standards.4.3 Qualifications and responsibilities4.3.1 Qualifications4.3.1.1 The designer and the manufacturer of horizontal vessels shall maintain a sound quality control system.4.3.1.2 The designer must hold an appropriate designer certificate of horizontal vessels. The manufacturer must hold a fabrication license of horizontal vessels.4.3.1.3 Qualifications of manufacturer and inspector of horizontal vessels should be in compliance with relevant provisions as stipulated in JB/T 4735.4.3.2 Responsibilities4.3.2.1 Responsibilities of designera) The designer shall be responsible for the correctness and completeness of all design documents.b)The design documents of horizontal vessels shall at least consists of design calculation sheets and engineering drawings.c) Design drawings of horizontal vessels should be provided with seal of design certificate for pressure vessels.4.3.2.2 Responsibilities of manufacturer4.3.2.2.1 The manufacturer shall ensure the constructed horizontal vessels in conformity with the requirements as prescribed on the design drawings.4.3.2.2.2 The Inspection Department of the manufacturer shall make all of the inspections and tests in details as specified by the provisions of this standard and in accordance with the requirements as prescribed on drawings during the whole course of manufacturing process as well as after completion of construction. After that, the Inspection Department shall provide inspection report, and be responsible for their correctness and completeness.4.3.2.2.3 For each horizontal vessel, the manufacturer shall at least provide the following technical documents for review, which shall be well retained for a period of seven years at least:a) Fabricating procedure drawings or fabricating process cards;b) Material certificates and bills;c) Data sheets of welding procedures and heat treatment process cards;d) Records of those items at the manufacturer’s option permitted by applicable Standards;e) Testing and inspection records during the course of fabricating process and after completion;f) As-built drawings.4.3.2.2.4 The manufacturer shall fill a product certificate and submit it to the user after the safety authority has verified that the vessel was constructed in accordance with the requirements of this standard and the corresponding drawings.4.4 General design requirements4.4.1 Definition of design pressure4.4.1.1 Design pressure shall not be lower than the working pressure.4.4.1.2 For horizontal vessel provided with pressure relief device, the design pressure shall be determined in accordance with Appendix B to GB 150.4.4.1.3 For horizontal vessel filling with liquefied gases and liquefied petroleum gas, design pressure should be in compliance with relevant provisions as stipulated in Technologic Supervision Regulations On Safety Of Pressure Vessels.4.4.1.4 For horizontal vessels under vacuum conditions, the design pressure shall be considered as external pressure. When the vessel is provided with the safety device like vacuum relief valve, the design pressure may be taken as 1.25 times the maximum difference in pressure between inside and outside of a vessel, or the value of 0.1MPa, whichever is lesser. When there is no safety device, the design pressure shall be defined as 0.1MPa.4.4.2 Determination of design temperature4.4.2.1 Design temperature shall not be less than the probable maximum metal temperature of element under operating conditions. For metal temperature below 0℃, the design temperatureshall be equal to or less than the probable minimum metal temperature of the vessel. Design temperature should be indicated on the nameplate.4.4.2.2 For different metal temperatures for elements of horizontal vessels at working status, it is applicable to set design temperature for each element.4.4.2.3 Design temperature of low-temperature horizontal vessel is to be determined as per Appendix C to GB 150.4.4.2.4 The metal temperature of element may be determined by the calculation of heat transfer, or measured on the similar vessel in-service, or be determined in accordance with the inside medium temperature.4.4.3 For horizontal vessel under different operating conditions, the design of vessel shall conform to the most severe operating condition. The corresponding pressures and temperatures of different operating conditions shall be indicated on the drawings or other technical documents.4.4.4. LoadThe following loads and combined loads should be consider for design:a) Pressure;b) Static head of liquids;c) Weight of horizontal vessel (including internal parts) and the contents under the normal operating or testing conditions;d) Centralized and uniformly distributed gravity load of attached equipments, platforms, insulations and liningse) Seismic load;f) Acting force from supports;g) Friction to supports and other acting forces as incurred by thermal expansion;The following loads should be considered if necessary:h) Acting force from connected pipelines and other parts;i) Impact load incurred by violent fluctuation of pressure;j) Impact reactions such as those due to fluid shock;k) Impact from changes to pressure and temperature;l) Acting force incurred during lifting and transportation.4.4.5 Additions to the thicknessAdditions to the thickness shall be determined by Formula (4-1):Where C-thickness addition, mm;C1-minus deviation of material thickness, mm;C2-corrosion allowance, mm4.4.5.1 Minus deviation of steel C1The minus deviation of steel plate or pipe thickness shall be in compliance with the requirements as specified in corresponding steel standards. The minus deviation may be neglected, when it is not greater than 0.25mm, and not exceeds 6% of the nominal thickness.4.4.5.2 Corrosion allowance C2The corrosion allowance shall be considered to protect vessel elements subjected to thinning by corrosion, erosion or mechanical abrasion. Specific provisions are stipulated as follows:a) For elements subjected to corrosion or abrasion, the corrosion allowance shall be determined inaccordance with the specified life of the vessel and the corrosive rate of the medium relative to the material.b) It is applicable to select different corrosion allowance in view of varied degree of corrosion to elements in horizontal vessels;c) For horizontal vessels constructed of carbon steels or low-alloy steels, the corrosion allowance shall be provided not less than 1mm.4.4.6 Minimum thickness of shells after forming, exclusive of any corrosion allowance shall be:a) No less than 3mm for horizontal vessels constructed of carbon steels or low-alloy steels;b) No less than 2mm for horizontal vessels constructed of high-alloy steels.4.5 Allowable stress4.5.1 Allowable stress for load-bearing elements and bolts for horizontal pressure vessels under different temperatures should be selected as per GB 150. Basis for determination of allowable stress is stated as follows: Refer to Table 4-1 for steels other than bolts. Refer to Table 4-2 for bolts. Allowable stress for materials of common horizontal pressure vessels should be selected as per JB/T 4735., but not exceedTable 4-2 Basis for Determination of Allowable Stress (2)In the Table 4-1 and 4-2:Lower limit for typical tensile strength of steels, MPa;Yield strength or 0.2% non-proportional extension strength of steel materials under normal temperature, MPa;Yield strength or 0.2% non-proportional extension strength of steel materials under design temperature, MPa;Mean value of creep rupture strength at design temperature for rupture after 10, 000 hours, MPa;Creep limit at design temperature for 1% of the creep rate after 10, 000 hours, MPa.4.5.2 The allowable stress at 20℃shall be applied for those with the design temperature below 20℃.4.5.3 The allowable stress for stainless steel clad plate:When the bond area between the cladding and the base metal are constructed to meet the requirements of Class B2 in JB4733 or even better, and should the strength of cladding be taken into account in design, the allowable stress for the stainless steel clad plate at design temperature may be determined by Formula (4-2):In the formula:Allowable stress for the stainless steel clad plate at design temperature, MPa;Allowable stress for the base metal at design temperature, MPa;Allowable stress for the cladding at design temperature, MPa;Nominal thickness of the base metal, mmNominal thickness of the cladding, exclusive of corrosion allowance, mm.4.5.4 For antiseptic lining not connected with the shell of horizontal vessel to form an integral part, strength of antiseptic lining can be neglected during design calculation.4.5.5 For the combination of seismic or other loads as stipulated in 4.4.4, the wall stress of vessel shall not exceed 1.2 times the allowable stress.4.5.6 Steel materials other than those as stipulated in GB150 as selected for horizontal vessel should be in compliance with relevant provisions as stipulated in Appendix A to GB 150.4.5.7 Allowable axial compressive stressSmaller value of and B for allowable stress of materials under design temperature is to be selected as the allowable axial compressive stress of drum or the tube. Value B is to be calculated according to the following procedures:a) Calculation coefficient A with Formula (4-3):Where:A---Coefficient;Inner radius of drum or tube, mm;Effective thickness of drum or tube, mm.b) Refer to corresponding charts in GB 150 as per specific materials. If value B is on the right side of material line under design temperature, just cross this point to shift upward for intersection with material line under design temperature (use inset method for intermediate temperature). After that, further shift to the right side by crossing this intersection point to obtain value B. If coefficient A is on the left side of material line under design temperature, value B should be calculated with Formula (4-4):Where:Elastic modulus of materials under design temperature, MPa.4.5.8 Allowable stress for non-load bearing elements other than saddle support shall be selected as per Article 5.4. Allowable stress for critical internal parts and supporting ring as welded on the load-bearing shell shall be selected in reference to bearing elements; whereas that for other shall be determined as per provisions as stipulated in GB 50017.4.6 Coefficient of welded joint4.6.1 For horizontal vessels, coefficient of welded joints Φshould be determined as per welding procedures (single-side or double-side welding; with or without gasket) and NDE length for load-bearing elements.a) For double-welded butt joints or other butt joints of full penetration equivalent to a double welded joint:100% NDE: ;Spot NDE:b) For single-welded butt joints with backing strip fitted on the base metal along the whole length of weld root:100% NDE:Spot NDE:4.6.2 For common horizontal pressure vessels, coefficient of welded joint Φshould be determined as per relevant provisions in JB/T 4735.4.7 Pressure testHorizontal pressure vessels as fabricated should subject to pressure test Types, requirements and testing pressure for pressure test should be indicated on the drawings.4.7.1 Pressure test for horizontal pressure vesselsNormally, pressure test for horizontal pressure vessels is represented by hydraulic test. Testing liquids should be in compliance with provisions as stipulated in GB 150. It is applicable to proceed with air pressure test for horizontal vessels unavailable for hydraulic test. Horizontal pressure vessels should satisfy relevant requirements as stipulated in GB 150 during air pressure test.Horizontal vacuum vessels should subject to pressure test under internal pressure.4.7.1.1 Testing pressureMinimum value of testing pressure for horizontal pressure vessels should be in compliance with the following requirements. Upper limit of testing pressure should satisfy limitations on calibrated stress in Article 4.7.1.2.4.7.1.1.1 Internal horizontal pressure vesselsHydraulic test pressure should be determined as per Formula (4-5):Air pressure test pressure should be determined as per Formula (4-6):Where:Test pressure, MPa;Design pressure, MPa;Allowable stress of vessel part material at test temperature, MPA;Allowable stress of vessel part material at design temperature, MPa;Note:1. When the maximum allowable working pressure is specified on the vessel nameplate, the design pressure p in the formula above shall be replaced by the maximum allowable working pressure.2. When the materials of pressure vessel parts are different, the minimum value of willbe selected.4.7.1.1.2 Horizontal vacuum vesselsTest pressure shall be determined with Formula (4-7):Where:Test pressure, MPa;Design pressure, MPa4.7.1.2 Stress verification before pressure testCalculate stress of drum with Formula (4-8) before pressure test:Where:Stress of drum under testing pressure, MPa;Inner diameter of drum, mm;Test pressure, MPa.Effective thickness of drum, mm;should be verified as per Formula (4-9) and (4-10):For hydraulic test:For air pressure test:Where:Yield strength or 0.2% non-proportional extension strength of drum material at testing temperature, MPa;Coefficient of welded joint for drum.4.7.2 Pressure test for horizontal atmospheric pressure vesselsHorizontal atmospheric pressure vessels as fabricated should subject to hydraulic test. For specific testing requirements, please refer to relevant provisions as stipulated in JB/T 4735.4.7.2.1 Test pressureHydraulic test pressure should be determined with Formula (4-11):select the bigger value of the twoWhere:Test pressure, MPa;Design pressure, MPa;Allowable stress of vessel part material at normal temperature, MPa;Allowable stress of vessel part material at design temperature, MPa;4.7.2.2 Stress verification before pressure testCalculate stress of drum with Formula (4-12) before pressure test:Where:Stress of drum under testing pressure, MPa;Inner diameter of drum, mm;Test pressure, MPa.Effective thickness of drum, mm;should be verified as per Formula (4-13):Where:Yield strength or 0.2% non-proportional extension strength of drum material at testing temperature, MPa;Coefficient of welded joint for drum.4.7.3 For horizontal pressure vessels unavailable for pressure test as per provisions in Article 4.7.1, designer shall submit measures for safe operation of vessels to the technical official for approval and indications on drawings.4.8 Leak testIf vessels contain extremely toxic or highly toxic substances, a leak test shall be conducted on those vessels after pressure test.4.8.1 Airtight testAirtight test should be carried out as per relevant provisions in Technologic Supervision Regulations On Safety Of Pressure Vessels.4.8.2 Other leak testExcept for airtight test, other leak tests can be carried out by using such mediums as ammonia, halogen and helium. Testing methods and items should be indicated on drawings.Note: Grading of toxicity of medium should be in compliance with relevant provisions in Technologic Supervision Regulations On Safety Of Pressure Vessels.5. Material5.1 Steel material for pressure elements of horizontal pressure vessel, steel grade, heat treatment status and allowable stress should be in compliance with provisions as stipulated in GB 150.5.2 Steel material for pressure elements of horizontal atmospheric pressure vessel, steel grade, heat treatment status and allowable stress should be in compliance with provisions as stipulated inJB/T 4735.5.3 Steels for non-load bearing elements should be those as incorporated into the material standards. Steel materials for welded pieces should have perfect welding performance. Steels for critical internal parts and stiffening rings as welded on the pressure shell should be in compliance with provisions in Article 5.1.5.4 Selected saddle materials are listed in Table 5-1.5.5 Base plate for connection of saddle with drum should be of the same material as the drum.5.6 Select Q235 anchor bolts as stipulated in GB/T 700 or Q345 anchor bolts as stipulated inGB/T 159. Allowable stress for Q235 and Q345 anchor bolts should be up to 147 andrespectively. For other carbon steels, ; for other low-alloy steels,.6. Structure6.1 SupportsSelect saddle support for horizontal vessels (See Figure 7-1). When supports are welded to the vessel, one of support should be slide one or in rolling structure.6.1.1 Arrangement of supportsMake sure that distance A between support center and end seal tangent line is below or equal to 0.5Ra. If it is impossible, value A should be over 0.2L.6.1.2 Saddle supportIf saddle support for horizontal vessel is selected as per JB/T 4712, verification of strength of saddle support can be omitted if conditions as stipulated in JB/T 4712 can be satisfied. Otherwise, it is necessary to proceed with strength verification as per Article 7.4.6.2 Perforation and connecting tubeHorizontal vessel should be provided with manhole, manual hole or access hole in addition to technical connecting tubes as required. Outlet should be arranged at the lowest point at vessel bottom. If it is impossible to arrange outlet at drum bottom, it is applicable to arrange bottom insert tube as shown in Figure 6-1. The minimum liquid discharge clearance B1 on the bottom insert tube end should be able to ensure adequate discharge space.All holes and stiffeners on the horizontal vessel should be in compliance with relevant provisions in GB 150.All holes and stiffeners on the horizontal atmospheric pressure vessel should be in compliance with relevant provisions in JB/T 4735.6.3 Arrangement of stiffening ringFigure 6-1: Structure of Outlet on Horizontal Vessel6.3 Arrangement of stiffening ringStiffening ring should be complete or nearly complete. Connection structure between stiffening ring and shell should be in compliance with relevant provisions in GB 150.6.3.1 In view of the fact that horizontal vessel is under local stress, it is applicable to set internal and external stiffening rings on the saddle plane (See Figure 7-8) or at the periphery of saddle plane (See Figure 7-9).6.3.2 In view of instability of horizontal vessel under external force, setting and calculation of stiffening ring should be in compliance with provisions as stipulated in GB 150.7. Strength calculation7.1 Calculate the strength of pressure elements of horizontal vessel as per relevant provisions in GB 150 or JB/T 4735 before checking calculation of strength and stability as per Article 7.3 and 7.4.In view of centralized load as incurred by accessory equipments (4.4.4d), it is applicable to proceed with checking calculation of strength and stability as per Appendix A (Informative Exhibit).7.2 Symbol descriptionDistance between center line of saddle base plate and end seal tangent line (See Figure 7-1), mm;切线Tangent line鞍式支座边角处Saddle support cornerThe sum of combined cross sectional area of all stiffening rings and effective stiffening sections of drum on one saddle, mm2Value as determined in reference to design external pressure as stipulated in GB 15 at design temperature, MPa;Value as determined with external pressure design methods as stipulated in GB 150 atnormal temperature, MPa;Inner diameter of drum, mm;Outer diameter of drum, mm;Counterforce of each support, N;The sum of inertia moment combined cross sectional area of all stiffening rings andeffective stiffening sections of drum on one saddle to sectional spindle X-X (See Figure 7-8, 7-9), mm4Load combination coefficient,Coefficient, refer to Table 7-1 and Table 7-9;Distance of end seal tangent line (See Figure 7-1), mm;Axial bending moment at the drum center, N-mm;Axial bending moment of drum at the saddle, N-mm;Average radius of drum, , mm;Inner radius of spherical part of disk end seal, mm;Inner radius of drum, mm;Axial width of drum, mmWidth of stiffening ring (See Figure 7-8 and 709), mmEffective width of drum, , mm;Effective width of drum when calculating combined cross sectional area of drumandstiffening rings, , mm;Width of saddle base plate (See Figure 7-6), mm;Gravitational acceleration, ;Depth of end seal camber, mm;Coefficient, when the vessel is not welded to the saddle; when the vessel is welded to the saddle;Mass of vessel (including mass of vessel itself, mass of water and medium filled as well as accessories and heat-insulation layer), kg;Design pressure, MPaCalculated pressure, MPa;。
